Precise Irrigation And Fertilization Management System Of Populus×Euramericana Cv. "74/76"

Water and fertilizer are two important factors for plant growth and development. Rational irrigation and fertilization management helps to exert plant's growth potential, while irrational irrigation and fertilization management dose not only limited the plant growth, but also leads to water loss and environment pollution. Based on mastering the law of water and fertilizer requirement, this research used split plot design to explore coupling effect and modeling of water and fertilizer, to establish precise irrigation and fertilization management system for high quality Populns×euramericana cv."74/76" with water-saving irrigation technology, and aims to build the fast-growing and high-yield plantation cultivate system for high quality seedlings by the core of water-saving and fertilizer-saving.The following is the main research results in this paper:(1)Clarified the annual variation growth rule of Populus×euramericana cv."74/76". A combination of the variation of seedlings height, ground diameter, above-ground biomass, and N, P, K content in leaves and stem made clear that plant growth accords with "slow—quick—slow" rule under 12 kinds of irrigation and fertilization scheme.The Logistic growth models for seedling height and basal diameter of 107 I1-0 were y=396.94/1+63.11e0.039t and y=28.15/1+22.66e0.034t,respectively. According to Logistic growth models, the annual growth cycle divided to three stages:Ⅰ,early growth stage:from the beginning of April to the ending of June, including the survival and teen, plant grows slowly;Ⅱ,fast-growing stage:from the beginning of July to the ending of August, it's the peak of growing and every indicators stays fast growing stage;Ⅲ,later growth stage:from the beginning of September to the end of year, each indicators grows slower and slower, and to suspend.It benefits for confirming the times of efficient irrigation and fertilization as to mastering annual variation rule.(2)Compared the growth differences of Populus×euramericana cv. "74/76" with different irrigation and fertilization schemes.By ANOVA analyzing, there were highly significant differences in seedlings height, ground diameter, above-ground biomass, and N,P, K content in leaves and stem.For seedlings height, ground diameter and above-ground biomass, the optimal presentation was treatment 10(watering to field capacity, N fertilizer application (pure N) is 15.08 g/per tree),the worst was treatment 3(no watering, no fertilization).Later analyzing multiple comparison, treatment 8(watering to 80% field capacity, N fertilizer application (pure N) is 8 g/per tree) has no significant differences with treatment 10.The N, P, K content of above-ground plant was different from morphological markers. For N content of above-ground plant, the optimal presentation was treatment 10, the worst was treatment 9(watering to 80% field capacity, no fertilization);For P content of above-ground plant, the optimal presentation was treatment 4(watering to 60% field capacity, N fertilizer application (pure N) is 15.08 g/per tree), the worst was treatment 6(watering to 60% field capacity, no fertilization);For K content of above-ground plant, the optimal presentation was treatment 11 (watering to field capacity, N fertilizer application (pure N) is 8 g/per tree), the worst was treatment 2(no watering, N fertilizer application (pure N) is 8 g/per tree).(3) Established regression models between seedling height, ground diameter and above-ground biomass and water, fertilizer, respectively.Regression model of between above-ground biomass(Y) and irrigation quantity (x1),N fertilizer application (x2):Y=297.378+4.018x1+33.876x2-0.046x12-2.015x22+0.412x1x2Regression model of between seedling height (Y) and irrigation quantity (x1),N fertilizer application (x2):Y=297.378+1.737x,+5.382x2-0.008x,2-0.197x22-0.015x1x2Regression model of between ground diameter (Y) and irrigation quantity (x1), N fertilizer application (x2):Y=21.487+0.093x1+0.248x2(4) Discussed the effect of water, fertilizer and coupling of water and fertilizer. Results showed:above-ground biomass increased as the increasing of irrigation and fertilization,the coupling effect is positive, the descending order of them was N fertilizer application, water quantity, the coupling of water and fertilizer; seedling height increased as the increasing of irrigation and fertilization, the coupling effect is negative, the descending order of them was N fertilizer application, water quantity, the coupling of water and fertilizer; N fertilizer application influence ground diameter more than irrigation quantity. (5) Built the irrigation and fertilization managements for cultivating different targets of Populus×euramericana cv."74/76'The optimum combination of irrigation quantity and N fertilizer application on aboveground biomass≥900g/per tree, seedling height between 360 and 400 cm,and ground diameter between 26 and 31 mm is:irrigation is between 36.13～41.35 kg/per tree, N fertilizer(pure N) is between 9.23～11.38g/per tree(urea is between 836.06～1030.81 kg/hm2).The optimum combination of irrigation quantity and N fertilizer application on aboveground biomass≤900g/per tree, seedling height between 300 and 360 cm,and ground diameter between 20 and 26 mm is:irrigation is between 12.56～18.18 kg/per tree, N fertilizer(pure N) is between 4.68～8.10g/per tree(urea is between 423.92～733.70 kg/hm2).(6) Launched validation test for confirming feasibility of irrigation and fertilization management system.The similar experiment was taken place to observing the growth of seedling height, ground diameter and above-ground biomass in 2010. It showed that there were still highly significant differences among different programs, the optimal presentation was treatment of watering to field capacity, N fertilizer application (pure N) is 15.08 g/per tree.By analyzing multiple comparison, it had no significant differences with treatment of watering to 80% field capacity, N fertilizer application (pure N) is 8 g/per tree. Combining each indicator, it's benefit for water-saving and fertilizer-saving to adopt treatment of watering to 80% field capacity, N fertilizer application (pure N) is 8 g/per tree.