Coupling Effects Of Water And Fertilizer On Walnut Yield And Quality Under Drip Irrigation

Test area is located in Hongqipo forestry, orchard experimental base, Xinjiang Agricultural University, Aksu City, Xinjiang Uygur Autonomous Region. The test crop was 7-year-old walnut tree. There were two factors mainly taking for consideration, which are irrigation and fertilizing. Three gradients was set as irrigation quota(225m3 / hm2?300 m3 / hm2?375 m3 / hm2) and 3 groups of repetition which were W1?W2 and W3 respectively. Three gradients were set as fertilizers(Nitrogen), which were conventional fertilization amount 0.5 times(236.93 kg / hm2)?conventional fertilization(473.85 kg / hm2)?conventional fertilizer doubled(947.7 kg / hm2) with 3 repeats represent as F1, F2 and F3 respectively. Fertilizer setting were processed randomly among 27 trees. Through the analysis of the growth index, photosynthetic characteristics, soil profile water content and soil profile nitrate nitrogen distribution, yield and quality of the indicators, the following conclusions were as follows:1) Soil moisture content changed mainly in the 0-100 cm depth before irrigation after irrigation, and soil moisture content increased with the increasing of irrigation. With the growing of fertilization, soil moisture content first increased and then decreased.2) With the increase of irrigation amount, nitrate nitrogen in root zone soil showed downward trend of migration. With the advanced growth stage, the content of nitrate nitrogen in soil decreased slightly, but more than certain amount of fertilizer would result in the accumulation of nitrate nitrogen in the soil. The excessive of fertilization and below level of irrigation water would cause accumulation of soil nitrate nitrogen.3) Under the same irrigation treatment, fertilizer played on walnut fruit volume were: medium fertilizer > high fertilization > low fertilizer. With the fertilizer increasing, leaf area index(LAI) showed first increased and then decreased. In the same irrigation level, with fertilizer application amount of walnut tree net photosynthetic rate increased, and the diurnal variation rules of transpiration rate and intercellular CO2 concentration were first increased and then decreased. The stomatal conductance decreased clone in moderate conditions. With the increasing of irrigation for walnut, net photosynthetic rate, transpiration rate, and stomatal conductance increased, and cell intercellular CO2 concentration increased at first and then decreased. The clone was reduced.4) The effects of water and fertilizer on yield showed a parabolic trend change. The supplying of Water and nutrients were too high or too low would conducive to the improvement of fruit quality. Under the reasonable irrigation W2 treatment, walnut fruit quality was improved with the increase of fertilization. Through the comparison of the datum above, it obtained that W2-F2 was optimal treatment among these fertigation system.