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利用室内试验 ,研究了点源施肥灌溉条件下硝态氮和铵态氮的分布规律。试验土壤为砂壤土 ,滴头流量的变化范围为 0 .6～ 7.8L / h、灌水量为 6～ 15 L、肥液 (NH4 NO3)浓度为 10 0～ 70 0 m g/ L。销态氮在距滴头 17.5 cm范围内呈均匀分布 ,其浓度随肥液浓度的增加而增加 ;在湿润边界上硝态氮产生累积 ;肥液浓度是影响硝态氮分布的主要因子。在距滴头 15 cm范围内 ,滴头流量和灌水量对土壤中硝态氮分布的影响不明显 ,在此范围以外 ,随滴头流量的增大或灌水量的减小 ,硝态氮浓度增加。铵态氮浓度在滴头附近出现高锋值 ,肥液浓度越高 ,锋值越大 ,且施肥灌溉对铵态氮分布的影响范围较小 ,一般在距滴头 10 cm范围以内
The indoor experiment was conducted to study the distribution of nitrate nitrogen and ammonium nitrogen under point source irrigation. The test soil is sandy loam, the drip flow varies from 0.6 to 7.8 L / h, the irrigation volume is from 6 to 15 L, and the concentration of NH4NO3 is from 10 0 to 70 0 m g / L. Nitrogen distribution is uniform in the range of 17.5 cm from the dripper. The concentration of nitrogen increases with the increase of fertilizer concentration. Nitrate accumulates on the moist boundary. Fertilizer concentration is the main factor affecting the distribution of nitrate nitrogen. In the range of 15 cm away from the dripper, drip flow and irrigation volume had no obvious effect on the distribution of NO3 - N in soil. Outside this range, with the increase of drip flow rate or the decrease of irrigation amount, the nitrate nitrogen concentration increase. Ammonium nitrogen concentration in the drip head near the high front, the higher the concentration of fertilizer, the front, the greater, and the impact of fertigation irrigation on the distribution of ammonium nitrogen is smaller, generally within 10 cm from the dripper