关键词: 涌泉根灌; 灌水量; 肥液入渗; 湿润体; 水氮分布;

Abstract: To study the characteristics of water and nitrogen migration and the variation of the characteristic values of the infiltration wetting body in bubbled-root irrigation, the infiltration experiment of fertilizer solution was carried out in the undisturbed soil of the jujube test base of the Yuanzhi Mountain dwarf dense planting area in Mizhi County, northern Shaanxi Province.The results showed that:(1) The irrigation volume had significant effects on the wetting front migration, wetting body volume, water content and nitrogen distribution and migration.In the horizontal profile, the wetting front migration distance in the horizontal direction and the vertical direction increased with the decrease of the irrigation volume.In the vertical profile, the irrigation volume was proportional to the wetting front migration distance in horizontal direction, and it was inversely proportional to the wetting front migration distance in vertical direction.(2) The wet front migration distance on horizontal and vertical profiles can be fitted by power functions.The larger the irrigation volume was, the larger the wetting body volume was, the wider and deeper the wetting body appeared, and the higher the water content at the same position of the wetting body at the end of the irrigation was.(3) In the process of water redistribution, the water content in the wetting body gradually stabilized, and the wetting body continued to expand, but the water content in the wetting body was significantly lower than that at the end of the irrigation.(4) The nitrogen content of the wetting body at different soil depths increased with the increase of irrigation volume.The nitrate nitrogen migration law and water movement law were similar.In the process of redistribution, the content of the nitrate nitrogen in different soil layers decreased with the increase of distribution time, and tended to be stable when the water content of the wetting body reached the field water holding capacity.The effect of water movement on the distribution and migration of ammonium nitrogen was not significant.In the process of water redistribution, the content of ammonium nitrogen in different soil depths increased first and then decreased with the increase of irrigation volume.The longer the redistribution time was, the more uniform the distribution of fertilizer solution in the wetting body was, but the ammonium nitrogen content in the soil generally decreased.

Key words: bubbled-root irrigation; irrigation volume; fertilizer solution infiltration; wetting body; water and nitrogen distribution;