Effects Of Shading,Drip Fertigation On Water Use Efficiency And Soil Microenvironment Of Arabica Coffee

Due to frequent seasonal drought,prominent water and heat contradictions,extensive water,fertilizer and light management in the planting region,Arabica Coffee planting is often restricted by multiple constraints of drought,nutrient deficiency and light stress.In order to find the suitable mode of shade and drip fertigation for Arabica Coffee,experiments contrast with no shade(NS:natural lighting),studied the effects of water and fertilizer environment,growth and water use efficiency under shading condition(S:60%natural lighting).Experiments set three irrigation levels:high water(W_H:1.2Ep),medium water(W_M:1.0Ep)and low water(W_L:0.8Ep);Three fertilization levels:high fertilization(F_H:37.1g),medium fertilization(F_M:21.2g)and low fertilization(F_L:5.3g).The main results of this study as follows:(1)Compared with F_L,the soil moisture content of F_M was significantly higher than that of F_L,while the increase of F_H was not obvious.Water content under S was significantly increased compared with NS.With the increase of fertilization,Arabica Coffee nutrients(soil content of nitrate nitrogen,available phosphorus and available potassium)showed a trend of rising,with the increase of irrigation,Arabica Coffee nutrients decreased.Compared with NS,the content of Arabica Coffee nutrients under S significantly decreased.(2)With the increase of irrigation,Coffee microorganisms(bacteria,fungi and actinomycetes)increased by 18.44%~97.17%,9.91%~41.75%and 9.14%~25.48%.With the increase of fertilization,Arabica Coffee microorganisms increased by21.78%~90.57%,10.70%~40.31%and 8.81%~26.63%.Compared with NS,S increased Arabica Coffee microorganisms by 16.22%~43.17%,9.99%~18.28%and7.75%~12.79%.Compared with NSF_LW_L,the soil microbial quantity of SF_MW_H significantly increased.(3)With the increase of irrigation,soil enzyme activity(urease,catalase and phosphatase)increased by 8.13%~18.50%,1.50%~4.08%and 5.50%~11.33%.With the increase of fertilization,soil enzyme activity increased by 26.21%~52.23%,20.51%~48.36%and 5.13%~16.55%.Compared with NS,S increased soil enzyme activity by 67.57%~75.47%,0.91%~1.11%and 14.64%~22.08%.Compared with NSF_LW_L,soil enzyme activity of SF_MW_H significantly increased.According to soil quality comprehensive index,SF_MW_H treatment evaluation index was the highest and the treatment effect was the best.(4)Increasing irrigation enhanced daily net photosynthetic rate,water use efficiency and radiation use efficiency of Arabica Coffee by 6.00%~13.91%,1.52%~7.16%and 5.63%~39.82%.With the increase of fertilization,daily net photosynthetic rate,water use efficiency and radiation use efficiency of Arabica Coffee increased first and then decreased,F_M increased by 8.38%,3.97%and 16.83%.Compared with NS,S increased daily net photosynthetic rate,water use efficiency and radiation use efficiency of Arabica Coffee by 17.14%,8.70%and 40.85%.Under the interaction of shading levels and drip fertigation,daily Pn,Tr,Ci and LRUE of SF_MW_L were the maximum.(5)Shading and drip fertigation have significant effects on the leaf area index of Arabica Coffee.With the increase of irrigation,leaf area index increased by7.26%~15.24%.With the increase of fertilization,leaf area index increased by14.51%~20.17%.Compared with NS,S increased leaf area index by 35.56%.Compared with NSF_LW_L,other treatments increased leaf area index by9.59%~87.75%.(6)With the increase of irrigation,total dry matter of Arabica Coffee increased by 5.87%~11.09%.Compared with F_L,F_M increased total dry matter by 18.83%,F_H did not increase significantly.Compared with NS,S increased total dry matter by6.60%.Under the interaction of shading levels and drip fertigation,the water use efficiency of SF_MW_L was the highest,which was 69.28%higher than that of NSF_LW_L.The comprehensive evaluation of the high efficiency of Arabica Coffee production based on TOPSIS method obtained the best comprehensive benefit of SF_MW_L treatment.The comprehensive effects on soil microbial microorganism and water use efficiency of Arabica Coffee was analyzed,it proved the optimal shading levels and drip fertigation mode was the combination of high water,medium fertilization and shade cultivation(SF_MW_H).