Continuous application of poultry litter (PL) significantly changes many soil properties, including soil test P (STP); Al, Fe, and Ca concentrations; and pH, which can affect the potential for P transport in surface runoff water. We conducted rainfall simulations on three historically acidic silt loam soils in Arkansas, Missouri, and Virginia to establish if long-term PL applications would affect soil inorganic P fractions and the resulting dissolved reactive P (DRP) in runoff water. Soil samples (0-5 cm depth) were taken to find sites ranging in Mehlich-3 STP from 20 to 1154 mg P kg-1. Simulated rainfall events were conducted on 3-m2 plots at 6.7 cm h-1, and runoff was collected for 30 min. Correlation between Mehlich-3 and runoff DRP indicated a linear relationship to 833 mg Mehlich-3 P kg-1. As Mehlich-3 STP increased, a concomitant increase in soil pH and Ca occurred on all soils. Soil P fractionation demonstrated that, as Mehlich-3 STP generally increased above 450 mg P kg-1 (from high to very high), the easily soluble and loosely bound P fractions decreased by 3 to 10%. Water-insoluble complexes of P bound to Al and Ca were the main drivers in the reduction of DRP in runoff, accounting for up to 43 and 38% of total P, respectively. Basing runoff DRP concentration projections solely on Mehlich-3 STP may overestimate runoff P losses from soils receiving long-term PL applications due to dissolution of water-insoluble Ca-P compounds.
展开▼
机译：连续施用家禽垫料（PL）会显着改变许多土壤特性，包括土壤测试P（STP）。铝，铁和钙的浓度;和pH，这可能会影响地表径流水中P的运输潜力。我们在阿肯色州，密苏里州和弗吉尼亚州的三种历史酸性粉砂壤土上进行了降雨模拟，以确定长期的PL施用是否会影响土壤无机P组分及其在径流水中的溶解性反应性P（DRP）。取土壤样品（深度为0-5厘米），以发现Mehlich-3 STP范围从20到1154 mg P kg -1 。在6.7 cm h -1 的3-m 2 地块上进行了模拟降雨事件，并收集了30分钟的径流。 Mehlich-3与径流DRP之间的相关性表明与833 mg Mehlich-3 P kg -1 呈线性关系。随着Mehlich-3 STP的增加，所有土壤上的土壤pH和Ca也随之增加。土壤P分馏表明，由于Mehlich-3 STP通常增加到450 mg P kg -1 （从高到非常高），易溶和松散结合的P组分降低了3％至10％。与铝和钙结合的P的水不溶性复合物是径流DRP减少的主要驱动力，分别占总P的43％和38％。仅基于Mehlich-3 STP的径流DRP浓度预测可能会高估由于水不溶性Ca-P化合物的溶解而长期接受PL施用的土壤的径流P损失。
展开▼
