| In view of the problems of soil nutrient accumulation,nutrient loss and low nutrient utilization rate caused by excessive fertilizer and water input in the production system of protected vegetables,field experiments were carried out in Protected Vegetables by setting up a micro run irrigation system,and the effects of fertilization(microbial agent)and irrigation on the soil of protected tomato and vegetable were systematically studied by means of soil solution extractor and soil drenching solution collecting barrel The effects of accumulation and leaching of nitrogen and phosphorus,the emission characteristics of nitrous oxide in soil were analyzed,and the effects of micro run irrigation combined with reduced fertilization on the loss of nitrogen and phosphorus in tomato soil and on the yield were revealed,which provided important theoretical basis and technical guarantee for water-saving,weight-loss,green environmental protection and improvement of yield and quality of protected vegetables.The experiment of protected tomato was mainly carried out in the main vegetable producing area of Yongqing County,Hebei Province.Main conclusion:1.A micro irrigation system for greenhouse of tomato was designed.According to a single facility tomato greenhouse,a set of micro irrigation system suitable for this condition is designed.The first hub includes water supply equipment,water tank,water level controller,valve,filtration equipment,fertilizer application equipment and pressure gauge,among which the upper water level after the design water tank rack height is 2 m.The size can be 1 m × 1 m × 1 m,opaque material;the water delivery pipeline is arranged according to the dry,branch,gross 4-level pipe,the normal working pressure of micro irrigation is 0.02-0.05 MPa,the main pipe and branch pipe are arranged along the direction of the shed,and a 5-8 m area is designed,and the water flow in each area can be controlled separately,which is convenient for flushing;the layout of the field micro lubrication pipe adopts the rectangular pipe network layout,with the outer diameter of 16 The buried depth of MM micro moistening pipe is 20cm.The system provides a research and development basis for the follow-up experiment of micro irrigation and reduced fertilization model.2.The dynamic characteristics of NO3--N content in soil profile of different treatments of greenhouse tomato were determined.The results showed that the content of NO3--N in 0-20 cm surface soil was CY(traditional irrigation+reduced fertilization)<WY(micro irrigation+reduced fertilization)<CT(traditional irrigation+conventional fertilization)and WY?CY<CT in 20-100 cm soil layer,CY and WY decreased 53.74%and 57.38%respectively compared with CT treatment,which effectively controlled the accumulation of soil nitrate nitrogen,and reduced fertilization was more prominent than water-saving irrigation.The NO3--N content of the 0-100cm soil profile of all treatments in each growth period first decreased,then increased and then decreased with the increase of soil depth,and the NO3--N accumulation peak appeared in the 60-80cm soil layer.3.The characteristics of N2O emission from different soil treatments in different growth stages of tomato were revealed.The results showed that the N2O emission fluxes of soil in different growth stages of tomato showed the same law of WY<CY<CT.Compared with the traditional water and fertilizer treatment CT,the peak value of N2O emission of CY and WY treatment decreased significantly in all growth stages of tomato,with the maximum decrease of 30.12%and 59.16%.In the process of tomato planting in the facility,the treatment of micro irrgation and reduced fertilization can significantly inhibit the emission of N2O in the soil,which is the strongest,and effectively control the loss of nitrogen emission.4.The effect of controlling soil nitrogen loss by micro irrigation combined with reduced fertilization was proved.It can be found that the total amount of NO3--N leaching in CT and CY treatment soil was 78.29 kg/hm2 and 59.71 kg/hm2,respectively.Compared with CT treatment,the amount of NO3--N leaching in CY treatment decreased by 23.73%,and no leaching in WY treatment.The nitrous oxide emissions of CT,cy and WY treatments were 82.12,62.79 and 2.61 kg/hm2,respectively.It was found that the total nitrogen loss of CT treatment accounted for 41.06%of the total nitrogen input,while CY treatment accounted for 53.21%of the total nitrogen input,while wt treatment only lost N2O,accounting for 2.21%of the total nitrogen input.At the same time,under the mode of reducing chemical fertilizer and controlling water,the yield of protected tomato did not decrease,but it could reduce the loss of soil nitrogen to the lowest level,which greatly hindered the loss of soil nitrogen.It can be recommended that the mode of micro run irrigation and reducing fertilizer should be applied to the protected tomato in the area of long-term high input of water and fertilizer.5.Clarified the effect of micro-irrigation combined with reduced fertilization to control phosphorus loss in tomato soil.During the whole growth period of tomato,only the traditional irrigation CT and CY treatments collected the leaching solution.The CT and CY treatment soil phosphorus leaching losses were 7.96kg/hm2 and 5.82kg/hm2,respectively.Phosphorus leaching loss was reduced by 26.88%,confirming that micro-irrigation can prevent the effective phosphorus of soil from leaching into the soil. |
PDF Full Text Request