Effects Of Irrigation Upper Limit And Fertilizer Application On Growth And Development,nutrient Utilization And Soil Environment Of Tomato In Greenhouse

In this experiment,tomato"Yingshidahong"was used as the test material to study the effects of different irrigation upper limit and fertilization ratio on growth,nutrient utilization and rhizosphere soil environment of tomato in solar greenhouse,in order to provide efficient management of water and fertilizer in solar greenhouse on the arid regions of Northwest China.This experiment used a field test method with two factors,contained irrigation and fertilization.The control group（CK）was treated with local conventional irrigation and fertilization（applied N 342 kg/hm²,P₂O₅ 516kg/hm²,K₂O 542 kg/hm²;border irrigation,irrigation volume is 8165.00 m³/hm²）;the experimental group was irrigated by drip irrigation,in the field water holding rate（θF）was regarded as the benchmark,then 50%θF is the lower irrigation limit,and three upper irrigation limits were set:W1（70%θF）,W2（80%θF）,and W3（90%θF）,N,P,K fertilization were also set three levels:F1(N 228 kg/hm²,P₂O₅ 132 kg/hm2,K₂O300 kg/hm²,F2（N 285 kg/hm²,P₂O₅ 165 kg/hm²,K₂O 375 kg/hm²）and F3（N 342kg/hm²,P₂O₅ 198 kg/hm²,K₂O 450 kg/hm²）.Therefore,there are 10 treatments combination.The main findings are as follows:1.Water and fertilizer integration significantly affected the plant height of tomato,which increased with the increasing of upper irrigation limit and fertilization rate,but had no significant effect on stem diameter.The plant height,stem diameter,root activity and dry matter quality of middle fertilizer and middle water treatment（F2W2）reached the highest,and they were significantly different from conventional irrigation and fertilization（CK）treatment,while the root-shoot ratio of middle fertilizer and high water（F2W3）treatment was significant higher than that of conventional irrigation and fertilization（CK）treatment.The Leaf photosynthetic rate（Pn）,transpiration rate（Tr）and stomatal conductance（Gs）of greenhouse tomato reached the highest value under the middle fertilizer and middle water（F2W2）treatment and intercellular CO₂ concentration（Ci）reached the highest value under the treatment of middle fertilizer and high water（F2W3）.Generally speaking,the chlorophyll content increased with the increasing of irrigation and fertilization rate.The interaction treatments of water and fertilizer showed significant effects on root activity,dry matter quality and root-shoot ratio of tomato.2.The interaction of different irrigation limits and fertilizer rates had significant effects on tomato yield,water use efficiency（WUE）,nutrient accumulation and nutrient utilization in greenhouse.The yield,water use efficiency and uptake accumulation of N,P and K in different organs all reached the highest value under the treatment of middle fertilizer and middle water（F2W2）,moreover the yield and WUE were 15.40%and 155.45%higher than that of conventional irrigation and fertilization（CK）treatment,respectively.The nutrient accumulation contents of N,P and K in tomato plants during the whole growth period were in the order of K>N>P,and the uptake contents of N and K by different organs were in the order of fruit>leaf>stem>root,then that of P was as follows fruit>stem>leaf>root.The absorption efficiency of N,P and K and the partial productivity of fertilizer reached the highest valueu nder the middle fertilizer and middle water（F2W2）treatment,and had significant difference when compared with CK treatment.The fertilizer utilization efficiency of N reached the highest value under the low fertilizer and high water（F1W3）treatment,P and K reached the highest value under low fertilizer and low water（F1W1）treatment.3.The EC-value of rhizospheric soil of tomato in greenhouse reached the highest value under the low fertilizer and high water（F1W3）treatment,while the pH value reached the lowest value under the middle fertilizer middle water（F2W2）treatment.In the middle of fruiting stage,the alkaline nitrogen reached the highest,in which the organic matter reached the highest under middle fertilizer and middle water（F2W2）treatment,the alkaline nitrogen reached the highest under middle fertilizer and high water（F2W3）treatment.The contents of total N,total P and total K in soil reached the highest values at the end of fruiting stage.The total N and total P reached the highest under the middle fertilizer and middle water（F2W2）treatment and total K reached the highest under the high fertilizer and middle water（F3W2）treatment,which were significantly different from the CK treatment.4.The activities of soil enzymes increased firstly and then decreased with the the growth period.Specificity,the overall change trend of enzymes activities under drip irrigation showed the trend of increasing first and then decreasing with the increasing of irrigation upper limit and fertilization application.The activities of soil sucrase and urease kept the highest value under the middle fertilizer and middle water（F2W2）treatment during the whole growth stages,which were 10.17%,17.14%,13.37%and 10.17%,17.14%,13.37%higher than that of conventional irrigation and fertilization（CK）treatment in the early middle and end of fruiting stage respectively.Catalase activity reached the highest at the early of fruiting stage under high fertilizer and high water（F3W3）treatment,and reached the highest tin the middle of fruiting stage under middle fertilizer and middle water（F2W2）treatment,and reached the highest in the end of fruiting stage under high fertilizer and middle water（F3W2）treatment.The activity value were 14.61%,35.30%and 31.54%higher than the CK treatment.The activities of soil sucrase,urease and catalase had the lowest value under low fertilizer and low water（F1W1）treatment and had significant differences with CK treatment.5.The numbers of bacteria,fungi and actinomycetes increased first and then decreased with the increase of irrigation limit and fertilization rate.Although the changes in the number of microorganisms in different growth stages were different,they all reached the highest in the early of fruiting stage,the bacteria,fungi and actinomycetes reached the highest number under the middle fertilizer and middle water（F2W2）treatment,which were 50.00（×10⁷ CFU/g,dry soil）,30.00（×10⁵CFU/g,dry soil）and 107.67（×10⁶ CFU/g,dry soil）,and had significantly different compared with the conventional irrigation and fertilization（CK）treatment.The indexes of tomato growth and development,nutrient absorption and utilization and rhizosphere soil environment in greenhouse were comprehensively analyzed,the comprehensive score of F2W2 treatment was the highest,suggested most favorable treatment for saving water,saving fertilizer and increasing yield,meanwhile this was the optimum irrigation upper limit and fertilizer amount for tomato growth in autumn and winter in greenhouse.Therefore,under the conditions of this study,F2W2 treatment is the most suitable combination of water and fertilizer,that is,the irrigation water limit was 80%of field water holding rate,and the fertilization level of nitrogen,phosphorus and potassium were N 285 kg/hm²+P₂O₅165 kg/hm²+K₂O 350 kg/hm²,tomato yield was 111422.15 kg/hm²,which increased15.40%of yield,saved 20%of fertilizer and saved 54.85%of water compared with conventional irrigation and fertilization,which could be used as a reference for integrated irrigation and fertilization system of tomato in autumn and winter period in greenhouse.