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Response of yield and nitrogen use efficiency to aerated irrigation and N application rate in greenhouse cucumber
Scientia Horticulturae 265 (2020) 109220
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Response of yield and nitrogen use efficiency to aerated irrigation and N application rate in greenhouse cucumber
T
Bing-Jing Cuia,b, Wen-Quan Niua,b,c,*, Ya-Dan Dua,b, Qian Zhanga,b a Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas of Ministry of Education, Northwest A&F University, Yangling, Shaanxi, 712100, China b College of Water Resources and Architectural Engineering, Northwest A & F University, Yangling, Shaanxi, 712100, China c Institute of Soil and Water Conservation, Northwest A & F University, Yangling, Shaanxi, 712100, China
A R T I C LE I N FO
A B S T R A C T
Keywords: Aerated irrigation Greenhouse cucumber Nitrogen use efficiency Economic benefits
Excessive irrigation and fertilization in greenhouse cultivation have a major negative impact, causing economic and environmental problems. Efficient water and fertilizer management methods to increase water use efficiency (WUE) and nitrogen use efficiency (NUE) have been studied often in greenhouses where vegetables are cultivated. However, optimizing the application of nitrogen under certain water conditions does not continue to increase yield. This may be due to oxygen deficiency caused by water saturation in the root zone after irrigation. Aerated irrigation (AI) may be an effective management measure to further reduce the application of nitrogen fertilizer and increase the yield. In order to determine the interaction among irrigation water aeration and N application, a greenhouse study was conducted in Yangling, China, setting up two irrigation methods(AI and drip irrigation)and three N application rates (0, 240, 360 kg ha−1). In this study, AI significantly improved the nitrogen use efficiency (NUE) and yield of cucumber (Qiande 777, p < 0.05). As compared to drip irrigation, the partial factor productivity of applied N (PFP) under AI increased 28.95 % and 18.53 % at 240 and 360 kg N ha-1 nitrogen levels, respectively; cucumber yield under AI was 17.50 % higher than that with drip irrigation condition. AI and N application significantly improved crop yield: the highest yield obtained at AI and nitrogen reduction treatment (I1N2) was 72.3 t ha−1, which was 1.19 and 1.29 times higher than that of non-aerated nitrogen reduction (I0N2) and conventional nitrogen application (I0N3) (p < 0.05). Therefore, AI along with nitrogen application of 240 kg ha−1 is recommended for greenhouse cultivation of cucumber.
1. Introduction In recent years, greenhouse vegetable cultivation has developed rapidly. Greenhouses can make effective use of solar radiation resources and due to their high controllability have become one of the most important facilities for producing vegetables in the world (Hassanien et al., 2016; Fan et al., 2018). The economic benefits of greenhouse cultivation drive farmers to use water and fertilizers in large quantities to achieve higher crop yields. Song et al. (2012) found that water and fertilizer inputs in traditional management far exceed the growth requirement of the greenhouse vegetables (Shi et al., 2009; Tian et al., 2010). Excessive application of N fertilizer results in very high levels of residual nitrate in soil (Min et al., 2012) and nitrate pollution of greenhouse groundwater is increased (Kraft and Stites, 2003; Thompson et al., 2007). Applying excessive nitrogen is a menace to environmental security (Vázquez et al., 2005). Reducing nitrogen
⁎
fertilizer input while maintaining high yield is required for sustainable development of agriculture, and studies on reasonable water and nitrogen management measures in greenhouse cultivation are needed. Efficient water and fertilizer management in greenhouses has become the focus of agricultural research. Compared to conventional irrigation methods, drip irrigation and optimal nitrogen application can significantly improve water use efficiency (WUE) and nitrogen use efficiency (NUE) (Antony and Singandhupe, 2004; Aujla et al., 2007; Sun et al., 2013). Many researchers have reported that reducing water and nitrogen fertilizer inputs reasonably can promote WUE, NUE, and fruit quality throughout the world in different greenhouse vegetables, such as tomato (Wang et al., 2015; Mahajan and Singh, 2006), cucumber (Zhang et al., 2011b; Fan et al., 2014), and wild rocket (Schiattone et al., 2018). However, even rationalized nitrogen applications under certain water conditions does not allow to optimize yield; this may be due to oxygen deficiency caused by water saturation in the root zone
Corresponding authors at: No. 26 Weihui Road, Yangling, Shaanxi Province, 712100, China. E-mail addresses: [email protected] (B.-J. Cui), [email protected] (W.-Q. Niu).
https://doi.org/10.1016/j.scienta.2020.109220 Received 7 July 2019; Received in revised form 12 January 2020; Accepted 18 January 2020 0304-4238/ © 2020 Elsevier B.V. All rights reserved.
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measurements were collected with an automatic weather station (HOBO ware, Onset, Massachusetts, USA) located in our greenhouse.
after irrigation. Aerated irrigation (AI) can improve the aeration conditions of root soil and may be an effective management measure for increasing yield, resulting in further reductions in the nitrogen fertilizer applied. AI is an effective irrigation method to improve crop yield (Bhattarai et al., 2006; Du et al., 2018a). Studies have shown that AI can ameliorate the lack of aeration in root soil without significantly increasing cost (Ben-Noah and Friedman, 2016; Abuarab et al., 2013). Soil aeration has an important effect on the growth and development of crops (Jacobsen and Hjelmsø, 2014; Lei et al., 2017). AI has the potential to strengthen soil nitrification processes, reduce N losses, increase N utilization rate (Hu et al., 2017; Zhao et al., 2011; Du et al., 2018b), and contribute to the growth and development of crops (Chen et al., 2010). Studies on soybean, tomato, and other crops have verified the beneficial function of AI (Bhattarai et al., 2008; Niu et al., 2012; Li et al., 2016). Most researches have concentrated on the effects of AI on fruit quality and yield of greenhouse crops, but there is not enough research on the effects of absorption and utilization of N fertilizer, and even less research focusing on mechanisms for increasing crop yield. In order to explain how aeration increases crop yield, the effects of different N application levels on photosynthetic characteristics, NUE, and yield of greenhouse cucumber under AI were studied. The purpose of this study is to verify whether the combination of aeration and nitrogen application can further improve yield as well as economic and ecological benefits, and ultimately provide a theoretical and scientific basis for reducing applied nitrogen under aeration in greenhouse cultivation.
2.2. Experimental design The cucumber variety used for the experiment was Qiande 777. Tomato was planted prior to cucumber. Fertilizer N, P, and K sources used in the present experiment were urea (N ≥ 46 % by weight), calcium super-phosphate (P2O5, P ≥ 16 %), and water-soluble potassium sulfate (K ≥ 51 %), respectively. A ridge is an experimental plot, each plot was 5.5 m long and 0.5 m wide, 15 cucumber plants were transplanted in it. Cucumber seedlings were transplanted on March 24, 2018, and the plant spacing was 45 cm, the row spacing was 50 cm, the soil surface was covered by a polyethylene film. Before transplanting, an underground drip irrigation belt (16 mm in diameter, 30 cm between drips) was laid in the center of each cultivation area, and the buried depth was 15 cm, the water flow of the drips is 3.6 l h−1 Subsurface drip irrigation was used in the experiment. Each branch was equipped with a flow meter and control valve to control the irrigation volume and the volume of air in each plot. Irrigation occurred once every 10 days, and the volume was the cumulative evaporation between two irrigation stages with an evaporating pan 20 mm in diameter. In this experiment, a Mazzei air injector model 684 (Mazzei Injector Company, Bakersfield, California, USA), which was used to mix air with irrigation water, was installed inline directly behind the water source. These air injectors were established to inject 17 % air by volume of water (Chen et al., 2018). The injection valve is opened in the aerated plot, the system injects the air into water, enters the drip line, and the injection valve is closed in the non-aerated plot. The total irrigation amount for the total experimental area was 30.7 m3 from colonization to pulling seedlings. This experiment is a randomized split-plot design, Aerated irrigation (AI) and non-aerated irrigation were randomly assigned to the main plots. AI treatment was expressed as I1 and the treatment of non-aerated irrigation was denoted I0. Three rates of N application (0, 240 and 360 kg ha−1) were randomly assigned to the subplots within each main plot. According to the local farmers' habits, we used conventional nitrogen application (N3); reduced nitrogen treatment, which was 66 % of the conventional nitrogen application (N2); and the control treatment (N1); the nitrogen application rates were 360, 240, and 0 kg ha−1, respectively. So the experimental had six treament and each treament had 4 replicate plots. 150 kg P2O5 ha−1 and 200 kg K2O ha−1 were applied as basal fertilizer, 40 % of the total nitrogen was used as the basal fertilizer in each nitrogen treatment plot, the remaining N fertilizer was supplied in 4 equal amounts through a drip irrigation tube.
2. Materials and methods 2.1. Experimental site This study was conducted in a greenhouse from 24 March to 9 June 2018 in Yangling, Shaanxi Province at 34″17′ N, 108″02′ E. This area is located on the south-central edge of the Loess Plateau, a semi-arid and humid area, with annual sunshine of 2163.8 h and a frost-free period of 210 d. The length × width of the greenhouse is 108 m × 8 m. The greenhouse has an east-west orientation, is passively ventilated by roof vents, and is covered with a 0.2 mm thick thermal polyethylene sheet. The soil type is Lou soil, which organic matter content was 16.48 g kg−1, with a total N of 0.96 g kg−1, total P of 0.36 g kg−1, and a total K of 10.4 g kg−1. The average dry bulk density of soil in the 1 m soil layer is 1.34 g cm3, and the field capacity is 28.17 %, pH value 7.82. The soil particle composition was as follows: gravel mass fraction, 25.4 %; powder particle mass fraction, 44.1 %; and clay particle mass fraction, 30.5 %. Throughout the cucumber growth period, the daily mean temperature and relative humidity showed inverse trends. Daily mean temperature ranges between 8.5 to 24.9 °C, and relative humidity between 73.5 to 100% (Fig. 1). The air temperature and relative humidity
2.3. Leaf photosynthetic characteristics The upper fourth leaf with the same growth and direction of light was used for measurements with an open gas exchange system (LI6400, Li-Cor, Inc., Lincoln, NE, USA) at 31 d (initial melon stage) and 47 d (full melon stage). Three plants were selected randomly for measurements in each treatment, and the average value was used as the final observation result. Each measurement was carried out from 10:00 to 11:00 with an open air path, CO2 concentration 390 ± 10 μmol mol−1, natural illumination and at a photosynthetic photon-flux density of 800 μmol m-2 s−1. The measured indicators included: leaf net photosynthetic rate (Pn, μmol m-2 s-1), transpiration rate (Tr, mmol m-2 s-1), and stomatal conductance (Gs, mol m-2 s-1). The chlorophyll content of cucumber leaves was measured at 31 d (early melon stage) and 47 d (full melon stage), selected leaves with the same leaf position as photosynthesis, and three plants per plot were selected for measurement. Chlorophylls (a and b) from cucumber leaves were extracted with 95 % ethanol solution, then the extracted samples were subjected to spectrophotometric absorbance at 665 nm, 649 nm and 470 nm, and the content of chlorophyll in cucumber leaves was
Fig. 1. Daily mean air temperature (T) and relative humidity (RH) during the growing season of greenhouse cucumber. 2
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gradually with the increase of nitrogen application. Mean values of Pn at the two growth stages under AI were 1.35, 1.17, and 0.99 times higher than in the non-aeration treatment, for N1, N2, and N3 respectively. Under AI, the Pn of reduced nitrogen treatment (I1N2) was the highest at 34.03 μmol m-2 s−1. The highest Pn of conventional nitrogen application (I0N3) was 33.81 μmol m-2 s−1 when no air was injected, the difference was not significant (p > 0.05). Stomatal conductance (Gs) increased significantly under AI (p < 0.05). The variation in Gs with nitrogen application rates was consistent with that of Pn in the full melon stage. Under AI and drip irrigation, Gs was highest in I1N2 treatment and I0N3 treatment, at 0.566 mmol m−2 s-1 and 0.486 mmol m−2 s-1, respectively. The transpiration rate (Tr) of aeration treatment was lower than that of nonaeration treatment significantly (p < 0.01). Under AI, Tr first increased and then decreased with the increase of nitrogen application rate, while Tr increased with the increase of nitrogen application rate in the nonaerated condition. The ANOVA showed that the interaction between AI and applied nitrogen had a significant effect on the Tr of the early melon stage (p < 0.05). The chlorophyll content of cucumber leaves under different treatments is shown in Fig. 2. The content of chlorophyll a was significantly increased by aeration (p < 0.05). When the nitrogen application rate was 0, 240, and 360 kg ha−1, the average chlorophyll a under the two growth stages was 9.2 %, 12.1 %, and 24.9 % higher than that of the unaerated treatment, respectively. With the increase of nitrogen application rate, the content of chlorophyll a in cucumber leaves increased, and the increase of chlorophyll a was enhanced by aeration. AI enhanced chlorophyll b significantly, and the chlorophyll content increased as the improvement of N application level.
calculated (Li et al., 2016). 2.4. Nitrogen uptake and NUE Three plants were randomly selected from each treatment during the maturity stage of cucumber. Stems, leaves, and fruits were separated into paper bags and then put in an oven, The samples were ovendried at 105 °C for 30 min and kept at 75 °C until a constant weight was attained(Du et al., 2016; Du et al., 2018b), and then weighed with an electronic balance (Yingheng high-precision electronic scale, accuracy of 0.01 g, Yingheng co., Ltd. China). The N content in plant was mensurated using the Kjeldahl method (Dordas and Sioulas, 2009). Four indicators were calculated to evaluate NUE:
Agronomic efficiency (AE, kg kg−1) =
TYN − TYCK TN
Physiological efficiency (PE, kg kg−1) =
Recovery efficiency (RE, %) =
(1)
TYN − TYCK TUN − TUCK
(2)
TUN − TUCK TN
Partial factor productivity of applied N (PFP, kg kg−1) =
(3)
TYN TN
(4)
−1
where TYN is the cucumber yield (kg ha ) in the treatments with N fertilization, TYCK is the cucumber yield (kg ha−1) in the control (CK), TUN is the crop N uptake (kg ha−1) in the treatments with N fertilization, TUCK is the crop N uptake (kg ha−1) in CK, and TN is the total input of fertilizer N (kg ha−1). 2.5. Yield and harvest index (HI) and economic benefits
3.2. Dry matter accumulation and harvest index (HI)
From the full melon stage, 47 d after transplanting, the cucumber was beginning to harvest. Fruits harvested in each treatment plot were weighed separately, the harvest date was recorded, and the total yield of each plot was calculated at the end of seedling pulling. The average fruit size is 191.09 g. The harvest index (HI) is defined as the ratio of fruit dry weight to total dry weight on the ground at harvest time. The economic benefits was calculated as fellow:
Yield value= Yield× cucumber market price
The effects of different nitrogen rates and aeration conditions on dry matter accumulation in cucumber at four growth stages is shown in Fig. 3. Statistics showed that the accumulation of dry matter at maturity with AI was 2.32 %, 15.33 %, and 1.33 % higher than that of the drip irrigation in the N1, N2, and N3 treatments, respectively (p > 0.05). Under drip irrigation, the accumulation of dry matter increased with the improvement of N application level and reached the maximum of 132.02 g plant−1 at I0N3; HI also reached the maximum in I0N3, at 0.45 (Fig. 4). Under AI, the maximum accumulation of dry matter and HI in cucumber were obtained at I1N2, which were 149.15 g plant−1 and 0.51, respectively (Figs. 3, 4). The interaction between AI and applying nitrogen had a significant effect on the HI of cucumber (p < 0.01).
(5)
Agricultural inputs= cucumber seedlings fees+ pesticides fees + fertilizers fees
(6)
Total inputs= Agricultural inputs+ Other inouts
(7)
Net income= Yield value− Total inputs
(8)
3.3. Nitrogen use efficiency At 240 and 360 kg N ha−1 nitrogen levels, AE was 85.5, 56.5, and 24.9, 29.9 kg kg−1 (Fig. 3a); PE was 162.9, 293.0 and 82.0, 148.3 kg kg−1 (Fig. 3b); RE was 52.5, 19.3 and 30.4, 20.1 % (Fig. 3c); and PFP was 301.1, 200.2 and 233.5, 168.9 kg kg−1 (Fig. 3d) under two irrigation modes, respectively. AE, RE, and PFP reached the highest level in I1N2 treatment. With the increase of nitrogen application, although PE continued to increase, in I1N2 treatment it was higher than in I0N2 and I0N3. The PFP of I1N2 treatment was 1.3- and 1.8-fold higher than in the I0N2 and I0N3 treatments, respectively. The results show that the NUE of cucumber was significantly improved by AI (p < 0.05), and changes in the four indexes of NUE caused by aeration were more obvious with increased nitrogen fertilizer (Fig. 5).
2.6. Statistical analysis The experimental data was collected and collated in Excel 2010 (Microsoft Corp., 2010). Data analysis with SPSS 18.0 software (IBM Corp., 2017). The significance of differences among treatments were tested by two-way analyses of variance (ANOVAs), and the means were compared by least significant difference (LSD) tests at p < 0.05. The figures were drawn using Origin 8.0 software (OriginLab Corp., USA). 3. Results 3.1. Photosynthetic characteristics
3.4. Yield and economic benefits
The net photosynthetic rate (Pn) of cucumber leaves under aerated conditions was significantly higher (p < 0.01) than that of non-aerated conditions (Table 1). The mean value of Pn increased by 7.1 % and 21.0 % at the early melon stage and the blooming stage, respectively. The differences in Pn between AI and non-aeration treatment decreased
The yield of cucumber was significantly increased by AI (p < 0.01). When the nitrogen application rate was 0, 240, 360 kg ha−1, the yield of cucumber under AI increased by 3.38 %, 28.96 %, and 18.55 % 3
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Table 1 Effect of different nitrogen application rates on photosynthetic characteristics of cucumber. Treatment
I1N1 I1N2 I1N3 I0N1 I0N2 I0N3 F-value Aeration factor (I) Nitrogen application factor (N) I×N
Net photosynthetic rate Pn/(μmol·m−2·s-1)
Stomatal conductance Gs/(mmol·m−2·s-1)
Transpiration rateTr/(mmol·m−2·s-1)
EMS
EMS
EMS
26.22 34.03 31.23 21.14 30.49 33.81
FMS ± ± ± ± ± ±
0.96ns 7.96** 1.29ns
1.17ab 3.61a 6.81ab 7.21b 0.77ab 1.09a
26.35 39.16 35.75 17.75 32.25 33.67
± ± ± ± ± ±
6.99bc 2.03a 1.69ab 1.39c 1.30ab 3.93ab
12.39** 27.83** 1.37ns
FMS
0.339 0.420 0.305 0.302 0.291 0.273
± ± ± ± ± ±
0.01ab 0.08a 0.01ab 0.07ab 0.02b 0.02b
9.35* 3.19ns 2.15ns
0.437 0.566 0.501 0.322 0.482 0.486
± ± ± ± ± ±
14.98** 19.83** 1.33ns
0.02bc 0.02a 0.04ab 0.02c 0.09ab 0.01ab
5.09 7.90 7.36 7.85 8.13 8.18
FMS ± ± ± ± ± ±
15.94** 9.07** 5.78*
0.49b 1.04a 0.09a 1.10a 0.38a 0.23a
8.38 ± 0.94d 10.14 ± 0.35abc 9.73 ± 0.21bcd 9.15 ± 0.63 cd 11.04 ± 1.05ab 11.49 ± 0.84a 15.68** 18.07** 1.17ns
Note: values followed by different small letters in the same column meant significant differences at 0.05, * means p < 0.05 and ** means p < 0.01, ns means P > 0.05, EMS: Early melon stage, FMS: Full melon stage.
Fig. 4. Harvest index of cucumber among different treatments. Fig. 2. Effects of different treatments on photosynthetic pigments of cucumber leaves. Note: values followed by different small letters in the same column meant significant differences at 0.05, * means p < 0.05 and ** means p < 0.01, ns means P > 0.05, EMS: Early melon stage, FMS: Full melon stage.
Compared with I0, the cucumber net income and the ratio of output to input in I1 increased by 3.70, 47.09, 28.11 % and 0.84, 43.36, 24.53 %, for N1, N2, and N3 respectively (Table 3). This result showed that AI significantly improved cucumber net income and the ratio of output to input (p < 0.05). The highest yield value, net income, and ratio of output to input were obtained in I1N2 treatment, which increased by 18.85, 28.82, and 25.77 % respectively compared with I0N3. 4. Discussion 4.1. NUE Nitrogen is an important element that provides nutrition for plant growth. (Tilman et al., 2002; Zhang et al., 2015). Yang et al. (2007) found that traditional excessive N application was not conducive to the absorption of nutrients by cucumbers, and 91.65 % of N fertilizer was lost (Bouchet et al., 2016). Improving the NUE of cucumber is therefore needed. Du et al. (2018b) reported that reducing the application of nitrogen under AI can promote plant N uptake. Zhu et al. (2015) found that soil aeration and nitrogen supply had a strong interaction with the total nitrogen concentration of the plant, AI improved the growth of roots and buds by promoting the formation of aerated tissue, and then the expression of OsPAD4 and OsNRT2.1 genes changed to increase total N acquired. Because root morphology and aerenchyma formation are both improved by AI, transport and acquisition of N in plants is also affected (Hu et al., 2014; Saengwilai et al., 2014; Zhu et al., 2015). Similar results were obtained in this study, AI increased the absorption and utilization of nitrogen fertilizer. Changes in AE, PE, RE, and PFP were more pronounced with increased nitrogen application rate. When the nitrogen application level is too high, the excess
Fig. 3. Dry matter accumulation at four growth stages under each treatment.
compared with the non-aerated treatment, respectively (Table 2). Under AI, the yield of cucumber increased first and then decreased as the improvement of nitrogen application level, and the yield of I1N2 was the highest at 72.3 t ha−1. The yield with non-aeration treatments increased with the increase of N application rate, and was highest in I0N3 at 60.8 t ha−1. The ANOVA showed that the interaction between AI and applying nitrogen had a significant effect on cucumber yield (p < 0.01). 4
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Fig. 5. Effects of nitrogen application under AI on AE, PE, RE, and PFP. Table 2 Yield and economic benefits of cucumber under different treatments. Treatments
Yield
Yield value
t ha−1 I1N1 I1N2 I1N3 I0N1 I0N2 I0N3
51.7 72.3 72.1 50.1 56.0 60.8
± ± ± ± ± ±
Agricultural inputs
Other inputs
Total inputs
Net income
Ratio of net income and input
3112 3167 3194 3112 3167 3194
4290 4290 4290 4075 4075 4075
7402 7457 7484 7187 7242 7269
8,878 15,279 15,195 8,561 10,388 11,861
1.20e 2.05a 2.03b 1.19e 1.43d 1.63c
US$ ha−1 1.22d 0.18a 1.27a 0.46e 0.15c 1.12b
16,280 22,736 22,679 15,748 17,630 19,130
± ± ± ± ± ±
377d 55a 394a 142e 48c 347b
Unit price of various expenses: cucumber market price is $0.31 kg–1; Agricultural inputs refer to cucumber seedlings ($2359.5 ha–1), pesticides ($643.5 ha–1) and fertilizers, fertiliser included urea ($0.23 kg–1), biological phosphorus ($0.11 kg–1), potassium sulphate ($0.46 kg–1); Other inputs refer to management fees, machinery, and the cost of harvesting cucumber.c.
were increased. Therefore, under AI, the increase of stomatal conductivity promoted the Pn of cucumber leaves. Furthermore, aerated leaves were higher in chlorophyll content than non-aerated leaves (similar to Paudel et al., 2019; Niinemets et al., 2005), which promotes the absorption and transfer of light energy and the synthesis of organic matter. This is consistent with the conclusion of Bhattarai et al. (2008). With the increase of nitrogen application rate, Pn increased at first and then decreased under AI, but kept increasing under drip irrigation. This may be due to the fact that under conventional irrigation, the anaerobic environment formed by high soil moisture promotes soil denitrification (Chen et al., 2018). The nutrients absorbed by plants mainly depend on external nitrogen application. While under AI, the increase of oxygen content promotes nitrification, and increases the available nutrients in soil. The promoting effect of suitable nitrogen application rate (N2) on crop growth was significant, but when the nitrogen application level is too high, it will have an inhibitory effect. Thus, the net photosynthetic rate was the highest under I1N2
nitrogen was partly accumulate in the soil and partly lost from the soil through ammonia volatilization (Sebilo et al., 2013; Zhou et al., 2016; Shang et al., 2013), which always decreases NUE (Zhang et al., 2015). In this study, the AE, RE, and PFP were maximized at I1N2, which means that the NUE of I1N2 was the highest. 4.2. Photosynthesis, dry matter, and HI under aeration and nitrogen application treatment Studies have shown that soil compaction decreases plant net photosynthetic rate, while AI is effective in aerating the rhizosphere and improving soil ventilation (Hoque and Kobata, 2015; Bhattarai et al., 2006; Niu et al., 2012). Li et al. (2016) found that AI reduced plant abscisic acid (ABA), and improved stomatal conductivity of leaves, to a certain extent. In the present study, the stomatal conductivity of cucumber leaves was significantly improved by AI (p < 0.05), the CO2 entering leaves was increased, and the raw materials of photosynthesis 5
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CRediT authorship contribution statement
treatment. N application may improve root growth and biomass accumulation (Kara and Mujdeci, 2010). In the present study, the accumulation of dry matter increased as nitrogen application increased under drip irrigation. On the one hand, compared with drip irrigation, the growth of plants under AI is robust, and is accompanied by high water consumption. This may lead to low soil moisture content, and the results indicated that Tr of cucumber leaves could be inhibited by AI, and the decreased transpiration rate reduced the loss of plant water. On the other hand, the enhanced leaf Pn (Table 1) in the experiment contributed to higher dry matter in the aeration treatment, because leaf photosynthesis is related to fruit yield in many crops (Olympios et al., 2003). N2 treatment produced the highest dry matter accumulation under AI, but the yield did not continue to improve with N application above this level; this may be because the excess nitrogen inhibited the transport of photosynthates to the fruit, and the HI decreased (Du et al., 2017). The HI of cucumber was increased by aeration, indicating that AI promoted the allocation of aboveground biomass to the fruit; Hamzei and Soltani (2012) and Li et al. (2010) reported similar results. The HI was highest at I1N2, which showed that under aeration conditions, appropriate reduction of nitrogen fertilizer use increased the allocation of aboveground biomass to the fruit, these results were similar to those of Bhattarai et al. (2006).
Bing-Jing Cui: Methodology, Software, Formal analysis, Writing original draft, Writing - review & editing. Wen-Quan Niu: Supervision, Writing - review & editing, Funding acquisition. Ya-Dan Du: Conceptualization, Writing - review & editing, Supervision. Qian Zhang: Investigation. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acknowledgments This study was supported by the National Key Research and Development Project (grant number: 2016YFC0400202) and National Natural Science Foundation Program (51679205). References Abuarab, M., Mostafa, E., Ibrahim, M., 2013. Effect of air injection under subsurface drip irrigation on yield and water use efficiency of corn in a sandy clay loam soil. J. Adv. Res. 4 (6), 493–499. Antony, E., Singandhupe, R.B., 2004. Impact of drip and surface irrigation on growth, yield and WUE of capsicum (Capsicum annum L.). Agric. Water Manag. 65, 121–132. Aujla, M.S., Thind, H.S., Buttar, G.S., 2007. Fruit yield and water use efficiency of eggplant (Solanum melongema L.) as influenced by different quantities of nitrogen and water applied through drip and furrow irrigation. Sci. Hortic. 112, 142–148. Ben-Noah, I., Friedman, S.P., 2016. Aeration of clayey soils by injecting air through subsurface drippers: lysimetric and field experiments. Agric. Water Manage. 176, 222–233. Bhattarai, S.P., Pendergast, L., Midmore, D.J., 2006. Root aeration improves yield and water use efficiency of tomato in heavy clay and saline soils. Sci. Hortic. 108 (3), 278–288. Bhattarai, S.P., Midmore, D.J., Pendergast, L., 2008. Yield, water-use efficiencies and root distribution of soybean, chickpea and pumpkin under different subsurface drip irrigation depths and oxygation treatments in vertisols. Irrig. Sci. 26 (5), 439–450. Bouchet, A.S., Bouchet, A.S., Laperche, A., Bissuel-Belaygue, C., Snowdon, R., Nesi, N., Stahl, A., 2016. Nitrogen use efficiency in rapeseed. A review. Agron. Sustain. Dev. 36 (2). Cao, Q.J., Sun, Q., Li, J.S., Guo, X.N., Chen, R., 2010. Effect of fertilizer on growth and yield of cucumber and optimum application rate of N in greenhouse. Northern Horticulture 8, 1–4 [in Chinese with English abstract]. Chen, X., Dhungel, J., Bhattarai, S.P., Torabi, M., Pendergast, L., Midmore, D.J., 2010. Impact of oxygation on soil respiration, yield and water use efficiency of three crop cspecies. J. Plant Ecol. 4 (4), 236–248. Chen, H., Hou, H.J., Hu, H.W., et al., 2018. Aeration of different irrigation levels affects net global warming potential and carbon footprint for greenhouse tomato systems. Sci. Hortic. 242, 10–19. Du, X.B., Chen, B.L., Zhang, Y.X., et al., 2016. Nitrogen use efficiency of cotton (Gossypium hirsutum L.) as influenced by wheat–cotton cropping systems. Eur. J. Agron. 75, 72–79. Du, Y.D., Cao, H.X., Liu, S.Q., Gu, X.B., Cao, Y.X., 2017. Response of yield, quality, water and nitrogen use efficiency of tomato to different levels of water and nitrogen under drip irrigation in Northwestern China. J. Integr. Agric. 16 (5), 1153–1161. Du, Y.D., Niu, W.Q., Gu, X.B., Zhang, Q., Cui, B.J., Zhao, Y., 2018a. Crop yield and water use efficiency under aerated irrigation: a meta-analysis. Agric. Water Manage. 210, 158–164. Du, Y.D., Niu, W.Q., Zhagn, Q., Cui, B.J., Gu, X.B., Guo, L.L., Liang, B.H., 2018b. Effects of nitrogen on soil microbial abundance, enzyme activity, and nitrogen use efficiency in greenhouse celery under aerated irrigation. Soil Sci. Soc. Am. J. 82, 606–613. Fan, Z., et al., 2014. Conventional flooding irrigation causes an overuse of nitrogen fertilizer and low nitrogen use efficiency in intensively used solar greenhouse vegetable production. Agric. Water Manag. 144, 11–19. Fan, J., Chen, B., Wu, L., Zhang, F., Lu, X., Xiang, Y., 2018. Evaluation and development of temperature-based empirical models for estimating daily global solar radiation in humid regions. Energy 144, 903–914. Hassanien, R.H.E., Li, M., Lin, W.D., 2016. Advanced applications of solar energy in agricultural greenhouses. Renew. Sustain. Energy Rev. 54, 989–1001. Hoque, M., Kobata, T., 2015. Growth responses of drought resistant rice cultivars to soil compaction under irrigated and succeeding non-irrigated conditions during the vegetative stage. Plant Prod. Sci. 1 (3), 183–190. Hu, B., Henry, A., Brown, K.M., Lynch, J.P., 2014. Root cortical aerenchyma inhibits radial nutrient transport in maize (Zea mays). Ann. Bot. 113, 181–189. Hu, W., Zhang, Y., Huang, B., Ying, T., 2017. Soil environmental quality in greenhouse vegetable production systems in eastern China: current status and management cstrategies. Chemosphere 170, 183–195.
4.3. Yield and economic benefits Sustainable agriculture refers to maintaining high NUE and productivity while decreasing environmental costs (Zhang et al., 2011a; Norse and Ju, 2015; Zhang et al., 2015). In this study, the highest yield of cucumber was obtained at I1N2, which was significantly higher than that of I0 (p < 0.05). Because the photosynthetic capacity and HI were improved by aeration, the partitioning of assimilates to different plant organs was optimized to maximize investment in reproductive structures without sacrificing functional integrity (Reynolds et al., 2012). Cao et al. (2010) and Wang et al. (2017) found that compared with traditional nitrogen application, reducing the application of nitrogen can result in higher economic benefits in the study of protected cucumbers. In the present study, the effect of aerated irrigation on cucumber yield was obvious, and our net income under AI was higher than that of all drip irrigation treatments in the experiment of Liu et al. (2014). The reduced nitrogen with AI had the highest economic benefit in greenhouse cultivation. The I1N2 treatment had the highest yield value, net income, and ratio of output to input, which shows that under AI, the use of nitrogen fertilizer could be moderately reduced, without reducing crop yield, and the purpose of increasing yield and reducing the application of nitrogen fertilizer could be realized at the same time. Our results also suggest that aerated irrigation and N application of 240 kg ha−1 should be combined to meet the needs of economic and ecological benefits of greenhouse cucumber. 5. Conclusions AI significantly improved the NUE and yield of cucumber (pc < 0.05). Compared with drip irrigation, the PFP under AI increased 28.95 % and 18.53 % at 240 and 360 kg N ha−1 nitrogen levels respectively, cucumber yield increased 17.50 %. AI along with N application significantly increased NUE and crop yield, the PFP of I1N2 treatment was 1.3 and 1.8-fold higher than the I0N2 and I0N3 treatments, respectively. The highest yield (72.3 kg ha−1) obtained at I1N2, which was 1.19 and 1.29 times higher than I0N2 and I0N3, respectively (p < 0.05). In order to increase greenhouse cucumber crop yield while further reducing application of nitrogen fertilizer, AI along with N application of 240 kg ha−1 is recommended in Northwest China. 6
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contamination in South-Eastern China. Nutr. Cycl. Agroecosystems 83, 73–84. Song, H., Guo, J.H., Ren, T., Chen, Q., Li, B.G., Wang, J.G., 2012. Increase of soil pH in a solar greenhouse vegetable production system. Soil Sci. Soc. Am. J. 76, 2074–2082. Sun, Y., Hu, K.L., Fan, Z.B., Wei, Y.P., Lin, S., Wang, J.G., 2013. Simulating the fate of nitrogen and optimizing water and nitrogen management of greenhouse tomato in North China using the EU-Rotate_N model. Agric. Water Manag. 128, 72–84. Thompson, R., Martinez-Gaitan, C., Gallardo, M., Gimenez, C., Fernandez, M., 2007. Identification of irrigation and N management practices that contribute to nitrate leaching loss from an intensive vegetable production system by use of a comprehensive survey. Agric. Water Manag. 89, 261–274. Tian, Y., Liu, J., Zhang, X., Gao, L., 2010. Effects of summer catch crop, residue management, soil temperature and water on the succeeding cucumber rhizosphere nitrogen mineralization in intensive production systems. Nutr. Cycl. Agroecosystems 88, 429–446. Tilman, D., Cassman, K.G., Matson, P.A., Naylor, R., Polasky, S., 2002. Agricultural sustainability and intensive production practices. Nature 418 (6898), 671–677. Vázquez, N., Pardo, A., Suso, M.L., Quemada, M., 2005. A methodology for measuring drainage and nitrate leaching in unevenly irrigated vegetable crops. Plant Soil 269, 297–308. Wang, C., Wang, C.X., Gu, F., Chen, J.L., Yang, H., Jiang, J.J., Du, T.S., Zhang, J.H., 2015. Assessing the response of yield and comprehensive fruit quality of tomato grown in greenhouse to deficit irrigation and nitrogen application strategies. Agric. Water Manag. 161, 9–19. Wang, F., Li, G.A., Wang, L.L., Zhou, J.B., Lou, Y.D., Yao, H.Y., 2017. Examining the effects of reduced nitrogen fertilization on the yield and fruit quality of greenhouse cultivated cucumber. Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban 28 (11), 3627–3633 [in Chinese with English abstract]. Yang, Z., Chen, M., Zhang, Q., Zhang, J., 2007. Effects of different fertilizer measurement on nutrient utilization in cucumber and nitrate leaching loss from soil in greenhouse. J. Soil Water Conserv. 21 (2), 57–60 [in Chinese with English abstract]. Zhang, F.S., Cui, Z.L., Fan, M.S., Zhang, W.F., Chen, Q.P., Jiang, R.F., 2011a. Integrated soil-crop system management: reducing environmental risk while increasing crop productivity and improving nutrient use efficiency in China. J. Environ. Qual. 40 (4), 1051–1057. Zhang, H.X., et al., 2011b. Yield and quality response of cucumber to irrigation and nitrogen fertilization under subsurface drip irrigation in solar greenhouse. Agric. Sci. China 10 (6), 921–930. Zhang, X., Davidson, E.A., Mauzerall, D.L., Searchinger, T.D., Dumas, P., Shen, Y., 2015. Managing nitrogen for sustainable development. Nature. 528 (7580), 51–59. Zhao, F., Xu, C.M., Zhang, W.J., Zhang, X.F., Cheng, J.P., Wang, D.Y., 2011. Effects of rhizosphere dissolved oxygen and nitrogen form on root characteristics and nitrogen accumulation of rice. Chin. J. Rice Sci. 25, 195–200 [in Chinese with English abstract]. Zhou, J.Y., Gu, B.J., Schlesinger, W.H., Ju, X.T., 2016. Significant accumulation of nitrate in Chinese semi-humid croplands. Sci. Rep. 6, 1–8. Zhu, J., Liang, J., Xu, Z., Fan, X., Zhou, Q., Shen, Q., Xu, G., 2015. Root aeration improves growth and nitrogen accumulation in rice seedlings under low nitrogen. AoB Plants 7 plv131.
Jacobsen, C.S., Hjelmsø, M.H., 2014. Agricultural soils, pesticides and microbial diversity. Curr. Opin. Biotech. 27 (5), 15–20. Kara, B., Mujdeci, M., 2010. Influence of late-season nitrogen application on chlorophyll content and leaf area index in wheat. Sci. Res. Essays 5, 2299–2303. Kraft, G.J., Stites, W., 2003. Nitrate impacts on groundwater from irrigated-vegetable systems in a humid North-Central US sand plain. Agric. Ecosyst. Environ. 100, 63–74. Lei, H.J., Hu, S.G., Pan, H.W., Zang, M., Li, K., 2017. Advancement in research on soil aeration and oxygation. Acta Pedo. Sin 54 (2), 297–308 [in Chinese with English abstract]. Li, Y., Niu, W., Lü, W., Gu, J., Zou, X., Wang, J., et al., 2016. Aerated irrigation improving photosynthesis characteristics and dry matter accumulation of greenhouse tomato. Trans. Chin. Soc. Agric. Eng. 32 (18), 125–132 [in Chinese with English abstract]. Liu, H.B., Chen, H., Fu, L.B., Yin, M., Chen, J.F., Hong, L.F., 2014. Effect of nitrogen and phosphorus Fertilizer Application rate on yield and Economic benefit of cucumber under drip irrigation and irrigation. Jiangsu Agric. Sci. 42 (1), 123–124 [in Chinese with English abstract]. Mahajan, G., Singh, K.G., 2006. Response of Greenhouse tomato to irrigation and fertigation. Agric. Water Manag. 84, 202–206. Min, J., Zhang, H.L., Shi, W.M., 2012. Optimizing nitrogen input to reduce nitrate leaching loss in greenhouse vegetable production. Agric. Water Manage. 111, 53–59. Niinemets, ÜL., Cescatti, A., Rodeghiero, M., Tosens, T., 2005. Leaf internal diffusion conductance limits photosynthesis more strongly in older leaves of Mediterranean evergreen broad‐leaved species. Plant Cell Environ. 28 (12), 1552–1566. Niu, W., Guo, Q., Zhou, X., Helmers, M.J., 2012. Effect of aeration and soil water redistribution on the air permeability under subsurface drip irrigation. Soil Sci. Soc. Am. J. 76, 815–820. Norse, D., Ju, X.T., 2015. Environmental costs of china’s food security. Agric. Ecosyst. Environ. 209, 5–14. Olympios, C.M., Karapanos, I.C., Lionoudakis, K., Apidianakis, I., 2003. The growth, yield and quality of greenhouse tomatoes in relation to salinity applied at different stages of plant growth. Acta Hort. 609, 313–320. Paudel, I., et al., 2019. Tolerance of citrus rootstocks to poor water quality is improved by root zone aeration via selective uptake of ions, higher photosynthesis and carbon storage. Sci. Hortic. 251, 9–19. Reynolds, M., Foulkes, J., Furbank, R., et al., 2012. Achieving yield gains in wheat. Plant Cell Environ. 35 (10), 1799–1823. Saengwilai, P., Nord, E.A., Chimungu, J.G., Brown, K.M., Lynch, J.P., 2014. Root cortical aerenchyma enhances nitrogen acquisition from low-nitrogen soils in Maize. Plant Physiol. 166, 726–735. Schiattone, M.I., et al., 2018. Impact of irrigation regime and nitrogen rate on yield, quality and water use efficiency of wild rocket under greenhouse conditions. Sci. Hortic. 229, 182–192. Sebilo, M., Mayer, B., Nicolardot, B., Pinay, G., Mariotti, A., 2013. Long-term fate of nitrate fertilizer in agricultural soils. Proc. Natl. Acad. Sci. U. S. A. 110 (45), 18185–18189. Shang, Q.Y., Gao, C.M., Yang, X.X., Wu, P.P., Ling, N., Shen, Q.R., Guo, S.W., 2013. Ammonia volatilization in Chinese double rice-cropping systems: a 3-year field measurement in long-term fertilizer experiments. Biol. Fertil. Soils 50 (5), 1–11. Shi, W.M., Yao, J., Yan, F., 2009. Vegetable cultivation under greenhouse conditions leads to rapid accumulation of nutrients, acidification and salinity of soils and groundwater
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Response of yield and nitrogen use efficiency to aerated irrigation and N application rate in greenhouse cucumber
T
Bing-Jing Cuia,b, Wen-Quan Niua,b,c,*, Ya-Dan Dua,b, Qian Zhanga,b a Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas of Ministry of Education, Northwest A&F University, Yangling, Shaanxi, 712100, China b College of Water Resources and Architectural Engineering, Northwest A & F University, Yangling, Shaanxi, 712100, China c Institute of Soil and Water Conservation, Northwest A & F University, Yangling, Shaanxi, 712100, China
A R T I C LE I N FO
A B S T R A C T
Keywords: Aerated irrigation Greenhouse cucumber Nitrogen use efficiency Economic benefits
Excessive irrigation and fertilization in greenhouse cultivation have a major negative impact, causing economic and environmental problems. Efficient water and fertilizer management methods to increase water use efficiency (WUE) and nitrogen use efficiency (NUE) have been studied often in greenhouses where vegetables are cultivated. However, optimizing the application of nitrogen under certain water conditions does not continue to increase yield. This may be due to oxygen deficiency caused by water saturation in the root zone after irrigation. Aerated irrigation (AI) may be an effective management measure to further reduce the application of nitrogen fertilizer and increase the yield. In order to determine the interaction among irrigation water aeration and N application, a greenhouse study was conducted in Yangling, China, setting up two irrigation methods(AI and drip irrigation)and three N application rates (0, 240, 360 kg ha−1). In this study, AI significantly improved the nitrogen use efficiency (NUE) and yield of cucumber (Qiande 777, p < 0.05). As compared to drip irrigation, the partial factor productivity of applied N (PFP) under AI increased 28.95 % and 18.53 % at 240 and 360 kg N ha-1 nitrogen levels, respectively; cucumber yield under AI was 17.50 % higher than that with drip irrigation condition. AI and N application significantly improved crop yield: the highest yield obtained at AI and nitrogen reduction treatment (I1N2) was 72.3 t ha−1, which was 1.19 and 1.29 times higher than that of non-aerated nitrogen reduction (I0N2) and conventional nitrogen application (I0N3) (p < 0.05). Therefore, AI along with nitrogen application of 240 kg ha−1 is recommended for greenhouse cultivation of cucumber.
1. Introduction In recent years, greenhouse vegetable cultivation has developed rapidly. Greenhouses can make effective use of solar radiation resources and due to their high controllability have become one of the most important facilities for producing vegetables in the world (Hassanien et al., 2016; Fan et al., 2018). The economic benefits of greenhouse cultivation drive farmers to use water and fertilizers in large quantities to achieve higher crop yields. Song et al. (2012) found that water and fertilizer inputs in traditional management far exceed the growth requirement of the greenhouse vegetables (Shi et al., 2009; Tian et al., 2010). Excessive application of N fertilizer results in very high levels of residual nitrate in soil (Min et al., 2012) and nitrate pollution of greenhouse groundwater is increased (Kraft and Stites, 2003; Thompson et al., 2007). Applying excessive nitrogen is a menace to environmental security (Vázquez et al., 2005). Reducing nitrogen
⁎
fertilizer input while maintaining high yield is required for sustainable development of agriculture, and studies on reasonable water and nitrogen management measures in greenhouse cultivation are needed. Efficient water and fertilizer management in greenhouses has become the focus of agricultural research. Compared to conventional irrigation methods, drip irrigation and optimal nitrogen application can significantly improve water use efficiency (WUE) and nitrogen use efficiency (NUE) (Antony and Singandhupe, 2004; Aujla et al., 2007; Sun et al., 2013). Many researchers have reported that reducing water and nitrogen fertilizer inputs reasonably can promote WUE, NUE, and fruit quality throughout the world in different greenhouse vegetables, such as tomato (Wang et al., 2015; Mahajan and Singh, 2006), cucumber (Zhang et al., 2011b; Fan et al., 2014), and wild rocket (Schiattone et al., 2018). However, even rationalized nitrogen applications under certain water conditions does not allow to optimize yield; this may be due to oxygen deficiency caused by water saturation in the root zone
Corresponding authors at: No. 26 Weihui Road, Yangling, Shaanxi Province, 712100, China. E-mail addresses: [email protected] (B.-J. Cui), [email protected] (W.-Q. Niu).
https://doi.org/10.1016/j.scienta.2020.109220 Received 7 July 2019; Received in revised form 12 January 2020; Accepted 18 January 2020 0304-4238/ © 2020 Elsevier B.V. All rights reserved.
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measurements were collected with an automatic weather station (HOBO ware, Onset, Massachusetts, USA) located in our greenhouse.
after irrigation. Aerated irrigation (AI) can improve the aeration conditions of root soil and may be an effective management measure for increasing yield, resulting in further reductions in the nitrogen fertilizer applied. AI is an effective irrigation method to improve crop yield (Bhattarai et al., 2006; Du et al., 2018a). Studies have shown that AI can ameliorate the lack of aeration in root soil without significantly increasing cost (Ben-Noah and Friedman, 2016; Abuarab et al., 2013). Soil aeration has an important effect on the growth and development of crops (Jacobsen and Hjelmsø, 2014; Lei et al., 2017). AI has the potential to strengthen soil nitrification processes, reduce N losses, increase N utilization rate (Hu et al., 2017; Zhao et al., 2011; Du et al., 2018b), and contribute to the growth and development of crops (Chen et al., 2010). Studies on soybean, tomato, and other crops have verified the beneficial function of AI (Bhattarai et al., 2008; Niu et al., 2012; Li et al., 2016). Most researches have concentrated on the effects of AI on fruit quality and yield of greenhouse crops, but there is not enough research on the effects of absorption and utilization of N fertilizer, and even less research focusing on mechanisms for increasing crop yield. In order to explain how aeration increases crop yield, the effects of different N application levels on photosynthetic characteristics, NUE, and yield of greenhouse cucumber under AI were studied. The purpose of this study is to verify whether the combination of aeration and nitrogen application can further improve yield as well as economic and ecological benefits, and ultimately provide a theoretical and scientific basis for reducing applied nitrogen under aeration in greenhouse cultivation.
2.2. Experimental design The cucumber variety used for the experiment was Qiande 777. Tomato was planted prior to cucumber. Fertilizer N, P, and K sources used in the present experiment were urea (N ≥ 46 % by weight), calcium super-phosphate (P2O5, P ≥ 16 %), and water-soluble potassium sulfate (K ≥ 51 %), respectively. A ridge is an experimental plot, each plot was 5.5 m long and 0.5 m wide, 15 cucumber plants were transplanted in it. Cucumber seedlings were transplanted on March 24, 2018, and the plant spacing was 45 cm, the row spacing was 50 cm, the soil surface was covered by a polyethylene film. Before transplanting, an underground drip irrigation belt (16 mm in diameter, 30 cm between drips) was laid in the center of each cultivation area, and the buried depth was 15 cm, the water flow of the drips is 3.6 l h−1 Subsurface drip irrigation was used in the experiment. Each branch was equipped with a flow meter and control valve to control the irrigation volume and the volume of air in each plot. Irrigation occurred once every 10 days, and the volume was the cumulative evaporation between two irrigation stages with an evaporating pan 20 mm in diameter. In this experiment, a Mazzei air injector model 684 (Mazzei Injector Company, Bakersfield, California, USA), which was used to mix air with irrigation water, was installed inline directly behind the water source. These air injectors were established to inject 17 % air by volume of water (Chen et al., 2018). The injection valve is opened in the aerated plot, the system injects the air into water, enters the drip line, and the injection valve is closed in the non-aerated plot. The total irrigation amount for the total experimental area was 30.7 m3 from colonization to pulling seedlings. This experiment is a randomized split-plot design, Aerated irrigation (AI) and non-aerated irrigation were randomly assigned to the main plots. AI treatment was expressed as I1 and the treatment of non-aerated irrigation was denoted I0. Three rates of N application (0, 240 and 360 kg ha−1) were randomly assigned to the subplots within each main plot. According to the local farmers' habits, we used conventional nitrogen application (N3); reduced nitrogen treatment, which was 66 % of the conventional nitrogen application (N2); and the control treatment (N1); the nitrogen application rates were 360, 240, and 0 kg ha−1, respectively. So the experimental had six treament and each treament had 4 replicate plots. 150 kg P2O5 ha−1 and 200 kg K2O ha−1 were applied as basal fertilizer, 40 % of the total nitrogen was used as the basal fertilizer in each nitrogen treatment plot, the remaining N fertilizer was supplied in 4 equal amounts through a drip irrigation tube.
2. Materials and methods 2.1. Experimental site This study was conducted in a greenhouse from 24 March to 9 June 2018 in Yangling, Shaanxi Province at 34″17′ N, 108″02′ E. This area is located on the south-central edge of the Loess Plateau, a semi-arid and humid area, with annual sunshine of 2163.8 h and a frost-free period of 210 d. The length × width of the greenhouse is 108 m × 8 m. The greenhouse has an east-west orientation, is passively ventilated by roof vents, and is covered with a 0.2 mm thick thermal polyethylene sheet. The soil type is Lou soil, which organic matter content was 16.48 g kg−1, with a total N of 0.96 g kg−1, total P of 0.36 g kg−1, and a total K of 10.4 g kg−1. The average dry bulk density of soil in the 1 m soil layer is 1.34 g cm3, and the field capacity is 28.17 %, pH value 7.82. The soil particle composition was as follows: gravel mass fraction, 25.4 %; powder particle mass fraction, 44.1 %; and clay particle mass fraction, 30.5 %. Throughout the cucumber growth period, the daily mean temperature and relative humidity showed inverse trends. Daily mean temperature ranges between 8.5 to 24.9 °C, and relative humidity between 73.5 to 100% (Fig. 1). The air temperature and relative humidity
2.3. Leaf photosynthetic characteristics The upper fourth leaf with the same growth and direction of light was used for measurements with an open gas exchange system (LI6400, Li-Cor, Inc., Lincoln, NE, USA) at 31 d (initial melon stage) and 47 d (full melon stage). Three plants were selected randomly for measurements in each treatment, and the average value was used as the final observation result. Each measurement was carried out from 10:00 to 11:00 with an open air path, CO2 concentration 390 ± 10 μmol mol−1, natural illumination and at a photosynthetic photon-flux density of 800 μmol m-2 s−1. The measured indicators included: leaf net photosynthetic rate (Pn, μmol m-2 s-1), transpiration rate (Tr, mmol m-2 s-1), and stomatal conductance (Gs, mol m-2 s-1). The chlorophyll content of cucumber leaves was measured at 31 d (early melon stage) and 47 d (full melon stage), selected leaves with the same leaf position as photosynthesis, and three plants per plot were selected for measurement. Chlorophylls (a and b) from cucumber leaves were extracted with 95 % ethanol solution, then the extracted samples were subjected to spectrophotometric absorbance at 665 nm, 649 nm and 470 nm, and the content of chlorophyll in cucumber leaves was
Fig. 1. Daily mean air temperature (T) and relative humidity (RH) during the growing season of greenhouse cucumber. 2
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gradually with the increase of nitrogen application. Mean values of Pn at the two growth stages under AI were 1.35, 1.17, and 0.99 times higher than in the non-aeration treatment, for N1, N2, and N3 respectively. Under AI, the Pn of reduced nitrogen treatment (I1N2) was the highest at 34.03 μmol m-2 s−1. The highest Pn of conventional nitrogen application (I0N3) was 33.81 μmol m-2 s−1 when no air was injected, the difference was not significant (p > 0.05). Stomatal conductance (Gs) increased significantly under AI (p < 0.05). The variation in Gs with nitrogen application rates was consistent with that of Pn in the full melon stage. Under AI and drip irrigation, Gs was highest in I1N2 treatment and I0N3 treatment, at 0.566 mmol m−2 s-1 and 0.486 mmol m−2 s-1, respectively. The transpiration rate (Tr) of aeration treatment was lower than that of nonaeration treatment significantly (p < 0.01). Under AI, Tr first increased and then decreased with the increase of nitrogen application rate, while Tr increased with the increase of nitrogen application rate in the nonaerated condition. The ANOVA showed that the interaction between AI and applied nitrogen had a significant effect on the Tr of the early melon stage (p < 0.05). The chlorophyll content of cucumber leaves under different treatments is shown in Fig. 2. The content of chlorophyll a was significantly increased by aeration (p < 0.05). When the nitrogen application rate was 0, 240, and 360 kg ha−1, the average chlorophyll a under the two growth stages was 9.2 %, 12.1 %, and 24.9 % higher than that of the unaerated treatment, respectively. With the increase of nitrogen application rate, the content of chlorophyll a in cucumber leaves increased, and the increase of chlorophyll a was enhanced by aeration. AI enhanced chlorophyll b significantly, and the chlorophyll content increased as the improvement of N application level.
calculated (Li et al., 2016). 2.4. Nitrogen uptake and NUE Three plants were randomly selected from each treatment during the maturity stage of cucumber. Stems, leaves, and fruits were separated into paper bags and then put in an oven, The samples were ovendried at 105 °C for 30 min and kept at 75 °C until a constant weight was attained(Du et al., 2016; Du et al., 2018b), and then weighed with an electronic balance (Yingheng high-precision electronic scale, accuracy of 0.01 g, Yingheng co., Ltd. China). The N content in plant was mensurated using the Kjeldahl method (Dordas and Sioulas, 2009). Four indicators were calculated to evaluate NUE:
Agronomic efficiency (AE, kg kg−1) =
TYN − TYCK TN
Physiological efficiency (PE, kg kg−1) =
Recovery efficiency (RE, %) =
(1)
TYN − TYCK TUN − TUCK
(2)
TUN − TUCK TN
Partial factor productivity of applied N (PFP, kg kg−1) =
(3)
TYN TN
(4)
−1
where TYN is the cucumber yield (kg ha ) in the treatments with N fertilization, TYCK is the cucumber yield (kg ha−1) in the control (CK), TUN is the crop N uptake (kg ha−1) in the treatments with N fertilization, TUCK is the crop N uptake (kg ha−1) in CK, and TN is the total input of fertilizer N (kg ha−1). 2.5. Yield and harvest index (HI) and economic benefits
3.2. Dry matter accumulation and harvest index (HI)
From the full melon stage, 47 d after transplanting, the cucumber was beginning to harvest. Fruits harvested in each treatment plot were weighed separately, the harvest date was recorded, and the total yield of each plot was calculated at the end of seedling pulling. The average fruit size is 191.09 g. The harvest index (HI) is defined as the ratio of fruit dry weight to total dry weight on the ground at harvest time. The economic benefits was calculated as fellow:
Yield value= Yield× cucumber market price
The effects of different nitrogen rates and aeration conditions on dry matter accumulation in cucumber at four growth stages is shown in Fig. 3. Statistics showed that the accumulation of dry matter at maturity with AI was 2.32 %, 15.33 %, and 1.33 % higher than that of the drip irrigation in the N1, N2, and N3 treatments, respectively (p > 0.05). Under drip irrigation, the accumulation of dry matter increased with the improvement of N application level and reached the maximum of 132.02 g plant−1 at I0N3; HI also reached the maximum in I0N3, at 0.45 (Fig. 4). Under AI, the maximum accumulation of dry matter and HI in cucumber were obtained at I1N2, which were 149.15 g plant−1 and 0.51, respectively (Figs. 3, 4). The interaction between AI and applying nitrogen had a significant effect on the HI of cucumber (p < 0.01).
(5)
Agricultural inputs= cucumber seedlings fees+ pesticides fees + fertilizers fees
(6)
Total inputs= Agricultural inputs+ Other inouts
(7)
Net income= Yield value− Total inputs
(8)
3.3. Nitrogen use efficiency At 240 and 360 kg N ha−1 nitrogen levels, AE was 85.5, 56.5, and 24.9, 29.9 kg kg−1 (Fig. 3a); PE was 162.9, 293.0 and 82.0, 148.3 kg kg−1 (Fig. 3b); RE was 52.5, 19.3 and 30.4, 20.1 % (Fig. 3c); and PFP was 301.1, 200.2 and 233.5, 168.9 kg kg−1 (Fig. 3d) under two irrigation modes, respectively. AE, RE, and PFP reached the highest level in I1N2 treatment. With the increase of nitrogen application, although PE continued to increase, in I1N2 treatment it was higher than in I0N2 and I0N3. The PFP of I1N2 treatment was 1.3- and 1.8-fold higher than in the I0N2 and I0N3 treatments, respectively. The results show that the NUE of cucumber was significantly improved by AI (p < 0.05), and changes in the four indexes of NUE caused by aeration were more obvious with increased nitrogen fertilizer (Fig. 5).
2.6. Statistical analysis The experimental data was collected and collated in Excel 2010 (Microsoft Corp., 2010). Data analysis with SPSS 18.0 software (IBM Corp., 2017). The significance of differences among treatments were tested by two-way analyses of variance (ANOVAs), and the means were compared by least significant difference (LSD) tests at p < 0.05. The figures were drawn using Origin 8.0 software (OriginLab Corp., USA). 3. Results 3.1. Photosynthetic characteristics
3.4. Yield and economic benefits
The net photosynthetic rate (Pn) of cucumber leaves under aerated conditions was significantly higher (p < 0.01) than that of non-aerated conditions (Table 1). The mean value of Pn increased by 7.1 % and 21.0 % at the early melon stage and the blooming stage, respectively. The differences in Pn between AI and non-aeration treatment decreased
The yield of cucumber was significantly increased by AI (p < 0.01). When the nitrogen application rate was 0, 240, 360 kg ha−1, the yield of cucumber under AI increased by 3.38 %, 28.96 %, and 18.55 % 3
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Table 1 Effect of different nitrogen application rates on photosynthetic characteristics of cucumber. Treatment
I1N1 I1N2 I1N3 I0N1 I0N2 I0N3 F-value Aeration factor (I) Nitrogen application factor (N) I×N
Net photosynthetic rate Pn/(μmol·m−2·s-1)
Stomatal conductance Gs/(mmol·m−2·s-1)
Transpiration rateTr/(mmol·m−2·s-1)
EMS
EMS
EMS
26.22 34.03 31.23 21.14 30.49 33.81
FMS ± ± ± ± ± ±
0.96ns 7.96** 1.29ns
1.17ab 3.61a 6.81ab 7.21b 0.77ab 1.09a
26.35 39.16 35.75 17.75 32.25 33.67
± ± ± ± ± ±
6.99bc 2.03a 1.69ab 1.39c 1.30ab 3.93ab
12.39** 27.83** 1.37ns
FMS
0.339 0.420 0.305 0.302 0.291 0.273
± ± ± ± ± ±
0.01ab 0.08a 0.01ab 0.07ab 0.02b 0.02b
9.35* 3.19ns 2.15ns
0.437 0.566 0.501 0.322 0.482 0.486
± ± ± ± ± ±
14.98** 19.83** 1.33ns
0.02bc 0.02a 0.04ab 0.02c 0.09ab 0.01ab
5.09 7.90 7.36 7.85 8.13 8.18
FMS ± ± ± ± ± ±
15.94** 9.07** 5.78*
0.49b 1.04a 0.09a 1.10a 0.38a 0.23a
8.38 ± 0.94d 10.14 ± 0.35abc 9.73 ± 0.21bcd 9.15 ± 0.63 cd 11.04 ± 1.05ab 11.49 ± 0.84a 15.68** 18.07** 1.17ns
Note: values followed by different small letters in the same column meant significant differences at 0.05, * means p < 0.05 and ** means p < 0.01, ns means P > 0.05, EMS: Early melon stage, FMS: Full melon stage.
Fig. 4. Harvest index of cucumber among different treatments. Fig. 2. Effects of different treatments on photosynthetic pigments of cucumber leaves. Note: values followed by different small letters in the same column meant significant differences at 0.05, * means p < 0.05 and ** means p < 0.01, ns means P > 0.05, EMS: Early melon stage, FMS: Full melon stage.
Compared with I0, the cucumber net income and the ratio of output to input in I1 increased by 3.70, 47.09, 28.11 % and 0.84, 43.36, 24.53 %, for N1, N2, and N3 respectively (Table 3). This result showed that AI significantly improved cucumber net income and the ratio of output to input (p < 0.05). The highest yield value, net income, and ratio of output to input were obtained in I1N2 treatment, which increased by 18.85, 28.82, and 25.77 % respectively compared with I0N3. 4. Discussion 4.1. NUE Nitrogen is an important element that provides nutrition for plant growth. (Tilman et al., 2002; Zhang et al., 2015). Yang et al. (2007) found that traditional excessive N application was not conducive to the absorption of nutrients by cucumbers, and 91.65 % of N fertilizer was lost (Bouchet et al., 2016). Improving the NUE of cucumber is therefore needed. Du et al. (2018b) reported that reducing the application of nitrogen under AI can promote plant N uptake. Zhu et al. (2015) found that soil aeration and nitrogen supply had a strong interaction with the total nitrogen concentration of the plant, AI improved the growth of roots and buds by promoting the formation of aerated tissue, and then the expression of OsPAD4 and OsNRT2.1 genes changed to increase total N acquired. Because root morphology and aerenchyma formation are both improved by AI, transport and acquisition of N in plants is also affected (Hu et al., 2014; Saengwilai et al., 2014; Zhu et al., 2015). Similar results were obtained in this study, AI increased the absorption and utilization of nitrogen fertilizer. Changes in AE, PE, RE, and PFP were more pronounced with increased nitrogen application rate. When the nitrogen application level is too high, the excess
Fig. 3. Dry matter accumulation at four growth stages under each treatment.
compared with the non-aerated treatment, respectively (Table 2). Under AI, the yield of cucumber increased first and then decreased as the improvement of nitrogen application level, and the yield of I1N2 was the highest at 72.3 t ha−1. The yield with non-aeration treatments increased with the increase of N application rate, and was highest in I0N3 at 60.8 t ha−1. The ANOVA showed that the interaction between AI and applying nitrogen had a significant effect on cucumber yield (p < 0.01). 4
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Fig. 5. Effects of nitrogen application under AI on AE, PE, RE, and PFP. Table 2 Yield and economic benefits of cucumber under different treatments. Treatments
Yield
Yield value
t ha−1 I1N1 I1N2 I1N3 I0N1 I0N2 I0N3
51.7 72.3 72.1 50.1 56.0 60.8
± ± ± ± ± ±
Agricultural inputs
Other inputs
Total inputs
Net income
Ratio of net income and input
3112 3167 3194 3112 3167 3194
4290 4290 4290 4075 4075 4075
7402 7457 7484 7187 7242 7269
8,878 15,279 15,195 8,561 10,388 11,861
1.20e 2.05a 2.03b 1.19e 1.43d 1.63c
US$ ha−1 1.22d 0.18a 1.27a 0.46e 0.15c 1.12b
16,280 22,736 22,679 15,748 17,630 19,130
± ± ± ± ± ±
377d 55a 394a 142e 48c 347b
Unit price of various expenses: cucumber market price is $0.31 kg–1; Agricultural inputs refer to cucumber seedlings ($2359.5 ha–1), pesticides ($643.5 ha–1) and fertilizers, fertiliser included urea ($0.23 kg–1), biological phosphorus ($0.11 kg–1), potassium sulphate ($0.46 kg–1); Other inputs refer to management fees, machinery, and the cost of harvesting cucumber.c.
were increased. Therefore, under AI, the increase of stomatal conductivity promoted the Pn of cucumber leaves. Furthermore, aerated leaves were higher in chlorophyll content than non-aerated leaves (similar to Paudel et al., 2019; Niinemets et al., 2005), which promotes the absorption and transfer of light energy and the synthesis of organic matter. This is consistent with the conclusion of Bhattarai et al. (2008). With the increase of nitrogen application rate, Pn increased at first and then decreased under AI, but kept increasing under drip irrigation. This may be due to the fact that under conventional irrigation, the anaerobic environment formed by high soil moisture promotes soil denitrification (Chen et al., 2018). The nutrients absorbed by plants mainly depend on external nitrogen application. While under AI, the increase of oxygen content promotes nitrification, and increases the available nutrients in soil. The promoting effect of suitable nitrogen application rate (N2) on crop growth was significant, but when the nitrogen application level is too high, it will have an inhibitory effect. Thus, the net photosynthetic rate was the highest under I1N2
nitrogen was partly accumulate in the soil and partly lost from the soil through ammonia volatilization (Sebilo et al., 2013; Zhou et al., 2016; Shang et al., 2013), which always decreases NUE (Zhang et al., 2015). In this study, the AE, RE, and PFP were maximized at I1N2, which means that the NUE of I1N2 was the highest. 4.2. Photosynthesis, dry matter, and HI under aeration and nitrogen application treatment Studies have shown that soil compaction decreases plant net photosynthetic rate, while AI is effective in aerating the rhizosphere and improving soil ventilation (Hoque and Kobata, 2015; Bhattarai et al., 2006; Niu et al., 2012). Li et al. (2016) found that AI reduced plant abscisic acid (ABA), and improved stomatal conductivity of leaves, to a certain extent. In the present study, the stomatal conductivity of cucumber leaves was significantly improved by AI (p < 0.05), the CO2 entering leaves was increased, and the raw materials of photosynthesis 5
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CRediT authorship contribution statement
treatment. N application may improve root growth and biomass accumulation (Kara and Mujdeci, 2010). In the present study, the accumulation of dry matter increased as nitrogen application increased under drip irrigation. On the one hand, compared with drip irrigation, the growth of plants under AI is robust, and is accompanied by high water consumption. This may lead to low soil moisture content, and the results indicated that Tr of cucumber leaves could be inhibited by AI, and the decreased transpiration rate reduced the loss of plant water. On the other hand, the enhanced leaf Pn (Table 1) in the experiment contributed to higher dry matter in the aeration treatment, because leaf photosynthesis is related to fruit yield in many crops (Olympios et al., 2003). N2 treatment produced the highest dry matter accumulation under AI, but the yield did not continue to improve with N application above this level; this may be because the excess nitrogen inhibited the transport of photosynthates to the fruit, and the HI decreased (Du et al., 2017). The HI of cucumber was increased by aeration, indicating that AI promoted the allocation of aboveground biomass to the fruit; Hamzei and Soltani (2012) and Li et al. (2010) reported similar results. The HI was highest at I1N2, which showed that under aeration conditions, appropriate reduction of nitrogen fertilizer use increased the allocation of aboveground biomass to the fruit, these results were similar to those of Bhattarai et al. (2006).
Bing-Jing Cui: Methodology, Software, Formal analysis, Writing original draft, Writing - review & editing. Wen-Quan Niu: Supervision, Writing - review & editing, Funding acquisition. Ya-Dan Du: Conceptualization, Writing - review & editing, Supervision. Qian Zhang: Investigation. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acknowledgments This study was supported by the National Key Research and Development Project (grant number: 2016YFC0400202) and National Natural Science Foundation Program (51679205). References Abuarab, M., Mostafa, E., Ibrahim, M., 2013. Effect of air injection under subsurface drip irrigation on yield and water use efficiency of corn in a sandy clay loam soil. J. Adv. Res. 4 (6), 493–499. Antony, E., Singandhupe, R.B., 2004. Impact of drip and surface irrigation on growth, yield and WUE of capsicum (Capsicum annum L.). Agric. Water Manag. 65, 121–132. Aujla, M.S., Thind, H.S., Buttar, G.S., 2007. Fruit yield and water use efficiency of eggplant (Solanum melongema L.) as influenced by different quantities of nitrogen and water applied through drip and furrow irrigation. Sci. Hortic. 112, 142–148. Ben-Noah, I., Friedman, S.P., 2016. Aeration of clayey soils by injecting air through subsurface drippers: lysimetric and field experiments. Agric. Water Manage. 176, 222–233. Bhattarai, S.P., Pendergast, L., Midmore, D.J., 2006. Root aeration improves yield and water use efficiency of tomato in heavy clay and saline soils. Sci. Hortic. 108 (3), 278–288. Bhattarai, S.P., Midmore, D.J., Pendergast, L., 2008. Yield, water-use efficiencies and root distribution of soybean, chickpea and pumpkin under different subsurface drip irrigation depths and oxygation treatments in vertisols. Irrig. Sci. 26 (5), 439–450. Bouchet, A.S., Bouchet, A.S., Laperche, A., Bissuel-Belaygue, C., Snowdon, R., Nesi, N., Stahl, A., 2016. Nitrogen use efficiency in rapeseed. A review. Agron. Sustain. Dev. 36 (2). Cao, Q.J., Sun, Q., Li, J.S., Guo, X.N., Chen, R., 2010. Effect of fertilizer on growth and yield of cucumber and optimum application rate of N in greenhouse. Northern Horticulture 8, 1–4 [in Chinese with English abstract]. Chen, X., Dhungel, J., Bhattarai, S.P., Torabi, M., Pendergast, L., Midmore, D.J., 2010. Impact of oxygation on soil respiration, yield and water use efficiency of three crop cspecies. J. Plant Ecol. 4 (4), 236–248. Chen, H., Hou, H.J., Hu, H.W., et al., 2018. Aeration of different irrigation levels affects net global warming potential and carbon footprint for greenhouse tomato systems. Sci. Hortic. 242, 10–19. Du, X.B., Chen, B.L., Zhang, Y.X., et al., 2016. Nitrogen use efficiency of cotton (Gossypium hirsutum L.) as influenced by wheat–cotton cropping systems. Eur. J. Agron. 75, 72–79. Du, Y.D., Cao, H.X., Liu, S.Q., Gu, X.B., Cao, Y.X., 2017. Response of yield, quality, water and nitrogen use efficiency of tomato to different levels of water and nitrogen under drip irrigation in Northwestern China. J. Integr. Agric. 16 (5), 1153–1161. Du, Y.D., Niu, W.Q., Gu, X.B., Zhang, Q., Cui, B.J., Zhao, Y., 2018a. Crop yield and water use efficiency under aerated irrigation: a meta-analysis. Agric. Water Manage. 210, 158–164. Du, Y.D., Niu, W.Q., Zhagn, Q., Cui, B.J., Gu, X.B., Guo, L.L., Liang, B.H., 2018b. Effects of nitrogen on soil microbial abundance, enzyme activity, and nitrogen use efficiency in greenhouse celery under aerated irrigation. Soil Sci. Soc. Am. J. 82, 606–613. Fan, Z., et al., 2014. Conventional flooding irrigation causes an overuse of nitrogen fertilizer and low nitrogen use efficiency in intensively used solar greenhouse vegetable production. Agric. Water Manag. 144, 11–19. Fan, J., Chen, B., Wu, L., Zhang, F., Lu, X., Xiang, Y., 2018. Evaluation and development of temperature-based empirical models for estimating daily global solar radiation in humid regions. Energy 144, 903–914. Hassanien, R.H.E., Li, M., Lin, W.D., 2016. Advanced applications of solar energy in agricultural greenhouses. Renew. Sustain. Energy Rev. 54, 989–1001. Hoque, M., Kobata, T., 2015. Growth responses of drought resistant rice cultivars to soil compaction under irrigated and succeeding non-irrigated conditions during the vegetative stage. Plant Prod. Sci. 1 (3), 183–190. Hu, B., Henry, A., Brown, K.M., Lynch, J.P., 2014. Root cortical aerenchyma inhibits radial nutrient transport in maize (Zea mays). Ann. Bot. 113, 181–189. Hu, W., Zhang, Y., Huang, B., Ying, T., 2017. Soil environmental quality in greenhouse vegetable production systems in eastern China: current status and management cstrategies. Chemosphere 170, 183–195.
4.3. Yield and economic benefits Sustainable agriculture refers to maintaining high NUE and productivity while decreasing environmental costs (Zhang et al., 2011a; Norse and Ju, 2015; Zhang et al., 2015). In this study, the highest yield of cucumber was obtained at I1N2, which was significantly higher than that of I0 (p < 0.05). Because the photosynthetic capacity and HI were improved by aeration, the partitioning of assimilates to different plant organs was optimized to maximize investment in reproductive structures without sacrificing functional integrity (Reynolds et al., 2012). Cao et al. (2010) and Wang et al. (2017) found that compared with traditional nitrogen application, reducing the application of nitrogen can result in higher economic benefits in the study of protected cucumbers. In the present study, the effect of aerated irrigation on cucumber yield was obvious, and our net income under AI was higher than that of all drip irrigation treatments in the experiment of Liu et al. (2014). The reduced nitrogen with AI had the highest economic benefit in greenhouse cultivation. The I1N2 treatment had the highest yield value, net income, and ratio of output to input, which shows that under AI, the use of nitrogen fertilizer could be moderately reduced, without reducing crop yield, and the purpose of increasing yield and reducing the application of nitrogen fertilizer could be realized at the same time. Our results also suggest that aerated irrigation and N application of 240 kg ha−1 should be combined to meet the needs of economic and ecological benefits of greenhouse cucumber. 5. Conclusions AI significantly improved the NUE and yield of cucumber (pc < 0.05). Compared with drip irrigation, the PFP under AI increased 28.95 % and 18.53 % at 240 and 360 kg N ha−1 nitrogen levels respectively, cucumber yield increased 17.50 %. AI along with N application significantly increased NUE and crop yield, the PFP of I1N2 treatment was 1.3 and 1.8-fold higher than the I0N2 and I0N3 treatments, respectively. The highest yield (72.3 kg ha−1) obtained at I1N2, which was 1.19 and 1.29 times higher than I0N2 and I0N3, respectively (p < 0.05). In order to increase greenhouse cucumber crop yield while further reducing application of nitrogen fertilizer, AI along with N application of 240 kg ha−1 is recommended in Northwest China. 6
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contamination in South-Eastern China. Nutr. Cycl. Agroecosystems 83, 73–84. Song, H., Guo, J.H., Ren, T., Chen, Q., Li, B.G., Wang, J.G., 2012. Increase of soil pH in a solar greenhouse vegetable production system. Soil Sci. Soc. Am. J. 76, 2074–2082. Sun, Y., Hu, K.L., Fan, Z.B., Wei, Y.P., Lin, S., Wang, J.G., 2013. Simulating the fate of nitrogen and optimizing water and nitrogen management of greenhouse tomato in North China using the EU-Rotate_N model. Agric. Water Manag. 128, 72–84. Thompson, R., Martinez-Gaitan, C., Gallardo, M., Gimenez, C., Fernandez, M., 2007. Identification of irrigation and N management practices that contribute to nitrate leaching loss from an intensive vegetable production system by use of a comprehensive survey. Agric. Water Manag. 89, 261–274. Tian, Y., Liu, J., Zhang, X., Gao, L., 2010. Effects of summer catch crop, residue management, soil temperature and water on the succeeding cucumber rhizosphere nitrogen mineralization in intensive production systems. Nutr. Cycl. Agroecosystems 88, 429–446. Tilman, D., Cassman, K.G., Matson, P.A., Naylor, R., Polasky, S., 2002. Agricultural sustainability and intensive production practices. Nature 418 (6898), 671–677. Vázquez, N., Pardo, A., Suso, M.L., Quemada, M., 2005. A methodology for measuring drainage and nitrate leaching in unevenly irrigated vegetable crops. Plant Soil 269, 297–308. Wang, C., Wang, C.X., Gu, F., Chen, J.L., Yang, H., Jiang, J.J., Du, T.S., Zhang, J.H., 2015. Assessing the response of yield and comprehensive fruit quality of tomato grown in greenhouse to deficit irrigation and nitrogen application strategies. Agric. Water Manag. 161, 9–19. Wang, F., Li, G.A., Wang, L.L., Zhou, J.B., Lou, Y.D., Yao, H.Y., 2017. Examining the effects of reduced nitrogen fertilization on the yield and fruit quality of greenhouse cultivated cucumber. Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban 28 (11), 3627–3633 [in Chinese with English abstract]. Yang, Z., Chen, M., Zhang, Q., Zhang, J., 2007. Effects of different fertilizer measurement on nutrient utilization in cucumber and nitrate leaching loss from soil in greenhouse. J. Soil Water Conserv. 21 (2), 57–60 [in Chinese with English abstract]. Zhang, F.S., Cui, Z.L., Fan, M.S., Zhang, W.F., Chen, Q.P., Jiang, R.F., 2011a. Integrated soil-crop system management: reducing environmental risk while increasing crop productivity and improving nutrient use efficiency in China. J. Environ. Qual. 40 (4), 1051–1057. Zhang, H.X., et al., 2011b. Yield and quality response of cucumber to irrigation and nitrogen fertilization under subsurface drip irrigation in solar greenhouse. Agric. Sci. China 10 (6), 921–930. Zhang, X., Davidson, E.A., Mauzerall, D.L., Searchinger, T.D., Dumas, P., Shen, Y., 2015. Managing nitrogen for sustainable development. Nature. 528 (7580), 51–59. Zhao, F., Xu, C.M., Zhang, W.J., Zhang, X.F., Cheng, J.P., Wang, D.Y., 2011. Effects of rhizosphere dissolved oxygen and nitrogen form on root characteristics and nitrogen accumulation of rice. Chin. J. Rice Sci. 25, 195–200 [in Chinese with English abstract]. Zhou, J.Y., Gu, B.J., Schlesinger, W.H., Ju, X.T., 2016. Significant accumulation of nitrate in Chinese semi-humid croplands. Sci. Rep. 6, 1–8. Zhu, J., Liang, J., Xu, Z., Fan, X., Zhou, Q., Shen, Q., Xu, G., 2015. Root aeration improves growth and nitrogen accumulation in rice seedlings under low nitrogen. AoB Plants 7 plv131.
Jacobsen, C.S., Hjelmsø, M.H., 2014. Agricultural soils, pesticides and microbial diversity. Curr. Opin. Biotech. 27 (5), 15–20. Kara, B., Mujdeci, M., 2010. Influence of late-season nitrogen application on chlorophyll content and leaf area index in wheat. Sci. Res. Essays 5, 2299–2303. Kraft, G.J., Stites, W., 2003. Nitrate impacts on groundwater from irrigated-vegetable systems in a humid North-Central US sand plain. Agric. Ecosyst. Environ. 100, 63–74. Lei, H.J., Hu, S.G., Pan, H.W., Zang, M., Li, K., 2017. Advancement in research on soil aeration and oxygation. Acta Pedo. Sin 54 (2), 297–308 [in Chinese with English abstract]. Li, Y., Niu, W., Lü, W., Gu, J., Zou, X., Wang, J., et al., 2016. Aerated irrigation improving photosynthesis characteristics and dry matter accumulation of greenhouse tomato. Trans. Chin. Soc. Agric. Eng. 32 (18), 125–132 [in Chinese with English abstract]. Liu, H.B., Chen, H., Fu, L.B., Yin, M., Chen, J.F., Hong, L.F., 2014. Effect of nitrogen and phosphorus Fertilizer Application rate on yield and Economic benefit of cucumber under drip irrigation and irrigation. Jiangsu Agric. Sci. 42 (1), 123–124 [in Chinese with English abstract]. Mahajan, G., Singh, K.G., 2006. Response of Greenhouse tomato to irrigation and fertigation. Agric. Water Manag. 84, 202–206. Min, J., Zhang, H.L., Shi, W.M., 2012. Optimizing nitrogen input to reduce nitrate leaching loss in greenhouse vegetable production. Agric. Water Manage. 111, 53–59. Niinemets, ÜL., Cescatti, A., Rodeghiero, M., Tosens, T., 2005. Leaf internal diffusion conductance limits photosynthesis more strongly in older leaves of Mediterranean evergreen broad‐leaved species. Plant Cell Environ. 28 (12), 1552–1566. Niu, W., Guo, Q., Zhou, X., Helmers, M.J., 2012. Effect of aeration and soil water redistribution on the air permeability under subsurface drip irrigation. Soil Sci. Soc. Am. J. 76, 815–820. Norse, D., Ju, X.T., 2015. Environmental costs of china’s food security. Agric. Ecosyst. Environ. 209, 5–14. Olympios, C.M., Karapanos, I.C., Lionoudakis, K., Apidianakis, I., 2003. The growth, yield and quality of greenhouse tomatoes in relation to salinity applied at different stages of plant growth. Acta Hort. 609, 313–320. Paudel, I., et al., 2019. Tolerance of citrus rootstocks to poor water quality is improved by root zone aeration via selective uptake of ions, higher photosynthesis and carbon storage. Sci. Hortic. 251, 9–19. Reynolds, M., Foulkes, J., Furbank, R., et al., 2012. Achieving yield gains in wheat. Plant Cell Environ. 35 (10), 1799–1823. Saengwilai, P., Nord, E.A., Chimungu, J.G., Brown, K.M., Lynch, J.P., 2014. Root cortical aerenchyma enhances nitrogen acquisition from low-nitrogen soils in Maize. Plant Physiol. 166, 726–735. Schiattone, M.I., et al., 2018. Impact of irrigation regime and nitrogen rate on yield, quality and water use efficiency of wild rocket under greenhouse conditions. Sci. Hortic. 229, 182–192. Sebilo, M., Mayer, B., Nicolardot, B., Pinay, G., Mariotti, A., 2013. Long-term fate of nitrate fertilizer in agricultural soils. Proc. Natl. Acad. Sci. U. S. A. 110 (45), 18185–18189. Shang, Q.Y., Gao, C.M., Yang, X.X., Wu, P.P., Ling, N., Shen, Q.R., Guo, S.W., 2013. Ammonia volatilization in Chinese double rice-cropping systems: a 3-year field measurement in long-term fertilizer experiments. Biol. Fertil. Soils 50 (5), 1–11. Shi, W.M., Yao, J., Yan, F., 2009. Vegetable cultivation under greenhouse conditions leads to rapid accumulation of nutrients, acidification and salinity of soils and groundwater
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