Impacts of timber harvest intensity and P fertilizer application on soil P fractions

Forest Ecology and Management 437 (2019) 295–303

Contents lists available at ScienceDirect

Forest Ecology and Management journal homepage: www.elsevier.com/locate/foreco

Impacts of timber harvest intensity and P fertilizer application on soil P fractions

T

⁎

José Henrique T. Rochaa,b, , Marcella L.C. Menegalec, Marcos Rodriguesd, Jose Leonardo de M. Gonçalvesa, Paulo S. Pavinatod, Estela Couvre Foltrana, Robert Harrisonc, Jason N. Jamesc Forest Science Department, “Luiz de Queiroz” College of Agriculture, University of São Paulo, Piracicaba, SP 13418-900, Brazil Agriculture and Forest Engineering College, FAEF, Garça, SP, Brazil c School of Environmental and Forest Sciences, University of Washington, Seattle, WA 98195-2100, USA d Soil Science Department, “Luiz de Queiroz” College of Agriculture, University of São Paulo, Piracicaba, SP 13418-900, Brazil a

b

A R T I C LE I N FO

A B S T R A C T

Keywords: Phosphorus fractionation Forest residue management Eucalyptus grandis P availability Minimum tillage

Research has shown significant effects of timber harvest residue management on soil organic carbon (SOC), but less impact has been observed on the available P pool. The objectives of this study were: (1) to estimate the effects of different timber harvest intensities and P fertilization on soil labile P and P fate over time; and (2) to identify which soil P fractions supply P to Eucalyptus plantations cultivated in soils with low P availability. P fractions were assessed using Hedley’s sequential extraction methodology, which corresponds to differing degrees of soil P lability. Three timber harvest intensities (stemwood only, whole tree and whole tree plus litter) and two levels of P fertilization (0 and 44 kg ha−1 of P) were used. A total of 70% of total soil P was found in a non-labile form in the whole tree plus litter removal treatment, while in the whole tree treatment only 66% was found in this form. Removal of harvesting and litter residues resulted in a 40% reduction in the labile P fraction when compared to stemwood only harvested treatment even with fertilizer application. Acid phosphatase activity, which is crucial in mobilizing P for plant uptake, was 45% higher in soils that did not receive P fertilizer, but it did not resulted in higher concentration of labile P. Timber harvest intensity and P fertilizer application did not influence the soil total P concentration over 12 years of Eucalyptus cultivation. However, there was an increase in non-labile and inorganic P fractions and a reduction of labile and organic P fractions with increasing timber harvest intensity. The organic, moderately labile P fraction was the main source of P to the trees under low P availability conditions. Acid phosphatase and low molecular weight organic acid excretion seem to be important strategies of Eucalyptus species to improve P uptake.

1. Introduction Forest productivity in tropical regions is often limited by P availability. Acidic tropical soils are often P deficient due to high weathering rates over long periods of time. This soil characteristic results in low available P (Chen et al., 2015) and increased amounts of P fixed by Fe and Al oxides and hydroxides (Novais et al., 2007; Sattari et al., 2012). In Brazil, research has recently shown that the wood volume of Eucalyptus plantations may be improved by approximately 50% with P fertilization (Bazani et al., 2014). However, low or no response to P application was observed when soil P extracted by anion exchange resin (AER) was higher than 4 mg kg−1 (Melo et al., 2016). Due to high the P fixation capacity of some soils, elevated P fertilizer

⁎

rates are frequently used for Brazilian grain crops. These rates can be 2–3 times greater than the crop uptake and removal (Rodrigues et al., 2016). On the other hand, P fertilizer rates are frequently equal or lower than the harvest removals from eucalypt plantations in Brazil. Harvest removals range from 30 to 60 kg P ha−1 during rotations lasting approximately 7 years (assuming a mean wood productivity of 30–50 m3 ha−1 y−1; Gonçalves et al., 2015; Santana et al., 2008; Rocha et al., 2016b), while P fertilizer application hardly ever exceeds 44 kg ha−1 per rotation (Gonçalves et al., 2013; Melo et al., 2016). This is because no responses have been reported from higher P fertilization rates (Melo et al., 2016). The high efficiency of P utilization in Eucalyptus plantations is attributed to plant species characteristics (e.g. high scavenger capacity, high P cycling and longer rotations when

Corresponding author at: Av. Pádua Dias, 11, Piracicaba, SP 13418-900, Brazil. E-mail address: [email protected] (J.H.T. Rocha).

https://doi.org/10.1016/j.foreco.2019.01.051 Received 28 September 2018; Received in revised form 21 December 2018; Accepted 29 January 2019 0378-1127/ © 2019 Elsevier B.V. All rights reserved.

Forest Ecology and Management 437 (2019) 295–303

J.H.T. Rocha et al.

compared with crops) and to high levels of soil organic matter (SOM) in soils cultivated with Eucalyptus. Even though inorganic P is normally found at very low concentrations in tropical soils (Condit et al., 2013), organic P is found in abundance (Turner and Engelbretch, 2011). These elevated levels of organic P may contribute to the nutrition of tropical trees after hydrolysis to inorganic phosphate by phosphatase enzymes synthesized by plants and microorganisms (Huang et al., 2015). Previous research shows that high SOM content corresponds to a high concentration of organic P forms in the soil and low fixation of inorganic P forms, consequently high P availability (Costa et al., 2016; Negassa and Leinweber, 2009; Rodrigues et al., 2016). However, decreases in SOM that occur in response to the removal of forest residues in Eucalyptus plantations have been found to result in little to no change in the available fraction of inorganic P (as extracted by AER, Mehlich, or Bray; Menegale et al., 2016; Nambiar and Harwood, 2014). The effects of timber harvest intensity and P fertilizer application on soil P dynamics under Eucalyptus plantations are not yet clear, but an understanding of this could be used to improve the P fertilizer efficiency and consequently ensure sustainability of Eucalyptus wood production. Our objective was to assess the effects of different timber harvest intensities combined with P fertilization on soil P lability and P fate over time. A second objective was to estimate which soil P fractions supply P to Eucalyptus grandis in soils with low P availability using the methodology of sequential P extraction proposed by Hedley et al. (1982), and modified by Condron et al. (1985). This method has been widely used to assess the distribution of organic and inorganic P fractions and corresponds to different degrees of lability for crops, forest plantations and natural vegetation (Negassa and Leinweber, 2009; Cross and Schlesinger, 1995).

Table 1 Soil physical and chemical attributes of the experimental site at stand establishment. Soil attribute

Soil layer (cm)

Texturea (g kg−1):

Clay Silt Sandy

pH (CaCl2 0.01 mol L−1) Organic Cb (g kg−1) Total Nc (g kg−1) Exch. cationsd (mmolc kg−1) Exch. Ale (mmolc kg−1) Total comp.f (%):

a b c d e f

SiO2 Al2O3 Fe2O3 TiO2

0–10

10–20

175 22 803 3.8 10.1 1.67 7.3 7.5 6.3 7.3 3.3 1.4

176 12 812 3.9 9.6 1.44 5.2 8.4

Pipette method. Wet oxidation. Determined using the micro Kjeldahl method after sulphuric digestion. Extracted by ion exchange resin. Extracted by 1 mol L−1 KCl. Determined after the sulphuric digestion in microwave.

Table 2 Forest residue management and nutrients applied in the treatments. Treatmenta

Forest residueb Canopy

Bark

Nutrientsc Litter layer

N

P

K

Ca

Mg

125 125 125 125 8

480 480 480 480 –

120 120 120 120 –

kg ha−1

2. Material and methods ReM + F ACR + F ReR + F ACR-P ReM-F

2.1. Study site The study was carried out at the Itatinga Forest Science Experimental Station of the University of São Paulo, Brazil (23° 06′S lat, 48° 36′W long and 857 m above sea level). The region has a humid subtropical (Cfa) climate, with an average annual temperature of 19.4 °C. The mean annual rainfall (last 30 years) was 1319 mm, with 75% concentrated between October and March (Alvares et al., 2013). The topography of the region is flat to undulating, and the soil is a very deep Ferralsol that was developed on Cretaceous sandstone (IUSS Working Group WRB, 2015; Latossolo Vermelho-Amarelo – Brazilian Classification System, and Oxisol – Soil Taxonomy). Clay content ranges from 17% in the surface (0–40 cm) to 25% in deeper soil layers. The mineralogy of this soil is dominated by quartz, kaolinite and oxyhydroxides of Al and Fe, with a low pH (Table 1). The original vegetation of the site was Cerrado stricto sensu (Brazilian savannah). The site has been planted with Eucalyptus species since 1940. In 1992, the site was harvested and replanted with Eucalyptus grandis Hill ex Maiden, which was then harvested (clearcutting) in 2004, when the present study was established.

M R R R M

M R R R M

M M R M M

130 130 130 130 10

44 44 44 – –

a

Detailed description in Section 2. M = maintained on the soil, R = removed from the area. c N, P, K, Ca, and Mg sources were ammonium sulfate, triple superphosphate, potassium chloride, and dolomitic limestone (mixture of CaCO3 and MgCO3), respectively. b

ReM + F – (Residues Maintained + Fertilization) Only stemwood was harvested; all forest residues (bark, canopy, and litter layer from the previous rotation) were maintained on the soil after clear-cutting; all macronutrients were applied by fertilizer, and the soil was dressed with dolomitic limestone (2 t ha−1; 24% of Ca and 6% of Mg). ACR + F – (Aboveground Components Removed + Fertilization) The whole-tree was harvested; the canopy (leaves and branches), bark, and wood were removed after clear-cutting, but the litter layer was maintained on the soil; all nutrients were applied as fertilizer, and the soil was dressed with limestone; ReR + F – (Residues Removed + Fertilization) All the forest residues (bark, canopy, and litter layer from the previous rotation) were removed from the plot after clear-cutting, and all nutrients were applied as fertilizer, and the soil was dressed with limestone; ACR-P – (Aboveground Components Removed – Phosphorus) The whole-tree was harvested; the canopy (leaves and branches), bark, and wood were removed after clear-cutting, but the litter layer was maintained on the soil; all nutrients were applied as fertilizer except for P, and the soil was dressed with limestone; ReM-F – (Residues Maintained – Fertilization) Only stemwood was harvested; all forest residues (bark, canopy, and litter layer from the previous rotation) were maintained on the soil after clear-cutting, and fertilizer and lime were not applied; The N, P, and K sources were ammonium sulfate, triple

2.2. Experimental treatments and management The study site was established in 2004 (R1) and then reinstalled in 2012 (R2) with three replicates of five treatments in a randomized block design. The plot sizes were 27 m × 18 m, with 81 trees per plot. Sampling was carried out in an inner plot of 15 m × 10 m (25 trees per plot). Five treatments with different management levels of forest residue removal and P fertilizer applications were assessed in this study (Table 2). The forest residues manipulated in this experiment include all organic residues remaining on the soil after wood harvesting of E. grandis plantations after 12-year growth: the leaves and branches less than 3 cm in diameter (canopy), bark, and litter layer. The following treatments were tested: 296

Forest Ecology and Management 437 (2019) 295–303

J.H.T. Rocha et al.

released by incubation of soil with p-nitrophenyl phosphate (PNP). Soil was sampled in the 0–5 cm layer in three locations along the plots at distances of 0.25, 0.75 and 1.5 m from the trees. Each sample was composed of 6 sub samples collected in the inner plot. After sampling, the soil was stored at −80 °C for further analysis.

superphosphate, and potassium chloride, respectively. The fertilizer was applied as one planting fertilizer application and two topdressing applications. The planting fertilizer was applied on the same day as planting; the triple superphosphate, fritted traced elements (9% Zn + 1.8% B + 0.8% Cu + 2% Mn + 3.5% Fe + 0.1% Mo), and 10 kg ha−1 of N and K were added in a small pit to the side of each seedling, whereas lime was applied to the whole area. The ReM-F treatment received a small amount of N and K with the base fertilizer to ensure the survival and initial development of plants. The topdressing of N, and K were applied around the seedlings within the ground area covered by the canopy at 3 and 8 months after planting. After clear-cutting the existing 12-year-old Eucalyptus grandis Hill ex Maiden plantation, the treatments were applied and a single progeny of E. grandis Hill ex Maiden seedlings were planted in June 2004 (one month after harvesting the previous plantation). The soil was prepared using a ripper at 40 cm depth. The first rotation (R1) was harvested at eight years old and replanted one month later (November/2012). The treatments for the second rotation (R2) were repeated exactly the same as the previous one. During clear-cutting, the trees canopy and bark of each plot were carefully retained on the same plot. The seedlings in R2 were planted in pits between the stumps of R1. R2 was managed in the same way as R1. Each experimental unit was maintained weed-free throughout the two rotations. Additional details of the site characterization, treatments and complete experimental design can be found in Rocha et al. (2016a) and Menegale et al. (2016).

2.4. Data analysis Soil P fractions were grouped into three broad categories according to the lability of the P extracted by each extractant: labile P, moderately labile P, and non-labile P (Cross and Schlesinger, 1995). The PAER in combination with the PBIC (organic and inorganic) fall within the category of labile P. The PHYD0.1 (Pi and Po), added to PHCl is categorized as moderately labile P. Finally, the sum of PHYD0.5 (Pi and Po) and the PResid was categorized as non-labile P. The grouping of PHYD-0.5 in the non-labile fraction of P was necessitated by the change in the order of the extraction procedure introduced by Condron et al. (1985). This is because the fraction corresponds to the P which is protected by intraaggregates of the soil, which would only be considered of moderate lability in cases of exhaustion of the more labile forms of P (Rodrigues et al., 2016). The statistical analyses were performed based on data obtained in each forest rotation, considering treatments and blocks as variation sources. Prior to the analysis, the data were tested for normality (Shapiro–Wilk test) and homoscedasticity (Box-Cox test). In almost all the cases, the log transformation was necessary to attain parametric assumptions. The F-test was applied and when found to be significant (p < 0.05), the LSD test at 5% of confidence level was performed for mean comparison. After grouping the results, an ANOVA test was performed for each form of P (i.e. organic and inorganic) and for its respective sum of lability level (i.e. labile, moderately labile and nonlabile). Statistical analysis was performed using the software SAS University Edition.

2.3. Soil sampling and analysis Soil samples were collected at 0–10 and 10–20 cm layers before the application or re-application of the treatments in the first (2004) and second (2012) rotations and at 40 months into the second rotation (2016). The sampling in 2004 was made by block, without treatment division. Soil was sampled using an auger for each treatment in 3 replications (blocks). The soil sample for each plot was composited from six subsamples taken from six points in the inner plot, arranged in a diagonal design. The collection points were located between the tree lines, in a way to avoid the place where the fertilizer was applied. Samples were then dried at 45 °C for three days and passed through a 2 mm sieve for chemical analysis. Sequential P fractionation was performed following the methodology proposed by Hedley et al. (1982), with the adaptations proposed by Condron et al. (1985). The extractions proceeded in the following order: (i) Anion exchange resin (PAER) using a anion resin membrane of 2 cm2 in water (AMI-7001 CRX – 1 × 2 cm); (ii) 0.5 mol L−1 NaHCO3 at pH 8.5 (PBic); (iii) 0.1 mol L−1 NaOH (PHYD0.1); (iv) 1.0 mol L−1 HCl (PHCl); (v) 0.5 mol L−1 NaOH (PHYD0.5); and (vi) Residual P (PResid). In a 15 mL centrifuge tube, 0.5 g of soil was added to 10 mL of the extractant. The tube was then shaken for 16 h in an orbital shaker at 60 rpm. Then, the suspensions were centrifuged at 4000 rpm (3278g) for 20 min and the clear supernatants were collected. This process was repeated for each extractant, except for PResid, in which the remaining soil was dried at 50 °C, milled and digested with H2SO4 plus H2O2 in the presence of saturated MgCl2. For the PAER extraction, resin membranes were placed in the soil/water solution prior to shaking, then removed and washed with 1.0 mol L−1 HCl for P determination. An aliquot of the alkali extracts were digested with H2SO4 and (NH4)2S2O8 in an autoclave at 121 °C for total P determination. Inorganic P in alkali extracts (PBic, PHYD0.1 and PHYD0.5) was determined by colorimetry (Dick and Tabatabai, 1977). Inorganic P in acid extracts (PAER and PHCl) and after digestion of the alkali extracts (PBic, PHYD0.1 and PHYD0.5) was determined by the Murphy and Riley (1962) colorimetric method. The organic P pools (Po) were estimated by the difference between total P and inorganic P (Pi) in each different extract. The activity of the phosphatase enzyme in the soil was determined based upon the methodology described by Tabatabai and Bremner (1969). Phosphatase activity was estimated by the organic moiety

3. Results The average total P concentration was 178 ± 13 mg kg−1 in the 0–10 cm layer and 138 ± 12 mg kg−1 in the 10–20 cm layer across all plots. From this total, 25 ± 3 and 21 ± 3% were found in organic forms in the 0–10 and 10–20 cm layers, respectively. The results for each P fraction observed in the soil at experiment establishment, at the end of the first rotation, and 40 months after the establishment of the second rotation of Eucalyptus cultivation are presented in Table 3. In general, the anion exchange resin fraction (PAER) represented only 3 and 1% of total P in the 0–10 and 10–20 cm layers, respectively. As a fraction of total P in the 0–10 cm and 10–20 cm layers, Bicarbonateextractable P represented around 7 and 6%, while 0.1 mol L−1 NaOH extracted 24 and 19%, HCl extracted less than 1% for both layers, NaOH 0.5 mol L−1 extracted around 10% for both layers, and the residual P fraction was 56 and 64% of total P, respectively. Most of the organic fraction (87% in the 0–10 cm layer and 79% at 10–20 cm depth) was extracted by 0.1 mol L−1 NaOH. The greatest differences between treatments were observed in the 0–10 cm layer, but some significant differences were also observed in the 10–20 cm layer, especially in the 2016 sampling season. The biggest differences were found in the bicarbonate and 0.1 mol L−1 NaOH extractions and no differences were found in the residual P fraction, except in 2016 in the layer 10–20 cm (Table 3). 3.1. Labile P fractions (PAER, PoBIC and PiBIC) Inorganic fractions composed more than 90% of the labile P. In 2012, the labile P (Pi + Po) in the 0–10 cm layer was significantly greater (p = 0.048) under ACR + F, ReR + F and ReM-F compared to the other treatments (Fig. 1). Total inorganic P was also significantly larger (p = 0.051) in these same treatments. The labile organic P was 297

Forest Ecology and Management 437 (2019) 295–303

J.H.T. Rocha et al.

Table 3 Soil P fractions (mg kg−1) extracted sequentially by anion exchange resin (PAER), bicarbonate in inorganic (PiBIC) and organic (PoBIC) forms, NaOH 0.1 mol L−1 (PiHYD0.1 and PoHYD0.1), HCl 1 mol L−1 (PHCl) NaOH 0.5 mol L−1 (PiHYD0.5 and PoHYD0.5) and residual P (PResid), in Eucalyptus grandis plantations under different timber harvest intensity and P fertilizer application. Treatment(1)

PAER

PiBIC

PoBIC

PiHYD0.1

PoHYD0.1

PHCl

PiHYD0.5

PoHYD0.5

PResid

0–10 cm Establishment of experiment (2004) 5.9 (2.1)(2) 13.6 (2.7)

0.9 (0.3)

4.9 (1.7)

41.6 (1.9)

0.19 (0.1)

11.4 (2.2)

3.0 (0.3)

96.4 (3.3)

End of first crop rotation ReM + F 4.5 ACR + F 6.2 ReR + F 5.2 ACR-P 3.9 ReM-F 6.8

2.5 3.3 0.9 1.6 0.6

a a b ab b

3.7 5.3 4.4 3.7 2.3

b a ab b c

32.1 38.9 30.5 27.9 48.7

40 months after re-installation of experiment (2016) ReM + F 5.1 a 12.2 a ACR + F 4.1 ab 10.2 ab ReR + F 2.6 c 7.2 b ACR-P 3.7 b 8.6 b ReM-F 5.2 a 12.9 a

1.0 0.8 1.2 0.3 0.7

ab bc a d c

3.0 6.7 2.9 3.3 1.6

bc a bc b c

10–20 cm Establishment of experiment (2004) 2.4 (0.3) 4.1 (0.8)

3.9 (0.3)

End of first crop rotation of experiment (2012) ReM + F 2.4 4.9 ACR + F 1.6 3.4 ReR + F 2.5 5.3 ACR-P 2.6 3.5 ReM-F 2.2 3.6

2.7 4.7 3.8 5.6 4.7

b ab ab a ab

2.7 3.2 4.1 6.1 3.0

40 months after re-installation of experiment (2016) ReM + F 2.0 3.1 b ACR + F 1.4 2.1 c ReR + F 1.7 0.4 d ACR-P 1.8 2.6 c ReM-F 2.0 6.1 a

3.0 4.2 7.3 7.0 3.3

c b a a c

7.4 5.3 5.6 3.9 5.0

of experiment (2012) c(3) 8.4 b ab 12.3 ab abc 13.4 a c 9.0 b a 12.8 a

3.4 (0.5) b ab ab a b

0.16 0.09 0.14 0.19 0.13

ab b ab a ab

8.8 8.3 13.2 11.5 13.9

39.5 35.1 40.4 40.1 39.7

0.19 0.33 0.14 0.21 0.57

c b c bc a

22.8 (1.7) 25.4 25.2 26.9 24.0 29.7 23.7 20.5 18.0 30.6 24.7

b ab b b a

b bc c a b

9.4 6.6 4.9 4.1 0.5

a ab b b c

90.0 101.5 107.9 98.1 102.9

13.0 13.8 11.6 14.3 12.5

10.0 7.2 4.4 5.1 6.4

a ab b b ab

96.0 104.0 104.9 106.9 102.4

0.43 (0.1)

10.6 (1.1)

1.1 (0.1)

0.04 0.10 0.28 0.07 0.07

10.6 11.0 9.8 11.9 8.3

2.6 3.9 4.9 4.5 0.1

b ab a ab c

90.1 91.9 90.9 95.0 89.2

1.8 5.0 5.0 6.6 0.1

c a a a d

97.5 93.1 95.6 106.6 105.0

0.09 0.19 0.09 0.16 0.09

b a b a b

11.1 9.3 13.0 9.6 19.9

b b a ab a

b b b b a

89.8 (9.5)

b b b a a

ReM + F – all forest residues were maintained on the soil after clear-cutting, all macronutrients were applied as fertilizer and the soil was dressed with limestone; ACR + F – the canopy and bark were removed after clear-cutting, and the same fertilization management as the ReM + F treatment was applied; ReR + F – all forest residues were removed from the plot after clear-cutting, and the same fertilization management as the ReM + F treatment was applied; ACR-P – the same of level of residue removal as ACR + F except that P fertilizer was not applied; ReM-F – The same as the ReM + F treatment except that fertilizer and lime was not applied; (2) Standard deviation; (3)Means followed by the same letter or not followed by any letter do not differ by LSD test at 5% of probability in each soil layer and time period of evaluation.

concentration of Pi compared to the others, but it still represents a very small percentage of total P. At 10–20 cm, no differences in moderately labile P were observed between the treatments tested. The ACR-P contained significantly higher amounts of moderately labile Pi, while the lowest concentration was observed under ReM-F (Fig. 1). In 2016, the ACR + F presented the highest Pi concentration and the smallest Po concentration, without any difference in the total moderately labile P among treatments in the 0–10 cm layer. In the 10–20 cm layer, the ACR-P showed a slight increase in the moderately labile P when compared to the other treatments as a consequence of the highest level of Po. No differences between treatments were observed between the inorganic forms of moderately labile P, with values considered very low, ranging from 3 to 6 mg kg−1 (Fig. 1).

higher (p = 0.013) under ReM + F and ACR + F treatments. At 10–20 cm, only the labile Po was influenced by the treatments, with ACR + F, ACR-P and ReM-F presenting higher values compared to ReM + F (Fig. 1). In 2016, the concentration of labile P in the 0–10 cm layer was significantly greater under ReM + F and ReM-F treatments (p = 0.014) compared to the others, and the same was observed for the labile Pi. The ReR + F and ACR-P treatments presented the lowest values for the aforementioned P fractions. The ACR-P presented the lowest (p < 0.001) concentration of Po when compared to the other treatments. At 10–20 cm, the highest (p = 0.007) concentration of labile P was observed in the ACR-P and ReM-F treatments. The ReM-F treatment contained a larger concentration of Pi when compared to the other treatments, while the ReR + F presented the lowest Pi level. The Po was significantly greater under ReR + F and ACR-P treatments compared to the others (Fig. 1).

3.3. Non-Labile P fractions (PiHYD0.5, PoHYD0.5 and PResid) The non-labile P constituted a sizeable fraction for all treatments. In general, the non-labile P concentrations in the 0–10 cm soil layer showed a significant increase over the 12 years of the experiment. In 2012, concentrations were greater (p = 0.012) under ReR + F treatment at 0–10 cm, while the ReM + F presented the lowest value ranging from 105.6 to 127.6 mg kg−1, respectively. The concentration of non-labile Pi was noticeably higher (p = 0.023) in ReR + F when compared to the other treatments, while the ReM + F presented the lowest value of non-labile Pi. At 10–20 cm, treatments did not

3.2. Moderately labile P fractions (PiHYD0.1, PoHYD0.1 and PHCl) Organic P (Po) represents more than 80% of the moderately labile P fraction in both seasons and layers evaluated here. In 2012, moderately labile P was noticeably higher in the ReM-F treatment compared to the other treatments in the 0–10 cm layer. This same treatment presented the highest moderately labile Po. In contrast, its inorganic form was the lowest among all treatments. The ACR + F treatment had a higher 298

Forest Ecology and Management 437 (2019) 295–303

J.H.T. Rocha et al.

Fig. 1. Labile, moderately labile and non-labile P concentration at 0–10 and 10–20 cm depths in a Ferralsol under a Eucalyptus grandis plantation with different timber harvest intensity and P fertilizer application just before the experiment installation (Inst.; 2004), at the end of the first experimental rotation (2012) and at 40 months into the second experimental rotation (2016). Columns followed by the same letter or not followed by any letter do not differ by LSD test at 5% of probability within each year. Lower case letters indicate the difference between each form (inorganic or organic) and capital letters indicate the differences in sum inorganic + organic.

2012, no differences among treatments were found. In 2016, the ReM-F and ACR-P contained the highest total P in this layer, as a consequence of the highest amount of total Pi for the ReM-F treatment, but the highest total Po for the ACR-P treatment (Fig. 2).

significantly differ regarding to non-labile P, but a slightly higher amount of Po in this fraction was observed under ReR + F compared to the others (Fig. 1). In the evaluation of 2016, non-labile P fractions were not significantly affected by treatments in the 0–10 cm layer, with values ranging from 118 to 125 mg kg−1, with a slightly higher amount of Po under ReM + F compared to the others. At 10–20 cm, concentrations of non-labile P were greater in ACR-P and ReM-F treatments. The ReM-F also presented the greatest amount of non-labile Pi but the lowest nonlabile Po concentration (Fig. 1).

3.5. Acid phosphatase activity (APA) The APA was strongly affected by the treatments applied (p = 0.005). The highest APA (1330 µg g−1 h−1 of p-nitrophenyl phosphate – PNP) was observed in ReM-F, but this did not significantly differ from ReM + F and ACR-P. The smallest APA (900 µg g−1 h−1 of PNP) was found under ReR + F, similar to the ACR + F treatment (Fig. 3).

3.4. Total P In 2012, the ReM-F, ACR + F and ReR + F treatments presented the highest total P at 0–10 cm (p = 0.049), as a consequence of the highest amount of total Pi under these treatments. In 2016, no differences in the total P among treatments were found in this layer. At 10–20 cm in 299

Forest Ecology and Management 437 (2019) 295–303

J.H.T. Rocha et al.

Fig. 2. Total P concentration (organic and inorganic) at the 0–10 and 10–20 cm depths in a Ferralsol under a Eucalyptus grandis plantation, with different timber harvest intensity and P fertilizer application, just before the experiment establishment (2004), at the end of the first experimental rotation (2012) and at 40 months into the second experimental rotation (2016). Columns followed by the same letter or not followed by any letter do not differ by LSD test at 5% of probability. Lower case letter indicate the difference between each form (inorganic or organic) and capital letters indicate the difference of sum inorganic + organic.

(Araújo et al., 2004; Rodrigues et al., 2016) and under crops (Rodrigues et al., 2016). Higher accumulation of P in organic forms in soils under Eucalyptus plantations can be associated with the high SOM content, the high C:P ratio of the Eucalyptus’s litter, and low or no tillage management (Rocha et al., 2016a, 2018). Approximately 10% of total P was found in labile forms (PAER and PBic). Similar proportions of labile P were reported under other Eucalyptus plantations (Foltran, 2017; Costa et al., 2016). Under native vegetation this proportion tends to be smaller (around 7%) and under crops tend to be higher (around 15%) due to high P fertilizer inputs (Negassa and Leinweber, 2009; Rodrigues et al., 2016). The moderately labile (PHID0.1 and PHCl) and non-labile P (PHYD0.5 and PResid) contributions were around 20 and 70%, respectively, similar to the values reported by Foltran (2017). Rodrigues et al. (2016) found moderately labile and non-labile P contributions of around 15 and 77% in soils under native vegetation and 28 and 57% under crop cultivation, respectively. Almost no P was extracted by HCl (< 1%), likely because HCl extracts P bound in calcium precipitates and this form of P is not expected in highly weathered soils with low pH and without apatite primary minerals (Cross and Schlesinger, 1995; Negassa and Leinweber, 2009; Hu et al., 2016).

Fig. 3. Acid phosphatase activity (APA) in the 0–5 cm layer of a Ferralsol under Eucalyptus grandis plantation with a different timber harvest intensity and P fertilizer application, at 40 months into the second experimental rotation (2016). Columns followed by the same letter do not differ by LSD test at 5% of probability. The bars indicates the standard deviation.

4. Discussion 4.2. Effect of timber harvest intensity 4.1. Total P and its availability Timber harvest intensity drastically influenced the P harvest output and consequently the amount of P maintained on the soil as forest residues – slash and litter (Rocha et al., 2016a; Menegale et al., 2016; Hernandez et al., 2009). Differences in harvest intensity also affect the soil pH, organic matter and microbial activity (Rocha et al., 2018; Menegale et al., 2016; Mendham et al., 2014; Achat et al., 2015; Nambiar and Harwood, 2014). All of the aforementioned factors are highly related to P cycling and consequently to P availability – however few effects of timber harvest intensity have been observed when soil P is extracted by traditional methods (e.g. AER, Mehlich and Bray) (Achat et al., 2015; Nambiar and Harwood, 2014; Menegale et al., 2016). From 2004 to 2012 no difference was found between the labile P fraction under ACR + F, ReR + F and ReM-F treatments, while there was a reduction in the concentration in the ReM + F treatment. During this time a reduction was also found in the moderately labile P fractions under ReM + F and ReR + F treatments. The decrease in labile and moderately labile P fractions under ReM + F, even being the treatment with smaller harvest P outputs in 2004 can be attributed to the highest tree growth and consequently highest P accumulation in the biomass in

The total soil P concentration was approximately 180 mg kg−1 at 0–10 cm deep, of which 30% was in organic forms and 70% in inorganic forms (Table 3). Foltran (2017) found similar concentrations of P and organic/inorganic proportions in an adjacent site with the same plant species and soil characteristics as the one utilized in this study. However, the total P observed here was smaller than most of the studies reported in the literature in tropical and subtropical regions (Rodrigues et al., 2016; Costa et al., 2016; Negassa and Leinweber, 2009). Smaller total P concentrations have been found only in sandy soils (Chen et al., 2015; Neufeldt et al., 2000). The low total P in our study is probably a consequence of many factors, including soil parent materials poor in P, high weathering levels (Chen et al., 2015), low clay contents (Costa et al., 2016), low P inputs in previous years, and relatively high P outputs by harvest (Menegale et al., 2016). In spite of low total P, the contribution of organic forms to the total P (30%) was similar to another 11 sites under Eucalyptus plantation even with clay content ranging from 7 to 67 % (Foltran, 2017; Costa et al., 2016). This contribution was higher than under native vegetation 300

Forest Ecology and Management 437 (2019) 295–303

J.H.T. Rocha et al.

Table 4 Biomass and P accumulated in forest residues (FR) maintained on the soil after harvest; wood volume; root density; and P accumulated in the biomass (stem, canopy and root) and deposited through litterfall assessed in the first (R1) and second (R2) experimental rotation. Treatments

FR maintained on the soil in 2004 (Mg ha−1)a P accumulated in the FR in 2004 (kg ha−1)b FR maintained on the soil in 2012 (Mg ha−1)a P accumulated in the FR in 2012 (kg ha−1)a Wood volume at 8 y in R1 (m3 ha−1)b P accumulated in the biomass at 8 y in R1 (kg ha−1)b Wood volume at 3.5 y in R2 (m3 ha−1)b P accumulated in the biomass at 3.5 y in R2 (kg ha−1)b Root density at 3.5 y of R2 in the 0–30 cm layerc Litterfall from 0.5 to 3.5 y in R2 (Mg ha−1)b P deposited from 0.5 to 3.5 y in R2 (kg ha−1)b 1 2 3 4

ReM + F

ACR + F

ReR + F

ACR-P

ReM-F

51 (3)4 27 (2) 49 (2) 20 (1) 430 (5) 88 (4) 199 (2) 25 (4) 9 (1) 13 (2) 3.2 (0.2)

24 (1) 12 (1) 22 (1) 11 (1) 403 (3) 76 (6) 176 (1) 21 (1) 7 (1) 13 (1) 3.3 (0.2)

0 0 0 0 396 (4) 78 (6) 171 (3) 18 (2) 6 (1) 13 (4) 3.3 (0.3)

24 (1) 12 (1) 18 (1) 5 (1) 369 (3) 70 (7) 155 (4) 18 (1) – 11 (5) 2.2 (0.5)

51 (3) 27 (2) 42 (2) 22 (3) 278 (3) 51 (6) 135 (3) 15 (2) – 12 (4) 3.0 (0.1)

Adapted from Menegale et al. (2016). Unpublished data. Adapted from Franci et al. (2014) – number of root intercepts each 25 cm2 assessed using the methodology proposed by Laclau et al. (2013). Standard deviation.

ReM + F treatment, respectively. In the ReR + F, these contributions were 7, 23 and 70%, respectively. The same behavior also was found by Rodrigues et al. (2016) in crop fields under no tillage. An increase was also found in the inorganic P fractions to the detriment of organic when increasing the timber harvest intensity. Rocha et al. (2018) assessed the soil organic carbon (SOC) in this site by wet oxidation during the same ages. There is a high positive correlation between the total Po with the SOC (r = 0.619; p = 0.021). This was also found by Costa et al. (2016) and Stutter et al. (2015) in a wider range of SOC soils. Thus, these findings highlight the importance of the maintenance of forest residues on the soil. This practice, which increase the SOC, have two main effects on the availability of P: (i) the increase of the P organic pool; (ii) the decrease of the non-labile P forms. On the other hand, the removal of forest residues reduce the fixation of P in non-labile P forms, which can reduce the P fertilizer efficiency, demanding higher rates of P fertilizer application in order to achieve similar levels of productivity.

2012 (Table 4). In the same experiment, Franci et al. (2014) also found an improvement of 30% (p < 0.01) in the fine root density in the ReM + F treatment when compared with the ReR + F in the 0–30 cm layer, but no difference among treatments in deeper layers (Table 4). This high root density may also have contributed to a higher P uptake from the top layer in the ReM + F treatment, consequently depleting labile P but also non-labile P forms (Fig. 1). Moreover, the inorganic non-labile P fraction increased 10% from the ReM + F to ACR + F treatment and 10% more from ACR + F to ReR + F treatment in 2012 (Fig. 1). This constant increase in the nonlabile P fraction when more timber harvest residues were removed may be associated with the reduction of soil organic carbon (SOC). Rocha et al. (2018) working in the same experimental area, found a reduction of 25% in the SOC concentration in 2012 compared to 2004, which was mainly in the most labile SOC fraction. Organic acids produced by SOM can compete with phosphate for adsorption sites on soil oxides, reducing P fixation (Brady and Weil, 2013). The largest amount of moderately labile P (mainly in organic form) was found in the ReM-F treatment. This can be attributed to the large amount of forest residue maintained on the soil in 2004 and to the low P uptake due to low Eucalyptus growth in 2012 (Table 4). Litterfall rates in 2016 were high, and consequently the rate of P cycling was high. Because of this, small differences among treatments were found in the moderately labile, non-labile and total P fractions (Table 4; Figs. 1 and 2). We also observed a decrease in the labile P fraction related to higher timber harvest intensity (Fig. 1). This indicates that the forest residue and the litter layer, despite of the high C:P ratio, are important sources of labile P for the system. It is especially important at the age (around 3.5 years old) in which the litter layer is composed mainly of leaves (Rocha et al., 2016a; Laclau et al., 2010). In the first 300 days after harvest for this site, Rocha et al. (2016a) reported a release of around 14 kg ha−1 of P from the forest residues to the ReM + F and ReM-F treatments. In the same experimental site, Menegale et al. (2016) found a negative P balance (inputs smaller than outputs) for both treatments, being −16 kg ha−1 in the ReM + F, −23 kg ha−1 in the ACR + F and −35 kg ha−1 in the ReR + F treatment. Even with the negative P balance pointed out by Menegale et al. (2016) for all treatments evaluated here, there was no decrease in total P in the surface 0–20 cm soil layer during the two forest rotations (from 2004 to 2016). However, we found a trend that the labile and moderately labile P fractions decrease and the non-labile P fraction increases with the removal of all forest residues (ReR + F). In 2016, the labile, the moderately labile and the non-labile P fractions contributed 10%, 24%, and 66% to total P in the

4.3. Effect of P fertilizer The effect of the timber harvest intensity in the soil P fractions was larger than the effect of P fertilizer application. However, the P fertilizer was localized to small pits next to the seedlings during application, and during the soil sampling these locations were avoided. We expected an effect of P fertilizer on P fractions after trees take up the fertilizer and cycle the nutrient. A wide literature review done by Negassa and Leinweber (2009) has reported that small amounts and infrequent P fertilizer applications hardly ever change the soil P fractions by the Hedley fractionation method. The results of the ACR + F and ACR-P treatments provide a unique contrast to isolate the effect of P fertilization on total P and P fractions. In the period between 2004 and 2012, no difference was found in the total P when P fertilizer was applied (ACR + F) and a reduction of 11% (p < 0.05) was seen when no P fertilizer was applied (ACR-P). This decrease was found only in the 0–10 cm layer and mainly on the moderately labile (60%) and labile (25%) P fractions. Also, the majority of this reduction (67%) was in the organic fraction, indicating that the organic labile and mainly moderately labile fractions are the main sources of P for trees when no P fertilizer is applied (Figs. 1 and 2). Foltran (2017), working with the same species and soil, also highlighted the importance of the moderately labile organic P fraction in plant P supply in initial growth stages (first 12 months) when no P was applied. Also, Negassa and Leinweber (2009) reported that in tropical soils the moderately labile P fractions are the main sources of P to plants (crops and forest) when low or no P fertilizer is applied. When high rates of P 301

Forest Ecology and Management 437 (2019) 295–303

J.H.T. Rocha et al.

found similar results in treatments both of whole-tree and of stem-only harvest. They also observed an increase of enzymatic activity in response to the increase in the amount of forest residue on the soil. This can lead to a consequent processing and recovery of key nutrients (Sinsabaugh et al., 2008; Zhou et al., 2012). Dalal (1982) reported that the addition of organic substances to the soil serves as a C source that enhances microbial biomass and phosphatase activity. Klose and Tabatabai (2002) also confirmed the hypothesis that phosphatase enzymes are originated predominantly from microbial biomass. An increase of 33% was found in the acid phosphatase activity in the no P fertilizer treatment (ACR-P) relative to ACR + F (Fig. 3). Spohn and Kuzyakov (2013) found that P fertilizer had little effect when applied to acidic phosphatase. Other studies (Foltran, 2017; Huang et al., 2015) found an increase in this enzyme’s activity under conditions with low P availability. Acid phosphatase exudation seems to be an important strategy of Eucalyptus species to improve the P scavenger capacity, especially under conditions in which a high level of organic P is present.

are applied, inorganic forms of P become the main source. In a greenhouse experiment, O’Hara et al. (2006) found that the light fraction of soil organic matter is an import source of P to Eucalyptus seedlings. Despite the contribution of organic forms, these sources were not enough to maintain tree growth rates, evidenced by the 8% reduction in wood volume at the end of R1 (2012) in the ACR-P treatment compared to the ACR + F treatment (Table 4). This highlights the importance of the P fertilizer in Eucalyptus plantations in soils with low available P pools. Menegale et al. (2016) found a negative P balance for both treatments, being −23 kg ha−1 in the ACR + F treatment and −61 kg ha−1 in the ACR-P treatment. Despite a negative P balance, there was no significant reduction in the soils total P after the ACR + F treatment. This lack of reduced total P may be attributed to P supply from soil below 20 cm depth. It may also have been related to other inputs – such as atmospheric deposition – as outlined in the study made by Menegale et al. (2016). Laclau et al. (2010) found wet P deposition lower than 1 kg ha−1 y−1 in the region of our study, although dry P deposition was not assessed. Lequy et al. (2014) found that 80% of the P deposition came from dry particulate deposition. The origin of the P which made up for the negative P balance warrants further study. From 2012 to 2016, total P remained constant within the ACR + F treatment, while the total P within the ACR-P treatment increased, reaching the same concentration found in 2004. This increase in the total P when no P fertilizer was applied can be associated with P incorporation from the P accumulated in the litter layer (around 9 kg ha−1) associated with a lower P accumulation in the biomass. In the same area, Rocha et al. (2016a) found releases of 70% of P accumulated in the litter layer 300 days after harvest of the first rotation. The lower growth in the ACR-P (13% smaller than the ACR + F in total biomass) and consequently low P accumulation (29% less than the ACR + F; Table 4) can also explain the smaller difference in the soil P concentration between the ACR + F and ACR-P found in 2016. With no difference in the total P, a reduction of 15% was still found within the labile P fraction under no P fertilizer application. No difference was found in the moderately labile fraction while an increase was discovered within the non-labile P fraction. Even with reduced growth, high productivity was found when no P fertilizer was applied. In the first rotation (2004–2012), the wood volume with bark in ACR-P was 369 m3 ha−1 (mean annual increment – MAI of 46 m3 ha−1 y−1) at 8 years old, and in the second rotation, it was 144 m3 ha−1 (MAI of 42 m3 ha−1 y−1) at 3.5 years old (Table 4). This high productivity even in a soil with low P availability to which no fertilizer was applied indicates that Eucalyptus are highly efficient P scavengers. The main process which improves the efficiency of P scavenging are: (i) excretion of phosphatase to accelerate the Po mineralization (Richardson et al., 2009; Fox et al., 2011); (ii) excretion of low molecular weight organic acids (LMWOA) such as malate, aspartate and citric acid (Plassard and Dell, 2010); and (iii) mycorrhizal association (Plassard and Dell, 2010; Bakker et al., 2009). The widely mutualistic association between mycorrhizal fungi and trees in forest ecosystems improves the extent of soil exploration and consequently the rates of water and nutrients uptake by trees (Osman, 2013).

5. Conclusions Timber harvest intensity and P fertilizer application were not substantial enough to influence the soil total P concentration over 12 years of Eucalyptus cultivation. However, there is an increase in non-labile and inorganic P fractions and a reduction of labile and organic P fractions when increasing the timber harvest intensity. Forest management practices that increase SOM play an important role in increasing soil P availability, particularly by reducing the non-labile P fractions. The high productivity even in a soil with low P pools and no P fertilizer application indicate the high P scavenger efficiency of Eucalyptus plantations. Acid phosphatase excretion seem to be an important strategy of Eucalyptus species to improve P scavenger capacity. Acid phosphatase was especially important when more organic matter was maintained on site, leading to large proportions of organic P. Acknowledgements The authors would like to thank the FAPESP/Brazil (Process: 2014/ 15876-1 and 2018/08338-4) and the University of Washington/USA for the financial support. We give thanks to Silviculture and Management Thematic Program (PTSM-IPEF/Brazil) for the financial support and for field collections. Funding This work was supported by the FAPESP/Brazil (Process: 2014/ 15876-1 and 2018/08338-4), the University of Washington/USA and the Forestry Science and Research Institute (PTSM-IPEF/Brazil). References Achat, D.L., Deleuze, C., Landmann, G., Pousse, N., Ranger, J., Augusto, L., 2015. Quantifying consequences of removing harvesting residues on forest soils and tree growth – a meta-analysis. For. Ecol. Manage. 348, 124–141. Acosta-Martinez, V., Cruz, L., Sotomayor-Ramirez, D., Perez-Alegria, L., 2007. Enzyme activities as affected by soil properties and land use in a tropical watershed. Appl. Soil Ecol. 35, 35–45. Adamczyk, B., Adamczyk, S., Kukkola, M., Tamminen, P., Smolander, A., 2015. Logging residue harvest may decrease enzymatic activity of boreal forest soils. Soil Biol. Biochem. 82, 74–80. Alvares, C.A., Stape, J.L., Sentelhas, P.C., Goncalves, J.L.D., Sparovek, G., 2013. Koppen's climate classification map for Brazil. Meteorol. Zeitschrift 22, 711–728. Araujo, M.S.B., Schaefer, C.E.R., Sampaio, E., 2004. Soil phosphorus fractions from toposequences of semi-arid Latosols and Luvisols in northeastern Brazil. Geoderma 119, 309–321. Bakker, M.R., Jolicoeur, E., Trichet, P., Augusto, L., Plassard, C., Guinberteau, J., Loustau, D., 2009. Adaptation of fine roots to annual fertilization and irrigation in a 13-yearold Pinus pinaster stand. Tree Physiol. 29, 229–238. Bazani, J.H., 2014. Eficiência de fertilizantes fosfatados solúveis e pouco solúveis, com ou sem complexação com substâncias húmicas, em plantações de eucalipto. In: Ciências

4.4. Acid phosphatase activity Soil enzymes (intracellular and extracellular) are the mediators and catalysts of biochemical processes important in soil functioning, including nutrient mineralization and cycling, decomposition and formation of SOM, and decomposition of chemical substances (Huang et al., 2015). Soils which are acidic and less fertile – including Oxisols and Ultisols – generally have higher enzyme activities than less weathered tropical soils, such as Inceptisols. This may be due to their higher OM content and finer texture (Acosta-Martinez et al., 2007). This study found an increase in APA in the ReM treatments, while a decrease was found in the enzyme activity in the treatment in which harvest residues were removed (ReR + F). Adamczyk et al. (2015) 302

Forest Ecology and Management 437 (2019) 295–303

J.H.T. Rocha et al. Florestais. USP, Piracicaba – SP, pp. 129. Brady, N.C., Weil, R.R., 2013. The Nature and Properties of the Soil. Bookmam, USA. Chen, C.R., Hou, E.Q., Condron, L.M., Bacon, G., Esfandbod, M., Olley, J., Turner, B.L., 2015. Soil phosphorus fractionation and nutrient dynamics along the Cooloola coastal dune chronosequence, southern Queensland, Australia. Geoderma 257, 4–13. Condit, R., Engelbrecht, B.M.J., Pino, D., Perez, R., Turner, B.L., 2013. Species distributions in response to individual soil nutrients and seasonal drought across a community of tropical trees. Proc. Nat. Acad. Sci. U. S. A. 110, 5064–5068. Condron, L.M., Goh, K.M., Newman, R.H., 1985. Nature and distribution of soil-phosphorus as revealed by a sequential extraction method followed by P-31 nuclear magnetic-resonance analysis. J. Soil Sci. 36, 199–207. Costa, M.G., Gama-Rodrigues, A.C., Goncalves, J.L.D., Gama-Rodrigues, E.F., Sales, M.V.D., Aleixo, S., 2016. Labile and non-labile fractions of phosphorus and its transformations in soil under Eucalyptus plantations, Brazil. Forests 7. Cross, A.F., Schlesinger, W.H., 1995. A literature-review and evaluation of the hedley fractionation – applications to the biogeochemical cycle of soil-phosphorus in natural ecosystems. Geoderma 64, 197–214. Dalal, R.C., 1982. Effect of plant-growth and addition of plant residues on the phosphatase-activity in soil. Plant Soil 66, 265–269. Dick, W.A., Tabatabai, M.A., 1977. Determination of orthophosphate in aqueous-solutions containing labile organic and inorganic phosphorus-compounds. J. Environ. Qual. 6, 82–85. Foltran, E.C., 2017. Dinâmica do P no sistema solo-planta em função da solubilidade de fertilizantes fosfatados, em plantios de Eucalyptus grandis In, Recursos Florestais. Universidade de São Paulo (ESALQ-USP), Piracicaba – Brasil, pp. 77. Fox, T., Miller, B.W., Rubilar, R., Stape, J.L., Albaug, T., 2011. Phosphorus nutrition of forest plantations: the role of inorganic and organic phosphorus. In: Bünemann, E.K., Oberson, A., Frossard, E. (Eds.), Phosphorus in Action: Biological Processes in Soil Phosphorus Cycling. Springer, Berlin, Germany, pp. 317–331. Franci, A.F., Rocha, J.H.T., Brandani, C.B., Gonçalves, J.L.M., 2014. Densidade de raízes finas sob diferentes métodos de manejo de resíduos florestais em um plantio de Eucalyptus grandis. In: Fertbio. SBCS, Araxá – Brasil, pp. 4. Gonçalves, J.L.D., Alvares, C.A., Higa, A.R., Silva, L.D., Alfenas, A.C., Stahl, J., Ferraz, S.F.D., Lima, W.D.P., Brancalion, P.H.S., Hubner, A., Bouillet, J.P.D., Laclau, J.P., Nouvellon, Y., Epron, D., 2013. Integrating genetic and silvicultural strategies to minimize abiotic and biotic constraints in Brazilian eucalypt plantations. For. Ecol. Manage. 301, 6–27. Gonçalves, J.L.D.M., Rocha, J.H.T., Bazani, J.H., Hakamada, R.E., 2015. Nutrição e adubação da cultura do eucalipto manejada no sistema de talhadia. In: Arthur Junior, J.C., Hakamada, R.E., Bazani, J.H., Rocha, J.H.T., Melo, E.A.S.C., Gonçalves, J.L.D.M. (Eds.), 48ª Reunião Técnico-Científica do Programa Cooperativo sobre Silvicultura e Manejo “Manejo da brotação de eucalipto para produção de madeira. IPEF, Brazil, pp. 82. Hedley, M.J., Stewart, J.W.B., Chauhan, B.S., 1982. Changes in inorganic and organic soil-phosphorus fractions induced by cultivation practices and by laboratory incubations. Soil Sci. Soc. Am. J. 46, 970–976. Hernandez, J., del Pino, A., Salvo, L., Arrarte, G., 2009. Nutrient export and harvest residue decomposition patterns of a Eucalyptus dunnii Maiden plantation in temperate climate of Uruguay. For. Ecol. Manage. 258, 92–99. Hu, B., Yang, B., Pang, X.Y., Bao, W.K., Tian, G.L., 2016. Responses of soil phosphorus fractions to gap size in a reforested spruce forest. Geoderma 279, 61–69. Huang, L.D., Zhang, Y.H., Shi, Y.M., Liu, Y.B., Wang, L., Yan, N., 2015. Comparison of phosphorus fractions and phosphatase activities in coastal wetland soils along vegetation zones of Yancheng National Nature Reserve, China. Estuar. Coast. Shelf Sci. 157, 93–98. Klose, S., Tabatabai, M.A., 2002. Response of phosphomonoesterases in soils to chloroform fumigation. J. Plant Nutr. Soil Sci.-Zeitschrift Fur Pflanzenernahrung Und Bodenkunde 165, 429–434. Laclau, J.-P., Ranger, J., de Moraes Goncalves, J.L., Maquere, V., Krusche, A.V., M'Bou, A.T., Nouvellon, Y., Saint-Andre, L., Bouillet, J.-P., Piccolo, M.d.C., Deleporte, P., 2010. Biogeochemical cycles of nutrients in tropical Eucalyptus plantations Main features shown by intensive monitoring in Congo and Brazil. For. Ecol. Manage. 259, 1771–1785. Laclau, J.-P., Da Silva, E.A., Rodrigues Lambais, G., Bernoux, M., Le Maire, G., Stape, J.L., Bouillet, J.-P., Gonçalves, J.L.D.M., Jourdan, C., Nouvellon, Y., Laclau, J.-P., da Silva, E.A., le Maire, G., Bouillet, J.-P., Gonçalves, J.L.D.M., 2013. Dynamics of soil exploration by fine roots down to a depth of 10 m throughout the entire rotation in Eucalyptus grandis plantations. Front. Plant Sci. 4, 243. Lequy, E., Calvaruso, C., Conil, S., Turpault, M.P., 2014. Atmospheric particulate deposition in temperate deciduous forest ecosystems: Interactions with the canopy and nutrient inputs in two beech stands of Northeastern France. Sci. Total Environ. 487, 206–215. Melo, E., Goncalves, J.L.D., Rocha, J.H.T., Hakamada, R.E., Bazani, J.H., Wenzel, A.V.A.,

Arthur, J.C., Borges, J.S., Malheiros, R., de Lemos, C.C.Z., Ferreira, E.V.D., Ferraz, A.D., 2016. Responses of clonal eucalypt plantations to N, P and K fertilizer application in different edaphoclimatic conditions. Forests 7. Mendham, D.S., Ogden, G.N., Short, T., O'Connell, T.M., Grove, T.S., Rance, S.J., 2014. Repeated harvest residue removal reduces E. globulus productivity in the 3rd rotation in south-western Australia. For. Ecol. Manage. 329, 279–286. Menegale, M.L.C., Rocha, J.H.T., Harrison, R., Goncalves, J.L.D.M., Almeida, R.F., Piccolo, M.D.C., Hubner, A.Y., Arthur Junior, J.C., Ferraz, A.D.V., James, J.N., Michels en-Correa, S., 2016. Effect of Timber Harvest Intensities and Fertilizer Application on Stocks of Soil C. N, P, and S, Forests 7, 319–333. Murphy, J., Riley, J.P., 1962. A modified single solution method for the determination od phosphate in natural waters. Anal. Chim., Acta 27, 31–36. Nambiar, E.K.S., Harwood, C.E., 2014. Productivity of acacia and eucalypt plantations in Southeast Asia. 1. Bio-physical determinants of production: opportunities and challenges. Int. Forest. Rev. 16, 225–248. Negassa, W., Leinweber, P., 2009. How does the Hedley sequential phosphorus fractionation reflect impacts of land use and management on soil phosphorus: a review. J. Plant Nutr. Soil Sci.-Zeitschrift Fur Pflanzenernahrung Und Bodenkunde 172, 305–325. Neufeldt, H., da Silva, J.E., Ayarza, M.A., Zech, W., 2000. Land-use effects on phosphorus fractions in Cerrado oxisols. Biol. Fertil. Soils 31, 30–37. Novais, R.F., Smyth, T.J., Nunes, F.N., 2007. Fósforo. In: Novais, R.F., Alvarez, V.H., Barros, N.F., Fontes, R.L.F., Cantarutti, R.B., Neves, J.C.L. (Eds.), Fertilidade do solo. SBCS, Viçosa, Brasil, pp. 276–374. O'Hara, C.P., Bauhus, J., Smethurst, P.J., 2006. Role of light fraction soil organic matter in the phosphorus nutrition of Eucalyptus globulus seedlings. Plant Soil 280, 127–134. Osman, K.T., 2013. Soils: Principles, Properties and Management. Springer, Netherlands. Plassard, C., Dell, B., 2010. Phosphorus nutrition of mycorrhizal trees. Tree Physiol. 30, 1129–1139. Richardson, A.E., Barea, J.M., McNeill, A.M., Prigent-Combaret, C., 2009. Acquisition of phosphorus and nitrogen in the rhizosphere and plant growth promotion by microorganisms. Plant Soil 321, 305–339. Rocha, J.H.T., Marques, E.R.G., Goncalves, J.L.D., Hubner, A., Brandani, C.B., Ferraz, A.D., Moreira, R.M., 2016a. Decomposition rates of forest residues and soil fertility after clear-cutting of Eucalyptus grandis stands in response to site management and fertilizer application. Soil Use Manage. 32, 289–302. Rocha, J.H.T., Gonçalves, J.L.D.M., Gava, J.L., Godinho, T.D.O., Melo, E.A.S.C., Bazani, J.H., Hubner, A., Arthur Junior, J.C., Wichert, M.P., 2016b. Forest residue maintenance increased the wood productivity of a Eucalyptus plantation over two short rotations. Forest Ecol. Manage. 379, 1–10. Rocha, J.H.T., Gonçalves, J.L.D.M., Brandani, C.B., Ferraz, A.V., Franci, A.F., Marques, E.R.G., Arthur Junior, J.C., Hubner, A., 2018. Forest residue removal decreases soil quality and affects wood productivity even with high rates of fertilizer application. Forest Ecol. Manage. 430 (188), 195. Rodrigues, M., Pavinato, P.S., Withers, P.J.A., Teles, A.P.B., Herrera, W.F.B., 2016. Legacy phosphorus and no tillage agriculture in tropical oxisols of the Brazilian savanna. Sci. Total Environ. 542, 1050–1061. Santana, R.C., de Barros, N.F., Novais, R.F., Leite, H.G., Comerford, N.B., 2008. Nutrient allocation in eucalypt plantations in brazil. Revista Brasileira De Ciencia Do Solo 32, 2723–2733. Sattari, S.Z., Bouwman, A.F., Giller, K.E., Van Ittersum, M.K., 2012. Residual soil phosphorus as the missing piece in the global phosphorus crisis puzzle. Proc. Nat. Acad. Sci. U. S. A. 109, 6348–6353. Sinsabaugh, R.L., Lauber, C.L., Weintraub, M.N., Ahmed, B., Allison, S.D., Crenshaw, C., Contosta, A.R., Cusack, D., Frey, S., Gallo, M.E., Gartner, T.B., Hobbie, S.E., Holland, K., Keeler, B.L., Powers, J.S., Stursova, M., Takacs-Vesbach, C., Waldrop, M.P., Wallenstein, M.D., Zak, D.R., Zeglin, L.H., 2008. Stoichiometry of soil enzyme activity at global scale. Ecol. Lett. 11, 1252–1264. Spohn, M., Kuzyakov, Y., 2013. Distribution of microbial- and root-derived phosphatase activities in the rhizosphere depending on P availability and C allocation – coupling soil zymography with C-14 imaging. Soil Biol. Biochem. 67, 106–113. Stutter, M.I., Shand, C.A., George, T.S., Blackwell, M.S.A., Dixon, L., Bol, R., MacKay, R.L., Richardson, A.E., Condron, L.M., Haygarth, P.M., 2015. Land use and soil factors affecting accumulation of phosphorus species in temperate soils. Geoderma 257, 29–39. Tabatabai, M., Bremner, J.M., 1969. Use of p-nitrophenyl phosphate for assay of soil phosphatase activity. Soil Biol. Biochem. 1, 301–307. Turner, B.L., Engelbrecht, B.M.J., 2011. Soil organic phosphorus in lowland tropical rain forests. Biogeochemistry 103, 297–315. Zhou, X.B., Zhang, Y.M., Downing, A., 2012. Non-linear response of microbial activity across a gradient of nitrogen addition to a soil from the Gurbantunggut Desert, northwestern China. Soil Biol. Biochem. 47, 67–77.

303