Construction of water-salt production function and its yield prediction for facility tomatoes under saline water irrigation
Saline water irrigation experiment was carried out with the southern region of Xinjiang facility tomato variety"Qinling Vegetable Yue"as the research object,and four saline water mineralization levels were set up,namely T1(2 g·L-1),T2(4 g·L-1),T3(6 g·L-1)and T4(8 g·L-1).Freshwater irrigation as the control(CK),the modified Jensen model was used to construct the water-salt production function of facility tomato under saline water irrigation conditions and to estimate tomato yields under saline water irrigation with different mineralization levels.The results showed that continuous irrigation with highly mineralized brackish water resulted in reduced tomato yields,and initial irrigation with brackish water of 2-4 g·L-1 mineralization ensured tomato yields and IWUE,whereas irrigation with brackish water greater than 4 g·L-1 significantly inhibited crop growth and resulted in severe yield reductions.In the vertical direction,soil water content and salinity gradually decreased with the depth of the soil layer,and the peak of water content appeared at a depth of 40 cm.Salinity was mainly gathered in the shallow layer,and the higher the mineralisation degree of brackish water,the greater the salinity content;the salt tolerance of tomatoes was weaker in the early stage and enhanced in the late stage,and the salt sensitivity index σ of tomatoes at different reproductive stages was in the order of seedling stage＞flowering and fruiting stage＞fruiting stage＞fruiting stage＞fruiting end stage.The water sensitivity index λ of the flowering and fruiting stage was the strongest,and was in the order of flowering and fruiting stage＞fruiting stage＞seedling stage＞fruiting end stage;the water and salt production function of facility tomato constructed on the basis of Jensen's model had a high precision of yield estimation,and the R2 was greater than 0.96,which could be used to guide the management of saline water irrigation for facility tomatoes in the southern region of Xinjiang.Considering the changes of saline water irrigation on tomato yield and soil water salinity,it was suggested that the optimal scheme of saline water drip irrigation for facility tomato in the southern region of Xinjiang was:under the condition of non-continuous saline water irrigation,the combination of fresh water full irrigation at the seedling and flowering and fruiting stages,deficit irrigation and saline water mineralization of 2-4 g·L-1 at the fruiting blooming and fruiting end stages.By constructing the water and salt production function of tomato under saline water irrigation conditions to achieve the purpose of precise management of crop water and salt and safe utilization of saline water resources.
saline water irrigationfacility tomatowater-salt production functionyield prediction
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