Litter inputs and phosphatase activity control the temporal variability of organic phosphorus in a tropical forest soil in the Central Amazon

Abstract Purpose. The tropical phosphorus-cycle and its impacts on phosphorus (P) availability are a major uncertainty in projections of forest productivity. In highly weathered soils with low P concentrations, plant and microbial communities depend on biological and physical processes to acquire P. We explored the seasonality and relative importance of drivers controlling the fluctuation of common P pools via processes such as litter production and decomposition, and soil phosphatase activity. Methods. We analyzed variation of standard tropical soil phosphorus pools over one year. In addition, we measured litterfall, its decomposition rates and soil extracellular phosphatase enzyme activity and tested their relation to the fluctuations in P-fractions. Results. Our results show clear patterns of seasonal variability of soil P fractions during the year. We found that modeled P released during litter decomposition is positively related to change in organic P fractions, while net change in organic P fractions was negatively related to phosphatase activities in the top 5 cm. Conclusion. We conclude that input of organic P forms by litter decomposition and organically produced phosphatases are the two main factors controlling seasonal soil P fluctuation, and therefore the P economy in P impoverished soils. Organic soil P follows a clear seasonal pattern, indicating tight cycling of the nutrient, while reinforcing the importance of studying soil P as an integrated dynamic system in a tropical forest context.

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Litter inputs and phosphatase activity affect the temporal variability of organic phosphorus in a tropical forest soil in the Central Amazon

Plant and Soil ◽

10.1007/s11104-021-05146-x ◽

2021 ◽

Author(s):

Karst J. Schaap ◽

Lucia Fuchslueger ◽

Marcel R. Hoosbeek ◽

Florian Hofhansl ◽

Nathielly Pires Martins ◽

...

Keyword(s):

Tropical Forest ◽

Phosphatase Activity ◽

Litter Decomposition ◽

Soil Phosphorus ◽

Litter Production ◽

P Availability ◽

Organic P ◽

Phosphorus Cycle ◽

P Fractions ◽

Soil P

Abstract Purpose The tropical phosphorus cycle and its relation to soil phosphorus (P) availability are a major uncertainty in projections of forest productivity. In highly weathered soils with low P concentrations, plant and microbial communities depend on abiotic and biotic processes to acquire P. We explored the seasonality and relative importance of drivers controlling the fluctuation of common P pools via processes such as litter production and decomposition, and soil phosphatase activity. Methods We analyzed intra-annual variation of tropical soil phosphorus pools using a modified Hedley sequential fractionation scheme. In addition, we measured litterfall, the mobilization of P from litter and soil extracellular phosphatase enzyme activity and tested their relation to fluctuations in P- fractions. Results Our results showed clear patterns of seasonal variability of soil P fractions during the year. We found that modeled P released during litter decomposition was positively related to change in organic P fractions, while net change in organic P fractions was negatively related to phosphatase activities in the top 5 cm. Conclusion We conclude that input of P by litter decomposition and potential soil extracellular phosphatase activity are the two main factors related to seasonal soil P fluctuations, and therefore the P economy in P impoverished soils. Organic soil P followed a clear seasonal pattern, indicating tight cycling of the nutrient, while reinforcing the importance of studying soil P as an integrated dynamic system in a tropical forest context.

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Dynamics of phosphorus fractions in soils treated with dairy manure

Soil Research ◽

10.1071/sr18325 ◽

2020 ◽

Vol 58 (3) ◽

pp. 289

Author(s):

L. B. Braos ◽

A. C. T. Bettiol ◽

L. G. Di Santo ◽

M. E. Ferreira ◽

M. C. P. Cruz

Keyword(s):

P Uptake ◽

Dairy Manure ◽

P Availability ◽

Organic P ◽

Triple Superphosphate ◽

P Fractions ◽

Inorganic P ◽

Soil P ◽

Plant P Uptake ◽

Inorganic P Fractions

The evaluation of phosphorus (P) transformations in soil after application of manure or mineral P can improve soil management and optimise P use by plants. The objectives of the present study were to assess organic and inorganic P forms in two soils treated with dairy manure and triple superphosphate and to establish relationships between soil P fraction levels and P availability. Soil organic and inorganic P fractions were quantified using a pot experiment with two soils, a typical Hapludox and an arenic Hapludult, with three types of fertiliser treatments applied (no fertiliser application, application of dairy manure, and application of triple superphosphate, by adding 100 mg P dm–3 in the form of fertiliser in the two latter treatments) and four incubation times (15, 45, 90, and 180 days). Inorganic P was fractionated into aluminium-bound, iron-bound, occluded, and calcium-bound P. Organic P was extracted sequentially using sodium bicarbonate, hydrochloric acid, microbial biomass, sodium hydroxide, and residual organic P. After incubation, maize plants were cropped to quantify dry matter yield and absorbed P. Application of dairy manure resulted in a significant increase in most of the organic P fractions, and application of triple superphosphate led to a significant increase in inorganic P fractions. Both fertilisers raised labile organic P fractions in the two soils. The major sinks of P in Hapludox were occluded and fulvic acid-associated P. In contrast, the major sink of P in Hapludult was iron-bound P. The available P levels were stable after application of dairy manure, and decreased with time when fertilised with triple superphosphate. In the Hapludox, the organic P fractions had a significant positive correlation with P uptake by plants. The results suggest that organic P mineralisation plays a more significant role in plant P uptake in the Hapludox soil and inorganic P forms are the main contributors to plant P uptake in the Hapludult soil.

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Improved Plant Diversity as a Strategy to Increase Available Soil Phosphorus

10.24047/bc103143 ◽

2019 ◽

Vol 103 (1) ◽

pp. 43-45 ◽

Cited By ~ 1

Author(s):

Carlos Crusciol ◽

João Rigon ◽

Juliano Calonego ◽

Rogério Soratto

Keyword(s):

Crop Yields ◽

Soil Phosphorus ◽

Cropping System ◽

P Availability ◽

P Fractions ◽

Crop Species ◽

Soil P ◽

Residue Decomposition ◽

Available Soil Phosphorus ◽

Crop Residue Decomposition

Some crop species could be used inside a cropping system as part of a strategy to increase soil P availability due to their capacity to recycle P and shift the equilibrium between soil P fractions to benefit the main crop. The release of P by crop residue decomposition, and mobilization and uptake of otherwise recalcitrant P are important mechanisms capable of increasing P availability and crop yields.

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Decreases in soil P availability are associated with soil organic P declines following forest conversion in subtropical China

CATENA ◽

10.1016/j.catena.2021.105459 ◽

2021 ◽

Vol 205 ◽

pp. 105459

Author(s):

Liuming Yang ◽

Zhijie Yang ◽

Xiaojian Zhong ◽

Chao Xu ◽

Yanyu Lin ◽

...

Keyword(s):

Forest Conversion ◽

P Availability ◽

Organic P ◽

Subtropical China ◽

Soil P ◽

Soil P Availability

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Seasonal Variations and Thinning Effects on Soil Phosphorus Fractions in Larix principis-rupprechtii Mayr. Plantations

Forests ◽

10.3390/f10020172 ◽

2019 ◽

Vol 10 (2) ◽

pp. 172 ◽

Cited By ~ 2

Author(s):

Huixia Tian ◽

Xiaoqin Cheng ◽

Hairong Han ◽

Hongyuan Jing ◽

Xujun Liu ◽

...

Keyword(s):

Seasonal Variations ◽

Management Practice ◽

Management Strategies ◽

Chemical Properties ◽

P Availability ◽

P Fractions ◽

Soil P ◽

Thinning Intensity ◽

Soil P Fractions ◽

P Bioavailability

Thinning is a common management practice in forest ecosystems. However, understanding whether thinning treatment will change the availability of phosphorus (P) in soils, and the effect of thinning on the seasonal dynamics of soil P fractions, are still limited. The objective of the present study was to assess seasonal variations in soil P fractions under different forest thinning management strategies in a Larch (Larix spp.) plantation in northern China. To accomplish this, we examined soil P fractions, soil physical–chemical properties, and litter biomass under control (CK), light (LT), moderate (MT) and high thinning (HT) treatments. Data were collected during the growing season of 2017. We found that most P fractions varied seasonally at different soil depths, with the highest values occurring in the summer and autumn. When compared to CK, MT enhanced the inorganic P (Pi) concentration extracted by resin strip (R-Pi). Labile organic P (Labile Po), moderately labile P and total P (TP) also increased in both MT and HT treatments irrespective of season. In contrast, less-labile Pi and Po fractions were lower in LT than in CK, especially when examining deeper soil layers. Our results suggest that LT leads to a strong ability to utilize Po and less-labile Pi. Moreover, the effect of thinning did not tend to increase with thinning intensity, P availability was maximized at the MT. Ultimately, we show that MT can improve soil P bioavailability and is recommended in Larix principis-rupprechtii Mayr. plantations of North China. Our results emphasize that the effect of thinning management on soil microenvironment is an important basis for evaluating soil nutrients such as soil P bioavailability.

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Effects of air-drying and freezing on phosphorus fractions in soils with different organic matter contents

Plant Soil and Environment ◽

10.17221/428/2010-pse ◽

2011 ◽

Vol 57 (No. 5) ◽

pp. 228-234 ◽

Cited By ~ 18

Author(s):

G. Xu ◽

J.N. Sun ◽

R.F. Xu ◽

Y.C. Lv ◽

H.B. Shao ◽

...

Keyword(s):

Organic Matter ◽

Surface Waters ◽

Organic Matter Content ◽

Phosphorus Fractions ◽

Climate Change Scenarios ◽

P Availability ◽

Organic P ◽

Air Drying ◽

Soil P ◽

Labile P

Little is known about the effects of air-drying and freezing on the transformation of phosphorus (P) fractions in soils. It is important that the way in which soils respond to such perturbations is better understood as there are implications for both P availability and loss to surface waters from soils. In this study, the effects of air-drying and freezing were investigated using two soils, one being a forest soil (FS) high in organic matter and the other being a sterile soil (SS) low in organic matter. Soil P was fractionated using a modified Hedley fractionation method to examine the changes of phosphorus fractions induced by air-drying and freezing. Generally, there were no significant differences of total phosphorus among the three treatments (CV% < 10%). Compared with field moist soils, freezing the soil evoked few changes on phosphorus fractions except that the resin-P increased in FS soil. On the contrary, air-drying significantly changed the distribution of phosphors fractions for both soils: increased the labile-P (especially resin-P) and organic-P (NaHCO<sub>3</sub>-Po, NaOH-Po and Con.HCl-Po) at the expense of NaOH-Pi and occlude-P (Dil.HCl-P and Con.HCl-Pi). Resin-P significantly increased by 31% for SS soil and by 121% for FS soil upon air-drying. The effect of air-drying seemed to be more pronounced in the FS soil with high organic matter content. These results indicated that drying seem to drive the P transformation form occlude-P to labile-P and organic-P and accelerated the weathering of stable P pool. This potentially could be significant for soil P supply to plants and P losses from soils to surface waters under changing patterns of rainfall and temperature as predicted by some climate change scenarios.  

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Responses of herbage yield and soil phosphorus fractions to phosphorus fertilisation on a degraded arid steppe

Crop and Pasture Science ◽

10.1071/cp18217 ◽

2018 ◽

Vol 69 (8) ◽

pp. 846 ◽

Cited By ~ 1

Author(s):

Dangjun Wang ◽

Zhibin He ◽

Zhen Zhang ◽

Qingfeng Du ◽

Yong Zhang ◽

...

Keyword(s):

Soil Phosphorus ◽

Pot Experiment ◽

Available Phosphorus ◽

P Availability ◽

Organic P ◽

Soil P ◽

Sheep Manure ◽

Arid Steppe ◽

Plant Yields ◽

Phosphorus Fertilisation

Low plant-available phosphorus (P) in degraded arid steppes greatly limits plant yields. However, whether exterior P addition will improve the soil P availability and thus increase plant yield in these degraded arid steppes is still not certain. In the current study, a severely degraded arid steppe in Inner Mongolia, China, with soil-available P <5 mg/kg, was fertilised annually with chemical or manure P for two years (2014, dry year; 2015, wet year). There were six fertilisation treatments: 0, 30 kg P/ha, 60 kg P/ha, 90 kg P/ha, 4000 kg sheep manure/ha (equalling 16.4 kg P/ha) and 8000 kg sheep manure/ha (32.8 kg P/ha). A pot experiment with Stipa krylovii (the dominant plant species in the tested steppe) and five P application rates (0, 30, 60, 90 and 120 kg P/ha) was also conducted, under well-watered and nitrogen-fertilised conditions, using surface soils from unfertilised plots in the field. Results indicated that the tested soils had strong P adsorption capacity and weaker desorption capacity, and that the labile P fractions were quickly transformed into less labile fractions, reducing P availabilities. Overall, chemical P fertiliser resulted in the accumulation of Ca10-P and occluded P, whereas sheep manure resulted in the accumulation of moderately resistant organic P and highly resistant organic P. Phosphorus fertilisation was associated with an increase in plant P concentrations in both 2014 and 2015, and a low P rate (30 kg P/ha in the current study) was able to improve the aboveground biomass in both the field experiment in the wet year and the pot experiment under well-watered conditions. Thus, in degraded arid steppes, P fertilisation may be unnecessary in dry years. A low rate of P fertilisation is recommended in wet years to improve soil P status and steppe plant productivity.

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Soil phosphorus fractionation after co-applying biochar and paper mill biosolids

Canadian Journal of Soil Science ◽

10.1139/cjss-2020-0098 ◽

2020 ◽

Author(s):

Noura Ziadi ◽

Xiangru Zhang ◽

Bernard Gagnon ◽

Eric Manirakiza

Keyword(s):

Sandy Loam ◽

Paper Mill ◽

Phosphorus Fractionation ◽

Stable Form ◽

P Availability ◽

P Fractions ◽

Soil P ◽

Soil P Fractions ◽

Soil P Availability ◽

Incubation Study

In recent decades, there has been a growing interest in the recycling of organic materials such as paper mill biosolids (PB) and biochar for use as soil amendments. However, the benefits of co-application of PB and biochar and its effects on soil P availability remain unknown. An incubation study was conducted on two acidic soils to assess the effect of two PB types (2.5% w/w) co-applied with three rates (0%, 2.5%, and 5% w/w) of pine (Pinus strobus L.) biochar on soil P fractions. An unfertilized control and a mineral NP fertilizer were used as a reference. Soil P fractions were determined by Hedley procedure after 2 and 16 weeks of incubation. Material fractionation indicated that the PB containing the highest total P and the lowest Al content had the highest proportion of labile P, whereas most P in the biochar was in a stable form. The incubation study revealed that the P-rich PB increased P availability in both soils to a level comparable to mineral fertilizer at the end of the incubation. The addition of biochar to PB, however, did not affect soil P availability, but the highest rate induced a conversion of P fixed to Al and Fe oxides towards recalcitrant forms, particularly in the sandy loam soil. We conclude that co-applying biochar and PB could be more beneficial than application biochar alone and soils amended with such a mixture would be expected to release part of their P slowly over a longer period of time.

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A novel isotope pool dilution approach to quantify gross rates of key abiotic and biological processes in the soil phosphorus cycle

Biogeosciences ◽

10.5194/bg-16-3047-2019 ◽

2019 ◽

Vol 16 (15) ◽

pp. 3047-3068 ◽

Cited By ~ 3

Author(s):

Wolfgang Wanek ◽

David Zezula ◽

Daniel Wasner ◽

Maria Mooshammer ◽

Judith Prommer

Keyword(s):

Soil Phosphorus ◽

Quality Data ◽

Organic P ◽

Phosphorus Cycle ◽

Soil P ◽

Environmental Controls ◽

Abiotic Controls ◽

Malachite Green Assay ◽

P Cycle ◽

Isotope Pool Dilution

Abstract. Efforts to understand and model the current and future behavior of the global phosphorus (P) cycle are limited by the availability of global data on rates of soil P processes, as well as their environmental controls. Here, we present a novel isotope pool dilution approach using 33P labeling of live and sterile soils, which allows for high-quality data on gross fluxes of soil inorganic P (Pi) sorption and desorption, as well as of gross fluxes of organic P mineralization and microbial Pi uptake to be obtained. At the same time, net immobilization of 33Pi by soil microbes and abiotic sorption can be easily derived and partitioned. Compared with other approaches, we used short incubation times (up to 48 h), avoiding tracer remineralization, which was confirmed by the separation of organic P and Pi using isobutanol fractionation. This approach is also suitable for strongly weathered and P-impoverished soils, as the sensitivity is increased by the extraction of exchangeable bioavailable Pi (Olsen Pi; 0.5 M NaHCO3) followed by Pi measurement using the malachite green assay. Biotic processes were corrected for desorption/sorption processes using adequate sterile abiotic controls that exhibited negligible microbial and extracellular phosphatase activities. Gross rates were calculated using analytical solutions of tracer kinetics, which also allowed for the study of gross soil P dynamics under non-steady-state conditions. Finally, we present major environmental controls of gross P-cycle processes that were measured for three P-poor tropical forest and three P-rich temperate grassland soils.

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Effect of Freeze–Thaw Cycles on Phosphorus Fractions and Their Availability in Biochar-Amended Mollisols of Northeast China (Laboratory Experiment)

Sustainability ◽

10.3390/su11041006 ◽

2019 ◽

Vol 11 (4) ◽

pp. 1006 ◽

Cited By ~ 1

Author(s):

Ying Han ◽

Xiangwei Chen ◽

Byoungkoo Choi

Keyword(s):

Moisture Content ◽

Path Coefficient ◽

P Availability ◽

P Fractions ◽

P Fractionation ◽

Soil P ◽

Freeze Thaw ◽

Soil P Fractions ◽

Labile P ◽

Biochar Amendment

Freeze–thaw cycles stimulate the release of available soil phosphorus (P) in winter, and biochar as a soil amendment could improve P availability. Nevertheless, it is unclear how freeze–thaw cycles and biochar amendment interact to affect the soil P fractions and their availability in winter, particularly under different soil water conditions. We simulateda freeze–thaw cycle experimentto assess the effects of three factors on soil P fractions: soil moisture content (22%, 31%, and 45%), frequencies of freeze–thaw cycles (0, 1, 3, 6, and 12 times) and biochar amendment (soil and biochar-amended soil). Modified Hedley sequential P fractionation was conducted to measure the soil P fractions. Increasing the number of freeze–thaw cycles increased soil labile P fractions in the soil with the lowest moisture content (22%). After biochar amendment, the content of labile P decreased as the number of freeze–thaw cycles increased. Biochar amendment enhanced P availability in Mollisols owing to the direct effect of NaOH-Po, which has a large direct path coefficient. Principal components analysis showed that moisture content was a major factor influencing the variation in the P fractions. The P fractions were separated by the interactive effects of biochar amendment and freeze–thaw cycles in soils with a higher moisture content (45%), indicating that the effects of freeze–thaw cycles on P availability appear to be more pronounced in biochar-amended Mollisols of higher water contents.

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