Influence Of Aerated Drip Irrigation On Soil Aeration Under Greenhouse Vegetable Production System

In the process of drip irrigation process,water infiltrates into the soil,resulting in the decrease of aeration porosity.Meanwhile,the soil moisture in the root zone is accumulating,restricting the gas exchange between the air in the atmosphere and the root,causing a lack of oxygen to root easily.Therefore,it is of great significance to ensure soil respiration during irrigation.Drip irrigation with aerated water(DIAW)is to aerate the rhizosphere by aerated irrigation water through the drip or subsurface drip irrigation system.DIAW can increase the oxygen content in irrigation water,thereby improving the soil respiration and meeting the need of root growth to achieve the purpose of promoting crop growth.Existing researches show that different oxygation techniques cause different effects on crop growth and yield in different soil types.In order to understand the effect of oxygation on the production of facility crops,three types of soils and two kinds of oxygation techniques were set up.With normal drip irrrgation as a control group,pot experiment was conducted to verify the effects of DIAW on crop growth.Then,suitable soil was selected,and used to study the response characteristics of soil respiration index under selecting and their mutual relationship between crop growth,physiology,nutrient utilization,crop yield and quality and soil aeration indexes was analyzed,thus to reveal the effect of oxygation on increasing yield and efficient use of water and fertilizers.Main conclusions were given as follows.(1)Crop growth response to DIAW in different soil typesBased on pot experiments,purple eggplant and tomato were seleted as test crops under Zhengzhou clay,Luoyang silt loam and Zhumadian loam soils.DIAW,normal drip irrigation,and hydrogen peroxide were used to study the crop growth reponses and nutrient utilization.Results showed that the crop growth index(i.e.,plant height,stem diameter),physiological index(i.e.,photosynthesis rate,stomatal conductance,transpiration rate,chlorophyll),yield and quality(i.e.,fruit hardness,total acid,soluble solids,soluble protein,and vitamin C)were all higher than the contron group,with significant differences in plant height,stem diameter,yield,and quality(p<0.05).The contents of total nitrogen,total phosphorus and total potassium in the plants were higher than those in the control group.Under same soil conditions,the total nitrogen,total phosphorus,and total potassium indexes of the treated soil were significantly higher than those of oxygation and chemical oxygation treatments.DIAW and hydrogen peroxide treatments increased the crop utilization and accumulation of nutrientsin plants,the depletion of soil nutrients,resulting a significant decrease in nutrient content in soil.In most cases,the indexes such as crop growth under DIAW are higher than hydrogen peroxide treatment,suggesting that DIAW treatment was more effective in the regulation of soil envirmental conditions required for crop growth and promotes the absorption and utilization of nutrients by crops.There is no significant difference in data of crop growth indexes between different soil types and same oxygation treatments.Among them,DIAW and chemical oxygation of crop growth,physiology,yield,and quality under Zhengzhou clay are more significantly effective than other soils.The treatment is relatively high,which showed that Zhengzhou clay soil was more suitable for oxygation treatment,and there was a good effect in crop growth promotion.(2)Influence of DIAW on the soil aeration under greenhouse purple eggplant productionTaking normal subsurface drip irrigation as a control group,DIAW was selected as the experimental group,the plot experiment was further carried out to explore the reponse differences in crop growth and nutrient utilization,and to reveal the mechanism of DIAW on the crop growth and soil aeration.Results showed that the growth indexes(i.e.,plant height,stem diameter,yield)of purple eggplant of oxygation was significantly higher than that of the control,and the difference was significant(p<0.05),and the physiological indexes(i.e.,photosynthesis rate,stomatal conductance,transpiration rate,leaf chlorophyll),soil chemical indexes(i.e.,soil total nitrogen,total phosphorus,total potassium)were higher in total nitrogen,total phosphorus,and total potassium than control treatments,soil physical properties(i.e.,soil moisture and temperature)showed no significane,and the daily discharge concentration trend of the biological properties(soil respiration)was basically the same as that of the control,but the oxygation treatment had higher soil respiration concentration and the time period was significantly different(p<0.05).Soil aeration indexes(i.e.,soil oxygen diffusion rate,oxydation-reduction potential,dissoloved oxygen,and aeration porosity)were significantly improved compared to the control under aeration treatment.DIAW increased the soil ventilation pores in the root zone of,and sufficient air facilitates crop respiration,improves the ventilation conditions of the soil,and facilitates the absorption of water and nutrients by the crops.Under controlled conditions,crop growth was inhibited under conditions of hypoxia.The difference between growth of DIAW and the control one was not significant,but the cumulative effect over the entire growth period indicated that DIAW treatment significantly promoted crop growth.