Effects Of Fertilizing Nitrogen And Irrigating Before Harvest On Fruit Quality And Brown Core Of Yali Pear

In order to study the effect of nitrogen fertilizing and irrigating before harvest on fruitquality and brown core of Yali pear at room and low temperature after harvest in10daysin advance and normal harvest periods, the fruit quality, the brown core and the contents ofnutrient elements are researched, which provide the basis for the specification for nitrogenand water management. The main research results are as follows:1.The soluble solid content of the fruit were the highest at60days after normalharvest with1.5kg carbamide at room temperature, while the content were the highest at90days after10days in advance before normal harvest at low temperature. The sugar-acidratio of fruit were biggest at normal harvest, with none signification with the nitrogenfertilization.2.The soluble solid content of the fruit were the highest at60days after normalharvest at room temperature, while the content were the highest with the irrigation depth of0.03m,0.05m at60days after normal harvest at low temperature. The sugar-acid ratio offruit were like with the one of the nitrogen fertilization.3.The ratio and index of brown core of the fruit became bigger with the time ofstorage. The brown core had been found at45days after harvest at room temperature, and60days biggest. The brown core at low temperature10days in advance before harvest hadbeen delayed than that of normal harvest, but both of them were biggest at150days afterharvest. The PPO activity of core at advanced harvest were biggest at harvest, that innormal harvest were least at15days at normal harvest, and that in advanced harvest wereleast at150days with the treatment of3kg carbamide having signification with the control.4. The effect of irrigating on ratio and index of brown core of fruit were the same withthe nitrogen fertilizing. The PPO activity of core were least at harvest at advanced harvest,least at30days, and that were least at15days after harvest at normal harvest.5. The treatment of both1.5kg and3kg were decline in the content of total nitrogen atadvanced and normal harvest. the content of total nitrogen were least at60days afterharvest, and that were biggest at150days at low temperature at advanced harvest, least at90days at normal harvest. The content of total calcium were biggest at60days atadvanced harvest at room temperature, least at45days at normal harvest, biggest at120 days at low temperature at advanced harvest, least at60days at low temperature at normalharvest. The ratio of nitrogen and calcium were bigger at45days after harvest at normalharvest and60days at low temperature, less at15days at room temperature at advancedharvest and90days at low temperature at normal harvest.6.The content of total nitrogen with the treatment of both0.03m and0.05m werebiggest at60days at advanced harvest, least at harvest with0.03m significantly, biggest at150days at low temperature at advanced harvest, least at harvest. The content of totalcalcium were biggest at60days at advanced harvest at room temperature, least at45daysat normal harvest, biggest at120days at low temperature at advanced harvest, least at60days at low temperature at normal harvest. The ratio of nitrogen and calcium were biggerat45days after harvest at advanced harvest and60days at low temperature at normalharvest, less at30days at room temperature and90days at low temperature at normalharvest.