| With the rapid development of china’s agriculture,straw mulching technology has brought great economic benefits to china’s agricultural production.The hole irrigation technology is an effective way of water-saving irrigation in agricultural production,this article makes full use of the technical characteristics of hole irrigation and straw mulching,through the field test and theoretical analysis on the combination of technical routes,the effects of different irrigation techniques and fertilization techniques on soil water and nitrogen heat transfer were studied,the main research results are as follows:(1)Under straw mulch the effects of irrigation techniques on the distribution of hole irrigation soil water and nitrogen soil heat transport.The technical elements of irrigation include: pit deep,hole diameter and irrigation volume three factors.At the same time the deeper the pit,the greater vertical wetting distance: with the distance from the pit bottom the soil moisture content of different pit depth decreases,under the same irrigation conditions,at the same point the greater the depth of the pit,the greater the soil moisture content;with different depths is higher the higher the content of nitrate nitrogen in the soil,under the same irrigation conditions,in the same point the higher the depth of the pit,the smaller the content of soil nitrate nitrogen.With the increase of soil depth the soil temperature at different pit depths increased first and then decreased,at the same location the higher the depth of the pit,the lower soil temperature.At the same time the larger the diameter of the pit,the smaller distance from the vertical wet runoff;with the distance from the pit bottom the soil moisture content of different pit depth decreases,under the same irrigation conditions,at the same point the larger the diameter of the pit,the higher the soil moisture content,the higher the content of nitrate nitrogen in the soil with different pit diameter is higher than that from the bottom of the pit;the content of nitrate nitrogen in the soil also increased with the increase of the diameter of the hole.With the increase of soil depth the soil temperature of different pit diameter increases and then decreases,at the same location the greater the diameter of the pit,the higher the soil temperature.At the same time the greater the amount of irrigation the greater the vertical wet front migration distance;with the distance from the pit bottom the soil water content of different irrigation amount decreased,under the same pit structure,the greater the irrigation amount,the greater the soil moisture content at the same point,with different irrigation volume the higher the content of nitrate nitrogen in the soil,the amount of nitrate nitrogen increased in the vicinity of the pit,the content of deep nitrate nitrogen in the pits increased.With the increase of soil depth the soil temperature of different irrigation levels increased first and then decreased,at the same location the greater the amount of irrigation,the lower the soil temperature.In the redistribution stage the soil moisture content of the pits under straw mulching was higher than that without straw mulching,straw mulching effectively promoted the migration of nitrate to deep soil,reducing the loss of nitrate nitrogen,at the bottom the diurnal variation of soil temperature in the pits under straw mulch was significantly less than that without straw mulching.(2)Under straw mulch the effects of fertilization techniques on the distribution of soil water and nitrogen in soil.Fertilization techniques include: amount of fertilizer and fertilization method.At the same time the greater the amount of fertilizer,the greater the distance between the vertical wet front migration;with the distance from the pit bottom the soil water content of different fertilizers decreased,under the same irrigation conditions,in the same point the greater the amount of fertilizer,the greater the soil moisture content;the higher the content of nitrate nitrogen in the soil with different fertilization,under the same irrigation elements,at the same point the greater the amount of fertilizer,the greater the amount of soil nitrate nitrogen,with the increase of soil depth the soil temperature of different fertilization levels increased first and then decreased,at the same location,the higher the amount of fertilizer,the higher the soil temperature.After irrigation 0h,the order of vertical wetting distance of different fertilization methods is irrigation with fertilizer,deep application,surface application.with the distance from the pit bottom the soil water content of different fertilization methods decreased,under the same test conditions,at the same point the soil moisture content of irrigation with fertilizer and deep application was higher than that of surface application.With the distance from the bottom of the pit the higher,with the distance from the pit the content of nitrate nitrogen in the soil,the contents nitrate nitrogen of surface application and deep application in the soils were significantly increased and then decreased.After irrigation redistribution stage,with the extension of time after irrigation soil moisture content and nitrate nitrogen gradually reduced.The distribution of soil water and nitrogen treated by different fertilization methods was similar to that at the end of irrigation. |
