Effects of Long-Term Application of Subsoiling and Organic Fertilizer on Distribution of Hydrogen and Oxygen Isotopes in Precipitation and Water Utilization of Maize

YANG Yonghui; WU Jiabin; ZHANG Yunhong; ZHANG Tinghao; GAO Cuimin; HAN Weifeng; PAN Xiaoying; HE Fang; Devotha G.NYAMBO; LUO Ning

doi:10.15933/j.cnki.1004-3268.2025.12.001

Abstract：In order to elucidate the effects of long-term subsoiling tillage and application of organic fertilizers on distribution of rainfall in soil and utilization,based on hydrogen and oxygen isotopes tracing method,the effects of long-term subsoiling tillage and application of organic fertilizers on the distribution of stable hydrogen and oxygen isotopes in soil and water use of maize were studied with conventional tillage treatment as control.The results showed that long-term subsoiling tillage and application of organic fertilizers improved soil structure and the distribution and utilization of precipitation in the soil.The soil moisture generally gradually decreased with the increase of soil depth at jointing and grain filling stages of maize.At harvest stage,the soil moisture obviously increased,and increased with the increase of soil depth.At jointing and grain filling stages,subsoiling tillage notably increased the 0-80 cm soil moisture.At harvest stage,both the subsoiling tillage and application of organic fertilizers treatments increased the 0-100 cm soil moisture.At jointing stage,the contribution rate of water from the 0-40 cm soil was obviously higher than those in other layers,reaching over 90%,and the contribution rate of water from the 20-40 cm soil was the highest.At grain filling stage,conventional tillage,subsoiling tillage and application of organic fertilizers treatments mainly utilized the water in 20-60 cm soil,and the water contribution rate reached 46.3%,53.4%and 92.7%,respectively.As the growth stage progressed,the soil water storage capacity of all treatments generally gradually increased.Compared with conventional tillage treatment,subsoiling tillage and application of organic fertilizers were more beneficial for increasing soil water storage at jointing and harvest stages,and decreasing water consumption during sowing—jointing and grain filling—harvest period;meanwhile,subsoiling tillage and application of organic fertilizers were more beneficial for increasing the net photosynthetic rate and stomatal conductance at grain filling stage of maize,as well as improving leaf water use efficiency at jointing and grain filling stages.Ultimately,subsoiling tillage and application of organic fertilizers significantly increased maize yield(10.6%,9.4%)and water use efficiency(13.6%,12.2%),although the difference between the two treatments was not significant.Correlation analysis showed that the contribution rate of water in 0-20 cm soil was significantly positively correlated with maize yield and water use efficiency at jointing stage,and significantly negatively correlated with maize yield and water use efficiency at grain filling stage.In conclusion,long-term subsoiling tillage and application of organic fertilizers can effectively regulate the rational distribution of precipitation in soil,improve the photosynthetic characteristics of maize,promote the efficient utilization of rainfall,and increase the yield and water use efficiency of maize.