Key Laboratory of Nonpoint Source Pollution Control, Ministry of Agriculture and Rural Affairs/Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, PR China.
Institute of Agricultural Environment and Resources, Yunnan Academy of Agricultural Sciences, Kunming, 650201, PR China.
Environ Pollut. 2020 Nov;266(Pt 2):115304. doi: 10.1016/j.envpol.2020.115304. Epub 2020 Aug 2.
The excessive application of manure has caused a high load of phosphorus (P) in the North China Plain. Having an understanding of how manure application affects soil P changes and its transport between different soil layers is crucial to reasonably apply manure P and reduce the associated loss. Based on our 28-year field experiments, the compositions and changes of P species and the risk of P loss under excessive manure treatments were investigated, i.e., no fertilizer (CK), mineral fertilizer NPK (NPK), NPK plus 22.5 t ha yr swine manure (LMNPK), and NPK plus 33.75 t ha yr swine manure (HMNPK). Manure application increased the content of orthophosphate and myo-inositol hexaphosphate (myo-IHP), especially the orthophosphate content exceeded 95%. The amount of orthophosphate in manure and the conversion of organic P to inorganic P in soil were the main reasons for the increased soil orthophosphate. Compared with NPK treatment, soil microbial biomass phosphorus and alkaline phosphatase activity in LMNPK and HMNPK treatments significantly increased. Compared with NPK treatment, a high manure application rate under HMNPK treatment could increase the abundance of organic P-mineralization gene phoD by 60.0% and decrease the abundance of inorganic P-solubilization gene pqqC by 45.9%. Due to the continuous additional manure application, soil P stocks significantly increased under LMNPK and HMNPK treatments. Furthermore, part of the P has been leached to the 60-80 cm soil layer. Segmented regression analysis indicated that CaCl-P increased sharply when Olsen-P was higher than 25.1 mg kg, however the content of Olsen-P did not exceed this value until 10 years after consecutive excessive manure application. In order to improve soil P availability and decrease the risk of P loss, the manure application rate should vary over time based on soil physicochemical conditions, plants requirements, and P stocks from previous years.
过量施用有机肥导致华北平原土壤磷（P）负荷过高。了解有机肥施用如何影响土壤 P 变化及其在不同土层之间的迁移，对于合理施用有机肥磷和减少相关损失至关重要。基于我们 28 年的田间试验，研究了过量有机肥处理下 P 形态的组成和变化以及 P 损失的风险，即不施肥（CK）、氮磷钾化肥（NPK）、NPK 加 22.5 t ha yr 猪粪（LMNPK）和 NPK 加 33.75 t ha yr 猪粪（HMNPK）。有机肥的施用增加了正磷酸盐和肌醇六磷酸盐（myo-IHP）的含量，尤其是正磷酸盐含量超过 95%。土壤中有机肥中磷含量和有机磷向无机磷的转化是土壤正磷酸盐增加的主要原因。与 NPK 处理相比，LMNPK 和 HMNPK 处理的土壤微生物生物量磷和碱性磷酸酶活性显著增加。与 NPK 处理相比，HMNPK 处理下高有机肥施用量可使有机磷矿化基因 phoD 的丰度增加 60.0%，无机磷溶解基因 pqqC 的丰度降低 45.9%。由于持续额外的有机肥施用，LMNPK 和 HMNPK 处理下土壤 P 储量显著增加。此外，部分 P 已淋洗到 60-80 cm 土层。分段回归分析表明，当Olsen-P 高于 25.1mg kg 时，CaCl-P 急剧增加，然而，在连续过量施用有机肥 10 年后，Olsen-P 含量才超过此值。为了提高土壤 P 的有效性并降低 P 损失的风险，应根据土壤理化性质、植物需求和前几年的 P 储量，及时调整有机肥的施用量。
