Effects Of Water-light Coupling On Growth,Photosynthetic And Ecological Characteristics,Yield And Quality Of Coffee Arabica In Dry-hot Valley Areas

Coffee arabica is one of the largest economic crops in Yunnan,and the planting area and output account for more than 90%.Dry-hot valley area is a suitable planting area for coffee arabica,but the growth and production are affected by long sunshine,drought and poor soil water retention.This study focuses on the effects of different irrigation and shading on the growth,photo synthetic characteristics,yield and quality of coffee arabica.The water and light management pattern of the high yield of coffee arabica,was explored under different irrigation and shading addition.In this study,coffee arabica as test materials,In Xinzhai village of Lujiang bra,Baoshan city in Yunnan Province(the first coffee village of China),it is carried out 2a irrigation and shading complete combination of this field test.The effects of different irrigation and shading on growth index,soil moisture content,photosynthetic characteristics,leaf water use efficiency,leaf light use efficiency,yield and quality of coffee arabica were studied.The experiment was set 3 irrigation levels:(high water-WH,medium water-WM and low water-WL);and 4 shading levels:(severe shade SH-40%natural light,moderate shade SM-55%natural light,light shade SL-70%natural light and no shade So-natural light).Some important conclusions are obtained:(1)Increasing irrigation amount,the growth index(plant height,stem diameter,crown width,shoot length and bud number)of coffee arabica increased significantly.Moderate and severe shading was not conducive to the growth of each indexes,but light shading promoted the growth of coffee arabica.The coupling of high water and linght shading was beneficial to the growth of plant height,stem diameter,crown width,shoot length and bud number of coffee arabica.(2)Under different irrigation and shading levels,net photosynthetic rate,transpiration rate,stomatal conductance and intercellular CO2 concentration of coffee arabica leaves mainly presented a single peak curve.Compared with low water,with increasing irrigation amount the maximum net photosynthetic rate increased by 10.96%-47.59%.In high water treatment,compared with no shade,moderate shade and severe shade reduced the net photosynthetic rate,but the light shading increased the net photosynthetic rate.(3)Under the WH,the moisture content and soil water storage of the same section were generally larger than WM and WL.The soil moisture content of the five sections of WHSH treatment were the maximum,and the average value was 17.50%,which was the highest among the 12 treatments.The soil moisture content of WHSM was also larger,the average value was 16.33%,only less than WHSM.(4)Compared with WL,increasing the irrigation amount,the dry beans yield of WH and WM increased by 97.07%～126.28%.Compared with So,the bean yield of SM and SH were reduced by 4.23%～29.08%,it is improved that moderate and severe shading reduced the yield of dry bean.While the dry bean yield of SL increased by 27.22%～27.96%,the light shading could increase the yield of dry bean.The largest 2a average value dry yield was the WHSL,which was 1467 kg/hm2,the coupled mode treatment with the shading of SL and the irrigation of WH significantly improved the yield of dry bean.(5)Compared with WL,the fat and chlorogenic of WM increased by 4.81%and 10.24%,and the caffeine reduced by 21.11%.The caffeine of WH reduced by 18.41%.Compared with So,the total sugar,protein,fat and chlorogenic acid of SL increased by 6.25%,9.49%,3.37%and 5.54%,and the caffeine reduced by 4.20%.The fat,caffeine and chlorogenic acid of SM and SH respectively reduced by 4.31%and 7.69%,12.71%and 10.88%as well as 13.94%and 19.48%.Compared withWHSO,the total sugar,protein,fat and chlorogenic acid of WMSL increased by 23.23%,14.07%,6.62%and 9.98%,and the caffeine reduced by 8.30%.The total sugar,protein,fat and chlorogenic acid of WHSL increased by 7.43%,15.50%,4.73%and 7.92%,and caffeine reduced by 11.52%,The main component analysis showed that WMSL and WHSL were the best treatments for integrated nutrient quality.Under this test condition,through the analysis of the growth characteristics,photosynthetic characteristics,water-light use efficiency,yield and quality of coffee arabica,considering from the perspective of high quality and high yield,it is proved that the optimal water-light combination model of coffee arabica is high water and light shade(WHSL).