Effects Of Alternate Micro-irrigation On Soil Moisture Migration And Spinacia Growth In Greenhouse

At the present stage,the contradiction between China's agricultural development and sharp decline in water resources is becoming increasingly prominent.Water resources as non-renewable resources,it also consumes more and more water in agricultural production,so water saving techniques such as micro-irrigation and alternate irrigation have become hot topics in the current study.Different depths and pressure heads were set up indoors,and to investigate soil moisture infiltration conditions under alternate moist irrigation conditions.Including cumulative infiltration,wetting front migration and wetting characteristics,soil moisture content changes in longitudinal profile.And select the appropriate parameters,doing experiment on the cultivation of spinach in outdoor.Making conventional quantitative irrigation as a control,and the growth and yield,water use and irrigation amount of spinach were analyzed.The results show that:(1)Indoors soil moisture infiltration experiment shown that,(1)The cumulative infiltration rate trends to increase on both sides of all treatments of alternate moistube irrigation,it was inverse proportion to the burial depth,and in positive proportional relationship with the pressure head.The formation of big wet body of one side will make the cumulative infiltration rate decreased of another side.The treatment of two cycles,the cumulative infiltration rate is less than which starts water infiltration first.(2)The section size of wet body had a positive correlation with pressure head,and a negative correlation with depth of all alternate moistube irrigation treatments.The section size of wet body was bigger than that side which starts water infiltration first when the wet body was intersected of two sides.The shape of wetting body is small above and bie bellow when the buried depth was 10 cm,the wetting front transport distance was closed to each other of different directions of other treatments,the shape of wetting body was about a circular,the migration distance and the infiltration time of wetting front were in accordance with the power function relation of S=ax~t,there was a significant correlation between them.(3)The soil moisture content was the largest in the infiltration contact surface,the soil moisture content of each sampling point along the wetting front migration direction decreases.In vertical direction,there has no effect of soil moisture content between both sides as the sample points were far apart.In horizontal direction,water infiltration will spread to the middle,the soil moisture of the middle part come from moisture diffusion of two sides when wet body intersection,water content of the end sample point was higher than single pipe moistube irrigation water infiltration.The treatment of two cycles,the soil moisture content increased and closed to each other of each sample point while the second cycle cumulative infiltration content is reduced.(2)Experiment on the cultivation of spinach outdoors:(1)The amount of irrigation of micro moist alternate irrigation was lower than that of conventional quantitative irrigation,but the soil moisture content was higher than that of conventional quantitative irrigation,the soil moisture content was the highest when the buried depth was 15 cm and the pressure head was 150 cm.(2)Under the condition of micro moist alternate irrigation,the height,fresh weight and dry matter accumulation of spinach were higher than conventional quantitative irrigation,the best treatment was 15 cm depth and 150 cm pressure head.The root length was also higher than the conventional quantitative irrigation,but there was no significant difference between micro alternate irrigation treatments.(3)As far as the yield of spinach and irrigation water productivity were concerned,compared with conventional quantitative irrigation,micro alternate irrigation was beneficial to increase yield,and with higher irrigated water productivity.In the micro alternate irrigation treatments,the yield was highest when the buried depth was 15 cm and the pressure head was 150 cm,also the highest irrigation water productivity.