长期水旱轮作条件下紫色土养分供应能力的研究

通过10年稻—麦水旱轮作定位试验,研究了紫色土生产力以及N、P、K自然供应能力和变化。结果表明,在水旱轮作下,紫色土对稻、麦产量的地力贡献率平均为58%和51%,肥料的增产贡献率可达42%～49%。紫色土N、P、K养分自然供给力在小麦上分别为60%、70%、91%,在水稻上分别为70%、90%、92%,小麦对肥料的依赖性高于水稻;N、P、K养分的自然供应量在小麦上分别为37.1、5.4、45.9kg.hm2,在水稻上分别为81.8、13.6、103.0kg.hm2。随着试验年份的延长,旱作季节紫色土N、P、K养分的供应能力逐年降低,水作季节N、P、K供应力则相对稳定,旱作对地力的消耗比水作大。环境输入的养分在维持水田稳定供肥能力发挥了重要作用。紫色土这种基础养分供给力可维持每年生产小麦1.4t.hm2、稻谷3.5t.hm2左右。

Study on nutrient supplying capacity of purple soil under long-term rice-wheat rotation

The N, P and K natural supplying capacities of purple soil and the basic productivity of purple soil and their varieties were studied with 10 years long-term fertilization experiment in the wheat-rice rotation system. The results of the experiment indicated that the contribution of the natural productivity of purple soil for the yields of wheat and rice were in 51% and 61%, respectively. The contributions of chemical fertilizers for the yield increases of rice and wheat were in 39% and 49%, respectively. The natural nutrient supplying capacities of purple soil to wheat were in 60% for N, 70% for P and 91% for K, and to rice were in 70% for N, 90% for P and 92% for K, respectively. The amount of nutrient demand in wheat was higher than that in rice. The average natural supplying amounts of N, P and K from purple soil with 10-year long-term experiment were 37.1, 5.4 and 46.0kg/(hm²·a) in wheat seasons, and were 81.8, 13.6 and 103.0 kg/(hm²·a) in rice seasons, respectively. In rice-wheat rotation system, the amounts of N, P, and K natural supplying by purple soil gradually decreased in wheat season year by year, while they were stable in rice seasons. That wheat crops gradually depleted the soil fertility was more distinct than rice. The nutrients input of the natural environment played an important role on keeping the stable paddy soil fertility. The natural productivity of purple soil could support some yields of crop, which were about 1.4 t/(hm²·a) for wheat and 3.5 t/(hm²·a) for rice.