Effect Of Different Drip Irrigation Methods On Soil Environment And Growth Of Tomato In Greenhouse

It is of great significance to carry out research on appropriate irrigation techniques and efficient irrigation patterns for greenhouse crops to achieve water conservation,promote high-quality and high-yield production,and improve soil ecological environment.In 2017,the effects of different drip irrigation methods on tomato growth and soil environment were studied in the greenhouse in Qiliying,Xinxiang city,Henan province.The experiment included 9 treatments:3 different irrigation modes(aerated subsurface drip irrigation(SDA),conventional subsurface drip irrigation(SDN)and surface drip irrigation(DN))and for each irrigation mode 3 irrigation levels were set up which based on 3 accumulated pan evaporation levels(1.1Epan,0.9Epan,0.7Epan).The morphological,physiological indexes,soil condition,soil nutrient status,yield and quality of tomato were observated and analysed systematically.The main results were as follows:1.There was no significant difference in soil temperature and soil moisture between SDA and SDN treatments.Compared with DN treatment,soil temperature in SDN treatment increased by 3.24% for the 0-10 cm soil layer,while it decreased by 1.3% for the 10-20 cm layer.Accoring to the soil moisture monitering data of the 0-60 cm soil profile,DN mainly affected the surface soil temperature,while SDN and SDA had comparatively greater influence on the 20-40 cm layer.This difference also made the DN treament have more root distributed in the upper soil layer and less in the deeper layer because of the root hydrotaxis trait.2.Soil available phosphorus,available potassium content,pH and the soil organic of SDA were less than that of the SDN treatment,while the soil nitrate increased,which proved that aeration could promote the absorption of soil nutrients by tomato roots and the soil organic matter.Compared with SDN,DN treatment had a tendency to reduce the above-mentioned nutrient criterias except the PH.The content of soil nutrient of the three drip irrigation methods showed a decline trend with the increase of irrigation water amount,showing that water had a positive effect on the absorption of nutrients.3.SDA promoted the growth and development of tomato and showed an effect on the physiological traits.Its stem length,leaf area index,aboveground plant fresh weight,and chlorophyll were all increased over SDN,and significantly higher than DN.For the net photosynthetic rate(Pn),stomatal conductance(gs),and transpiration rate(Tr),the SDA treatment were 6.34%,2.47%,and 1.96% higher than that of SDN,respectively.4.Compared with the SDN treatment,the SDA treatment increased the yield by 16.9%,3.6%,and-0.1% at high(Kcp=1.1),medium(Kcp=0.9)and low irrigation water levels(Kcp=0.7),respectively.Aeration showed a positive effect on yield at a higher irrigation quota.Compared with DN,the SDN treatment increased yield by 3.6% and 2.7% respectively under low and medium water levels.At the lower irrigation quota the yield of SDN was higher than the DN irrigation mothod.5.Tomato quality affected by both irrigation amount and aeration.The solid content,organic acid,and vitamin C decreased as irrigation amount increased.Aerated irrigation increased sugar-acid ratio and vitamin C content of tomato fruit.The result of analsis of the quality of fruit collected in different stages during the growing period showed that the medium irrigation lever(Kcp=0.9)was suitable for subsurface drip irrigation and aeration was able to ensure the stability of yield and quality at this level.6.The SDA treatment increased water use efficiency(WUE)by 7.6%,15.1%,and 20.9% under Kcp=0.7,0.9 and 1.1 irrigation levels,respectively over the SDN treatment,and the SDN treatment improved by 5.02%,2% and 1.41%,correspondingly over the DN treatment.For the same irrigation method,WUE decreased with the increase in irrigation quota.