Fruit quality and yield in orchards will decrease after long-term planting. To analyze the changes of soil quality under different planting years and identify the key factors of the declining of orchard soil quality could provide scientific foundation for optimizing fertilization management of orchard soil. In this study, we analyzed the changes of soil physical, chemical, and biological properties of loquat orchard under different planting years (<10 years, 10-15 years, 15-20 years, ≥20 years) in Ninghai County, Zhejiang Province, and evaluated soil health by using soil quality index, multifunctionality index, and sensitivity and resistance indicators. The results showed that, compared with the orchards planting less than 10 years, soil bulk density in the orchards with planting years of 10-15 years and over 20 years increased by 12.8% and 13.6%, respectively. Soil pH decreased by 8.8%, 8.6%, and 7.5% in the orchards with planting years of 10-15 years, 15-20 years and over 20 years, respectively. With the increase of planting years, soil microbial biomass carbon, soluble organic carbon, soluble organic nitrogen, available phosphorus, available potassium, total organic carbon, total nitrogen decreased, and the soil quality and multifunctionality index of loquat orchard soil decreased. Compared with the orchards planting less than 10 years, soil quality index and soil multifunctionality index decreased by 20.4% and 17.9% for the orchards with the planting years of 10-15 years, 38.1% and 25.2% for the orchards with the planting years between 15-20 years, and 50.7% and 35.5% for the orchards planting over 20 years, respectively. The key factors affecting soil quality of loquat orchards were soil soluble nitrogen, available potassium, and available phosphorus. Amongst the available nutrients, NH4+ and NO3- were the sensitive indices in orchard soil. In conclusion, long-term planting decreased soil quality and available nutrient content in loquat orchards.
果园经过长时间种植后,果实品质、产量均会出现下降。分析不同种植年限下果园土壤质量的变化,明确造成果园土壤质量下降的关键因素,可为优化果园土壤施肥管理提供科学依据。本研究以浙江省宁海县不同种植年限下(＜10年、10～15年、15～20年、≥20年)枇杷果园土壤为研究对象,分析土壤物理、化学和生物学性质的变化,并运用土壤质量指数、多功能性指数、敏感性和抗性指标,对不同种植年限的枇杷果园土壤进行健康评价。结果表明: 种植年限为10～15年和≥20年的果园土壤容重分别比＜10年的果园土壤提高12.8%和13.6%。10～15年、15～20年和≥20年的果园土壤pH与＜10年的相比分别下降8.8%、8.6%和7.5%。随着种植年限的增加,果园土壤微生物生物量碳、可溶性有机碳、可溶性有机氮、有效磷、有效钾、总有机碳、全氮等养分和有机碳组分均有不同程度的下降,果园土壤质量和多功能性指数下降。相较于＜10年的果园,土壤质量指数和多功能性指数在种植10～15年时分别下降20.4%和17.9%,在15～20年时分别下降38.1%和25.2%,种植年限≥20年时分别下降50.7%和35.5%。随机森林模型分析发现,土壤可溶性氮、有效钾、有效磷等有效态养分是影响枇杷果园土壤质量变化的关键因子;而有效态养分中,铵态氮和硝态氮是果园土壤相对敏感的指标。枇杷果园长期种植使土壤质量持续降低、有效养分含量下降。.
Keywords: loquat; orchard soil; soil health evaluation; soil nutrient; soil quality.