松嫩平原不同耕作模式与秸秆还田量对土壤磷组分及大豆产量的影响

了解黑土地区外源介质与不同耕作模式对土壤磷影响，对于优化黑土地区农业系统施肥具有重要意义。玉米秸秆因其自身性质对土壤理化性质具有良好调控作用，该研究在完全随机设计的基础上，通过田间试验分阶段监测不同耕作模式和秸秆还田量对土壤磷组分变化的影响。研究结果表明：1)秸秆通过改善土壤的环境稳定性提高土壤的固磷能力。深耕(DP)搭配9 750 kg/hm²的秸秆还田后，土壤的总磷(TP)含量增加了31%。2)秸秆改善土壤环境增加了土壤磷酸酶含量。与浅耕(SP)相比，深耕搭配9 750kg/hm²的秸秆可使酸性和碱性磷酸酶含量分别提高到12%和32.5%。深耕搭配9 750 kg/hm²的秸秆还田量在大豆植株需磷关键时期时土壤植酸酶含量最低；与0秸秆还田相比，植酸酶含量减少了11.3%～19.4%。3)Langmuir模型在解释磷吸附数据方面优于Freundlich模型，可以更好地评估磷的最大吸附值，秸秆处理的最大磷吸附量、磷吸附亲和常数和最大缓冲容量分别比0秸秆还田处理低2.4%～8.3%、8.3%～13.9%和2.2%～26.3...

Effects of cultivation modes and straw return on soil phosphorus composition and soybean yield in the Songnen Plain of China

Northeast Plain is one of the most important soybean-producing areas in China. Phosphorus can be used to optimize the fertilization for the growth of soybean seedlings, root development, and crop resistance to natural disasters, such as drought. The depth of cultivated land can also affect the soil nutrient content. Compared with no tillage treatment, shallow and deep tillage can improve the soil structure and environment of the tillage layer for the soil nutrient content. A combination of exogenous media and cultivation has been widely used to improve the soil structure and physicochemical properties in recent years. Therefore, it is of great significance to understand the variations in the soil phosphorus that are caused by exogenous media and cultivation modes in black soil areas. Previous research of phosphorus form was focused mainly on individual fertilization or the regulation of individual cultivation modes. It is very necessary to explore the interaction and impact of maize straw returning to the field, and then apply the different cultivation modes to the soil phosphorus. In this study, a series of field experiments were carried out to monitor the effects of different tillage modes and straw returning on the soil phosphorus components in various stages. The results indicate that: 1) Straw returning significantly enhanced the stability of the soil environment and the fixation capacity of soil phosphorus. The total phosphorus (TP) content of the soil increased by 31% after deep tillage (DP) combined with 9750kg/hm² of straw returning to the field. (2) Straw also improved the soil environment and phosphatase content. Compared with the shallow tillage (SP), the DP combined with 9750kg/hm2 of straw increased the content of acid and alkaline phosphatase to 12% and 32.5%, respectively. The application of 9750 kg/hm² of straw for the DP resulted in the lowest content of soil phytase in the critical period, when the soybean plants needed phosphorus; Compared with the CK, the phytase content decreased by 11.3%-19.4%. (3) The Langmuir model better represented the phosphorus adsorption data, compared with the Freundlich. The maximum adsorption of phosphorus was evaluated as well. The maximum phosphorus adsorption capacity, phosphorus adsorption affinity constant, and maximum buffer capacity of straw treatment were 2.4%-8.3%, 8.3%-13.9%, and 2.2%-26.3% lower than those of CK treatment, respectively. (4) Both straw application and DP treatment improved the soil phosphorus availability. According to Hedley''s phosphorus grading, the DP combined with straw returning promoted the soil phosphorus components under different environments. The content of unstable phosphorus in the soil was always higher than that of the CK group. The application of straw significantly increased the phosphorus content of each component in the soil, indicating the greatest impact on the unstable phosphorus component. The regulation model of DP combined with 9750 kg/hm² straw returning to the field improved the effective phosphorus content in the soil, when applying 9750 kg/hm² maize straw during deep cultivation. The highest soybean yield reached 1425kg/hm², indicating a better improvement in the soybean yield. The finding can provide a scientific basis to improve the utilization efficiency of soil phosphorus. Strong reference and guidance can also be offered to maintain the soil fertility and farmland soil cultivation in black soil areas.