Effects Of N And K On Growth In The Nutrient Solution Of Summer Squash In Substrate Culture

In order to solve the problem of low production, poor quality and low efficiency of the production of the summer squash. "Little Prince" was chosen in this experiment as the experimental material, and an completely random experiment plan was designed from research on single factor K and N in nutrient regulation to the summer squash substrate cultivation to the interaction of two factors of N and K in nutrient solution at three levels. In order to study the absorption characteristics and utilization efficiency of the nutrients by the summer squash substrate cultured, the effects of N and K as well as their interaction on the growth, yield, quality of summer squash as well as absorption characteristics of mineral nutrition by summer squash were studied, so as to obtain the optimal formulation of nutrient solution for the cultivation of summer squash and provide theoretical basis and technical parameters for the preparation of the nutrient solution and the nutrient distribution in the late stage. The main results are as follows:1. When the concentration of N in nutrient solution was 12.6mmol/L, K at CK, chlorophyll content at different growth stages of summer squash, yield per plant(1616.72g), content of Vc(63.8mg/100g) and soluble protein(1.55mg/g) in the fruit of the summer squash was significantly higher than that of +20N and-20%N treatment(P<0.05); for plant height, +20%N treatment was beneficial to the growth. The summer quash plants showed leggy when N concentration was too high, and the chlorophyll content was lowed, the reproductive growth of summer squash was inhibited at the late growth stage and the the yield of squash fruit was lowed. It could be concluded from the above results that the level of N in nutrient solution suitable for the growth and development of summer squash was 12.6mmol/L.2. when the concentration of K in the nutrient solution was 6.6mmol/L, N was supplied at the original CK concentration, yield per plant(1235.09g), content of Vc(60.19mg/100g), soluble protein(2.21mg/g), NO3-(0.12mg/kg) and organic acid(0.193%) in the fruit of summer squash was significantly higher than that of-10%(K) and-20%(K) treatment(P<0.05). Therefore, the proper concentration of K had a certain promotion effect on the fruit quality It was concluded that the K levels in the nutrient solution suitable for the growth and development of the summer squash was 6.6mmol/L.3. The growth of various organs of summer squash and N, P and K, Ca and Mg absorption, as well as the rate of nutrient distribution in different organs were significantly affected by different N and K interaction treatment When N=15.4mmol/L, K=6mmol/L, the summer squash had the highest quality of dry matter at different organ and dry matter of the whole plant. When N=14mmol/L, the quality of dry matter of all organs and the whole plant showed a decreasing trend with the increase of K level. Low N and high K levels, namely N=12.6mmol/L, K=6.6mmol/L, the N uptaken by stem, leaf and whole plant was significantly higher than that of low and middle K levels. The K uptake of each organ decreased with the increased level of N. when K=6.6mmol/L, K uptake by showed an increasing trend. The uptake of K by root, stem, leaf and whole plant was significantly higher for the plant grown at N=15.4mmol/L than that of N=12.6mmol/L. When the plants were grown at N=12.6mmol/L, the P content in each organ was significantly higher for squash plants grown at high K level than that of at the middle and low K levels, The distribution rate of P of different parts was also higher than other treatments. Ca absorption by stems and leaves as well as whole plant was significantly higher when the plants were grown at the level of N=14mmol/L than that at N=15.4mmol/L.4. When concentration of N was 12.6mmol/L, and K was 6.6 mmol/L in the nutrient solution, yield of summer squash fruit per plant(1235.09g), contents of Vc(60.19mg/100g), soluble protein(2.21mg/g), NO3-(0.12mg/kg) and organic acid(0.193%) in the fruit of summer squash was significantly higher than that of treatments-10%(N), CK(K) and CK(N), +10%(K)(P<0.05). It was found that the yield and fruit quality of summer sqush was promoted by the interaction of N and K within certain range. It could be concluded that the optimal nutrient solution for the growth and development of the summer sqush in this study was: N =12.6mmol/L, K=6.6mmol/L, Ca, P, Mg, S element formula for general formula.