[Soil carbon and nitrogen sequestration and associated influencing factors in a sustainable cultivation system of fruit trees intercropped with cover crops].

We comprehensively quantified the influence of cover crops on soil carbon and nitrogen storage in Chinese orchards by a meta-analysis based on the literature published during 1990 to 2020. The factors influencing soil carbon and nitrogen storage were also analyzed. The results showed that compared with clean tillage, soil carbon and nitrogen storage under the cultivation of cover crops considerably increased by 31.1% and 22.8%, respectively. Intercropping legumes enhanced soil organic carbon storage by 4.0% and total nitrogen storage by 3.0% compared with non-legumes. The effect of mulching duration was most prominent at 5-10 years, with 58.5% and 32.8% increases in soil carbon and nitrogen storage, respectively. The largest increase in soil carbon and nitrogen storage (32.3% and 34.1%, respectively) occurred in areas with low initial organic carbon (<10 g·kg-1) and total nitrogen (<1.0 g·kg-1). In addition, suitable mean annual temperature (10-13 ℃) and precipitation (400-800 mm) markedly contributed to soil carbon and nitrogen storage in the middle and lower reaches of the Yellow River. The findings indicated that multiple factors influence the synergistic changes in soil carbon and nitrogen storage in orchards, while intercropping with cover crops is an effective strategy for enhancing soil carbon and nitrogen sequestration.基于1990—2020年间已发表的文献数据,应用荟萃分析综合量化种植覆盖作物对中国果园土壤碳氮储量的影响,并分析其影响因素。结果表明:与清耕相比,种植覆盖作物能显著增加土壤碳氮储量,增加效应分别为31.1%和22.8%。与非豆科作物相比,种植豆科作物使土壤有机碳和全氮储量分别提高4.0%和3.0%;覆盖年限为5～10年时对土壤碳氮储量的增加效应最显著,分别增加58.5%和32.8%。土壤基础条件较差的地区(初始有机碳<10 g·kg-1,初始全氮<1.0 g·kg-1)土壤碳氮储量增加效应最高,分别达32.3%和34.1%;此外,黄河中下游年均温度(10～13 ℃)和年均降水(400～800 mm)条件适宜的地区土壤碳氮储量增加效应更明显。综上,果园土壤碳氮储量的协同变化关系受到多种因素的影响,果树间套作覆盖作物是提升土壤碳氮固存的有效途径。.