Effects On Physiological And Ecological Characteristics Of Coffee Arabica Under Water And Nitrogen Coupling

Coffee arabica is one kind of agricultural products with unique advantages in Yunnan Province, Water and nitrogen affect its growth and yield as two important limiting factors. In Yunnan province, these areas are in problems what is perennial water shortage and serious contradictory of water and heat, extensive management of water and fertilizer. According to the problems that drought and water shortage, drought and under nutrition is restricting production and quality of coffee arabica. This study focused on the effects of transformation and utilization of water and nitrogen in root zone, Photo synthetic characteristic, activities of antioxidant enzyme, morphological index and production. The project seeks for efficient mechanism of water and nitrogen on coffee arabica under water and nitrogen coupling. And optimizes decision of irrigation and nitrogen, and perfects theory of efficiency use of water and nitrogen on coffee arabica.This study took coffee arabica as an example, adopted pot experiment, set four water treatment:Sufficient water (WS), High water(WH), Medium water(WM), Low water(WL) and three nitrogen treatment:High nitrogen(WH),Medium nitrogen(WM),Low nitrogen(NL).The experiment conducted in the greenhouse of intelligent control in Faculty of modern Agricultural Engineering, Kunming University of Science and Technology from April,2013 to December,2014. The primary research of this paper concentrate on the effect of nitrogen application and watering on growth characteristics and physiological property, photosynthetic characteristics, activities of antioxidant enzyme, production of coffee arabica under water and nitrogen coupling. The main results of this study as follows:(1) Nitrate accumulation and mobile in soil profile mainly affected by nitrogen and soil water content, and positively correlated with nitrogen, negatively correlated with soil moisture content. Nitrate content in soil with high, medium nitrogen treatment was higher than low, no nitrogen treatment significantly. At the same nitrogen treatment, irrigation of low water has a positive effect on nitrogen accumulation.(2) Compared with WL treatment, WS treatment decreased net photosynthetic rate of coffee arabica, Excessive fertilization can reduce the transpiration rate of coffee arabica. Compared with WL treatment, WM treatment increased SOD activity of coffee Arabica leaves by 4.89%, POD activity can be increased by 97.70%. APX activity can be increased by167.61%. Full irrigation and severe deficit irrigation can reduce resistance of coffee Arabica, low nitrogen and Medium water treatment can make coffee Arabica to obtain better resistance(3) Under the same Nitrate treatment, increasing irrigation could clearly increase the growth of coffee Arabica, and improve the morphological index(plant height, stem diameter, crown breadth, number of leaves, divarication and length of growing branch),but low water treatment under full nitrogen application is not conducive to the advancement of the morphological index. Compared with WL treatment, WS treatment increased plant height, stem diameter, divarication, crown breadth and number of leaves by 37.50%,27.93%,98.95%,38.52% and 96.67%; WH treatment increased length of growing branch by 48.28%.(4) Under the same Nitrate treatment, WS treatment can harvest the biggest fresh ripe bean weight. Peak value of ripe bean weight appeared in NM-WS treatment.Under NM-WS treatment, the ripe bean weight increased by 4.88%and 125.63% than NH-WS, NL-WS treatment, full nitrogen application would not clearly increase the weight of ripe bean. Coffee Arabica beans total mass under NM-WH treatment is 196.34g, the dry-fresh ratio is the minimum value (4.75). Compared with NM-WH treatments coffee Arabica beans total mass under other nine treatments are clear reduced,and the dry-fresh radio are also clear higher.That means, on the basis of NM-WH treatments, neither increasing irrigation or nitrogen can obviously improve the total output of Coffee Arabica, but reducing irrigation or nitrogen can clear reduce the total output of Coffee Arabica, and increase water content of Coffee Arabica beans. Coffee Arabica beans got the maximum volume under NM-WH treatment at the same time.From what has been discussed above, medium nitrogen and high water treatment is the best water and nitrogen utilization combination for guaranteeing coffee Arabica healthy growth and high yield.