摘要
研究了田间原位条件下,棉田滴灌不同施氮量下氮肥在土壤中的空间分布与作物吸收后残留规律。结果表明硝酸盐在水平方向和垂直方向具有明显的空间变异。同一氮肥用量下,以滴头为中心,硝酸盐在水平方向分布顺序为0 cm<10 cm<20 cm<40 cm<30 cm,在水平方向上硝酸盐随水移动且可以扩散到离湿润锋后部,垂直方向硝酸盐变化顺序为0-20 cm>20-40 cm>40-60 cm,为浅层累积型。无论水平方向还是垂直方向,氮肥用量对硝酸盐分布均有显著性影响。收获后,残留硝酸盐分布在点源水平距离5-40 cm,垂直距离0-60 cm土体内,残留硝酸盐累积量随氮肥用量的增加而增加。这些结果说明土壤硝酸盐存在明显空间变异,施肥显著增加了其浓度和残留量,同时可能会淋洗出根层,造成养分利用率下降和环境污染。因此,适宜的氮肥用量是控制硝酸盐向深层移动和累积的主要措施。
Nitrogenous Spatial Variation and accumulation after harvest under fertigation was studied in Situ. Results demonstrated that nitrate had obvious spatial variation and randomicity in lateral direction and vertical direction of soil profile. Nitrate distribution in lateral direction of soil profile increased in the order of 0 cm〈10 cm〈20 cm〈40 cm 〈30 cm, the peak appeared at the back of boundary of the wetted volume and decreased in the order of 0-20 cm〉20-40 cm〉40-60 cm in vertical direction, nitrate tend to accumulating in upper soil layer. The amount of N fertilizer applied had significant effect on distribution of nitrate. Residual nitrate accumulated in a range of 5-40 cm laterally and 0-60 cm vertically from the point source, increasing with the amount of fertilizer applying after harvest. The experiment revealed that spatial variation of nitrate is obvious. Nitrate increased with application of N fertilizer definitely, showing a large potential to be leached into groundwater and environment. Therefore, optimum amount of N fertilizer is a main measurement to control the transport of nitrate to the deeper soil layer and accumulation.
出处
《西北农业学报》
CAS
CSCD
北大核心
2007年第2期70-74,共5页
Acta Agriculturae Boreali-occidentalis Sinica
基金
农业部"948"重大专项(2003-Z53)资助
关键词
氮肥用量
棉田
滴灌
硝酸盐
累积
空间变异
N rate
Cotton field
and accumulation. Drip irrigation
Nitrate
Accumulation
Spatial variation
