Abstract:

To investigate the impact of various tillage methods on soil properties and winter wheat yield when straw is returned to the field in conjunction with a straw decomposing agent, this study established five experimental treatments: rotary tillage with straw returning (CK), rotary tillage with straw returning (XH), subsoiling with straw returning (SH), subsoiling with straw returning and straw decomposing agent (SH+F), and rotary tillage with straw returning and straw decomposing agent (XH+F). The results indicated that compared to CK, other treatments improved soil pH, reduced soil conductivity and bulk density. Compared to CK, XH and SH treatments exhibited increases in soil organic matter, total nitrogen, available nitrogen, available phosphorus and available potassium, although these differences were not statistically significant. Conversely, XH+F and SH+F treatments demonstrated significant improvements in soil organic matter, available nitrogen, and available potassium, thereby enhancing soil fertility. Moreover, compared to CK, XH treatment showed a modest increase in soil enzyme activity, whereas SH, XH+F and SH+F treatments significantly elevated the activities of urease, catalase, dehydrogenase, alkaline phosphatase and invertase in the soil. Compared to the CK treatment, the number of spikes, grains per spike, 1000-grain weight and theoretical yield increased to varying degrees in all treatments. Specifically, the XH treatment significantly enhanced the 1000-grain weight and theoretical yield. Additionally, SH, XH+F and SH+F treatments significantly boosted the number of spikes, grains per spike, 1000-grain weight and theoretical yield per hectare of wheat. Notably, the SH+F treatment demonstrated the highest yield, with a 10.67% increase over the CK treatment. Soil urease activity emerged as the primary factor influencing yield and composition parameters based on correlation analysis. Therefore, soil urease played a pivotal role in determining yield and its composition under the experimental conditions. Considering soil properties and wheat yield, incorporating subsoil straw and implementing straw decomposition proved to be a more suitable tillage approach in this experimental context.

Key words: straw returning, straw decomposing agent, tillage method, winter wheat, soil physicochemical properties, soil enzyme activity, yield