广西红壤果园土壤肥力退化研究

根据广西第2次土壤普查资料,对广西柑桔、荔枝、龙眼和芒果4种果园土壤肥力状况进行调查。结果表明:广西红壤果园土壤环境恶化,主要表现在果园土壤普遍酸化,柑桔、荔枝、龙眼和芒果4种果园土壤pH分别下降了0.95、0.70,0.89和0.64个单位;有机质减少,其中芒果园和柑桔园下降较多,降幅分别达50.63%和22.45%;有效阳离子交换量(ECEC)下降,柑桔园下降43.64%,而芒果园和龙眼园也有30.77%和27.27%的降幅;容重增加,比第2次普查时增加14%~39%。受施肥投入影响, N、P、K养分在柑桔、荔枝和龙眼园上有增加的趋势,而芒果园在全N、速效P、速效K方面则有较大的下降。利用数理统计软件SPSS对果园土壤环境和养分因素进行综合分析显示,柑桔、龙眼和芒果园均表现出退化,其中芒果园退化最为严重,而荔枝园由于施肥投入较多而使土壤肥力有一定进化。

FERTILITY DEGRADATION OF ORCHARD SOILS IN RED EARTH REGION OF GUANGXI

Based on the data of the secondary soil survey of Guangxi province, soil fertility of four orchards, Orange, Litchi, Longan and Mango was investigated in Guangxi province. Results showed that the orchards all deteriorated in soil environment , which was mainly expressed generally in the form of acidification, decreasing organic matter content, lowering ECEC and rising density. For instance, soil pH in the four orchards (Orange, Litchi, Longan and Mango) dropped separately by 0.95, 0.70, 0.89 and 0.64 unit; soil organic matter decreased in content, especially in the Orange and Mango orchards, by 50.63% and 22.45% separately; soil ECEC lowered by 43.64% in the Orange orchard, 30.77% in the Mango and 27.27% in the Longan; and soil bulk density increased by 14 to 37%. As a result of increased fertilizer application, soil N, P and K showed an increasing trend in the Orange, Litchi and Longan orchards, But total N, readily available P and readily available K in the Mango orchard dropped significantly. Integrated analysis of the soil environment and nutrient factors of the orchard soils with the mathematical statistic softwareSPSS shows that soil fertility degradates in the Orange, Longan and Mango orchards, especially in the Mango orchard. Thanks to higher NPK application in the Litchi orchard, soil fertility there has somewhat improved.