Effects Of Moistube Irrigation And Fertilization On Soil Water And Nitrogen Transport And Vegetable Growth

Moisture irrigation is a new water-saving irrigation technology after drip irrigation.Compared with drip irrigation,moisture irrigation has the advantages of convenient and efficient water-saving.Micro-moisten pipe is a new water supply technology that can supply water to root uninterruptively in real time by using semi-permeable membrane principle and slowly exudes through pores under the joint action of internal and external water potential difference,soil matrix action and water gravity itself.According to the principle and characteristics of moisture irrigation,this paper carried out indoor soil box simulation test,open-air vegetable planting test and greenhouse vegetable planting test by integrating water and fertilizer technology of moisture irrigation.The test parameters decrease according to the test.The laboratory test was carried out by setting the bulk density of 1.25g/cm3 and 1.35 g/cm3 in two groups,three concentrations of 0mg/L,200 mg/L and 400 mg/L in each group,and two water heads of 1m and 1.5m.To explore the distribution of water and nitrogen in various treatments.On the basis of the laboratory test,a small open-air test was carried out,and the accuracy of the laboratory experiment was verified through various indicators of vegetables,considering only the effect of concentration and water head.In the greenhouse test,there was sufficient base fertilizer applied before the test,so only the influence of pressure water head on facility vegetables was considered,and a reasonable,convenient,water-saving and high-yield combination method was found through the measurement of the whole growth cycle and the final yield.The main conclusions of the experiment are as follows:The results of indoor soil box simulation show that the bulk density,the concentration of fertilizer solution and the pressure water head have effects on the cumulative infiltration amount,wetting front migration,soil water distribution and soil nitrogen distribution.The cumulative infiltration amount is a quadratic function with time change,and the infiltration speed increases first and then decreases.The wetting front is obviously affected by pressure,concentration and bulk density,and the increase of the three factors will lead to the expansion of the wetting front.The water distribution is radially diffused along the center of the micro moisture pipe,and the water content changes significantly in the vertical downward direction.The distribution of nitrogen in the fertilization group was that the closer to the moistening tube,the higher the content was,while in the control group,it was in line with the characteristic of"salt goes with water".The results of open-air lettuce planting experiment showed that the plant physiological indexes and soil indexes were easily affected by pressure water head and concentration of fertilizer solution,and the plant height,stem diameter,leaf area,yield and other aspects increased with the increase of pressure water head and concentration of nitrogen solution.However,the influence on leaf water content was not obvious.For soil correlation measurement,it also indicates that there are high levels of pressure water head and concentration of fertilizer solution,which can better promote plant growth.The optimal treatment combination was pressure water head of 1.5 m and fertilizer rate of 400mg/L.The maximum fresh weight,dry matter accumulation,lettuce yield of 2276.5 g/m~2,irrigation water productivity and nitrogen agronomic efficiency were obtained in this treatment.The results of vegetable experiment in greenhouses showed that cucumber plants in greenhouses grew better under the condition of cucumber planting in greenhouses and the same nitrogen application level and irrigation pressure of 1.5 m.Compared with 1m head,all the indicators are greatly improved,which verifies the results of open-air test.Among all treatments,the cucumber plants with irrigation pressure of 1.5 m close to water supply T3 had the best growth and development,and the cucumber yield per plant under this treatment was the highest.In the continuous micro-watering irrigation,the yield is 36.22%higher than that of the diffuse irrigation,indicating that micro-watering irrigation can achieve the effect of efficient water use and increased yield.