Water-saving Irrigation Mode Of Greenhouse Tomato In Jianshui County Of Yunnan Province

Jianshui County in Yunnan Province is located in the karst rift basin area,where "the soil is upstairs and the water is downstairs".In addition,the strong evaporation of water leads to the prominent seasonal water shortage phenomenon.Water has become a key bottleneck problem limiting the economic development and vegetation restoration in the rocky desertification area of the faulted basin.The development and utilization of water resources in the southwest karst area is low and the development of related infrastructure is lagging behind.In agricultural production,water-saving irrigation is used to improve the utilization efficiency of water resources and achieve the goal of water saving and high yield.In this study,tomatoes were taken as the experimental object,and 4 water-saving irrigation methods(drip irrigation under mulch film,infiltration irrigation,trace irrigation and alternate irrigation)are set with 75%?85%,65%?75%and 55%?65%soil relative water content as the irrigation lower limit.A total of 12 irrigation treatments.The effects of different irrigation treatments on tomato growth,quality and yield were explored in order to provide efficient water-saving irrigation schemes and theoretical basis for tomato water-saving production in Jianshui County of Yunnan Province and typical karst rift basin areas.The results are as follows:(1)As for the growth of tomato plants,a higher lower irrigation limit is beneficial to the growth and biomass accumulation of plants.The root-shoot ratio increases with the lower limit of irrigation.The mechanism for tomato to adapt to low water content is that root growth increases the root-shoot ratio.Trace irrigation and alternate irrigation have more developed root growth,which can significantly improve the root-shoot ratio of plants.Under the same irrigation lower limit,the order of root-shoot ratio from big to small is alternate irrigation,trace irrigation,infiltration irrigation and drip irrigation under film.The root-shoot ratio of trace irrigation and alternate irrigation with lower irrigation limit of 55%?65%was the highest in all treatments,which was significantly higher than other treatments.(2)The chlorophyll content decreased with the lowering of the lower irrigation limit.Under the same irrigation limit,trace irrigation and alternate irrigation could increase the chlorophyll content of the leaves.Among the photosynthesis indicators of leaves,the net photosynthetic rate,stomatal conductance and transpiration rate of tomato growth decreased with the lowering of irrigation limit.At the same irrigation limit,the net photosynthetic rate of trace irrigation was higher than the other three treatments in the whole period,the trace irrigation level of 75%?85%of the trace irrigation can make the leaves better photosynthetic.Role and accumulation of matter.(3)The higher the lower irrigation limit,the higher the total yield of the treatment,but at the end of the result,the yield of the treatment with less irrigation increased.Among the different irrigation methods,drip irrigation under film has the highest total output,trace irrigation is the second,infiltration irrigation is the third,and alternate irrigation is the smallest.Among the different irrigation methods,alternate irrigation has the highest utilization efficiency of irrigation water,followed by trace irrigation,infiltration irrigation and drip irrigation under film.In all treatments,the yield of drip irrigation under mulch with 75%?85%lower irrigation limit was 5704.0kg/Mu,but the water use efficiency was the lowest.The water use efficiency of alternate irrigation with limit of 65%?75%is the highest,42.86kg/m3,but the yield decreases by 12.25%.The yield of trace irrigation with limit of 75%?85%is only reduced by 0.67%,while the irrigation water use efficiency is increased by 21.83%,which can ensure that the yield is not reduced while water is used efficiently.If you want to ensure the highest yield of fruit products and high irrigation efficiency in the production process,it is recommended to use trace irrigation and the irrigation lower limit is 75%?85%of the field water capacity for irrigation.(4)In fruit quality,the fruit quality of the lower irrigation limit is better than the lower limit of medium and high irrigation.Under the same irrigation water limit,the comprehensive quality of fruit under alternate irrigation and trace irrigation is better than that under infiltration irrigation,and drip irrigation under mulch film is the worst.Using trace irrigation and alternate irrigation can significantly improve fruit quality.According to grey correlation analysis,the comprehensive quality of tomato fruits treated by trace irrigation and alternate irrigation with lower irrigation limit of 55%?65%are ranked first and second respectively,while drip irrigation with lower irrigation limit of 75%?85%has the highest irrigation amount and yield but the worst fruit quality.If you want to ensure the quality of fruits in the production process,it is recommended to use trace irrigation and the irrigation lower limit is 55%?65%of the field capacity for irrigation.(5)Using the TOPSIS method to evaluate the comprehensive benefits of tomato quality,yield and irrigation efficiency,it is concluded that among the four water-saving irrigation methods,the comprehensive benefits of alternate irrigation is the best,followed by trace irrigation,and drip irrigation under mulch film is the worst.The alternate irrigation treatment with the lower irrigation limit of 65%?75%in all treatments has the highest comprehensive evaluation,which can promote the quality of tomato quality,stable production and water saving.The irrigation water utilization efficiency of this irrigation mode reaches 42.86kg/m3.It is suggested to use alternate irrigation in the greenhouse tomato planting in the dry season of the karst fault basin to control the irrigation method with a lower irrigation limit of 65%?75%of the field water holding capacity.