Study On Management Techniques Of Water And Fertilizer On Rellis-Cultivated Melon

Based on local field investigation on yields and fertilization situation of trellis-cultivated melon（Cucumis melo var. saccharinus Naud） in Kashi region, this research takes the trellis-cultivated melon as anexample in south of Xinjiang, through making field experiments of the fertilizer and water-nitrogencoupling effects, the balanced fertilizing parameters, phosphorus fertilizer effect, water-nitrogen couplingeffect, the index of nitrogen nutrition diagnosis and the photosynthetic characteristics of trellis-cultivatedmelon have been studied by field monitoring and statistic analyzing. The results are as follows:（1） Accounting for93%of investigated farmers had tradition of applying farmyard manure. Thefarmyard manure of base fertilizer was36000kg/ha and the chemical fertilizer was339kg/ha. Thefarmyard manure of top application was13000kg/ha and the chemical fertilizer was364kg/ha. Theapplication rate of N, P₂O₅and K₂O was296,410and278kg/ha. Ratio of N:P₂O₅:K₂O was1:1.4:0.9. Thehighest yield was68000kg/ha and the lowest yield26000kg/ha.（2） Trellis-cultivated melon need amount of N, P₂O₅and K₂O in different growing period accountingfor0.12%,0.05%,0.10%（seeding） and6.78%,6.35%,4.80%（stretch tendril） and85.70%,74.90%,63.20%（fruit rapid-expanding） and7.40%,18.70%,31.90%（maturation stage） of total absorptive amountrespectively under the optimum combinations of fertilizers. The amount of N, P₂O₅and K₂O absorbed by100kg trellis-cultivated melon was207.0,43.1and536.6g accordingly. The ratio of N: P₂O₅: K₂O was1:0.21:2.59. The utilization coefficient of nitrogen, phosphorus and potassium are1.87（1.71-2.0）,1.02（0.87-1.26） and1.30（0.73-1.93）. The utilization rate of nitrogen, phosphorus and potassium fertilizer are26.2%,13.5%and47.8%. The yields regression equation was Y=-0.3833X2+173.36X+49854.64, theresults suggest that as the yield was close to69452kg/ha, the appropriate phosphorus application was222.6kg/ha. The excessive application of phosphorus could not increase the yields and lead to excessiveaccumulation in soil.（3） Nitrogen lead to fruit weight increasing, the yield increased31.0%. The rotten fruit ratio increasedsignificantly when the nitrogen level increased by375kg/ha and quantities of water close to8250m3/ha.The highest NAE was obtained with quantities of water in6750-7500m3/ha and decreased as the N levelincreased. The highest IWUE was obtained with applications of nitrogen close to225kg/ha. The Vccontent for N375was the lowest that was11.3%to25.6%lower than N0. The flesh ratio and skin ratio werenot influenced by the irrigation, while nitrogen could increase the flesh ratio and reduce the percentage ofplacenta and seeds weight. The results suggested that as the yield close to81745kg/ha, the optimumcombinations of nitrogen and irrigation were303kg/ha and7405m3/ha without lessening quality.Daily changes of Pn of trellis-cultivated melon leaf presented a bimodal curve, peak value appeared at 11:00-13:00and17:00. Irrigation quantity （6750,8250m3/ha） improved the Pn and Gs of the melon leaf.The Pn and WUE increased significantly at the application amount of nitrogen were225,375kg/ha, and nosignificant difference between225and375kg/ha.（4） Each of the critical value of soil nitrate nitrogen was48.8-77.8,44.6-72.6and29.2-45.9,25.1-35.5mg/kg under condition of0-30cm and30-60cm soil in fruit setting stage and fruit rapid-expanding stage.The recommended nitrogen was148.0-417.2,145.4-412.3and134.8-399.4,148.7-421.0kg/ha.185.4-370.4kg/ha nitrate N was found in depth of0-150cm soil after harvested, with66.6-81.5%of it accumulating indepth of0-60cm, and33.9-62.8%of it accumulating in depth of0-30cm. No evident nitrate accumulationwas found in deep layer of soil（90-150cm） after harvested. Icreased nitrate N caused by N fertilizerapplication accounted for38.5%（N225kg/ha） and49.7%（N375kg/ha） of fertilizer N, respectively.