冬小麦限水灌溉条件下土壤硝态氮变化与氮素平衡

Studies on the Soil Nitrate Content and Nitrogen Balance in Winter Wheat Plants under Limited Irrigation Condition

研究结果表明 ,冬小麦拔节期 1m土层的硝态氮含量主要受基肥施氮量的影响 ,开花期和成熟期的硝态氮含量除了与追肥与否及追肥施氮量有关外 ,还受基肥施氮量的一定影响。土壤硝态氮含量的分布 ,在拔节期处理间差异主要在 0～ 6 0cm土层内 ,在开花期和成熟期则整个 1m根层内都有差异。 14 4～ 2 13kg/hm2 的施氮量 ,都能维持土壤氮素的表观平衡 ,但以 14 4kg/hm2 施氮量、全部基施的处理吸氮比例 (作物吸氮量 /施氮量 )最高 ,残留比例 (土壤残留量 /作物吸氮量 )最低。

The nitrate contents in 1 m soil profile at stem elongation stage were mainly affected by the nitrogen amount applied as basal dressing. And the nitrat e contents in soil profile at blooming stage and maturing stage were related to the nitrogen amount applied as top dressing at stem elongation stage, as well as the nitrogen amount of basal dressing. The differences of nitrate distribution between the treatments at stem elongation stage mainly observed in 0-60 cm soil profile, while the differences at blooming stage and maturing stage observed in whole 1 m soil profile. Finally, it is found that the apparent nitrogen balance in soil wheat plant system could be maintained when 144-213 kg/ha was applied , but treatment which whole 144 kg/ha was applied as basal dressing had a highe st absorption ratio, and a lowest residual ratio.