Consequences of Ontario P index recommendations for reduced manure and fertilizer phosphorus applications on corn yields and soil phosphorus

2016 ◽  
Vol 96 (2) ◽  
pp. 191-198 ◽  
Author(s):  
M.A. Ribey ◽  
I.P. O’Halloran

Environmental indices for soil P limit P applications when soil tests and risk of P losses exceed a given threshold. Producers’ reluctance to reduce P inputs often stem from concerns regarding reduced crop production and soil fertility. Our objectives were to identify changes in soil P fractions after 4 yr of repeated manure or fertilizer P applications at rates ≤ crop removal by corn (Zea mays L.), and the impact of these applications on yields. Olsen P and soil P fractions extracted using a modified Hedley P fractionation procedure were measured. Corn yields were nonresponsive to P applications. After 4 yr, Olsen P was 16.6 and 24.6 mg kg−1 at the application rates of 0 and 33 kg P ha−1 yr−1, respectively, for the inorganic fertilizer treatment indicating that soil P drawdown was occurring. Only the most labile forms of Pi (resin and bicarbonate extractable) were affected by treatment, with greater values at higher P application rates. Adherence to Ontario’s P index recommendations for P applications at or below crop removal should not be a crop production concern. Furthermore, given the rate of soil labile P drawdown, routine soil testing (every 3–5 yr) would identify agronomically significant changes in soil test P before the crop yield is impacted.

2019 ◽  
Vol 11 (4) ◽  
pp. 1006 ◽  
Author(s):  
Ying Han ◽  
Xiangwei Chen ◽  
Byoungkoo Choi

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.


Author(s):  
Xiaojun Yan ◽  
Wenhao Yang ◽  
Xiaohui Chen ◽  
Mingkuang Wang ◽  
Weiqi Wang ◽  
...  

Excess phosphorus (P) accumulation in the soil can change the bioavailability of P and increase the leaching risks, but the quantitative evaluation of these responses in acidic red soil is lacking. This study aimed to investigate the composition of soil P fractions under different phosphorus apparent balances (PAB) in acidic red soil and the bioavailability and the leaching change-points of different P fractions. Five phosphorus (P) fertilization rates were applied (0, 16.38, 32.75, 65.50, 131.00 kg P·ha−1) in every sweet corn cultivation from the field experiment, and the treatments were marked as P0, P1, P2, P3, and P4, respectively. The PAB showed negative values in P0 and P1 which were −49.0 and −15.0 kg P·ha–1 in two years, respectively. In contrast, PAB in P2 as well as in P3 and P4 were positive, the content ranging from 40.2 to 424.3 kg P·ha−1 in two years. Per 100 kg ha−1 P accumulate in the soil, the total P increased by 44.36 and 10.41 mg kg−1 in the surface (0–20 cm) and subsurface (20–40 cm) soil, respectively. The content of inorganic P fractions, including solution phosphate (Sol-P), aluminum phosphate (Al-P), iron phosphate (Fe-P), reduction phosphate (Red-P), and calcium phosphate (Ca-P), significantly increased by 0.25, 16.22, 22.08, 2.04, and 5.08 mg kg−1, respectively, in surface soil per 100 kg ha−1 P accumulated in the soil. Path analysis showed that the most important soil P fractions contributing to Olsen-P were Sol-P and Al-P, which can directly affect Olsen-P, and their coefficients were 0.24 and 0.73, respectively. Furthermore, the incubation experiments were conducted in the laboratory to investigate the leaching risk of different P fractions, and they showed Sol-P was a potential source of leaching, and the leaching change-points of Al-P and Fe-P were 74.70 and 78.34 mg·kg–1, respectively. Continuous P that accumulated in soil changed the composition of P fractions, and the bioavailability as well as the leaching risks increased. This is important in optimizing soil P fertilization management in agricultural ecosystems based on the bioavailability and critical levels for leaching of P fractions.


Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 172 ◽  
Author(s):  
Huixia Tian ◽  
Xiaoqin Cheng ◽  
Hairong Han ◽  
Hongyuan Jing ◽  
Xujun Liu ◽  
...  

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.


2020 ◽  
Vol 36 (3) ◽  
pp. 524-535 ◽  
Author(s):  
Stefania C. Appelhans ◽  
Pedro Anibal Barbagelata ◽  
Ricardo Jose Miguel Melchiori ◽  
Flavio Gutierrez Boem

Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 784 ◽  
Author(s):  
Waqas Ahmed ◽  
Kailou Liu ◽  
Muhammad Qaswar ◽  
Jing Huang ◽  
Qinghai Huang ◽  
...  

Elevated mineral fertilization may change the composition and increase the availability of soil phosphorus (P) in subtropical paddy soils and thus affect long-term plant growth. However, an understanding of the response of soil P fractions to long-term nitrogen, phosphorus and potassium (NPK) additions remains elusive. This study aimed to explore the responses of soil P-fractions and their mobility to different long-term chemical fertilization rates under a double rice cropping system. The rates of nitrogen (N), phosphorus (P), and potassium (K) in the low NPK treatment (LNPK) were 90, 45, and 75 kg ha−1 year−1, respectively, and in the high NPK treatment (HNPK), they were 180, 90, and 150 kg ha−1 year−1, respectively. The results showed that the concentrations of soil organic matter (SOM), total P, Olsen P, total N, and mineral N were remarkably increased under HNPK by 17.46%, 162.66%, 721.16%, 104.42%, and 414.46%, respectively, compared with those under control (CT). Compared to the CT P fractions, HNPK increased the labile P fractions (i.e., NaHCO3-Pi and NaHCO3-Po) by 322.25% and 83.53% and the moderately labile P fractions (i.e., NaOH-Pi, NaOH-Po and HCl. dil. Pi) by 163.54%, 183.78%, and 3167.25% respectively, while the non-labile P was decreased by the HNPK addition. P uptake and grain yield were increased by LNPK and HNPK by 10.02% and 35.20%, respectively, compared with CT. P use efficiency indices were also higher under HNPK than under LNPK. There was a strong positive relationship between grain yield and P use efficiency (R2 = 0.97). A redundancy analysis (RDA) showed a strong correlation between soil chemical properties and the labile and moderately labile P pools. Structural equation modeling (SEM) revealed that SOM, mineral N, and available P strongly control the labile P pool. In conclusion, NPK additions under the paddy soils significantly influences the soil P fractions. The soil P dynamics and the mechanisms governing the interactions between plants and soil nutrients are clearly explained in this study.


PLoS ONE ◽  
2017 ◽  
Vol 12 (6) ◽  
pp. e0179275 ◽  
Author(s):  
Xinghua Li ◽  
Baona Wang ◽  
Tewu Yang ◽  
Duanwei Zhu ◽  
Zhongnan Nie ◽  
...  

2020 ◽  
Vol 53 (1) ◽  
pp. 149
Author(s):  
Adel Ghoneim, et al.

<p>Understanding of P transformations following organic amendments addition to highly calcareous soils is necessary for developing better management practices that can help enhance P fertilizer use efficiency. Phosphorus solubility and availability for plant uptake under the conditions of arid calcareous soil is very low, making P nutrient supply a critical issue under these conditions. The aim of this study was to evaluate the impact of various types of organic amendments (chicken compost, cow compost and a mixture of humic-fulvic acid) applied alone at different rates of KH2PO4 fertilizer on P fractions in calcareous soil using the sequential chemical extraction method. Amended calcareous soil was incubated under laboratory conditions and soil samples were collected at 0, 4, 8 and 16 weeks of the incubation periods. Soil was sequentially extracted and analyzed for P different fractions. The results indicated that the addition of chicken and cow compost increased soluble and exchangeable-P and Ca-P fractions in calcareous soil and the increases depend on application rates. The results indicated that combination of chicken and cow compost with different KH2PO4 fertilizer application rates increased the concentration of soluble and exchangeable-P in the soil compared to organic amendments or KH2PO4 fertilizer applied alone. The P associated with Ca was the dominant P fractions in soil, ranging between 51 to 59% regardless of the different treatment and the period of incubations. The Al- and Fe-associated P fractions varied between 2 and 9%, with the maximum value being observed at the eighth week of incubation. The residual-P fraction ranged between 5 and 22% at different incubation periods.</p>


Author(s):  
M.B. O'Connor ◽  
B.J. Hunt ◽  
K.W. Perrott

The Kaipara clay soils and associated soil types occupy some 36 000 ha in Northland. The soils are naturally high in P and P fertilisers have been used sparingly in the past but with increasing farming intensity a fall in soil Olsen P values (to < 20) is occurring and responses to P fertilisers are becoming more common. Lime is widely used. In December 1996, a field trial, conducted over 6 years, was established on a Kaipara clay soil near Ruawai. The first phase (1996-1999) consisted of six rates of P (0, 20, 40, 60, 80, 100 kg P/ha) with or without lime at 5 t/ha applied once. The initial pH was 5.8 and Olsen P was 16. Results indicated a marked rates response to P without lime but with lime a marked Psparing effect occurred equivalent to 50-60 kg P/ha. The effect was consistent over 3 years. An explanation for this finding is due to lime improving plant growth probably by N mineralisation and N uptake, thus giving improved root growth and allowing those roots to explore a greater volume of soil and absorb more P. Plant chemical analyses and soil P fractionation studies indicated that more P was being taken up by plants on the lime/no P plots. The second phase (2000-2003) involved splitting plots and applying additional lime to some to give a pH range from 5.6-7.0. Results indicated no benefit to increasing pH above 6.0 but there was a suggestion that the reapplication of lime itself was beneficial. The P sparing effect of lime will best be utilised where soil Olsen P levels remain above 20. Keywords: P-sparing effect, lime, phosphate, Kaipara clay


Author(s):  
Noura Ziadi ◽  
Xiangru Zhang ◽  
Bernard Gagnon ◽  
Eric Manirakiza

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.


Plants ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 404 ◽  
Author(s):  
Lianhai Wu ◽  
Martin Blackwell ◽  
Sarah Dunham ◽  
Javier Hernández-Allica ◽  
Steve P. McGrath

The phosphorus (P) supply from soils is crucial to crop production. Given the complexity involved in P-cycling, a model that can simulate the major P-cycling processes and link with other nutrients and environmental factors, e.g., soil temperature and moisture, would be a useful tool. The aim of this study was to describe a process-based P module added to the SPACSYS (Soil Plant and Atmosphere Continuum System) model and to evaluate its predictive capability on the dynamics of P content in crops and the impact of soil P status on crop growth. A P-cycling module was developed and linked to other modules included in the SPACSYS model. We used a winter wheat (Triticum aestivum, cv Xi-19) field experiment at Rothamsted Research in Harpenden to calibrate and validate the model. Model performance statistics show that the model simulated aboveground dry matter, P accumulation and soil moisture dynamics reasonably well. Simulated dynamics of soil nitrate and ammonium were close to the observed data when P fertiliser was applied. However, there are large discrepancies in fields without P fertiliser. This study demonstrated that the SPACSYS model was able to investigate the interactions between carbon, nitrogen, P and water in a single process-based model after the tested P module was implemented.


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