Study On Tree Growth, Fruit Development, Nutrition And Water Absorption In Kiwifruit Cv Xuxiang

In order to confirm nutrient and water absorption of kiwifruit at different stages of growth and development for fertilizer and water management, we studied the effect of different nutrient concentration (50 mg.L^-1, 100 mg.L^-1, 200 mg.L^-1, on the basis of nitrogen content) to nutrient and water absorption. We also did some research on vegetative growth, fruit quality, content of mineral elements in different organs and we compared with common orchard in the same variety and age.The results showed:(1) Low nitrogen promoted vegetative growth (shoot length and diameter, trunk diameter)in the early development stage.Net photosynthesis rate and transpiration increased. The stomata conductance was larger than others. The total shoot growth and leaf area of medium nitrogen was larger throughout the year .The fruits growth pattern was'double S'curve.Vertical and horizontal size of fruits, volume, the single fruit weight, specific gravity were larger for control with CPPU than the treatment, but there was no significant difference among treatments. The fruit shape index was not obviously different between the treatment and control.(2) In field, the soluble total sugar, amylum, soluble solid were slightly higher than that treatment, but the soluble total sugar and soluble solid were no significant difference among treatments.Vc and amylum with low nitrogen were lower. The titratable acid with high nitrogen was significantly higher than other treatments. Protein and amino acids were no significant difference between treatments and control. Generally speaking, medium nitrogen was beneficial to improve the quality of fruit.(3) The analysis about dry matter and mineral elements content of various organs in kiwifruit cv Xuxaing showed that: During the growth and development period, dry matter content of fruit, leaves, and shoot were no significant differences between treatments.In fruit, N, K and Cu with low nitrogen were higher; P with high nitrogen was the highest. There were no significant changes among treatments .Fe and Mg were not obviously affected by the concentration. Zn, Mn with medium nitrogen were the highest. In shoot, N, Mg with low nitrogen were the highest and P, K, Ca, Fe, Mn with high nitrogen were the highest, but Zn with medium nitrogen was the highest.Cu with low nitrogen and medium nitrogen was the highest. Along with the fruit growth, the gap of Fe content between treatment and CK reduced. During the whole fruit growth and development, the leaf N, P, K, Mg, Ca, Fe, Zn, Mn, Cu were the highest with high nitrogen.(4)During the whole growth and development, in addition to Zn and Cu, NO₃^-1-N, NH₄⁺-N, P, K, Mg, Ca,, Fe, Mn uptake were proportional to nutrient solution concentration, and tree traits with medium nitrogen were better,so we took medium nitrogen as fertilizer reference, Amount of fertilizer per acre: flowering period N 5.82 kg, P 0.17 kg, K 0.81 kg, Ca 2.48 kg; fruit expansion period N 2.21 kg, P 0.33 kg, K 1.28 kg, Ca 2.69 kg; the slowly growing period N 2.05 kg, P 0.2 kg, K 1.04 kg, Ca 2.47 kg; harvesting period N 1.33kg, P 0.11 kg, K 0.39 kg, Ca 1.03 kg. Amount of fertilizer per square meter leaf area: flowering period N 4.37 g, P 0.13 g, K 0.61 g, Ca 1.86 g; fruit expansion period N 1.66 g, P 0.25 g, K 0.96 g, Ca 2.02 g; the slowly growing period N 1.54 g, P 0.15 g, K 0.78 g, Ca 1.85 g; harvesting period N 1.00 g, P 0.08 g, K 0.3 g, Ca 0.77g.(5)We took medium nitrogen as a standard to calculate water uptake.Water consumption per unit leaf area L/m2: flowering period 13.59L, fruit expansion period 30.28L, the slowly growing period 38.44L, harvesting period 24.86L.Daily water consumption L/plant.Day: flowering period 1.44L, fruit expansion period 2.69L, the slowly growing period 3.24L, harvesting period 4.33L.Water consumption per mu: flowering period 18.12m³, fruit expansion period 40.37m³, the slowly growing period 51.26m³, harvesting period 33.14m³, annual water consumptions 142.9 m3.