Effects Of Quantifying Irrigation And Nitrogen Fertilizer On Yield And Quality Of Coffee Arabica

As one of the greatly imported and planted special industrial crops in Yunnan, Coffee Arabica, accounts for more than 90% in sown area and yield nationwide, mainly distribute in dry-hot valleys and humid tropical areas. This research elaborate the effects of quantitative irrigation and nitrogen on water periodic change, eco-physiological characteristics, dry matter accumulation of coffee arabica’s root zone, as well as yield and quality, seek high efficient management mode under quantitative irrigation and nitrogen application, to optimize the volume of irrigation and nitrogen and perfect water-nitrogen high efficient application theory on good quality and high yield of coffee arabica.This research takes coffee arabica as tested materials, conduct an experiment lasted for 2.5 a by greenhouse planting grooves and an experiment lasted 2.0a by Baoshan Institute plots of Tropical Crops, and set four irrigationlevels:sufficient irrigation(W1), high irrigation(W2), medium irrigation(W3), low irrigation(W4), and three levels of nitrogen application:high nitrogen(N1), medium nitrogen(N2), low nitrogen(N3).This subject studies the effects of different irrigation and nitrogen levels on coffee arabica’s growth, physiological property, photosynthetic characteristics, and root area water change, especially yield and quality. Hence the following theories:(1)Increased irrigation can respectively improve coffee arabica’s plant height, stem diameter, crown breadth, new-branch length, sub-branch numbers and blade numbers by 4.79%～20.42%,0.91%～3.74%,11.16%～14.23%,10.34%～18.45%,11.90% ～20.01% and44.54%～60.82%; increased nitrogen can respectively improve coffee arabica’s plant height, stem diameter, crown breadth, new-branch length, sub-branch numbers and blade numbers by 5.46%～16.32%,4.56%～6.91%,9.05%～14.15%, 4.01%～9.14%,11.90%～20.45% and 14.51%～17.32%, While increasing irrigation and nitrogen fertilization can significantly improve the growth index of coffea Arabica.(2)Two days after respective irrigation. The effect of the same irrigation on net leaf photosynthetic rate is less than that of respective irrigation, increased irrigation can improve the net photosynthetic rate by 26.11%～163.69%,19.86%～464.91%, 27.13%～386.96% and 20.41%～372.27% under respective irrigations. Under W1、W2 and W3 levels, increased nitrogen can reduce the net photosynthetic rate by 29.93%～68.36%,15.46%～90.06%,42.61%～89.28% and 30.61%-85.05% within the same irrigation, when there is sufficient water, proper increasednitrogen can improve leaf transpiration rate while excessive nitrogen can reduce leaf transpiration rate, increased irrigation can improve the leaf water potential by 6.59%～10.98%, 6.19%～9.41% and 4.95%-9.41% under respective irrigation, increased nitrogen can reduce the leaf water potential by 4.45%～9.41%,7.26%-12.85%,6.19%～9.79% and 6.59%～16.48%. The activities of antioxidant enzymes (Superoxide Dismutase, Peroxidase and Ascorbate Peroxidase) firstly increased and then decreased with the decreasing moisture content, and the peaks ofthe activities of three antioxidant enzymes were shown in the W3 treatment, and increased by7.47%,116.35% and 146.15% respectively compared to W4 treatment. The result indicated that the enzyme showed the highest activity when moisture content was relatively lack. Compared to the same time after two day’s respective irrigations, the leaf WUE after two day’s same irrigation is far less than that of respective irrigations, respective irrigations can make effective use of water to promote the plant’s photosynthesis, water can not be fully absorbed under the same irrigation,thus costing certain water loss. (3) Increased irrigation can respectively improve the coffee arabica’s total sugar contents, protein, crude fat and chlorogenic acid by 3.08%-3.55%,4.62%-18.42%, 9.42%～20.82% and 16.94%-31.55%,and reduce the caffeine, crude fiber by 1.31%～11.27% and 4.31%～11.03%..Increased nitrogen can respectively improve coffee arabica’s caffeine, total sugar contents, crude fiber, protein, crude fat, chlorogenic acid by 4.68%-9.79%,2.91%-6.84%,5.77%～11.23%,5.83%～7.36%, 4.10%～4.67% and 6.94%-12.59%.The yield of both fresh and dry beans was the largest under N2W2 condition, while the dry-fresh ratio is the smallest. N2W2 treatment increased WUE meanwhile increased protein and chlorogenic acid but reduced fiber of dry bean. Based on the comprehensive consideration of growth and physiological characteristics, yield and quality, the best combination is N2W2 (medium nitrogen and high irrigation)...