Water and fertilizer coupling model for the yield of greenhouse eggplant in winter cropped in Ningxia southern mountain region.

[Objective] The research aimed to study the coupling model of water and fertilizer for the yield of winter eggplant in greenhouse in Ningxia southern mountain region and provide reference for the criteria and cost-saving cultivation of agriculture vegetables in Ningxia southern mountain region.[Method] By using quadratic general rotary unitized design,the mathematics simulation was made on the main cultivation factors(irrigated amount,N application amount,K application amount)that affected the greenhouse eggplant yield in winter cropping in Ningxia southern mountain region.[Result] Three cultivated factors had obvious effects on the eggplant yield in winter cropping and the water and K showed negative effects on the eggplant yield generally.And N showed the positive effect.The order of the influences of three factors on the eggplant yield was as:potassiumnitrogenwater.The single factor effect showed that the eggplant yield increased gradually with the irrigated amount when the irrigation amount was lower than 8 250 m3/hm2.When the irrigation amount was 8 250 m3/hm2,the eggplant yield was the highest,being 159 253.5 kg/hm2.And then the eggplant yield decreased gradually with the irrigated amount.When N application amount was lower than 900 kg/hm2,the eggplant yield increased significantly with the increase of N application amount.When N application amount was 900 kg/hm2,the eggplant yield was the highest,being 158 782.5 kg/hm2.And then the eggplant yield decreased gradually with N application amount.When K application amount was lower than 712.5 kg/hm2,the eggplant yield increased gradually with K application amount.When K application amount was 712.5 kg/hm2,the eggplant yield was the highest,being 160 195.5 kg/hm2.And then the eggplant yield decreased significantly with K application amount.[Conclusion] When the greenhouse eggplant yield in winter cropping in Ningxia southern mountain region,it was recommended that the irrigated amount was 7 500-8 000 m3/hm2,N application amount was 900-950 kg/hm2 and K application amount was 850-900 kg/hm2.