秸秆与不同水平氮素配施对陇中黄土高原旱作农田土壤氮素矿化的影响

为了探明秸秆配施氮素对陇中黄土高原旱作农田土壤氮素矿化的影响,采用Stanford间歇淋洗培养法,经过120d室内培养,测定分析小麦秸秆0t/hm^2+施纯氮0kg/hm^2(N0)、小麦秸秆4.5t/hm^2+施纯氮0kg/hm^2(SN0)、小麦秸秆4.5t/hm^2+施纯氮50kg/hm^2(SN50)、小麦秸秆4.5t/hm^2+施纯氮100kg/hm^2(SN100)4种施肥方式下陇中黄土高原旱作农田土壤氮素矿化的特征。研究发现:①秸秆配施氮素降低了土壤氨化速率和硝化速率;②与N0相比,SN0、SN50、SN100处理土壤氮素累积矿化量分别下降了19.14%、17.22%、13.47%;③土壤氮素累积矿化量的变化是硝态氮的变化引起的。表明秸秆配施氮素能够降低土壤氮素矿化水平。

Effects of Straw Combined with Different Nitrogen Levels on Soil Nitrogen Mineralization in the Loess Plateau of Central Gansu Province

In order to investigate the effects of straw combined with nitrogen application on nitrogen mineralization in the loess plateau of central Gansu province,Stanford batch elution culture method was used.After 120 days of indoor culture,4 fertilization application models including wheat straw 0 t/hm^2 + pure nitrogen 0 kg/hm^2(N0),wheat straw 4.5 t/hm^2 + pure nitrogen 0 kg/hm^2 (SN0),wheat straw 4.5 t/hm^2 + pure nitrogen 50 kg/hm 2 (SN50) and wheat straw 4.5 t/hm^2 + pure nitrogen 100 kg/hm^2 (SN100) were set to discuss the characteristics of nitrogen mineralization in the loess plateau of central Gansu province.The results showed that:(a) the ammoniation rate and nitrification rate of soil were decreased by straw combined with nitrogen application;(b) compared with N0,the amount of soil nitrogen accumulation mineralization in SN0,SN50,SN100 treatment decreased by 19.14%,17.22% and 13.47% respectively;(c)the change of soil nitrogen accumulation mineralization was caused by the change of nitrate nitrogen.In conclusion,straw combined with nitrogen application can reduce the level of soil nitrogen mineralization.