Effects of organic manure substituting chemical fertilizer on soil fertility and fruit yield and quality in citrus orchard

Abstract

为探究猪粪和鸡粪有机肥部分替代化肥对椪柑橘园土壤培肥及果实产量品质的影响，通过2年定位试验，选用鸡粪和猪粪2种有机肥，开展7.5 t·hm^-2和15 t·hm^-2替代施用量对椪柑橘园土壤肥力、果实产量及品质的影响效果研究。结果表明，采用鸡粪和猪粪2种有机肥部分替代化肥的模式，可明显提升柑橘园土壤肥力。与全化肥处理相比，施用有机肥替代化肥处理的土壤酸化有所改善，全氮、有效磷、速效钾和有机质含量分别提高16.1%~54.7%、15.9%~30.1%、12.9%~36.9%和6.8%~39.6%。土壤微生物多样性的香农指数和均匀度增加，平均CO₂产生率总体随着有机肥替代量的增加而提高，微生物数量明显增加。在同等有机肥替代化肥施用量条件下，猪粪有机肥培肥地力和增加土壤微生物数量及多样性的效果优于鸡粪有机肥。有机肥替代化肥处理较全化肥处理提高柑橘产量5.1%~19.5%，增加果实可溶性总糖2.7%~11.8%、维生素C 2.1%~10.8%、可溶性固形物5.9%~10.8%。7.5 t·hm^-2猪粪有机肥替代化肥处理柑橘产量最高，而15 t·hm^-2猪粪有机肥替代化肥处理柑橘品质最好。研究表明，采用有机肥部分替代化肥的施肥模式，有利于提高椪柑橘园土壤肥力和微生物多样性，进而提高果实产量、改善柑橘品质。

This study investigated the effect of substituting chemical fertilizer with organic manure on soil fertility and the yield and quality of the fruit in a ponkan citrus orchard. A 2-year field experiment including two different application rates(7.5 t·hm^-2 and 15 t·hm^-2) of chicken manure and pig manure was conducted. Results showed that substituting chemical fertilizer with organic manure significantly improved soil fertility in a citrus orchard. The soil pH as well as the contents of the total nitrogen, available phosphorus, available potassium, and organic matter in the organic manure substituting chemical fertilizer treatments were higher than those in the only chemical fertilizer-applied treatment and increased by 16.1%-54.7%, 15.9%-30.1%, 12.9%-36.9%, and 6.8%-39.6%, respectively. The soil microbial diversity index of Shannon and Evenness increased upon substituting chemical fertilizer with organic manure, and correspondingly the average soil CO₂ production rate increased. Pig manure showed stronger improving effects on soil fertility and microbial quantity and diversity than chicken manure. Furthermore, substituting chemical fertilizer with organic manure was beneficial for ponkan citrus production by increasing the yields by 5.1%-19.5%, total soluble sugar 2.7%-11.8%, vitamin C 2.1%-10.8%, and soluble solids 5.9%-10.8%. The highest yield was found in the treatment with 7.5 t·hm^-2 pig manure, while the best fruit quality was found in the treatment with 15 t·hm^-2 pig manure. Overall, substituting chemical fertilizer with organic manure is an effective strategy for improving soil fertility and microbial activity, thus increasing the yield and quality of citrus.