Nutrient Management and Water Quality Group, Department of Environmental Science and Technology, University of Maryland, College Park, MD, 20742, USA.
Arkansas Water Resources Center, University of Arkansas System Division of Agriculture, Fayetteville, AR, 72704, USA.
Chemosphere. 2022 Dec;308(Pt 2):136220. doi: 10.1016/j.chemosphere.2022.136220. Epub 2022 Aug 28.
In many intensive animal production areas, the over-application of manure has resulted in a build-up of soil phosphorus (P) and the creation of legacy P soils that threaten water quality. We investigated dissolved P forms losses in runoff using simulated rainfall in packed soil boxes amended with three poultry litter and products, including raw (unprocessed) litter, granulated litter with the addition of urea, and heated raw litter. These were applied at 3 kg water-extractable P (WEP) ha as determined with three litter-to-water extraction ratios (1:10, 1:100, and 1:200). Over three simulated rainfall events, the amount of dissolved reactive P (DRP) lost was significantly greater in runoff from soils amended with granulated litter (1.09 ± 0.02 kg ha) than raw (0.81 kg ha) and heated (0.58 kg ha) litters. No significant differences in the amount of dissolved unreactive P (DUP) in runoff (0.38 ± 0.07 kg ha) were observed among three litter amended soils. The soil test P (i.e., Mehlich 3-P) increased from 6.9 mg kg in control to 10.4-11.6 mg kg in litter amended soils, whereas the total WEP (0.26 ± 0.03 mg kg) in soils was similar after three rainfall simulation events. We conclude that (1) an accurate litter-to-water extraction ratio (>1:200) is critical to determine the amount of WEP in manure as it will ensure similar amounts of soluble P application and will result in identical runoff losses of dissolved P, and (2) the granulation and heating of litter created a product that could enhance the use of poultry litter, especially in non-agricultural markets, resulting in sustainably using manure and reducing the risk of P loss to water bodies.
在许多集约化动物生产区，过度施用粪便导致土壤磷（P）积累，并形成了威胁水质的遗留 P 土壤。我们通过在装有三种家禽粪便和产品的填充土壤箱中进行模拟降雨，研究了径流中溶解 P 形态的损失，这些产品包括未经处理的原始粪便、添加尿素的颗粒状粪便和加热的原始粪便。这些产品的施用量为 3 公斤水可提取磷（WEP）公顷，这是根据三种粪便与水的提取比例（1:10、1:100 和 1:200）确定的。在三次模拟降雨事件中，用颗粒状粪便处理的土壤中流失的溶解反应性磷（DRP）量明显大于原始（0.81 公斤/公顷）和加热（0.58 公斤/公顷）粪便。在三种添加粪便的土壤中，径流中溶解非反应性磷（DUP）的量没有明显差异（0.38 ± 0.07 公斤/公顷）。土壤测试磷（即 Mehlich 3-P）从对照中的 6.9 毫克/公斤增加到添加粪便土壤中的 10.4-11.6 毫克/公斤，而三次降雨模拟后土壤中的总 WEP（0.26 ± 0.03 毫克/公斤）相似。我们得出结论：（1）准确的粪便与水的提取比例（>1:200）对于确定粪便中的 WEP 量至关重要，因为它将确保可溶性 P 的施用量相似，并且会导致溶解 P 的径流损失相同，（2）粪便的颗粒化和加热创造了一种可以增强家禽粪便利用的产品，特别是在非农业市场，从而可持续地利用粪便并降低 P 流失到水体的风险。
