不合理施肥引起高产稻田土壤退化研究

Degradation process of paddy soils with high yield caused by irrational fertilization

以湖南省醴陵市的健康稻田土壤——河沙泥和红黄泥为供试土壤,以常规早稻品种湘早籼17号、杂交晚稻品种金优207为供试作物,采用盆栽试验,研究了几种不合理施肥实践导致的健康稻田土壤的退化过程.主要结果如下:1)过量施肥引起土壤肥力过高和土壤供肥能力过强,不平衡施肥导致土壤肥力不平衡,二者均导致水稻生长不平衡和减产;长期不施肥对第一季的水稻产量影响较小,但第二季的水稻产量明显低于其他施肥处理.2)过量施肥导致土壤N,P,K的渗漏损失,以化学肥料的过量施用为甚.N,P,K素的渗漏损失分别主要发生在插秧后60,15,30 d.过量施用有机肥明显促进晚稻生育期间的磷素渗漏和对水体环境的污染.

The pot experiment on the degradation process of the paddy soils in relation to irrational fertilization practices was conducted in alluvial sandy earth and reddish yellow clayey earth in 2005. The main results showed as follows： 1） Excessive fertilization could cause excessive soil fertility; it was wasteful and would do harm to rice growth and pollute the environment. 2） All irrational fertilization treatments facilitated leakage loss of N, P, and K nutrient. N leaching appears within 60 days after transplanting rice, P leaching within 15 days, and K leaching within 30 days mostly. Application of inorganic fertilizer was one of the important factors that could lead to water eutrophication. It was noticeable that serious P vertical leaching caused by application of organic manure was threatening to water environment.