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Geoderma ◽  
2022 ◽  
Vol 407 ◽  
pp. 115546
Yanju Gao ◽  
Akash Tariq ◽  
Fanjiang Zeng ◽  
Corina Graciano ◽  
Zhihao Zhang ◽  

SOIL ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 1-15
Zuzana Frkova ◽  
Chiara Pistocchi ◽  
Yuliya Vystavna ◽  
Katerina Capkova ◽  
Jiri Dolezal ◽  

Abstract. At the early stages of pedogenesis, the dynamics of phosphorus (P) in soils are controlled by microbial communities, the physicochemical properties of the soil and the environmental conditions. While various microorganisms involved in carrying out biogeochemical processes have been identified, little is known about the actual contribution of microbial processes, such as organic P hydrolysis and microbial P turnover, to P cycling. We thus focused on processes driven by microbes and how they affect the size and cycling of organic and inorganic soil P pools along a soil chronosequence in the Chamser Kangri glacier forefield (Western Himalayas). The rapid retreat of the glacier allowed us to study the early stages of soil formation under a cold arid climate. Biological P transformations were studied with the help of the isotopic composition of oxygen (O) in phosphate (δ18OP) coupled to sequential P fractionation performed on soil samples (0–5 cm depth) from four sites of different age spanning 0 to 100–150 years. The P bound to Ca, i.e., 1 M HCl-extractable P, still represented 95 % of the total P stock after approximately 100 years of soil development. Its isotopic composition was similar to the parent material at the most developed site. Primary phosphate minerals, possibly apatite, mostly comprised this pool. The δ18OP of the available P and the NaOH-extractable inorganic P instead differed from that of the parent material, suggesting that these pools underwent biological turnover. The δ18OP of the available P was mostly controlled by the microbial P, suggesting fast exchanges occurred between these two pools possibly fostered by repeated freezing–thawing and drying–rewetting cycles. The release of P from organic P becomes increasingly important with soil age, constituting one-third of the P flux to available P at the oldest site. Accordingly, the lighter isotopic composition of the P bound to Fe and Al oxides at the oldest site indicated that this pool contained phosphate released by organic P mineralization. Compared to previous studies on early pedogenesis under alpine or cold climate, our findings suggest a much slower decrease of the P-bearing primary minerals during the first 100 years of soil development under extreme conditions. However, they provide evidence that, by driving short-term P dynamics, microbes play an important role in controlling the redistribution of primary P into inorganic and organic soil P pools.

Mengke Zhu ◽  
Bocong Huang ◽  
Zongyang Liu ◽  
yue Wang ◽  
jiao Teng ◽  

The distribution and availability of phosphorus (P) fractions in restored cut slope soil aggregates along altitude gradients were studied. We examined soil aggregates total phosphorus (TP), available phosphorus (AP) and phosphorus activation coefficient (PAC), and discovered that there was no significant difference in TP at four altitudes (p> 0.05), but there was a significant difference in AP at 3009 m, 3347 m and 3980 m (p< 0.05). At 3009 m, 3347 m and 3654 m, the AP accumulation in small size aggregates were more advantageous. Overall, PAC dropped steadily as aggregate size increased, as shown by PAC (3654 m)> PAC (3347 m)> PAC (3009 m)> PAC (3980 m) in altitudes. In all particle size soil aggregates, total inorganic phosphorus (TPi) > total organic phosphorus (TPo) > residual phosphorus (R-P) at 3009 m, 3347 m and 3654 m; TPo> TPi> R-P at 3980 m. Through correlation and multiple stepwise regression analysis, we concluded that active NaHCO3-Pi was the main AP source. It was suggested that more attention should be paid to the ratio of small particle size aggregates, so as to increase soil AP storage. At low (3009 m) and high altitude (3980 m), inorganic P fertilizer and P activator were added into soil to improve the activation ability of soil P and the AP supply, so as to promote the healthy development of slope soils ecosystem.

A. Limon-Ortega ◽  
A. Baez-Perez

Abstract Environmental conditions contribute to a large percentage of wheat yield variability. This phenomenon is particularly true in rainfed environments and non-responsive soils to N. However, the effect of P application on wheat is unknown in the absence of N fertilizer application. This study was conducted from 2012 to 2019 in permanent beds established in 2005. Treatments were arranged in a split-plot design and consisted of superimposing three P treatments (foliar, banded and broadcast application) plus a check (0P) within each one of four preceding N treatments (applied from 2005 to 2009). Foliar P generally showed a greater response than granular P treatments even though the soil tests high P (>30 mg/kg). Precipitation estimated for two different growth intervals explained through regression procedures the Years' effect. Seasonal precipitation (224–407 mm) explained variation of relative yield, N harvest index (NHI) and P agronomic efficiency (AE). Reproductive stage precipitation (48–210 mm) explained soil N supply. In dry years, foliar P application improved predicted relative yield 14% and AE 155 kg grain/kg P compared to granular P treatments. Similarly, soil N supply increased 15 kg/ha in dry moisture conditions during the reproductive stage. The NHI consistently improved over the crop seasons. This improvement was relatively larger for 0 kg N/ha. On average, NHI increased from about 0.57 to 0.72%. Normalized difference vegetation index (NDVI) readings at the booting growth stage were negatively associated with NHI. Foliar P in this non-responsive soil to N showed the potential to replace granular P sources. However, the omission of granular P needs to be further studied to estimate the long-term effect on the soil P test.

Soil Systems ◽  
2022 ◽  
Vol 6 (1) ◽  
pp. 6
Chad J. Penn ◽  
Mark R. Williams ◽  
James Camberato ◽  
Nicholas Wenos ◽  
Hope Wason

Soil phosphorus (P) solubility and kinetics partly control dissolved P losses to surface water and uptake by plants. While previous studies have focused on batch techniques for measuring soil P desorption kinetics, flow-through techniques are more realistic because they simulate P removal from the system, akin to runoff, leaching, and plant uptake. The objectives were to measure soil P desorption by a flow-through technique at two flow rates and several batch methods, and utilize both for understanding how flow rate impacts the thermodynamics and kinetics of soil P desorption. Desorption obeyed first-order kinetics in two different phases: an initial rapid desorption phase followed by a gradual release. Desorption was limited by equilibrium and the kinetics of physical processes as demonstrated by an interruption test. Dilution-promoted desorption occurred with increasing cumulative volume, which increased desorption rate via first-order kinetics. The batch tests that simulated cumulative solution volume and time of flow-through were similar to the flow-through results; however, the batch methods overestimated the desorption rates due to less limitations to diffusion. Fast flow rates desorbed less P, but at a greater speed than slow flow rates. The differences were due to contact time, cumulative time, and solution volume, which ultimately controlled the potential for chemical reactions to be realized through physical processes. The interaction between these processes will control the quantity and rate of desorption that buffer P in non-point drainage losses and plant uptake.

2022 ◽  
Dorit Julich ◽  
Vera Makowski ◽  
Karl-Heinz Feger ◽  
Stefan Julich

AbstractThe assessment of impacts of an altered nutrient availability, e.g. as caused by consistently high atmospheric nitrogen (N) deposition, on ecosystem phosphorus (P) nutrition requires understanding of P fluxes. However, the P translocation in forest soils is not well understood and soil P fluxes based on actual measurements are rarely available. Therefore, the aims of this study were to (1) examine the effects of experimental N, P, and P+N additions on P fluxes via preferential flow as dominant transport pathway (PFPs) for P transport in forest soils; and (2) determine whether these effects varied with sites of contrasting P status (loamy high P/sandy low P). During artificial rainfall experiments, we quantified the P fluxes in three soil depths and statistically analyzed effects by application of linear mixed effects modeling. Our results show that the magnitude of P fluxes is highly variable: In some cases, water and consequently P has not reached the collection depth. By contrast, in soils with a well-developed connection of PFPs throughout the profile fluxes up to 4.5 mg P m−2 per experiment (within 8 h, no P addition) were observed. The results furthermore support the assumption that the contrasting P nutrition strategies strongly affected P fluxes, while also the response to N and P addition markedly differed between the sites. As a consequence, the main factors determining P translocation in forest soils under altered nutrient availability are the spatio-temporal patterns of PFPs through soil columns in combination with the P nutrition strategy of the ecosystem.

2022 ◽  
Pei-Shan Chien ◽  
Ya-Ting Chao ◽  
Chia-Hui Chou ◽  
Yu-Ying Hsu ◽  
Su-Fen Chiang ◽  

To understand the genetic basis in governing phosphorus (P) acquisition, we performed genome-wide association studies (GWAS) on a diversity panel of Arabidopsis thaliana by two primary determinants of P acquisition, phosphate (Pi)-uptake activity and PHOSPHATE TRANSPORTER 1 (PHT1) protein abundance. Association mapping revealed a shared significant peak on chromosome 5 (Chr5) where the PHT1;1/2/3 genes reside, suggesting a strong correlation between the regulation of Pi-uptake activity and PHT1 protein abundance. Genes encoding transcription factors, kinases, and a metalloprotease associated with both traits were also identified. Conditional GWAS followed by statistical analysis of genotype-dependent expression of PHT1;1 and transcription activity assays revealed an epistatic interaction between PHT1;1 and MYB DOMAIN PROTEIN 52 (MYB52) on Chr1. Analyses of F1 hybrids generated by crossing two subgroups of natural accessions carrying specific SNPs associated with PHT1;1 and MYB52 further revealed the strong effects of potential variants on PHT1;1 expression and Pi uptake activity. Notably, the soil P contents in A. thaliana habitats were found to coincide with PHT1;1 haplotype, underscoring how fine-tuning of the activity of P acquisition by natural variants allows plants to adapt to their environments. This study sheds light on the complex regulation of P acquisition and offers a framework to systematically assess the effectiveness of GWAS approaches in the study of quantitative traits.

Agronomy ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 130
Dario Fornara ◽  
Elizabeth M. E. Ball ◽  
Christina Mulvenna ◽  
Henry Reyer ◽  
Michael Oster ◽  

The over-supplementation of animal feeds with phosphorus (P) within livestock-production systems leads to high rates of P excretion and thus to high P loads and losses, which negatively impact the natural environment. The addition of phytase to pig and poultry diets can contribute to reducing P excretion; however, cascading effects of phytase on plant–soil systems remain poorly understood. Here, we addressed how three different diets containing various levels of exogenous phytase, i.e., (1) no-phytase, (2) phytase (250 FTU), and (3) superdose phytase (500 FTU) for pigs (Sus scrofa domesticus) and broilers (Gallus gallus domesticus) might affect P dynamics in two different plant–soil systems including comfrey (Symphytum ×uplandicum) and ryegrass (Lolium perenne). We found that differences in phytase supplementation significantly influenced total P content (%) of broiler litter and also pig slurry (although not significantly) as a result of dietary P content. P Use Efficiency (PUE) of comfrey and ryegrass plants was significantly higher under the intermediate ‘phytase’ dose (i.e., commercial dose of 250 FTU) when compared to ‘no-phytase’ and ‘superdose phytase’ associated with pig slurry additions. Soil P availability (i.e., water soluble P, WSP) in both comfrey and ryegrass mesocosms significantly decreased under the intermediate ‘phytase’ treatment following pig slurry additions. Dietary P content effects on P losses from soils (i.e., P leaching) were variable and driven by the type of organic amendment. Our study shows how commercial phytase levels together with higher dietary P contents in pig diets contributed to increase PUE and decrease WSP thus making the plant–soil system more P conservative (i.e., lower risks of P losses). Our evidence is that dietary effects on plant–soil P dynamics are driven by the availability of P forms (for plant uptake) in animal excretes and the type of organic amendment (pig vs. broiler) rather than plant species identity (comfrey vs. ryegrass).

2022 ◽  
pp. 416-430
Hendrik J. Smith ◽  
Gerhardus Trytsman ◽  
Andre A. Nel

Abstract A project under the Farmer Innovation Programme (FIP) that aimed to adapt Conservation Agriculture (CA) among grain farmers in South Africa was implemented in a commercial farming area of the North West Province. The following on-farm, collaborative-managed trials produced key findings concerning: (i) plant population densities (high versus low) under CA; (ii) conventional crop systems versus CA crop systems; (iii) the testing and screening of cover crops; (iv) green fallow systems for soil restoration; and (v) livestock integration. Key results from these trials were that the yield of maize was significantly higher under high-density no-till (NT) systems compared to the normal NT systems. The yield of maize in local conventional systems was lower than the yield in NT systems tested on three farmer-managed trials. The screening trial assisted in testing and learning the suitability and the different attributes of a range of cover crops in that area. Cover crop mixtures used as a green fallow system with livestock showed that CA can facilitate the successful restoration of degraded soil.

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