Measures For Cultivation Of Yulin Mountainous Areas And Study The Key Technology To Control Preharvest Dropping In Honey Crisp Apple

In order to explore the suitable techniques for the cultivation of apple trees in the Yulin Mountain,in the Yulin Mountain Apple Technology Experiment Demonstration Station of Northwest Forestry University,different protection measures were implemented for the newly-planted apple trees in the fall,including: setting double-layered barrel membrane,setting single-layered barrel membrane,wrapping the cotton blanket around the trunk and then setting a single-layered barrel membrane,burying the soil,no any protection measures;setting a single-layered barrel membrane for fruit trees planted in the spring.It conducts the observation and statistics on the survival rate and the situation of growth and development for different treated seedlings.In order to explore the key technologies for the prevention and treatment of pre-harvesting fruit drop for 'Honey crisp',the Yulin Mountain Apple Technology Experiment Demonstration Station of the Northwest A&F University and the Luochuan Apple Experimental Station of the Northwest A&F University simultaneously conduct the research from three aspects :1 In the young fruit period of "Honey crisp",it conducts the marking,separately,such as: ?big fruit',?small fruit',?long-handle fruit',?short-handle fruit'.The situation of the pre-harvest fruit drop and fruit quality is counted.2 It conducts the marking for the fruit handle with different lengths,and the situation of the pre-harvest fruit drop is counted.3 It takes different prevention measures of the pre-harvest fruit drop for ?Honey crisp? fruit trees,they are respectively: it retains the marginal fruits when fixing the fruit,and shortens the spacing between the fruits to be 20 cm,it sprays calcium fertilizer during the young fruit period,and sprays NAA before harvest.The pre-harvest fruit drop rate is counted,and the fruit quality is measured.The main findings are as follows:(1)Under the different planting methods in Yulin area,the germination rate,new growth volume,leaf area,leaf fresh weight,plant height,the increase amount of trunk wideness,total aboveground biomass,and fine root fresh weight of the seedlings between those were supplied with the wrapping with cotton blanket + setting single-layered barrel membrane and those were supplied with the setting double-layered barrel membrane were significantly better than those with other treatments,and there was no significant difference between the two treatments.The production cost of wrapping cotton blanket + setting single-layered barrel membrane after autumn planting was higher than other treatments.After the autumn planting,the seedlings with double-layered barrel membrane had the earliest germination time,and the production efficiency was also higher than that with the treatment of wrapping cotton blanket +setting single-layered barrel membrane and conducting the buried soil after the autumn planting.Therefore,the planting method of the setting double-layered barrel membrane after the autumn planting is most suitable for use in the Yulin area.(2)In the Yulin area,apple tree seedlings that do not adopt cold protection measures after planting in the fall have a survival rate that is 20-40% lower than that of the apple tree seedlings that adopt cold protection measures,are easy to drain,are late in germination time,and have a small amount of growth.Therefore,planting apple seedlings in autumn in Yulin area requires taking cold measures.(3)Apple tree seedlings with single layered barrel film after spring planting in Yulin area,the survival rate,germination rate,new growth,leaf area,leaf fresh weight,plant height,trunk thickness increase,total aboveground biomass The fine root and fresh weight is superior to the saplings that are not covered with cold measures after planting the single layer barrel film after planting in the fall,burying the plants after the autumn planting,and planting plants in the fall.And the production cost and efficiency are slightly better than the double-layered barrel film after the autumn planting and the wrapped cotton felt+single-layer barrel film after the autumn planting.Therefore,it is feasible to plant single-layered barrel membranes for spring apple tree seedlings in Yulin area.(4)The fruit ?Honey crisp? was sprayed with 8000 times NAA every two weeks in one month before the harvest.The pre-harvest fruit drop rate(7.5%,13.2%)was much lower than that of the control group(43.8%,28.1%).There was no significant change in fruit quality.(5)‘Honey crisp? in the young fruit period were supplemented with calcium once every 15 days in Zizhou and Luochuan.The pre-harvest fruit drop rate(17.4%,14.3%)was much lower than that of the control group(43.8%,28.1%).It significantly increased the single fruit weight,the fruit size and the peeling hardness,and reduced the acidity.(6)The ?Honey crisp? marginal fruits in Zizhou and Luochuan,the pre-harvest fruit drop rate(36.5%,21.3%)was not significantly lower than that of the control group(43.8%,28.1%).It significantly reduced the single fruit weight,fruit size and fruit shape index.(7)The ?Honey crisp? fruits with increasing load amount(spacing between the fruits is 20cm)in Zizhou and Luochuan,the pre-harvest fruit drop rate(46.4% and 29.2%)was not significantly different from that of the control group.It significantly reduced the single fruit weight and fruit size.(8)Short handle was the direct cause of the occurrence of the ?Honey crisp? pre-harvest fruit drop.After 15 days of ?Honey crisp? fruit setting,for the fruit with the transverse diameter <20mm and fruit handle >20mm,the pre-harvest fruit drop rate was lower but the single fruit weight significantly decreased after the fruit ripening.