| Fertilization was one of the most effective cultivation ways to regulate tea yield and quality. In this paper all the fertilizer factors (kinds of nitrogen fertilizer and its rate, combinations of N, R K, selenium application), which had an effect on tea yield and quality, were designed on the condition that fertilizer was applied to the same tea varieties. The main objective was to compare the different effects of fertilizer treatments on tea yield and quality. Three years old of Mengshan 213 was grown in container. Tea was picked out to determine content of amino acid, tea polyphenols, catechins, NO3--N and NO2--N of leaves. Three aspects were studied throw statistic analysis: a) effect of different kinds and amount of nitrogen fertilizer on quality of tea; b) modeling for fertilizer measure of tea high yield; c) effect of selenium application on selenium content and chemical quality of tea .The main results are as below:1. Effect of different kinds of nitrogen fertilizer and its rate on yield and quality of teaYield of tea was significantly increased by application of urea.Kinds of nitrogen fertilizer, nitrogen fertilizer rate, kinds and rate all had significant effect on qualities of tea harvested in spring (except soluble sugars). Content of NO3- and NO2- were significantly increased using NO3--N fertilizer included ammonium nitrate and calcium nitrate, but ammonium sulphate, ammonium bicarbonate and urea had few effects on content of NO3- and NO2-.Applying the five kinds of nitrogen fertilizer improved qualities of tea harvested in different seasons. Considering qualities of tea picked in spring, summer and autumn, urea was the best nitrogen fertilizer, and 0.5g/kg soil was the optimum amount.2. Effect of nitrogen, phosphorus and potassium combined application on yield of tea The regression equations of the relationship between N, P2O5 and K2O on the yield of tea were established as follows: Y'=22.802+2.177X1+4.494X2+5.079X3-0.196X12-1.06X22-1.022X32+0.054X1·X2+111X1·X3+0.226X2·X3.Yield of tea would increase with high nitrogen supply, and phosphorus and potassium had certain effects on it, the order is N>P>K, the interactions of N-P, N-K to the yield were significant. Considering both the yield and quality of the hot pepper, the combinations of N, P2O5 and K2O were optimized as follows: N: 0.406-0.435g/kg soil, P2O5: 0.159-0.170g/kg soil, K2O: 2.98-3.16g/kg soil, and N : P2O5 : K2O was 1 : 0.39 : 0.46.3. Effect of selenium application on yield and quality of teaApplying selenium to foliar or soil not only significantly increased yield and selenium content of tea but also highly improved chemical qualities of tea. The selenium content of tea harvested in spring tea-producing season reached maximum in the 12th day after sodium selenite spaying at concentration 120ug/ml. The selenium content of tea harvested in summer and autumn tea-producing season reached maximum in the 18th day after sodium selenite spaying at concentration 180ug/ml. Selenium-enriched tea was harvested after applying selenium to soil over 500-ug/kg soil.When selenium concentration of spaying was 180ug/ml, chemical qualities of tea harvested in summer tea-producing season was the most highly improved, and the proportion of tea polyphenols and amino acid was 65.73% of CK while the content of soluble sugar was 116.30% of CK. The catechins content of tea harvested in different tea-producing season decreased after foliar fertilization but it had not obviously changes after applying selenium to soil. In improving chemical qualities of tea especially tea harvested in spring, applying selenium to soil was better than foliar fertilization.
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