Effets Of Irrigation Threshold And Fertilization On Growth And The Utilization Of Water And Nutrient Of Greenhouse Fertigation Tomato

To explore the effective mode of fertigation in greenhouse about improving tomatogrowth and yield, a tomato greenhouse fertigation experiment was conducted. The experimentaimed at analyzing the effect of different irrigation threshold and fertilization on tomatogrowth, physiological properties, quality, yield and the use of nutrient. Three irrigationthreshold treatments were W1(65%F), W2(75%F) and W3(85%F) respectively, threefertilization treatments were F1(N(120kg/hm~2), P2O5(60kg/hm~2), K2O(75kg/hm~2)), F2(N(180kg/hm~2), P2O5(90kg/hm~2), K2O(112.5kg/hm~2)) and F3(N(240kg/hm~2),P2O5(120kg/hm~2), K2O(150kg/hm~2)). The main conclusion is as follows:(1) Results showed that tomato plant height, leaf area and dry weight could be modifiedby different irrigation threshold and fertilization. Compared to the treatment of low irrigationthreshold(W1), the treatment of middle irrigation threshold(W2) and the high irrigationthreshold(W3) could increase tomato plant height, leaf area and dry weight significantly. Andinfluence of he treatment of middle irrigation threshold(W2) was the most significantly. Aswell, compared to the treatment of low fertilization(F1), the treatment of middlefertilization(F2) and the high fertilization(F3) could increase tomato plant height, leaf areaand dry weight significantly. And influence of he treatment of middle fertilization(F2) was themost significantly. But at tomato apparent growth period, excessive irrigation threshold(W3)and fertilization(F3) was detrimental to tomato height, leaf area and dry weight.(2)Results showed that tomato photosynthetic rate, transpiration rate, stomatalconductance and leaf water use efficiency could be modified by different irrigation thresholdand fertilization. Irrigation threshold or fertilization increased appropriately(W2or F2) couldavoid "Pn sleep at noon", promote tomato photosynthetic rate, transpiration rate, stomatalconductance and leaf water use efficiency, and the peak value appeared at12:00~14:00. Butexcessive irrigation threshold(W3) or fertilization(F3) was not conducive to thephotosynthetic rate, transpiration rate, stomatal conductance and leaf water use efficiency oftomato plant.(3) Results showed that every quality index of tomato could be modified by different irrigation threshold and fertilization. For the same irrigation threshold, soluble solids, Vc,lycopene and sugar/acid ratio had a significant increase with increased fertilization, butexcessive fertilization was detrimental to above tomato quality indexes; the content of acidand NO3--N of tomato increased by fertilizer amount increased. For the same fertilization,irrigation threshold increased appropriately benefited tomato sugar/acid ratio, excessiveirrigation threshold was not conducive to the tomato sugar/acid ratio; the content of acid oftomato increased by irrigation threshold increased; but the content of NO3--N of tomatodecreased by irrigation threshold increased.(4) Results showed that tomato yield could be modified by different irrigation thresholdand fertilization. Compared to the treatment of low irrigation threshold(W1), the treatment ofmiddle irrigation threshold(W2) and the high irrigation threshold(W3) could increase tomatoyield significantly. And influence of he treatment of middle irrigation threshold(W2) was themost significantly. As well, compared to the treatment of low fertilization(F1), the treatmentof middle fertilization(F2) and the high fertilization(F3) could increase tomato yieldsignificantly. And influence of he treatment of middle fertilization(F2) was the mostsignificantly. But at tomato apparent growth period, excessive irrigation threshold(W3) andfertilization(F3) was detrimental to tomato yield. Besides, in guarantee under the premise oftomato yield and water use efficiency, irrigation threshold increased appropriately isrecommended, but it couldn’t be increased too much.(5) N, P, K accumulation amount, N、P、K PEP and N、P、K UPE of tomato crop could be modifiedby different irrigation threshold and fertilization. For the same irrigation threshold, N, P, Kaccumulation amount of the treatment of W1and W3increased by fertilizer amount increased, butthe trend of N, P, K accumulation amount of W2treatment was that: F2>F3>F1; N、P、K PEP and N、P、K UPE of tomato crop decreased by fertilizer amount increased. For the same fertilization, N, P,K accumulation amount and N、P、K UPE of tomato crop was increased at first and then dropped byirrigation threshold increased; but the effect of N、P、K PEP was not significant by differentirrigation threshold. In conclusion, treatment of W2F2was most conductive to the absorptionof N, P, K of tomato crop.