Effects Of Nitrogen Rates And The Formulation On Yield And Quality Of Sweet Orange In Sichuan Province

Based on the production practice, production investigation, field experiment, indoor test, this research does research into issues such as nutrient status、the situation of fertilizer nutrition diagnosis, to know the problem of sweet orange production in Sichuan. Understanding the influence of nitrogen fertilization on sweet orange production, we establish an effective model of nitrogen.This research selected 7 major orange-producing counties of Sichuan as test ground. The field experiments include three major trials as follows:(1) the total nitrogen control test:we set up 4 nitrogen(N) dosage levels(N fertili-zation free,70% optimized N fertilization, optimized N fertilization,130% optimized N fertilization, noted as N0, N1, N2, N3 respectively); (2) N fertilizer regulation in stages test: we set up 3 nitrogen(N) application patterns(the first pattern is that bud fertilizer, steady fruit fertilizer and strong fruit fertilizer are applied as 40%,40%,20% respectively; the second pattern is that spring fertilizer and strong fruit fertilizer are applied as 60%,40%; the third pattern is that the spring fertilizer is applied as 100%; three different patterns are noted as Na, Nb, Nc respectively); (3) the fruit trees formula fertilization experiment:we set up 5 types of fertilizer(Farmers conventional fertilization, large area formula fertilization, minor adjustment on the basis of regional big formula fertilization, organic-inorganic fertilization, slow release fertilization, noted as A,B,C,D1,D2). P,K were disposable used as basic manure. we analyzed correlation among Sichuan sweet orange production, quality, mid-nutrition, the nutrient element of soil and leaf, fruit production and quality. The major research results are as follows:(1) The a major source of income is sweet orange production for most of the farmers in Sichuan.There are many problems seriously affected the further development of sichuan sweet orange like planting technology lagged behind, lack of scientific fertilizer application, no new varieties of sweet orange and government policy support is insufficient.(2) The orange garden soil effective mineral elements content is relatively rich in sichuan.Soil alkali-hydrolysable N, exchangeable Ca and effective Fe,Mn content are reaching or higher than good value and not too much; Effective Zn,B content is slightly lower effectively; and the remaining elements in the appropriate level.the N,K,Zn and Cu of leaf content is lower; More than 90% of the region of leaf P element is in high quantity even excessive levels; Ca, Fe and B of leaf content rich; Mn content is appropriate but Cu content is lower.(3) Our researches specify that soil effective mineral elements of rich or lack is certain corresponding relationship with the match up mineral elements of rich or lack about leaf, but there is no significant correlation between corresponding elements. It is indicate that the rich or lack condition of soil nutrient in sweet orange orchard does not necessarily reflect the rich or lack condition of corresponding nutrient element in leaves. The content of high and low about effective mineral elements in soil is not a simple corresponding relationship with nutrient elements of leaves.(4) Our researches specify that when the corresponding amount of nitrogen fertilizer of N2 and the ratio of bud fertilizer, steady fruit fertilizer and strong fruit fertilizer apply as 2:2:1, the effect to sweet orange production and quality is optimum. And the yeld, edible rate, juice rate of fruits were imprived, the sugar accumulation was increased, TA was reduced.It is indicate that when the corresponding amount of nitrogen fertilizer of N2 and the ratio of bud fertilizer, steady fruit fertilizer and strong fruit fertilizer apply as 2:2:1 can improve production and quality of Sichuan sweet orange effectively.(5) Our researches specify formulated fertilization such as D1,D2 improves the yield of Sichuan sweet orange when traditional fertilization (A) was used as control sample. D1 increases production by 21.49% while the D2 improves the yield by 21.40%. furthermore, the indication of juice percentage, edible rate, total sugars, vitamin C and solid content to titration acid demonstrates the change rule as follows:D2>D1>C>B>A, while the change regulation shows the adverse results. And no significant change in the content of soluble solid content.