Effects Of Water And Fertilizer Coupling On Growth,Yield And Quality Of Greenhouse Tomato

In order to solve the current situation of low water and fertilizer utilization ratio and environmental pollution caused by the blind large water and fertilizer in the production of protected tomato,the optimal irrigation and fertilizer combination under the cultivation mode of composite substrate mainly composed of vermiculite was studied,in this experiment,“Win-win Pioneer”tomato was used to study the coupling effect of water and fertilizer,a half of the four-factor five-level quadratic orthogonal rotation combination design was implemented,with a total of 18 treatments,the effects of different water and fertilizer treatments on growth,yield,fruit quality,leaf physiological characteristics and water and fertilizer use efficiency of greenhouse tomato were studied.The main findings are as follows:（1）The plant height,stem diameter,leaf number and leaf area of all treatments increased continuously during the whole growth period of tomato.The growth rate of the whole growth period showed a slow-fast-slow S-type change law.Under the condition of 78%water-holding rate in the field,N-340 kg/hm²,P₂O₅-185 kg/hm²,K₂O-310 kg/hm²were applied,the growth of tomato was the optimal level,the plant height was 148.44 cm,the stem diameter was 10.01 mm,the number of leaves was 24.67,leaf area was 357.38 cm²,dry matter was 155.62 g,root fresh weight was 68.51 g,root activity was 659.99 mg/g/h,78%～85.2%of field water holding capacity was beneficial to the increase of fresh root weight and root activity.The coupling effects of water and nitrogen,water and phosphorus,nitrogen and phosphorus on the growth of tomato were analyzed.The results showed that the coupling effects of water and nitrogen were significant.（2）In the field,the water and fertilizer use efficiency of tomato reached the maximum when N-496 kg/hm²,P₂O₅-99 kg/hm²,K₂O-454 kg/hm²were applied.High irrigation rate（90%of field water holding rate）or low irrigation rate（66%of field water holding rate）will decrease water use efficiency.Under the same fertilization rate,the increase of irrigation（78%～85.2%of field water holding rate）was beneficial to the increase of fertilizer partial productivity.The correlation between the amount of fertilizer applied and the yield was greater than that of irrigation,and the amount of fertilizer applied played a major role in determining the yield.The correlation between water use efficiency（WUE）and yield was very significant,and the increase of wue was beneficial to the increase of yield.（3）When W18 reached 9846.02 kg/667m²and the irrigation rate was 78%of the field water holding rate,N-340～496 kg/hm²,P₂O₅-99～185 kg/hm²and K₂O-310-454 kg/hm²could effectively increase the yield The yield and fruit quality of each treatment were evaluated comprehensively.W6 treatment was the best water-fertilizer coupling treatment,that is,N-496 kg/hm²,P₂O₅-99kg/hm²,K₂O-454 kg/hm²under 70.8%field water-holding rate,the yield and quality of tomato could be improved effectively by using vermiculite and yellow sand as substrate and mushroom residue as substrate.（4）The chlorophyll SPAD Value,SOD activity,CAT activity,proline（Pro）content and soluble sugar（SS）content in tomato leaves increased first and then decreased during the growth period,POD activity and malondialdehyde（MDA）,soluble protein（SP）content showed an upward trend,high level and low level irrigation（90%of field water holding rate,66%of field water holding rate）will lead to rapid increase of MDA content and decrease of enzyme activity,applying medium level fertilizer（N-340 kg/hm²,P₂O₅-185 kg/h m²,K₂O-310 kg/hm²）could increase the content of POD,CAT,SS,and photosynthesis.A pplying high level fertilizer（N-496 kg/hm²）could increase the content of SP.To sum up:the Comprehensive Evaluation of tomato yield and fruit quality,the best water and fertilizer scheme is the field water-holding rate of 70.8%irrigation,N-496 kg/hm²,P₂O₅-99kg/hm²,K₂O-454 kg/hm²,it is beneficial to increase yield and fruit quality,and to achieve maximum water and fertilizer use efficiency,which is helpful to achieve high-quality and efficient production of protected tomato in South Xinjiang.