Productivity and nutrient budget of rice ecosystem in lower reaches of Liaohe River plain under effects of different fertilization patterns
不同施肥模式对下辽河平原水稻生态系统生产力及养分收支的影响

To study the effects of different fertilization patterns on the rice ecosystem's productivity and nutrient budget in the lower reaches of Liaohe River plain,a field experiment was conducted at the Shenyang Ecological Experimental Station of Chinese Academy of Sciences The results showed that with the increasing degree of balanced fertilization,rice ecosystem's productivity increased gradually,being the highest in treatment NPK.Among the chemical fertilizers,N fertilizer contributed most to the rice productivity(20% to biomass and 34% to grain yield),while P and K fertilizers had the similar contribution rates.As for the allocation of the absorbed nutrients in rice plant,N was mainly in grain and stalk,while P and K were more concentrated in grain and in stalk,respectively.Under fertilization,less fluctuation was observed on the contents of soil organic matter and total N,P and K,but the amounts of soil available nutrients varied greatly,especially for available P and available N.Fertilization with organic manure induced a higher content of soil available nutrients,compared with applying chemical fertilizers alone.