State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, 712100, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.
J Environ Manage. 2022 Jun 15;312:114921. doi: 10.1016/j.jenvman.2022.114921. Epub 2022 Mar 22.
Loess Plateau is important for maize production in China. Therefore, a good understanding of soil phosphorus (P) behavior in the Loess region is crucial for optimizing fertilization in its agriculture systems. To date, research on factors influencing P adsorption/desorption has mainly focused on fertilization. Widespread application of straw return and increasing soil fauna in agricultural croplands inevitably affect soil P behavior either directly or indirectly in this area. However, less attention has been focused on these effects and their interactions. Here, a field plot experiment was performed based on a completely randomized design to investigate the response of P adsorption-desorption characteristics to the presence/absence of earthworms and straw return. Treatments included: (1) control without earthworms and straw (E0S0); (2) treatment with only earthworms (E1S0); (3) treatment with only straw (E0S1); (4) treatment with both earthworms and straw. The Langmuir model was superior to the Freundlich model in interpreting the P adsorption data and allowed better evaluation of the maximum P adsorption values. The maximal P adsorption, P adsorption affinity constant, and maximum buffer capacity in the earthworm and straw treatments were 2.4-8.3%, 8.3-13.9%, and 2.2-26.3% lower than those in E0S0. The readily desorbable P, standard P requirement, and degree of P saturation increased by 15.6-44.3%, 13.1-23.1%, and 4.4-16.5%, respectively, in earthworm and straw treatments. Additionally, earthworm inoculation and straw return treatments significantly increased total soil P, Olsen P, soil organic carbon, free FeO, and CaCO contents and specific surface area of the soil. Redundancy analysis showed that soil organic carbon explained most (14.7%) of the total variation in P adsorption and desorption. These results show that combining earthworm inoculation with straw return can effectively reduce soil P adsorption capacity, increase its P desorption capacity, and thus, increase its available P content. These results provide a scientific basis for improving the utilization efficiency of soil P.
黄土高原是中国玉米生产的重要基地。因此，深入了解黄土地区土壤磷（P）的行为对于优化农业系统施肥至关重要。迄今为止，影响磷吸附/解吸的因素研究主要集中在施肥方面。秸秆还田和增加土壤动物在农业耕地中的广泛应用不可避免地直接或间接地影响该地区土壤 P 的行为。然而，人们对这些影响及其相互作用的关注较少。在这里，基于完全随机设计进行了田间试验，以研究蚯蚓和秸秆还田的存在与否对 P 吸附-解吸特性的响应。处理包括：（1）无蚯蚓和秸秆（E0S0）对照；（2）仅蚯蚓处理（E1S0）；（3）仅秸秆处理（E0S1）；（4）蚯蚓和秸秆同时处理。Langmuir 模型在解释 P 吸附数据方面优于 Freundlich 模型，并且可以更好地评估最大 P 吸附值。蚯蚓和秸秆处理的最大 P 吸附量、P 吸附亲和力常数和最大缓冲容量分别比 E0S0 低 2.4-8.3%、8.3-13.9%和 2.2-26.3%。可解吸 P、标准 P 需求和 P 饱和度分别增加了 15.6-44.3%、13.1-23.1%和 4.4-16.5%。此外，蚯蚓接种和秸秆还田处理显著增加了土壤全磷、Olsen P、土壤有机碳、游离 FeO 和 CaCO3 含量以及土壤比表面积。冗余分析表明，土壤有机碳解释了 P 吸附和解吸总变异的 14.7%。这些结果表明，结合蚯蚓接种和秸秆还田可以有效地降低土壤 P 的吸附能力，增加其 P 的解吸能力，从而增加其有效 P 含量。这些结果为提高土壤 P 利用效率提供了科学依据。
