淹水稻田氮素淋溶损失及其控制

Nitrogen Leaching in Paddy Rice Field and Its Countermeasure

稻田土壤氮素淋溶研究较少,报道稻田氮素淋溶导致地下水NO3--N污染超标的例子更少。稻田紧实的犁底层,导致土壤渗漏率大大降低。目前研究稻田氮素淋溶的方法主要有模拟土柱法、田间实测法、平衡估算法以及数学模型法。试验报道稻田氮素淋溶量差异较大,普遍认为高施氮量可导致较大的氮素淋溶,且各层次的NO3--N淋溶量远大于NH4+-N。通过降氮的施肥管理和选择需氮量低的前茬作物,有利于控制氮素淋溶。

There were fewer researches on nitrogen leaching in paddy rice field. The examples of high NO3^--N contamination in groundwater due to nitrogen leached from paddy field were also very fewer. Practices like puddling of soils imade the layer of 15 cm - 30 cm tight and solid （ so - called furrow bottom layer） resulting in reduced percolation rates. The current research methods of nitrogen leaching in paddy field mainly are modeling soil column, on - site measurement in field, N - budget estimation and mathematical modeling method. And each of them has its advantages and disadvantages, The leaching nitrogen from paddy soil reparted by experiments was different from each other. But it is universally regarded that high N application will lead to high nitrogen leaching, And the leaching NO3^--N is far more than NH4 ^＋ - N. The management of lowering N - fertilization and selection of lower N demanded rotational crop is good for controlling nitrogen leaching.