| China has the largest cultivated area of greenhouse tomato in the world.Greenhouse tomato has become an important industry in vegetable planting area,plays a critical role in increasing farmers’ income and rural revitalization.The irrigation method including furrow irrigation,drip irrigation and micro-sprinkler irrigation are commonly used in greenhouse tomato cultivation,and the changing state of soil Moisture are under alternate wetting and drying.In an irrigation cycle,In an irrigation cycle,the soil moisture is in a higher state at the earlier stage of irrigation,and it will cause the oxygen deficit in root zone.At the later stage of irrigation,a large amount of soil water is consumed by soil evaporation and plant transpiration,it will cause the decrease in soil moisture,which in turn results water stress in the tomato root zone.As a new water-saving irrigation technology,subsurface irrigation with ceramic emitters has the characteristics of green,energy conservation and environmental protection.The ceramic emitter can automatically adjust the flow rate according to the soil moisture,and realize the adaptive continuous irrigation,which can provide a stable and suitable soil moisture for crops.In order to determine the suitable technical parameters of the greenhouse tomato subsurface irrigation with ceramic emitters,this paper study the effects of different design flow rate on the water consumption characteristics,soil evaporation and plant transpiration of tomato,established the evapotranspiration estimation method of greenhouse tomato,used the principal component analysis method,combined with tomato yield and quality,and determine the suitable technical parameters of the greenhouse tomato subsurface irrigation with ceramic emitters.The main conclusions are as follows:(1)The water consumption characteristics of subsurface irrigation with ceramic emitters greenhouse tomatoes were revealed.In autumn cultivation,the water consumption and plant transpiration in the whole growth period of subsurface drip irrigation were 307.8 mm and273.8 mm,respectively,while those of subsurface irrigation with ceramic emitters were 282.7mm and 255.0 mm.Compared with the subsurface drip irrigation,the water consumption and plant transpiration during the whole growth period of subsurface irrigation with ceramic emitters were reduced by 8.9% and 7.4%.In spring cultivation,the water consumption and plant transpiration in the whole growth period of subsurface drip irrigation were 434.3 mm and 396.5 mm,respectively,while those of subsurface irrigation with ceramic emitters were391.0 mm and 361.4 mm.Compared with the subsurface drip irrigation,the water consumption and plant transpiration during the whole growth period of subsurface irrigation with ceramic emitters were reduced by 11.1% and 9.7%.The results showed that subsurface irrigation with ceramic emitters has better water-saving and yield-increasing effects under the suitable technical parameters.Compared with subsurface drip irrigation,water consumption reduced by 8.1%,yield increased by 1.6%,and water use efficiency increased by 11.6%.(2)Based on the water consumption characteristics of tomato,a method for estimating greenhouse tomato evapotranspiration in subsurface irrigation with ceramic emitters was established,which comprehensively consider meteorological factors,soil moisture status and tomato growth characteristics,and the model accuracy was verified by the experiments.The effect of the design flow and burial depth of the ceramic emitter on the tomato evapotranspiration was analyzed by the model.The results showed that the soil evaporation and plant transpiration increased with the increase of the design flow of the ceramic emitter.When the flow rate of emitter increased from 0.15 L/h to 0.30 L/h,the soil moisture content increased from 69.7% to 83.5% of the field water holding rate,the soil evaporation increased from 21.0 mm to 28.7 mm,and the evaporation increased by 39.5%.The transpiration of tomato increased from 272.5 mm to 362.6 mm,and the evaporation increased by 32.3%.The soil evaporation and surface soil moisture content decreased with the increase of the burial depth of the ceramic emitter.When the burial depth of the emitter was increased from 5 cm to30 cm,the surface soil moisture content decreased from 67.9% to 55.7% of the field water holding rate,the soil evaporation decreased from 30.4 mm to 20.6 mm,and the evaporation decrease by 42.4%.While the tomato transpiration firstly increase and then decrease with the increase of the burial depth of ceramic emitter,and when the burial depth was 20 cm,the value reaches a maximum value of 326.3 mm.(3)The technical parameters of subsurface irrigation with ceramic emitters suitable for greenhouse tomato were determined.In order to achieve the purpose of increasing the yield and quality of greenhouse tomato,the water consumption,yield and water use efficiency of tomato were taken as the evaluation indicators of high-yield water-saving,and the sugar-acid ratio,lycopene,vitamin C and single fruit weight of tomato fruit were taken as the evaluation indicators of high-quality.The component analysis method finally determined the suitable technical parameters of subsurface irrigation with ceramic emitters for greenhouse tomatoes:the design flow rate of the ceramic emitter was 0.26 L/h,and the burial depth was 15 cm. |
PDF Full Text Request