滴灌施肥条件下土壤水分和速效氮迁移分布规律

Distribution of Soil Water and Available Nitrogen in Purple Soil Under Drip Fertilization

以紫色土为供试土壤,采用室内模拟方式进行滴灌施肥试验,研究粘壤土（CL）、壤质粘土（LC）和砂质壤土（S）中水分、NO-3-N和NH4＋-N的运移分布规律以及滴灌施肥浓度对NO3--N和NH4＋-N运移分布的影响。结果表明,以小滴头流量进行滴灌施肥,水分以垂直运移为主;LC水分含量随土层深度和径向距离增加而逐渐减少,S和CL水分含量随径向距离增大而减少,随土层深度增大表现为先减小后增加,且继续向下移动趋势明显。NO3--N可同步到达土壤湿润锋处,其移动规律与水分运动相似;NO3--N的垂直运移比径向移动更显著,且在土箱底部大量累积;滴灌施肥浓度增大,NO3--N在整个土层的含量增加,在较深土层的累积量增加;NO3--N在土壤中的迁移能力表现为S〉CL〉LC。NH＋4-N几乎只在0-5cm表层土壤中聚集,垂直迁移困难;NH4＋-N在土壤中移动受质地影响较大,移动能力表现为S〉CL〉LC;滴灌施肥浓度增大能促使CL和LC中r为3~8cm,d为0~7.5cm土层范围的NH4＋-N含量显著增加,但对促进NH4＋-N向下迁移无明显作用。

The simulative soil box with drip fertilization test was used to research the movement and migration behavior of water and available nitrogen in three purple soils as clay loam,loamy clay and sandy loam,the influence of drip fertilization concentration on available nitrogen distribution were investigated as well.The results showed that with little dripper discharge,water was priority to the vertical transportation.Water content in LC gradually reduced with distance in all the directions from the emitter while in S and CL,it firstly decreased and then increased with the increase of soil depth,and decreased with the increase of level distance.N3O--N could reach the soil wetting front,and showed the similar movement regular with water.A large number of NO3--N accumulated in the bottom of soil box and NO3--N showed signs of spread down.NO3--N content in the soil layer increased with drip fertilization concentration resulting a large amount of NO3--N accumulation in deeper soil layer.The migration ability of NO3--N in three soil was S〉CL 〉LC.NH4＋-N almost stayed in 0-5cm depth soil.soil texture greatly influenced NH4＋-N movement,and the migration ability of NH4＋-N was S〉CL〉LC.NH4＋-N content in the soil region of 3~8cm（r）,0~7.5cm（d）in CL and LC significantly increased with increasing the drip fertilization,but there was no obvious effect on promoting NH4＋-N moving down to deeper soil.