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Effects of Organic Manure Application with Chemical Fertilizers on Nutrient Absorption and Yield of Rice in Hunan of Southern China
Agricultural Sciences in China
October 2008
2008, 7(10): 1245-1252
Effects of Organic Manure Application with Chemical Fertilizers on Nutrient Absorption and Yield of Rice in Hunan of Southern China XU Ming-gang1, LI Dong-chu1, LI Ju-mei1, QIN Dao-zhu1, Kazuyuki Yagi2 and Yasukazu Hosen2 1
Key Laboratory of Plant Nutrition and Nutritional Cyclying, Ministry of Agriculture/Institute of Agricultural Resources and Regional
Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R.China 2 Crop Production and Environment Division, Japan International Research Center for Agricultural Sciences, 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
Abstract To evaluate the effect of organic manure application with chemical fertilizers on rice yield and soil fertility under long-term double-rice cropping system, a six year field experiment was conducted continually in the paddy soil derived from Quaternary red clay in Hunan Province of southern China. Four different treatments, i.e., no nitrogen with chemical P and K (PK), swine manure only (M), N, P and K chemical fertilizers only (NPK), and half chemical fertilizers combined with half swine manure (NPKM) with four replications were included. Each N, P and K application rate was the same at all the treatments (except the N application rate at PK) and N application rate was 150 kg N ha-1. All fertilizers were applied to soil tillage layer with once application as baseal fertilizers. The nutrients uptake rate, grain yield, nitrogen use efficiency, and soil organic matter content at each treatment were investigated. The NPKM treatment achieved the highest mean annual yield of 12.2 t ha-1 (68% higher than that of PK). Higher dry matter accumulation and nutrients absorption were observed during the middle-late growth period in the NPKM treatment, with higher panicle number per unit and filled-grain number per panicle. Its average nitrogen use efficiency was 36.3% and soil organic matter increased by 18.5% during the experimental period in the NPKM treatment, which were significantly higher than those in the NPK treatment. Organic manure application with chemical fertilizers increased the yield and nitrogen use efficiency of rice, reduced the risk of environmental pollution and improved soil fertility greatly. It could be a good practical technique that protects the environment and raises the rice yield in this region. Key words: rice, chemical fertilizer, organic manure, nutrient absorption, yield
INTRODUCTION Organic manure is an important fertilizer in agricultural production in China. It is used to fertilize soil and increase crop yield in Chinese traditional agricultural production for a long time (Soil and Fertilizer Institute, Chinese Academy of Agricultural Sciences 1994). In order to develop the high intensive agriculture, more
chemical fertilizers are applied to the soil that result in soil degeneration and environment deterioration. Application of organic manure combined with chemical fertilizer is an important approach to maintaining and improving the soil fertility, and increasing fertilizer use efficiency. Hence it is very useful to study the effect of application of organic manure combined with chemical fertilizer on the nutrient absorption, soil fertility change, and reduction of fertilizer loss, which have been
This paper is translated from its Chinese version in Scientia Agricultura Sinica. Correspondence XU Ming-gang, Professor, Tel: +86-10-82108661, E-mail: [email protected]
© 2008, CAAS. All rights reserved. Published by Elsevier Ltd.
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the research focuses all over the world (Reganold 1995; Conacher J and Conacher A 1998; Liu et al. 1996). Application of organic manure combined with chemical fertilizer could maintain the soil nutrients balance, amend soil physical and chemical properties, increase the soil organic matter and nutrient availability, decrease fertilizer loss rate, and then enhance soil fertility and ecosystem productivity (Conacher J and Conacher A 1998; Zhou and Yang 1992; He and Wang 1989). Application of organic manure could improve the soil quality and is more profitable in environment protection compared with application of chemical fertilizer alone (Reganold 1995; Conacher J and Conacher A 1998). The soil with organic manure continually applied had lower bulk density and higher porosity values, porous and buffering capacities (Edmeades 2003). The influence of different nutrients applied to soil on farmland ecosystem was different (Yang et al. 2004). Application of organic manure combined with chemical fertilizer was propitious to the increase of soil fertility and improved soil physical and chemical properties. Thus it could increase crop production. The direct reasons for the increasing of crops yield were the dry matter accumulation and nutrients absorption. Yang et al. (2004) had studied the effect of application of chemical fertilizer, chemical fertilizer added with crop straw and chemical fertilizer added with farmyard manure on the rice dry matter accumulation and nutrients distribution, and reported that application of organic manure combined with chemical fertilizer was propitious to the transferability and distribution of nutrients from shoot to seed of rice. Zhou et al. (2002, 2003) reported that the nitrogen uptake by rice and system productivity increased with the long-term combination degree between organic manure and chemical NPK fertilizer. However, the total effect of application of organic manure combined with chemical fertilizer on the yield of rice, environment, and soil fertility, especially under long-term double rice-rice cropping system in southern China, was not clear. The current paper reported the characteristics of nutrient uptake by rice, yield of rice, nitrogen use efficiency, and the soil organic matter under application of organic manure combined with chemical fertilizer in six years field experiment. These results would provide a theoretic basis for the sustainable production of rice and
XU Ming-gang et al.
fertilization technique.
MATERIALS AND METHODS Experimental site and soil basic properties The field trial was conducted in paddy field of Qiyang Red Soil Experimental Station (26°45´36´´N, 111°52´12´´E), Hunan Province, South of China. It belongs to subtropical monsoon climate with annual rainfall 1 454 mm, sunlight 1 620 h, and average annual temperature 18.6°C. The paddy soil, which is commonly distributed in southern China, is derived from Quaternary red clay. The soil is heavy clay with 41.5% clay, 48.8% silt, and 9.6% sand. It has 24.3 g kg-1 total organic matter, 1.58 g kg-1 total N, 7.7 mg kg-1 available P, and 71 mg kg-1 exchanged K. It has a pH of 6.8 (1:1 soil/water) and a bulk density of 1.26 g cm-3.
Experimental design The experiment was started in early rice of year 1998 and ended in late rice of year 2003. The primary hybrid varieties with early rice Xiangliangyou 68 (from the end of April to the end of July) and late rice Peiliangyou Teqing (from the end of July to 15-25 of October) were planted. The transplant density was 20 cm × 20 cm. Four treatments with four replications were included in this experiment, which was laid out in the field as Latin Square Design. The treatments are (1) PK, control (without nitrogen, each crop applied 43.7 kg P ha-1 and 90.9 kg K ha -1); (2) NPK, chemical fertilizers (applied 150 kg N ha-1, 43.7 kg P ha-1, and 90.9 kg K ha-1 per crop); (3) M, organic fertilizer (25 000 kg ha-1 pig manure-dry matter weight, which contained 0.60% N, 0.40% P2O5, and 0.44% K2O); and (4) NPKM, halfinorganic and half-organic N, P and K. Equal amounts of N, P, K were applied in each plot in the experiment except the control. Chemical N, P and K fertilizers as urea, calcium superphosphate, and KCl were used, respectively. All of the fertilizers including manure were applied in the cultivation layer as basal fertilizer one day before transplanting. Plot area was 5 m × 5 m, and concrete wall with 6 cm width and
© 2008, CAAS. All rights reserved. Published by Elsevier Ltd.
Effects of Organic Manure Application with Chemical Fertilizers on Nutrient Absorption and Yield of Rice in Hunan
50 cm height was used to separate each plot to avoid the overflow of floodwater.
Sample collection and analysis Plant samples were collected every 10 days after rice transplanted. N, P, and K contents after drying were weighed up and measured . The soil samples were also collected at the beginning of the trial (1998) and soil organic matter content was measured 5 years later (2002). Total N, total P, and total K were determined by digestion of the plant samples with H2SO4 and H2O2. For all samples, the concentrations of N and P were determined colorimetrically by the molybdenum-blue and indophenol-blue methods, while total K was determined by the flame atomic absorption spectrometry.
RESULTS Characteristics of N, P, K uptake by rice with different fertilization The N, P, K contents in rice plant in the treatments with N fertilizer added were higher significantly than that of control (PK) (P < 0.05) (Figs.1-3). The N, P, K uptake by early rice mainly occurred during the middlelate period and the amount of nutrient accumulated in rice plant from spike formation to maturing stage accounted for above 65% of total nutrient absorbed, while was less than 40% in late rice. The N, P, K uptake by late rice mainly occurred during tillering to spike for-
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mation stage. Nutrients accumulation in the treatment was higher than in the treatments with organic manure added at early stage, while the phenomenon was contrary at late stage from spike formation to maturing. Nitrogen accumulation in the early rice was observed in the order of NPKM M NPK > PK, and followed the sequence of M NPKM > NPK > PK in the late rice due to the climate effect. The P accumulation in the NPK treatment was mainly focused in early to middle growth period. The P absorbed by rice in the M and NPKM treatments rapidly increased and exceeded that of NPK treatment after spike formation stage, and it accounted for 65% of total P absorbed in the NPKM treatment from spike formation to maturing in early rice. These characters provided the nutrient bases to maintain high photosynthetic rates and seed formation. K accumulative absorptions in the M and NPKM treatments were higher than that of NPK treatment due to the more K provided by mineralization in the late growth period of rice.
Yield of rice and yield compositions under different fertilization There were significant correlations between the cumulative yield of rice and the time (year) under six years fertilization (Fig.4), indicating that in all treatments there was the same trend of cumulative yield increasing with years. The cumulative yield in NPKM, NPK, M, and PK treatments were 73.2, 70.2, 69.7, and 43.6 t ha -1 respectively. The stability of yield with application of organic manure plus chemical fertilizer was more obvi-
Fig. 1 Accumulation of nitrogen absorbed by early rice (left) and late rice (right) under different fertilization.
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XU Ming-gang et al.
Fig. 2 Accumulation of phosphorus absorbed by early rice (left) and late rice (right) under different fertilization.
Fig. 3 Accumulation of potassium absorbed by early rice (left) and late rice (right) under various fertilization.
Fig. 4 Regression of total yearly seed yield of rice with year (19982003) under different fertilization. ** indicates significant correlation at P < 0.01.
ous than that with chemical fertilizer alone and control according to the determination coefficient (R2). Application of organic manure combined with chemical fer-
tilizer could increase yield of rice by adjusting nutrient release rate in soil and fertilizer (Zhou et al. 2002). The mean annual yield followed the sequence of NPKM (12 201 kg ha-1) NPK (11 703 kg ha-1) M (11 612 kg ha -1) > PK (7 260 kg ha -1). The yield of rice in NPKM treatment increased by 68% compared with that of control (Table 1). The yield composition was different among the treatments. The treatment with application of organic manure combined with chemical fertilizer had higher total panicles and filled grains per panicle. The filled grains per panicle in NPKM and M treatments were higher than that of NPK treatment. Application of organic manure was propitious to rice seed formation. 1 000-grain weight had no difference among different treatments. Filled grain rate was higher in the NPKM treatment, to which high photosynthetic rates in late growth period of rice were related, than that of NPK treatment.
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Effects of Organic Manure Application with Chemical Fertilizers on Nutrient Absorption and Yield of Rice in Hunan
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Table 1 Average rice yield annually and yield compositions under different fertilization during six years plantation (1998-2003) Treatment PK NPK M NPKM
Biomass (kg ha -1)
Seed yield (kg ha -1)
12 564 b 20 915 a 20 277 a 21 370 a
7 260 b 11 702 a 11 612 a 12 201 a
Yield composition Panicle (104 × No. ha-1) 437 ± 102 623 ± 115 564 ± 96 633 ± 104
Filled grain (No./panicle)
1 000-grain wt. (g)
Filled grain rate (%)
84 ± 17 97 ± 11 107 ± 17 103 ± 18
24.8 ± 0.9 24.5 ± 1.0 24.3 ± 1.0 24.4 ± 1.0
82.2 ± 3.0 79.2 ± 4.6 83.4 ± 4.3 81.2 ± 1.6
Values with different letters in a column were different significantly (P < 0.05); ± followed with standard error. The same as below.
Nitrogen use efficiency under different fertilization Nutrient efficiency usually denoted the relative value of nutrient absorbed and utilized by plant (Yan and Zhang 1997). Nitrogen adsorbed annually by rice plant and nitrogen use efficiency were showed in Table 2. Nitrogen absorbed annually by rice plant followed the same order as that of rice yield: NPKM M NPK > PK (Table 2). Application of organic manure and organic manure combined with chemical fertilizer could increase nitrogen use efficiency greatly. The annual mean nitrogen use efficiency with NPKM and M were 36.3 and 34.7%, respectively, and 26.2% with NPK.
matter under application of organic manure combined with chemical fertilizer (NPKM) and under application of chemical fertilizer (NPK) alone were higher than that of control (PK) by 4.7 and 1.7 g kg -1 respectively.
Table 2 Average nitrogen use efficiency under six years various fertilization Treatment PK NPK M NPKM
N uptake by rice (kg ha-1) 130.3 ± 34.6 208.9 ± 34.6 234.4 ± 38.2 239.1 ± 35.0
b a a a
Nitrogen use efficiency (%) 26.2 ± 4.2 b 34.7 ± 3.4 a 36.3 ± 2.2 a
Fig. 5 Change of soil organic matter under 5 years fertilization.
Change of soil organic matter
DISCUSSION
The soil organic matter was important basic substance in soil fertility. The soil organic matter was increased except control after five years fertilization (Fig.5). Comparing with initial soil organic matter content, it increased by 6.5% in NPK treatment, and was significantly less than that in NPKM (18.5%) and M (37.1%) treatments. Therefore, application of organic manure or organic manure combined with chemical fertilizer was propitious to the increase of soil organic matter and improvement of soil fertility. The soil organic matter in M treatment (34.0 g kg-1) was higher than in NPKM (29.4 g kg-1), NPK (26.4 g kg-1), and PK (24.7 g kg-1) treatments under five years fertilization. The soil organic matter with no fertilization was decreased slightly under five years plantation. The soil organic
Application of organic manure, or application of chemical fertilizer combined with organic manure were propitious to the cumulation of soil organic matter and improvement of soil fertility. Yields of rice all reached a high level with different fertilization. The stability of yield, soil organic matter, nitrogen use efficiency, and soil organic matter with application of chemical fertilizer in combination with organic manure increased significantly compared with that of application of chemical fertilizer alone. Application of chemical fertilizer combined with chemical fertilizer was propitious to alleviating environment load caused by nitrogen losses (Xu et al. 2002), this was consistent with the former results (Yu et al. 2007). Application of organic manure only would result in late-maturing because of the ex-
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cessive application rate of nitrogen in late growth period of rice. The nutrient absorbed by rice plant and accumulation of dry matter were influenced by the rice varieties, fertilizers and management methods. Yield of rice was determined by nutrient absorption and especially by the nutrient absorbed in heading stage (Ling 1995). The accumulation of dry matter and nutrient absorption were mainly focused in tillering stage to spike formation stage under application of chemical fertilizer alone and focused in heading stage to maturing under application of organic manure and chemical fertilizer combined with chemical fertilizer. That would be propitious to meet the nutrient requirement for rice growth (Zou et al. 2002). The former results indicated that there were difference on increasing yield of rice and soil fertilization under different fertilizers in combination with organic manure fertilization (Zheng et al. 2001). Therefore different fertilizers include chemical fertilizer and organic manure should select to study on the nutrients requirement of rice in different stage according to the character of nutrient absorbed and rule of rice growth. The soil degeneration was urgent problem in world’s agriculture. The amending methods and preventing strategies were studied in most countries. Application of organic manure was an important approach in soil fertility improvement (Han et al. 2004). The soil organic matter would keep balance under long term application of chemical fertilizer only and it was increased significantly under long term application of organic manure or organic manure combined with chemical fertilizer (Wang et al. 2000; Sui et al. 2005). The results from this paper showed that the soil organic manure increased by 18.5-37.1% under five years continual application of organic manure and organic manure combined with chemical fertilizer. The soil organic matter increased slightly under five years application of chemical fertilizer alone because of an amount of root residue in the soil as the rice plantation. The stability of rice yield under long term application of chemical fertilizer was decreased and was easily influenced by the change of climate. The middle and micro-elements such as Mg, S, and Zn would be absent under long term application of chemical fertilizer alone. Application of chemical fertilizer combined with organic manure was propitious to coordinate the balance of
XU Ming-gang et al.
carbon and nitrogen pools, and then increased system productivity (Kaur et al. 2007). Thus application of chemical fertilizer combined with organic manure was a simple and feasible environment protection and fertilization technique in double rice cropping system in south of China. However, the use value of organic matter decreased along with the organic resources continually increasing under the background of agriculture with high input, high output and high efficiency (Xi et al. 2004). The quality of organic matter was irregular from different sources of straw residue, legumes cake fertilizers, farmyard manure of livestock and poultry, industry waste residue and cities garbage, in which there were harmful elements as well as much useful nutrients for crops. There were high nutrient content of manure and cake fertilizer as well as low content of organic waste. The mineralization rate and humification coefficient were different in different organic matters. Therefore, the reasonable application of organic matter has attracted more and more attention. There were reported that excessive nitrate cumulated in different soil layers of dry land after long term application of excessive organic manure (Stumborg et al. 2007; Tong et al. 1997). There were also reported that organic waste and organic manure are in process of becoming harmful and fatal polluted resources by the more and more organic manure application. High rate application of organic manure brings the raise of the heavy metal content in brown rice and result in health risk. Application of chemical fertilizer combined with reasonable organic manure was the available approach in developing sustainable agriculture by keeping the balance of microelement and decreasing the risk of heavy metal pollution (Kong and Ni 2006). Organic manure returning to the soil was necessary for resolving the negative environment effect by excessive application of organic manure and the atmosphere pollution by straw setting on fire. The study on method of organic material returning to soil is needed. That includes the straw decomposing fleetly, the excrement of human and livestock fermenting, the waste selecting and disinfecting. The industrialization and commercialization of organic manure would be the developing direction with the intensive agriculture and the denseness of labor force. Long term applications of chemical fertilizer or organic ma-
© 2008, CAAS. All rights reserved. Published by Elsevier Ltd.
Effects of Organic Manure Application with Chemical Fertilizers on Nutrient Absorption and Yield of Rice in Hunan
nure alone were against to the development of soil health for the soil-plant system. Application of chemical fertilizer combined with organic manure plays an important role in decreasing the soil nitrate content (Yang et al. 2005), increasing the soil buffering capacity and soil organic matter, improving the soil function and continually increasing yield of crops.
CONCLUSION
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Agriculture, 20, 294-296. (in Chinese) He D Y, Wang K R. 1989. Role and function of organic fertilizer in agroecosystem. Research of Agricultural Modernization, 10, 12-15. (in Chinese) Kaur T, Brar B S, Dhillon N S. 2007. Soil organic matter dynamics as affected by long-term use of organic and inorganic fertilizers under maize-wheat cropping system. Nutrient Cycling in Agroecosystems, 10, 110-121. Kong W J, Ni W Z. 2006. Effects of integrated fertilization with commercial organic manure and chemical fertilizers on heavy metal balance in soil-rice cropping system. Chinese Journal
(1) Application of chemical fertilizer combined with organic manure was propitious to steady and increase yield of rice, which yield was 12.2 t ha-1 yr-1, and increased by 68% of control (7.3 t ha-1 yr-1) with no N fertilization. (2) Application of chemical fertilizer combined with organic manure was propitious to the nutrient accumulation and uptake by rice during the middle and late growing period, and increased total panicles and filled grains per panicle. The nitrogen use efficiency was 36.3% in average under application of chemical fertilizer combined with organic manure. (3) Application of chemical fertilizer combined with organic manure was propitious to increase the soil organic matter, and it increased by 18.5% after six years plantation. It was a practical fertilization technique that protects the environment in southern China.
Achnowledgements This study was financially supported by the National Key Technologies R & D Program of China (2006BAD05B09, 2006BAD02A14), the National Basic Research Program of China (2007CB109308), and the China-Japan Collaboration Project. We also thank to Dr. Zhang Huimin for his help in English modification.
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(Suppl.), 147-156. (in Chinese) Yan X L, Zhang F S. 1997. Plant Nutrition Genetics. China Agriculture Press, Beijing. (in Chinese) Yang C M, Yang L Z, Yan T M, Ou Y Z. 2004. Effects of nutrient
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October 2008
2008, 7(10): 1245-1252
Effects of Organic Manure Application with Chemical Fertilizers on Nutrient Absorption and Yield of Rice in Hunan of Southern China XU Ming-gang1, LI Dong-chu1, LI Ju-mei1, QIN Dao-zhu1, Kazuyuki Yagi2 and Yasukazu Hosen2 1
Key Laboratory of Plant Nutrition and Nutritional Cyclying, Ministry of Agriculture/Institute of Agricultural Resources and Regional
Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R.China 2 Crop Production and Environment Division, Japan International Research Center for Agricultural Sciences, 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
Abstract To evaluate the effect of organic manure application with chemical fertilizers on rice yield and soil fertility under long-term double-rice cropping system, a six year field experiment was conducted continually in the paddy soil derived from Quaternary red clay in Hunan Province of southern China. Four different treatments, i.e., no nitrogen with chemical P and K (PK), swine manure only (M), N, P and K chemical fertilizers only (NPK), and half chemical fertilizers combined with half swine manure (NPKM) with four replications were included. Each N, P and K application rate was the same at all the treatments (except the N application rate at PK) and N application rate was 150 kg N ha-1. All fertilizers were applied to soil tillage layer with once application as baseal fertilizers. The nutrients uptake rate, grain yield, nitrogen use efficiency, and soil organic matter content at each treatment were investigated. The NPKM treatment achieved the highest mean annual yield of 12.2 t ha-1 (68% higher than that of PK). Higher dry matter accumulation and nutrients absorption were observed during the middle-late growth period in the NPKM treatment, with higher panicle number per unit and filled-grain number per panicle. Its average nitrogen use efficiency was 36.3% and soil organic matter increased by 18.5% during the experimental period in the NPKM treatment, which were significantly higher than those in the NPK treatment. Organic manure application with chemical fertilizers increased the yield and nitrogen use efficiency of rice, reduced the risk of environmental pollution and improved soil fertility greatly. It could be a good practical technique that protects the environment and raises the rice yield in this region. Key words: rice, chemical fertilizer, organic manure, nutrient absorption, yield
INTRODUCTION Organic manure is an important fertilizer in agricultural production in China. It is used to fertilize soil and increase crop yield in Chinese traditional agricultural production for a long time (Soil and Fertilizer Institute, Chinese Academy of Agricultural Sciences 1994). In order to develop the high intensive agriculture, more
chemical fertilizers are applied to the soil that result in soil degeneration and environment deterioration. Application of organic manure combined with chemical fertilizer is an important approach to maintaining and improving the soil fertility, and increasing fertilizer use efficiency. Hence it is very useful to study the effect of application of organic manure combined with chemical fertilizer on the nutrient absorption, soil fertility change, and reduction of fertilizer loss, which have been
This paper is translated from its Chinese version in Scientia Agricultura Sinica. Correspondence XU Ming-gang, Professor, Tel: +86-10-82108661, E-mail: [email protected]
© 2008, CAAS. All rights reserved. Published by Elsevier Ltd.
1246
the research focuses all over the world (Reganold 1995; Conacher J and Conacher A 1998; Liu et al. 1996). Application of organic manure combined with chemical fertilizer could maintain the soil nutrients balance, amend soil physical and chemical properties, increase the soil organic matter and nutrient availability, decrease fertilizer loss rate, and then enhance soil fertility and ecosystem productivity (Conacher J and Conacher A 1998; Zhou and Yang 1992; He and Wang 1989). Application of organic manure could improve the soil quality and is more profitable in environment protection compared with application of chemical fertilizer alone (Reganold 1995; Conacher J and Conacher A 1998). The soil with organic manure continually applied had lower bulk density and higher porosity values, porous and buffering capacities (Edmeades 2003). The influence of different nutrients applied to soil on farmland ecosystem was different (Yang et al. 2004). Application of organic manure combined with chemical fertilizer was propitious to the increase of soil fertility and improved soil physical and chemical properties. Thus it could increase crop production. The direct reasons for the increasing of crops yield were the dry matter accumulation and nutrients absorption. Yang et al. (2004) had studied the effect of application of chemical fertilizer, chemical fertilizer added with crop straw and chemical fertilizer added with farmyard manure on the rice dry matter accumulation and nutrients distribution, and reported that application of organic manure combined with chemical fertilizer was propitious to the transferability and distribution of nutrients from shoot to seed of rice. Zhou et al. (2002, 2003) reported that the nitrogen uptake by rice and system productivity increased with the long-term combination degree between organic manure and chemical NPK fertilizer. However, the total effect of application of organic manure combined with chemical fertilizer on the yield of rice, environment, and soil fertility, especially under long-term double rice-rice cropping system in southern China, was not clear. The current paper reported the characteristics of nutrient uptake by rice, yield of rice, nitrogen use efficiency, and the soil organic matter under application of organic manure combined with chemical fertilizer in six years field experiment. These results would provide a theoretic basis for the sustainable production of rice and
XU Ming-gang et al.
fertilization technique.
MATERIALS AND METHODS Experimental site and soil basic properties The field trial was conducted in paddy field of Qiyang Red Soil Experimental Station (26°45´36´´N, 111°52´12´´E), Hunan Province, South of China. It belongs to subtropical monsoon climate with annual rainfall 1 454 mm, sunlight 1 620 h, and average annual temperature 18.6°C. The paddy soil, which is commonly distributed in southern China, is derived from Quaternary red clay. The soil is heavy clay with 41.5% clay, 48.8% silt, and 9.6% sand. It has 24.3 g kg-1 total organic matter, 1.58 g kg-1 total N, 7.7 mg kg-1 available P, and 71 mg kg-1 exchanged K. It has a pH of 6.8 (1:1 soil/water) and a bulk density of 1.26 g cm-3.
Experimental design The experiment was started in early rice of year 1998 and ended in late rice of year 2003. The primary hybrid varieties with early rice Xiangliangyou 68 (from the end of April to the end of July) and late rice Peiliangyou Teqing (from the end of July to 15-25 of October) were planted. The transplant density was 20 cm × 20 cm. Four treatments with four replications were included in this experiment, which was laid out in the field as Latin Square Design. The treatments are (1) PK, control (without nitrogen, each crop applied 43.7 kg P ha-1 and 90.9 kg K ha -1); (2) NPK, chemical fertilizers (applied 150 kg N ha-1, 43.7 kg P ha-1, and 90.9 kg K ha-1 per crop); (3) M, organic fertilizer (25 000 kg ha-1 pig manure-dry matter weight, which contained 0.60% N, 0.40% P2O5, and 0.44% K2O); and (4) NPKM, halfinorganic and half-organic N, P and K. Equal amounts of N, P, K were applied in each plot in the experiment except the control. Chemical N, P and K fertilizers as urea, calcium superphosphate, and KCl were used, respectively. All of the fertilizers including manure were applied in the cultivation layer as basal fertilizer one day before transplanting. Plot area was 5 m × 5 m, and concrete wall with 6 cm width and
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Effects of Organic Manure Application with Chemical Fertilizers on Nutrient Absorption and Yield of Rice in Hunan
50 cm height was used to separate each plot to avoid the overflow of floodwater.
Sample collection and analysis Plant samples were collected every 10 days after rice transplanted. N, P, and K contents after drying were weighed up and measured . The soil samples were also collected at the beginning of the trial (1998) and soil organic matter content was measured 5 years later (2002). Total N, total P, and total K were determined by digestion of the plant samples with H2SO4 and H2O2. For all samples, the concentrations of N and P were determined colorimetrically by the molybdenum-blue and indophenol-blue methods, while total K was determined by the flame atomic absorption spectrometry.
RESULTS Characteristics of N, P, K uptake by rice with different fertilization The N, P, K contents in rice plant in the treatments with N fertilizer added were higher significantly than that of control (PK) (P < 0.05) (Figs.1-3). The N, P, K uptake by early rice mainly occurred during the middlelate period and the amount of nutrient accumulated in rice plant from spike formation to maturing stage accounted for above 65% of total nutrient absorbed, while was less than 40% in late rice. The N, P, K uptake by late rice mainly occurred during tillering to spike for-
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mation stage. Nutrients accumulation in the treatment was higher than in the treatments with organic manure added at early stage, while the phenomenon was contrary at late stage from spike formation to maturing. Nitrogen accumulation in the early rice was observed in the order of NPKM M NPK > PK, and followed the sequence of M NPKM > NPK > PK in the late rice due to the climate effect. The P accumulation in the NPK treatment was mainly focused in early to middle growth period. The P absorbed by rice in the M and NPKM treatments rapidly increased and exceeded that of NPK treatment after spike formation stage, and it accounted for 65% of total P absorbed in the NPKM treatment from spike formation to maturing in early rice. These characters provided the nutrient bases to maintain high photosynthetic rates and seed formation. K accumulative absorptions in the M and NPKM treatments were higher than that of NPK treatment due to the more K provided by mineralization in the late growth period of rice.
Yield of rice and yield compositions under different fertilization There were significant correlations between the cumulative yield of rice and the time (year) under six years fertilization (Fig.4), indicating that in all treatments there was the same trend of cumulative yield increasing with years. The cumulative yield in NPKM, NPK, M, and PK treatments were 73.2, 70.2, 69.7, and 43.6 t ha -1 respectively. The stability of yield with application of organic manure plus chemical fertilizer was more obvi-
Fig. 1 Accumulation of nitrogen absorbed by early rice (left) and late rice (right) under different fertilization.
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XU Ming-gang et al.
Fig. 2 Accumulation of phosphorus absorbed by early rice (left) and late rice (right) under different fertilization.
Fig. 3 Accumulation of potassium absorbed by early rice (left) and late rice (right) under various fertilization.
Fig. 4 Regression of total yearly seed yield of rice with year (19982003) under different fertilization. ** indicates significant correlation at P < 0.01.
ous than that with chemical fertilizer alone and control according to the determination coefficient (R2). Application of organic manure combined with chemical fer-
tilizer could increase yield of rice by adjusting nutrient release rate in soil and fertilizer (Zhou et al. 2002). The mean annual yield followed the sequence of NPKM (12 201 kg ha-1) NPK (11 703 kg ha-1) M (11 612 kg ha -1) > PK (7 260 kg ha -1). The yield of rice in NPKM treatment increased by 68% compared with that of control (Table 1). The yield composition was different among the treatments. The treatment with application of organic manure combined with chemical fertilizer had higher total panicles and filled grains per panicle. The filled grains per panicle in NPKM and M treatments were higher than that of NPK treatment. Application of organic manure was propitious to rice seed formation. 1 000-grain weight had no difference among different treatments. Filled grain rate was higher in the NPKM treatment, to which high photosynthetic rates in late growth period of rice were related, than that of NPK treatment.
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Effects of Organic Manure Application with Chemical Fertilizers on Nutrient Absorption and Yield of Rice in Hunan
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Table 1 Average rice yield annually and yield compositions under different fertilization during six years plantation (1998-2003) Treatment PK NPK M NPKM
Biomass (kg ha -1)
Seed yield (kg ha -1)
12 564 b 20 915 a 20 277 a 21 370 a
7 260 b 11 702 a 11 612 a 12 201 a
Yield composition Panicle (104 × No. ha-1) 437 ± 102 623 ± 115 564 ± 96 633 ± 104
Filled grain (No./panicle)
1 000-grain wt. (g)
Filled grain rate (%)
84 ± 17 97 ± 11 107 ± 17 103 ± 18
24.8 ± 0.9 24.5 ± 1.0 24.3 ± 1.0 24.4 ± 1.0
82.2 ± 3.0 79.2 ± 4.6 83.4 ± 4.3 81.2 ± 1.6
Values with different letters in a column were different significantly (P < 0.05); ± followed with standard error. The same as below.
Nitrogen use efficiency under different fertilization Nutrient efficiency usually denoted the relative value of nutrient absorbed and utilized by plant (Yan and Zhang 1997). Nitrogen adsorbed annually by rice plant and nitrogen use efficiency were showed in Table 2. Nitrogen absorbed annually by rice plant followed the same order as that of rice yield: NPKM M NPK > PK (Table 2). Application of organic manure and organic manure combined with chemical fertilizer could increase nitrogen use efficiency greatly. The annual mean nitrogen use efficiency with NPKM and M were 36.3 and 34.7%, respectively, and 26.2% with NPK.
matter under application of organic manure combined with chemical fertilizer (NPKM) and under application of chemical fertilizer (NPK) alone were higher than that of control (PK) by 4.7 and 1.7 g kg -1 respectively.
Table 2 Average nitrogen use efficiency under six years various fertilization Treatment PK NPK M NPKM
N uptake by rice (kg ha-1) 130.3 ± 34.6 208.9 ± 34.6 234.4 ± 38.2 239.1 ± 35.0
b a a a
Nitrogen use efficiency (%) 26.2 ± 4.2 b 34.7 ± 3.4 a 36.3 ± 2.2 a
Fig. 5 Change of soil organic matter under 5 years fertilization.
Change of soil organic matter
DISCUSSION
The soil organic matter was important basic substance in soil fertility. The soil organic matter was increased except control after five years fertilization (Fig.5). Comparing with initial soil organic matter content, it increased by 6.5% in NPK treatment, and was significantly less than that in NPKM (18.5%) and M (37.1%) treatments. Therefore, application of organic manure or organic manure combined with chemical fertilizer was propitious to the increase of soil organic matter and improvement of soil fertility. The soil organic matter in M treatment (34.0 g kg-1) was higher than in NPKM (29.4 g kg-1), NPK (26.4 g kg-1), and PK (24.7 g kg-1) treatments under five years fertilization. The soil organic matter with no fertilization was decreased slightly under five years plantation. The soil organic
Application of organic manure, or application of chemical fertilizer combined with organic manure were propitious to the cumulation of soil organic matter and improvement of soil fertility. Yields of rice all reached a high level with different fertilization. The stability of yield, soil organic matter, nitrogen use efficiency, and soil organic matter with application of chemical fertilizer in combination with organic manure increased significantly compared with that of application of chemical fertilizer alone. Application of chemical fertilizer combined with chemical fertilizer was propitious to alleviating environment load caused by nitrogen losses (Xu et al. 2002), this was consistent with the former results (Yu et al. 2007). Application of organic manure only would result in late-maturing because of the ex-
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cessive application rate of nitrogen in late growth period of rice. The nutrient absorbed by rice plant and accumulation of dry matter were influenced by the rice varieties, fertilizers and management methods. Yield of rice was determined by nutrient absorption and especially by the nutrient absorbed in heading stage (Ling 1995). The accumulation of dry matter and nutrient absorption were mainly focused in tillering stage to spike formation stage under application of chemical fertilizer alone and focused in heading stage to maturing under application of organic manure and chemical fertilizer combined with chemical fertilizer. That would be propitious to meet the nutrient requirement for rice growth (Zou et al. 2002). The former results indicated that there were difference on increasing yield of rice and soil fertilization under different fertilizers in combination with organic manure fertilization (Zheng et al. 2001). Therefore different fertilizers include chemical fertilizer and organic manure should select to study on the nutrients requirement of rice in different stage according to the character of nutrient absorbed and rule of rice growth. The soil degeneration was urgent problem in world’s agriculture. The amending methods and preventing strategies were studied in most countries. Application of organic manure was an important approach in soil fertility improvement (Han et al. 2004). The soil organic matter would keep balance under long term application of chemical fertilizer only and it was increased significantly under long term application of organic manure or organic manure combined with chemical fertilizer (Wang et al. 2000; Sui et al. 2005). The results from this paper showed that the soil organic manure increased by 18.5-37.1% under five years continual application of organic manure and organic manure combined with chemical fertilizer. The soil organic matter increased slightly under five years application of chemical fertilizer alone because of an amount of root residue in the soil as the rice plantation. The stability of rice yield under long term application of chemical fertilizer was decreased and was easily influenced by the change of climate. The middle and micro-elements such as Mg, S, and Zn would be absent under long term application of chemical fertilizer alone. Application of chemical fertilizer combined with organic manure was propitious to coordinate the balance of
XU Ming-gang et al.
carbon and nitrogen pools, and then increased system productivity (Kaur et al. 2007). Thus application of chemical fertilizer combined with organic manure was a simple and feasible environment protection and fertilization technique in double rice cropping system in south of China. However, the use value of organic matter decreased along with the organic resources continually increasing under the background of agriculture with high input, high output and high efficiency (Xi et al. 2004). The quality of organic matter was irregular from different sources of straw residue, legumes cake fertilizers, farmyard manure of livestock and poultry, industry waste residue and cities garbage, in which there were harmful elements as well as much useful nutrients for crops. There were high nutrient content of manure and cake fertilizer as well as low content of organic waste. The mineralization rate and humification coefficient were different in different organic matters. Therefore, the reasonable application of organic matter has attracted more and more attention. There were reported that excessive nitrate cumulated in different soil layers of dry land after long term application of excessive organic manure (Stumborg et al. 2007; Tong et al. 1997). There were also reported that organic waste and organic manure are in process of becoming harmful and fatal polluted resources by the more and more organic manure application. High rate application of organic manure brings the raise of the heavy metal content in brown rice and result in health risk. Application of chemical fertilizer combined with reasonable organic manure was the available approach in developing sustainable agriculture by keeping the balance of microelement and decreasing the risk of heavy metal pollution (Kong and Ni 2006). Organic manure returning to the soil was necessary for resolving the negative environment effect by excessive application of organic manure and the atmosphere pollution by straw setting on fire. The study on method of organic material returning to soil is needed. That includes the straw decomposing fleetly, the excrement of human and livestock fermenting, the waste selecting and disinfecting. The industrialization and commercialization of organic manure would be the developing direction with the intensive agriculture and the denseness of labor force. Long term applications of chemical fertilizer or organic ma-
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Effects of Organic Manure Application with Chemical Fertilizers on Nutrient Absorption and Yield of Rice in Hunan
nure alone were against to the development of soil health for the soil-plant system. Application of chemical fertilizer combined with organic manure plays an important role in decreasing the soil nitrate content (Yang et al. 2005), increasing the soil buffering capacity and soil organic matter, improving the soil function and continually increasing yield of crops.
CONCLUSION
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Agriculture, 20, 294-296. (in Chinese) He D Y, Wang K R. 1989. Role and function of organic fertilizer in agroecosystem. Research of Agricultural Modernization, 10, 12-15. (in Chinese) Kaur T, Brar B S, Dhillon N S. 2007. Soil organic matter dynamics as affected by long-term use of organic and inorganic fertilizers under maize-wheat cropping system. Nutrient Cycling in Agroecosystems, 10, 110-121. Kong W J, Ni W Z. 2006. Effects of integrated fertilization with commercial organic manure and chemical fertilizers on heavy metal balance in soil-rice cropping system. Chinese Journal
(1) Application of chemical fertilizer combined with organic manure was propitious to steady and increase yield of rice, which yield was 12.2 t ha-1 yr-1, and increased by 68% of control (7.3 t ha-1 yr-1) with no N fertilization. (2) Application of chemical fertilizer combined with organic manure was propitious to the nutrient accumulation and uptake by rice during the middle and late growing period, and increased total panicles and filled grains per panicle. The nitrogen use efficiency was 36.3% in average under application of chemical fertilizer combined with organic manure. (3) Application of chemical fertilizer combined with organic manure was propitious to increase the soil organic matter, and it increased by 18.5% after six years plantation. It was a practical fertilization technique that protects the environment in southern China.
Achnowledgements This study was financially supported by the National Key Technologies R & D Program of China (2006BAD05B09, 2006BAD02A14), the National Basic Research Program of China (2007CB109308), and the China-Japan Collaboration Project. We also thank to Dr. Zhang Huimin for his help in English modification.
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