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.

Key words: Organic fertilizer, Subsoiling tillage, Hydrogen and oxygen isotopes, Photosynthetic characteristics, Water use

摘要： 为探明长期深松和增施有机肥对降水在土壤中分布和利用的影响，以常规耕作处理为对照，利用氢、氧同位素示踪技术研究长期深松和增施有机肥对降水中氢、氧同位素在土壤中的分布和玉米水分利用的影响。结果表明，长期深松和增施有机肥改善了土壤结构和降水在土壤中的分布、利用。随着土层加深，玉米拔节期和灌浆期所有处理土壤含水率总体上均呈逐渐降低的趋势。收获期，所有处理土壤含水率明显回升，随土层加深总体上均呈逐渐增加的趋势。拔节期和灌浆期，深松处理均明显提高了0~80 cm土层土壤含水率。收获期，深松和增施有机肥处理均提高了0~100 cm土层土壤含水率。在拔节期，所有处理0~40 cm土层水分贡献率明显高于其他土层，均达90%以上，以20~40 cm土层水分贡献率最高。灌浆期，常规耕作、深松和增施有机肥处理均主要利用了20~60 cm土层的水分，其水分贡献率分别达46.3%、53.4%、92.7%。随玉米生育进程的推进，所有处理土壤储水量和玉米耗水量总体上均呈逐渐增加的趋势。与常规耕作处理相比，深松、增施有机肥处理均利于增加拔节期、收获期土壤储水量，降低玉米播种—拔节期和灌浆—收获期的耗水量。且深松、增施有机肥处理均有利于提高玉米灌浆期的净光合速率和气孔导度，提高拔节期和灌浆期叶片水分利用效率。最终，深松、增施有机肥处理显著提高了玉米产量（10.6%、9.4%）和水分利用效率（13.6%、12.2%），但两处理之间差异不显著。相关性分析结果表明，拔节期，0~20 cm土层土壤水分贡献率与玉米产量和水分利用效率均呈显著正相关；灌浆期，0~20 cm土层土壤水分贡献率与玉米产量和水分利用效率均呈显著负相关。综上，长期深松和增施有机肥可有效调控降水在土壤中的合理分布，改善玉米光合特性，促进降水资源的高效利用，提高玉米产量和水分利用效率。

关键词: 玉米, 有机肥, 深松, 氢、氧同位素, 光合特征, 水分利用