模拟降雨条件下成垄压实对硝态氮迁移的影响

利用人工模拟降雨研究了成垄压实施肥条件下不同的垄坡度及不同压实的障碍层对硝态氮迁移的影响。结果表明,对一次60mm的降雨,无障碍层存在时,平地施肥条件下NO3--N淋溶剧烈,土壤表层施肥部位的NO3--N仅余总施入量的0.1%左右。垄沟施肥因其将入渗水分与施肥区分开,从而可以降低NO3--N的淋溶。不同的垄坡度对NO3--N的淋溶略有影响,30垄坡条件下上层土壤NO-残留量略大于20、40。相对于不同坡度垄沟,在施肥带部位通过压实形成水分运动的障碍层对防止NO3--N淋溶的效果较为显著,当压实层的土壤容重为1.36g/cm3时,施肥部位残余NO3--N就可达727.40mg,占原施入量的17.2%;对容重1.42g/cm3的压实层,其施肥部位残余NO3--N已占到原施入量的23.6%。以上结果表明通过压实在施肥部位形成障碍层的成垄压实施肥法,减小通过施肥区的入渗水量,从而可减少施肥部位的NO3--N随入渗水分向深层土壤的迁移和累积,这对提高氮肥利用率,保护地下水资源具有重要意义。

Study on nitrogen movement under localized compaction and ridge tillage by use of artificial rainfall

The effect of the rows' slope and different compaction of localized compaction and ridge on the nitrate leaching were studied in the paper The results showed that there was only 0.1% nitrate left in the application position after 60mm artificial rainfall in flat tillage The leaching was reduced by ridge tillage since the infiltration water was separated from the fertilizer band by the ridges The most left nitrate in the application position was found under 30° slope rows, which was account for 0.4% of the total application approximately The influence of the different bulk density barriers to nitrate leaching was more prominent than that of the rows' slope The left nitrate in the application position under 1.36 g/cm3 barriers was 727.40 mg, accounting for 17.2% of the total application And 25% of the total application was left under 1.51 g/cm3 barriers This indicated that infiltration water through the fertilizer band was reduced by the compacted barriers As a result, the NO₃^--N movement to deep soil was reduced This implied that the nitrate use efficiency could be improved and the ground water could be protected by the fertilizer system