Effects Of Negative Pressure Irrigation And Soil Conditioner On Soil Moisture And Maize Growth

Negative pressure irrigation is a new type of irrigation technology,which has the characteristics of continuous and stable water supply.On the one hand,this technology can realize the function of automatic water supply and save the cost of manual irrigation.On the other hand,the precise water supply demand can be realized,and the suitable water state for crop growth can be met by changing the negative pressure.Soil conditioner can effectively improve soil physical and chemical properties and increase crop yield.The comprehensive application of soil conditioner and negative pressure irrigation is of great significance to popularize negative pressure irrigation technology.Two-dimensional infiltration in this article,through indoor soil column experiment,outdoor evaporation experiment,pot experiment and field experiment,the preliminary research on the negative pressure irrigation and soil water infiltration with different soil conditioner for distribution,the influence of the moisture evaporation and crop growth,and potted negative pressure irrigation system based on the negative pressure irrigation system in the field under the condition of using the preliminary inquiry,the following conclusions:(1)Soil column infiltration test showed that under the condition of negative pressure irrigation,soil water accumulated infiltration amount and wetting front were dynamic and increased with the increase of negative pressure.The addition of soil conditioner can significantly promote the cumulative infiltration amount and the migration rate of wetting front,and the promotion effect increases with the increase of application amount,which is a power function and a quadratic function with time,respectively.(2)Evaporation test shows that: Under-7k Pa～-1k Pa negative pressure irrigation,the soil moisture content could be controlled in the range of 12%-24.55%,and the addition of soil conditioning agents could increase the moisture content to 13.94%-28.69%,and the moisture content increased with the increase of soil conditioning application amount.The cumulative evaporation of soil water increased with the increase of negative pressure.Biochar had no significant effect on soil moisture evaporation.The water-retaining agent had inhibition effect on soil moisture evaporation at various negative pressure levels,while the biochar + water-retaining agent had promotion effect on soil moisture infiltration and evaporation at various negative pressure levels.(3)The pot experiment showed that: Under-7k Pa～-1k Pa negative pressure irrigation,soil moisture content can be controlled within 7.85%～19.44%,and water retention agent can be added to increase it to 8.88%～22.75%,and the effect of improvement increases with the increase of the application amount of water retention agent.Under negative pressure of-7k Pa～-1k Pa irrigation,each growth index of maize firstly increased and then decreased with the increase of negative pressure.The addition of water-retaining agent would inhibit the growth of each maize under-1k Pa and promote the growth of maize under-3k Pa and-7k Pa,and the application of 40kg/ mu water-retaining agent under-3k Pa had the best promoting effect.(4)Field experiments showed that negative pressure irrigation could increase maize yield on the basis of water saving,and the yields of-1k Pa,-3k Pa and-7k Pa were 90.35%,84.62% and76.73% of those of full irrigation,respectively.However,the water saving rate was 63.27%,73.68% and 83.79%,respectively,and the water saving effect was significant.The experiment of negative pressure irrigation under field condition shows that the negative pressure irrigation is completely feasible in actual agricultural production.In conclusion,negative pressure irrigation can change soil water infiltration and evaporation capacity by combining with soil conditioner.Applying soil conditioner at appropriate negative pressure irrigation level can improve crop yield.At the same time,the negative pressure irrigation technology can be used in actual production to achieve the effect of saving water and increasing production.