Study On Drip Irrigation Schedule Of Kiwifruit On Seasonal Drought In Southern China

The planting area of kiwifruit in Pujiang county,Sichuan province is 100,000 mu,which is an important local economic support and has a broad market prospect.Due to the large difference in rainfall between the local seasons and the lack of research on suitable soil moisture ranges for kiwifruit growth,it not only causes a waste of water resources,but also affects the yield and quality of kiwifruit.In view of this solution,the characteristic fruit Jinyan kiwifruit was used as the research object.)Set the soil moisture in the low water interval（SD）,middle and low water interval（MD-1）,middle and high water interval（MD-2）,high water interval（LD）and middle water interval（CK）within the range of0-60cm In the interval,observe the dynamic changes of soil moisture in the range of0～60cm under different treatments,determine the water consumption index,physiological growth index,fruit quality index and yield of kiwifruit,and analyze it in conjunction with the irrigation system used in the experiment,and finally based on the principal component analysis method And the local rainfall data for many years recommended a suitable irrigation system for kiwifruit,providing a theoretical basis for the development of water-saving,quality-enhancing and yield-increasing kiwifruit cultivation in seasonal arid areas in the south.The main conclusions of the study are as follows:（1）The soil moisture content changes in W shape with time,and the interval is mainly concentrated between 14.6%and 24.2%;the change of water content of soil profile is mainly concentrated in 10-60cm,of which the 30-40cm soil layer is significantly higher than that of other depths.The water consumption intensity of each growth period is from stage III（4.00mm/d）>stage II（3.40mm/d）>stage IV（2.80mm/d）>stage I（2.53mm/d）;water consumption and water consumption modulus are stage IV>stage III>stage II>stage I;（2）The net photosynthetic rate（P_n）and transpiration rate（T_r）of kiwifruit leaves basically increased after rehydration,with obvious compensation effect.The stomatal conductance（G_s）,intercellular carbon dioxide（C_i）,and instantaneous water use efficiency（WUE_n）of kiwifruit leaves were all reduced after rehydration,and had a significant inhibitory effect.Under different water treatment levels（SD,MD-1,MD-2,LD,CK）,P_nshowed MD-2>LD before rehydration during flowering and fruit setting,and CK>LD and SD>CK after rehydration in ripening stage;Tr showed CK>MD-1>MD-2 trend under different water treatments before flowering and fruit setting stage rehydration,T_r fruit showed MD-2>LD trend after rehydration;G_s sprout stage The trend of MD-2>CK>SD and MD-1>LD before and after rehydration,respectively,and the MD-1>LD law before rehydration in G_s flowering and fruiting stage.The G_s fruit showed a trend of CK>LD after rehydration.The G_s fruit showed MD-1>MD-2>LD law after rehydration in mature stage;the C_i fruit showed MD-2<MD-1 law before rehydration in the swelling stage of C_i fruit,and LD<CK before and after rehydration in C_i fruit mature LD<CK change;WUE_nshowed LD>CK changes before flowering and fruiting stage before rehydration,and WUE_n fruit showed LD>MD-2 and MD-2<MD-1 laws before and after rehydration respectively.WUE_n fruit showed MD-1>LD>SD and MD-1>MD-2 before and after rewatering.（3）Kiwifruit growth and development The most suitable treatments to improve fruit growth under different water treatments in stages are I～IV I-MD-1,II-SD,III-SD,IV-SD;increase the SPAD value under different water treatments in stages I～IV The most suitable treatments are I-SD,II-LD,III-SD,IV-SD;the most suitable treatments for increasing shoot length under different moisture treatments in stages I～IV are I-LD,II-MD-2,III-MD-2,IV-SD;the most suitable treatments for increasing the tip diameter under different water treatments in stages I～IV are I-LD,II-CK,III-MD-2,and IV-SD.（4）Under different water treatments（SD,MD-1,MD-2,LD,CK）in the growth period of I-IV,the suitable treatments to increase the volume of single fruit in each period were SD and CK,and the suitable treatments to increase the weight of single fruit in each period were MD-2 and CK SD,MD-1,LD;SD,MD-1,CK,CK are the appropriate treatments to increase the dry matter content in each period;SD,SD,SD,SD are the appropriate treatments to increase the hardness in each period;SD,SD,CK,LD are the appropriate treatments to increase the VC content in each period;MD-2,SD,MD-2,SD are the appropriate treatments to increase the soluble solid content in each period.LD,LD,MD-1 and SD are the most suitable water-saving treatment to increase the content of titrated acid.SD is the water-saving treatment to increase the content of glucose,fructose and sucrose.MD-2,MD-1,LD and LD are the water-saving treatment to increase the output.MD-2,MD-1,CK and LD are the treatment to increase WUE_ET and WUE_I.（5）Principal component analysis method was used to analyze the relationship between growth,physiology,quality and soil moisture of kiwifruiton,the conclusion shows that::Under the condition of rain-drip irrigation,the appropriate irrigation system is treated as T4,which corresponding soil moisture is 75%～81%,62%～68%,65%～71%and65%～71%of the field water holding capacity.Combining the precipitation in different hydrological years and the division of kiwifruit growth period,based on the soil moisture interval corresponding to T4 treatment,a suitable irrigation system under field conditions was proposed.In the dry year（75%）,irrigation was carried out once in phase I,and each in phase II-III Irrigation 2 times,a total of 5 irrigations,the total irrigation quota is 150.17mm,1 irrigation in the dry season（85%）,2 irrigations in the 2nd phase,3 irrigations in the 3rd phase,6 irrigations in total,total irrigation The quota is 172.62mm;irrigation in the special drought year（95%）is once in stage I,twice in stage II,and three times in stage III,for a total of 6 times,and the total irrigation quota is 185.17mm.