Research On The Appropriate Weather Conditions For Cherry Cultivation In Tongchuan, Shaanxi Province

Large cherry, the first spring fruit,has great nutritional value and high market price,farmers may acquire high economic benefits by planting cherry trees in greenhouses. However, it’s difficult to cultivate Cherry trees.This reaserch on the cherry weather conditions was carried out in Tongchuan,Shaanxi province.In this study,in order to research the weather conditions for cherry growth system atically,7-year-old cherry trees of different chilling requirement varieties were used,such as ‘hongdeng’,Brooks,‘meizao’,‘zaodaguo’,etc.The main subjects included:estimating the chilling requirement during the period of cherry dormancy for planting cherry successfully. determining the suitable covering date for greenhouses on the basis of average date for low chilling requirement during cherry dormancy periods. Analyzing the climate conditions during cherry growing in Tongchuan,the date of reaching the satandard chilling requirement for different levels in different climatic zone in Tongchuan. the greenhouse effects under different weather condition,comparing the phonological periods of cherry trees cultivated in different cultivating style. Tentatively we proposed the climate conditions index affecting the quality of cherry fruit.The main results are as follows:1. Generally, the average cumulative amount of hours from 0 to 7.2 centigrade degree are over the chilling requirements,meeting the chilling requirement for cherry dormancy for variety cherry trees in Tongchuan.2. On the basis of average date for low chilling requirement,determining the suitable covering date for greenhouses, the covering dates are as follows: from 15 to 20 Dec. in northern region, from 25 to 30 Dec. in central region and from late Dec. to early Jan. in southern region.3. The greenhouse effects are significant from Jan. to Feb., whether clear or cloudy or overcast and rainy days,however this effect became weaker in Mar.The diurnal cycle of air temperature outside the greenhouse was almost the same as the inside of the greenhouse during the period from Jan. to Mar. The daily minimum and the maximum temperature inside the greenhouses occurred at about 7 to 8 AM in the morning and 12 to 13 PM in the afternoon respectively. The daily maximum temperature inside the greenhouses occurred 3 hours earlier than that of outside. The diurnal changes of the air temperature inside the greenhouses were remarkable in Mazui than those in Zhouling and Shennong demonstration zone.4. The phonological periods of cherry trees cultivated in artificial-controlled greenhouse are obviously advanced than natural greenhouse and open fields.The budding dates are 34 and 69 days earlier than that of two later, respectively. The flowering dates are 15 and 64 days ahead of the two later,respectively. The mature dates occured 15 and 60 days ahead of time than the later, respectively. The mature periods of cherry fruit in natural greenhouses was 46 days earlier than that in open field. This cultivating technology extended the cherry fruit market period and maximized the benefits.The dates of breaking dormancy of cherry are 80 and 85 days earlier in artificial-controlled greenhouse and natural greenhouse than that in open fields,respectively.5. The reasons to dehiscent fruit were discussed. High air temperature and low relative humidity were one of the main reasons for dehiscent fruit. The rate of dehiscent fruit raised as the high temperature and low humidity conditions last longer, the longer the time,the higher the rate of dehiscent fruit. The key measure to improve the microclimate in greenhouse is to control the air temperature inside greenhouses via ventilation from 10:30 to 11:00 AM and from 13:00 to 14:00 PM, avoiding the air temperature increase rapidly.6. The quality of cherry fruit produced in central region was better than that in southern regions in Tongchuan. The quality of cherry fruit produced in greenhouses was better than that in open fields. The advantages of climate conditions for cherry trees planted in open fields in central area are that the higher daily temperature difference during the coloring period.The low air temperature during flowering stage and too much precipitation during the fruit maturity stages are the adverse conditions for cherry trees in open fields in southern area.The minimum temperature conditions could be improved in greenhouses, but the daily temperature difference decreased, which was harmful to the sugar content accumulation during the coloring period.