Abstract:Soil microbial respiration and its entropy (soil metabolic entropy and microbial entropy) are important parameters indicating soil carbon metabolic activity and sensitivity indicators of soil quality, which can reveal the impact of environmental or biological factor changes on soil earlier. Ridge-furrow mulching system is an efficient water-saving cultivation mode widely used in dry farmland in China. In order to prove the influence of limited supplementary irrigation on soil quality under the condition of wheat field, three rainfall conditions (high flow year was 275mm, normal flow year was 200mm, and dry year was 125mm) and four irrigation treatments (150mm, 75mm, 37.5mm, and 0mm) under the ridge-furrow mulching system (RF) were set up during the growth period. Traditional flat planting (TF) was used as the control. The soil microbial respiration, microbial biomass carbon, and its entropy (soil metabolic entropy and microbial entropy) were determined in different soil layers under RF and TF. The results obtained after three years (October 2017 to June 2020) showed that RF had more significant effects on the soil microbial respiration and microbial entropy in the upper soil layer compared with those in the deep soil. Under the same amount of rainfall and supplementary irrigation during the growth period of winter wheat, soil microbial respiration levels under RF in the upper and deep soil layers were 2.47%~21.67% and 3.28%~24.59% higher compared with TF, respectively, and the difference was significant in the years with low flow year (125mm). The microbial entropy was increased by 9.09%~27.05% and 11.9%~24.76% in the upper and deep soil layers, respectively, under RF. These results provided a scientific basis for predicting the soil quality and planning irrigation management for fields under RF by clarifying its effects on the sustainable development of land.
