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在大田试验条件下,研究了施肥方式(滴灌施肥和沟施)和施氮量(单次每株25、50、75 g)对欧美108杨人工林土壤氮素垂向运移动态的影响.结果表明:不同施肥方式和施氮量下,土壤中铵态氮和硝态氮含量均随土层深度的增加而降低;滴灌施肥下铵态氮和硝态氮主要集中在0~40 cm土层,随时间变化呈先升后降的变化趋势,分别于施肥后第5天和第10天达到最大值(211.1和128.8 mg·kg-1).沟施下铵态氮和硝态氮主要集中在0~20 cm土层,硝态氮含量随时间呈逐渐增加的变化趋势,于施肥后第20天达到最大值(175.7 mg·kg-1),但铵态氮随时间无显著变化;滴灌施肥下氮素在土壤中的有效时长约为20 d,而沟施下氮素在土壤中有效时长超过20 d.滴灌施肥下,土壤中铵态氮和硝态氮的含量和运移距离均随施氮量的增加而增加;沟施下,施氮量越高土壤中硝态氮含量越高,但对铵态氮含量无显著影响.滴灌施肥下林地土壤中尿素的水解、硝化速率和运移深度均高于沟施,且施氮量越大,氮素在深层土壤的积累量越高.结合欧美108杨根系和土壤氮素分布特征,滴灌施肥能够为更大的细根分布区提供氮素,更适用于人工林培育.当单次施氮量为每株50 g时,既可保证细根主要分布区内有较高含量的氮分布又不会造成淋溶,肥料利用效率可能更高.
Under field conditions, the effects of fertilization (drip irrigation and furrow application) and nitrogen application rate (25,50 and 75 g per plant per plant) on the vertical dynamics of soil nitrogen vertical movement in 108 European-owned plantations were studied. The results showed that the content of ammonium nitrogen and nitrate nitrogen in soil decreased with the depth of soil under different fertilizations and nitrogen rates. The concentrations of ammonium nitrogen and nitrate nitrogen in drip irrigation were mainly concentrated in 0-40 cm soil Layer, with the trend of increasing firstly and then decreasing gradually with time, reached the maximum value (211.1 and 128.8 mg · kg-1) on the 5th and 10th day after fertilization respectively.The main nitrogen and nitrate nitrogen Concentrated in the 0-20 cm soil layer, the content of nitrate nitrogen increased gradually with time, reaching the maximum (175.7 mg · kg-1) on the 20th day after fertilization, but the ammonium nitrogen had no significant change with time. The effective duration of nitrogen in soil was about 20 days under drip irrigation and that of nitrogen under furrow irrigation for more than 20 days in the soil.Under drip irrigation, the contents of ammonium and nitrate in soil and the migration distance With the increase of nitrogen application rate. Under the furrow application, the higher the amount of nitrogen application, the higher the content of nitrate nitrogen in soil, but no significant effect on the content of ammonium nitrogen. The hydrolysis, nitrification rate and depth of urea in soils under fertilizer-undergrowth were higher than those under furrow irrigation, and the higher nitrogen application, the higher nitrogen accumulation in deep soils. , Drip fertilization can provide more nitrogen for fine root distribution and is more suitable for plantation cultivation.When the single nitrogen application rate is 50 g per plant, it can not only ensure a high content of Nitrogen distribution will not cause leaching, fertilizer utilization efficiency may be higher.