Responding Mechanism Of Greenhouse Cucumber To Different Drip Irrigation Amount Ang Various Fertilization Methods

Shortage of water resources and soil-water environment pollution are two main factors that restrict the sustainable development of agriculture vegetable production in Northwest China. With the development of modern agriculture, fertigation is the most effective water and fertilizer saving technology. Effectively promote fertigation technology in water shortage area of Northwest China, will be very important to improve the yield and quality of vegetable, water and fertilizer saving.In view of the questions of unreasonable irrigation and nitrogen method in the vegetable greenhouse, effects of irrigation amount and drip fertigation method on growth, physiology, yield, quality, nutrient uptake and nutrient transfer of cucumber in greenhouse were investigated in order to optimize the arid and semi-arid region of Northwest China, water and fertilizer management model for greenhouse vegetable greenhouse vegetables, water and fertilizer regulation to achieve scientific, efficient water-saving, high yield and high qualityproduction targets and provide a theoretical basis. Taking cucumber as experimental plant, an experiment was conducted to study the effects of irrigation amount and drip fertigation method on growth, yield and quality of cucumber in plastic greenhouse. The experiment had designed two irrigation levels, i.e. 100% ET0(W1) and 75% ET0(W2), and four drip fertigation methods, i.e. equal amount of fertilizer were applied through fertigation at the levels of 100%, 66.6%, 33.3% and 0%(Z100, Z66, Z33, Z0) by 8 times, and the corresponding remainders(0%, 33.3%, 66.6% and 100%) were applied to soil as basic fertilization before the planting according to the recommended fertilization rate(N 360 kg·hm-2, P2O5 180 kg·hm-2, K2 O 540 kg·hm-2), and no fertilizer treatment was set up as the control(CK). Specific results are as follows:(1). Water and fertilizer has remarkable effect on the plant height and leaf area. High water(W1) treatment, the plant height and leaf area was significantly higher than that of low water(W2) treatment. With the decrease of drip irrigation and fertigation rate, plant height and leaf area showed a decreasing trend. Each organ dry mass accumulation was positively correlated with the amount of irrigation and drip irrigation and fertigation rate. Photosynthesis and respiration intensity increased with irrigation and drip irrigation and fertigation rate. Fertigation methods significantly influence on chlorophyll a, chlorophyll b and total chlorophyll. With the increase of fertigation rate, chlorophyll content increased, but the effect of irrigation on chlorophyll content was not significant. Z100 treatment could increase the growth indices in the late growth stage. The plant height, aboveground dry weight and chlorophyll content, shoot dry matter and total chlorophyll had significant positive correlation.(2). Effects of irrigation and Fertilization on Yield and quality of greenhouse cucumber was significantly. Increasing the amount of irrigation can increase the yield of cucumber, fruit number and fruit weight. Coupling effect of water and fertilizer had no significant effect on the number and fruit weight of cucumber. The water use efficiency of W2 treatment was significantly greater than W1 treatment. W2 treatment had highest water use efficiency, reaching 47.71 kg·m-3. The yield of W2Z100 is 3.43% lower than W1Z100, but can save 25% of irrigation water. The greenhouse cucumber yield of Z100 treatment was higher 2.66%, 7.36%, 15.34% and 59.37% than Z66, Z33, Z0 and CK treatment. Irrigation had significant effects on vitamin C and nitrate content of cucumber. Varouis fertigation methods had extremely significant effect on the indexes of quality of cucumber in greenhouse. Compared with Z0, Z100 treated cucumber yield and dry weight increased by 15.3% and 16.8%; the water use efficiency increased by 19.1%, while increasing the content of cucumber fruit of vitamin C, soluble protein and soluble sugar. Under various fertigation methods, yield and quality(except soluble sugars) were positively correlated with the amount of irrigation and fertigation rate. Increase the amount of irrigation, yield, vitamin C and soluble protein content increased, but WUE and soluble sugar content decreased. In the same amount of irrigation and fertigation methods conditions, increasing the proportion of fertigation can achieve high yield and quality effect.(3). The “small number of multi-frequency”of fertigation mode has significant yield and higher fertilizer use efficiency. Irrigation and fertigation had significant effect on nutrient accumulation in plant organs, the absorption and utilization efficiency. Accumulation of nitrogen phosphorus and potassium content in different organs showed: the fruit > leaf > stem > root, and significantly affected with irrigation. The average phosphorus and nitrogen, potassium uptake of Z100 treatment was higher 21.1%, 21.9% and 22.2% than Z0 treatment, and was significantly higher than that in other treatments. PFP of W1Z100 treatment was the largest, reaching 62.7 kg·kg-1. In the case of irrigation 25% higher than W2Z100, PFP only 3.4% high than W2Z100. The fertilizer use efficiency of fertigation by times is higher than once base, and more conducive to improving the quality of cucumber fruits. Graded top dressing fertilizer can promote high yield and quality of greenhouse cucumber.(4). The increase of the content of irrigation water and increase the proportion of drip fertilization can reduce soil nitrate nitrogen, available phosphorus and available potassium. Under irrigation and plant root absorption, soil nitrate accumulation to the edge of the moist body. The upper layer of soil nitrate nitrogen variation of Z0 treatment. Varied significantly between the different treatments. The soil available phosphorus content and mobility are relatively small. Small changes in soil available phosphorus in growth period, and is mainly distributed in the upper soil. The soil available phosphorus content is low under 40 cm. The content of available potassium in soil is greater than phosphorus and nitrogen. With the growth period, potassium concentration decreased along the horizontal direction and vertical direction. The available potassium decreased rapidly in the 0 ~ 40 cm soil layer. With the increase of the proportion of soil available potassium fertigation reduces in the early fertility stages. With the increase in the proportion of fertigation of soil available potassium decreased the growth end stage. The content of soil available potassium in Z0 treatment was significantly lower than that of Z100 treatment.