Effects Of Water Deficit On Growth,Soil Microorganism And Enzyme Activity Of Grape Under Delayed Cultivation

This experiment was carried out in 2016 in Yongdeng County of Lanzhou City,Gansu province.The process of growing grapes have been divided into five stages.Each growth stage set up two irrigation levels,moderate water stress(soil water content lower level accounted for 55% of field capacity)and light water stress(soil water content lower level accounted for 65% field moisture content).In order to refine the research,adds a high moisture level in the fruit enlargement period(soil moisture limit of about 85% of field capacity),and also set up a CK treatment(the whole growth stage,soil moisture accounted for 75% of field capacity).A total of 12 treatments were set up.Test analysis of water deficit at different growth stages under delayed grape plant growth,soil water consumption changes in the law,soil microbes(bacteria,fungi and actinomycetes)colony quantity change,soil enzymes(invertase,amylase,urease)activity changes,hoping to provide the basis for the regulation of grape growth and improved microbial community structure.The results show that :(1)Under the condition of water deficit in different growth period,the growth of the longitudinal and horizontal diameter of the grape in the facilities were all in accordance with the double "S" growth curve.The first rapid growth stage was 7-17 days after anthesis,and the average daily growth rate of the longitudinal diameter was 0.4mm/d,which was significantly higher than the average daily growth rate of 0.3mm/d.The average daily growth rate of each treatment showed the basic trend of CK> mild water deficit treatment > medium water deficit treatment >EA.The second rapid growth period was 62-96 days after anthesis,during this period,the average daily growth of the vertical and horizontal diameter was basically the same,both in the 0.12-0.14mm/d.Compared with the first rapid growth,the average daily growth rate was reduced.Curve regression analysis of shoot length and diameter of the dynamic process is carried out with SPSS software,according to the square of the correlation coefficient of maximum value to determine the optimal regression model of delayed grape shoot length and diameter growth were three polynomial.(2)The variation of soil water content decreased with the increase of soil depth.When the medium deficit was produced in the bud stage,the water consumption increased significantly during the shoot growth period,and the lower soil moisture content in 20-60 cm soil layer decreased significantly.The treatment of water deficit at the shoot growth stage was beneficial to the distribution of grape roots in 60-80 cm IV soil layer,so as to facilitate the use of deep soil moisture.Under the condition of moderate water deficit at flowering stage,the soil water consumption of 60 cm soil layer was more.Under the condition of slight water deficit at flowering stage,the grape plants mainly use the soil moisture in the 40 cm soil layer.Similar to the treatment of water deficit at flowering stage,fruit enlargement period of moderate water deficit can promote the grape root distribution of water in the deep layer of 40-60 cm,and mild water deficit treatment is the main root absorption distribution of water at 20-40 cm.While the fruit enlargement period of full irrigation,the soil reservoir of water is abundant,therefore the grape soil moisture changes are from the surface to the deep are increasing or decreasing.(3)Grape production in a certain range with the increase of irrigation amount does not increase significantly,water deficit too large or too small is not conducive to the increase of yield,water deficit in different growth stage also has an important influence on the yield.The yield of ES treatment was 24600.55 kg/hm2,the total irrigation amount and total water consumption were the smallest,and the maximum values of WUE and IWUE were 7.57Kg/m3 and 10.85Kg/m3,respectively.The highest yield of EA was 31184.45kg/hm2,and the total irrigation amount and total water consumption were also the largest.The WUE and IWUE values were lower,which were 7.04 Kg/m3 and 7.90 Kg/m3,respectively.From the yield components,the single grain weight of FM and CM was the largest,which was 11.88 g,11.93 g.The minimum single grain weight is EA and GM for 8.88 g,8.83 g.GM,EA and CK treatments had the best fruit shape index.Judging from the physiological and biochemical indexes of fruit quality,ripe period of mild water deficit treatment increased soluble solids and fruit vitamin C content is good,the implementation of new shoot growth period of mild water deficit could increase the POD content in fruit.(4)The results showed,the change process of soil bacterial number decreased gradually from the beginning of germination to the growth period of the new shoots.The flowering period reached the minimum value of the whole growth stage,then increased rapidly to the peak value in the fruit expanding period,and finally decreased slowly.The number of soil fungal colonies showed "M" type change.The variation of the number of actinomycetes in soil showed the trend of "M" type.Different from the fungi,the number of actinomycetes increased slowly from the bud stage to the growth stage of the new shoots,and the reduction process of the fruit expansion period to the color maturity stage was also slow.The number of soil microorganism in different periods of water deficit treatment showed a difference in the growth period of grape,and also showed different in the same period.The change of soil invertase activity was not the same in the whole growth process,and the effect of water deficit treatment was also the highest,but it was the highest in the fruit expanding period.The range of soil amylase activity in the whole growth period was 2.98-18.58mg/g.The change law of soil urease was the same,all treatments showed the inverted "V" type change law,that is,all increased first and then decreased,and the vertices were distributed in the flowering period or fruit expansion period.