摘要
研究了陕北黄绵土,关中(土娄)土与陕南水稻土土壤剖面中硝酸盐的分布与累积,分析了硝酸盐淋移与土壤剖面粘粒含量的关系.结果表明,黄绵土由于粘粒含量少,土壤疏松,氮肥施入土壤后硝化作用速度快,氮素多以硝态氮存在于土壤中,遇到过量的灌溉或降水,容易引起硝酸盐淋失.在米脂的川道地,施肥2个月后,硝酸盐峰值在50 cm 左右,4个多月后,峰值下移至100 cm 左右,6个月后,该峰值下降到130 cm 左右,一年内,硝酸盐的峰值已经消失,分布在130至 350 cm 之间.因此,在黄绵土地区可以灌溉的川道地,氮素损失的主要途径是硝酸盐淋失.关中(土娄)土,粘粒含量相对较高,硝化作用速度快,但由于在80-120 cm有一粘化层,阻碍了水分与硝酸盐的向下淋移,使得大部分硝酸盐累积在0-100 cm 土层,其累积量占到0-400 cm总累积量的64% ～ 74%,而200-400 cm仅占到7% ～ 13%.而且淋移到100 cm 以下的硝酸盐,也通过反硝化损失了.陕南水稻土,由于深层土壤水饱和,硝酸盐难以向下淋移,氮素主要累积在土壤表层.由于下层土壤长期处于厌气条件,即使淋移到下层的硝酸盐也通过反硝化作用而损失掉了.
Nitrate distribution and accumulation in soil profile in Entisol in northshaanxi, Anthrosol in Guanzhong plain,Paddy soil in southshaanxi, were studied and the relationship between soil texture and nitrate leaching was described in this paper. The results indicated that due to less clay content and looseness and a fast speed of nitrification, of Entisol, nitrogen input to the soil mostly presented as nitrate, in the bottom-land of Loess Plateau, 2 months later after fertilization, the peak of the nitrate content was located in 50 cm depth, and was moved down to 100 cm depth after 4 months, 130 cm after 6 months, the peak was disappeared after near one year and the nitrate was distributed between 130 and 350 cm depth. Therefore, nitrate leaching is the main way of N losses in bottom-land in Entisol area, where the irrigation could be carried out. However, in Anthrosol, Guanzhong plain, due to a higher clay content relatively and fast speed of nitrification, and a clay layer in 80-120 cm depth was found, which block the nitrate and water leaching through, so most of the nitrate was accumulated in 0-100 cm depth, which account for 64%-74% of total N accumulated in 0-400 cm depth, and N in 200-400 cm depth was only account for 7%-13% . Even some nitrate leached deeper than 100 cm depth, which would loss by denitrification. So, there was no nitrate peak movement could be seen in the soil profile. Since soil water saturated in deep layer, in Paddy soil in Southshaanxi, it isvery difficult for water and nitrate leaching down, so nitrate was mainly accumulated in top soil layer. Nitrate leached down to deeper layer where there is an anaerobic condition, losses through denitrification.
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2005年第4期435-441,共7页
Journal of Plant Nutrition and Fertilizers
基金
瑞典国际开发署(Sida)资助
中国-瑞典氮肥合作项目的部分内容
国家自然科学基金项目(30370822)资助。
关键词
硝酸盐淋移与累积
粘粒含量
土壤剖面
黄绵土
塿土
水稻土
nitrate leaching and accumulation
clay content
soil profile
Entisol
Anthrosol
Paddy soil
