Abstract: Different NPK supply levels were applied in different fertility soils to study the effects of nutrient supplyand soil fert ility on super rice yields and the nutrient use efficiency. Experimental results can be summarized as follows:with the increase of N supply, super rice yields increased first, then decreased with peak occurring at N supply of 180kg/ ha.Positive correlation between nitrogen background value in soil and yield in blank plots was observed with R=01893 0, that is, high yield can be harvested even with no applicat ion of N as long as the nitrogen background value insoil is high enough. As for nitrogen use efficiency, it demonstrated extremely significant negative correlation with N supplylevel and accorded to a single-peak curve with nitrogen background value in soil. The nitrogen harvest index decreaseswith the increase of N supply while soil nitrogen content doesnct inf luence it. Under condition of severer deficiency ofphosphorus and potassium, supply of P and K can significantly increase the yields with posit ive correlation between the supply level and yields, R=01984.1 and R= 01940.8 for P and K, respect ively.And with the increase of soil phosphorusand potassium contents, the yield- increasing effects decreased steadily and even reduced the yield when soil phosphoruscontent>10 mg/ kg. Significant negative correlation between the agronomic use efficiency and apparent utilization rat io ofphosphorus and potassium and their application value can be observed with R= - 01961.1 and R= - 01904.9 for phosphorus,R= - 01953.4 and R= - 01947.2 for potassium, respectively. Physiological use efficiency is determined by soilbackground value and has complicated relations with application value. Correlations between phosphorus agronomic use efficiency,apparent ut ilization ratio and phosphorus background value in soil accord to a one-peak curve with peak of phosphorususe efficiency occurring when there is slight deficiency of soil phosphorus content. Correlation between potassiumagronomic use efficiency and soil potassium content is similar with that of phosphorus while negative correlation was observedbetween its apparent utilizat ion ratio and soil potassium content. Harvest index of phosphorus and potassium is similarwith that of nitrogen, decreasing with the increase of applicat ion value and soil phosphorus and potassium content hasno effects. Based on the afore-ment ioned results, it can be conclude that local soil fertility conditions should be consideredin super rice production.To achieve high yields and high fertilizer use efficiency, efforts should be concentrated on decreasing fert ilizer application value while increasing the use efficiency.

Key words: Different fertility soils, Different nutrient levels, Super rice, Nutrient use eff iciency

CLC Number: 

• S147.2

• S275.4