连续施肥对土壤供肥和水稻吸肥的影响

连续１０ａ不施肥的土壤仍保持一定的基本肥力．水稻从土壤吸收的养分三要素中有相当一部分通过稻茬、稻根自然归还土壤，这是水稻土保持一定养分水平的物质基础．随着生育期的进展，水稻植株的吸肥总量不断提高．施用化肥不但可提高植株三要素的含量，而且也提高植株吸肥总量，化肥配合增施有机肥（如猪粪或稻草）又有进一步增加植株吸肥强度和吸肥容量的效果．土壤中的速效养分含量随着水稻生育期的进展而逐渐减少．增施化肥有提高土壤中有效养分的作用，如再配施有机肥则有进一步提高的趋势．施肥１０ａ对土壤三要素产投比有明显影响．

Effect of Successive Fertilization on Fertilizer Absorption by Rice and Fertilizer Provision from Soil

A successive fertilization was conducted from 1979 to 1988 to study its effect on fertilizer provision from soil and fertilizer absorption by rice plants.The result revealed that the basic fertility in the soil of non-fertilizing plots still maintained in a certain degree. Among the nutrition of three essential elenents (N, P, K) which absorbed by rice plants from soil, a large amount was come from the return of rice straw and root into the plots. This is the material basis to maintain the nutrition cohdition of paddy soil in a certain levcl. The total fertilizer-absorbing amount of rice plants increased following with the development of rice growing period.Fertilization can not only increase the content of three essetial elements in rice plants but also improved the total fertilizer-absorbing ampunt of rice.The combining application of fertilizer with organic manure,such as pig dung and rice straw, can further enhance the fertilizcr-absorbing intensity and capacity of riet plants.The available nutrition content decteased following with the development of rice growing periord.The increase of fertilizer amount improved the nutrition efficiency in paddy soil;the combining application with organic manure tended to further enhance the efficiency.Successive fertilization obviously affected the input / output ratio of three essential elements in soil.