不同灌溉方法对不同氮肥在温室土壤-植株中的氮素分配影响

以番茄为供试作物,采用田间微区试验的方法研究了不同灌溉方法和不同氮肥种类对氮素在土壤不同层次间的残留以及在番茄植株不同部位之间的分配。结果表明,在番茄整个生育期内,土壤中无机氮主要以NO3--N的形式存在,NH4+-N所占比例很小。0～100cm土层中,滴灌和沟灌各处理土壤中NH4+-N的含量在整个生育期内含量均比较低(低于6mgkg-1),且变化幅度不大,各土层NH4+-N的含量受灌溉方式和施肥的影响较小。无论是滴灌还是沟灌,番茄全生育期内0～20cm土层土壤NO3--N含量始终较高。沟灌易引起土壤中NO3--N向下层迁移,而滴灌对40～60cm土层及其以下各层次土壤的NO3--N分布影响作用不明显。硝态氮肥较铵态氮肥和酰胺态氮肥更易随水向深层土壤迁移。灌溉方式对肥料15N在果实、茎、叶中的分配比例没有明显影响,肥料15N在番茄地上部分各器官所含的量以果实为最高,其次为叶,茎中的含量最少;两种灌溉方法间肥料15N在果实、茎、叶的分配比例差异不大,平均为2.9∶1∶1.6。

Effects of Irrigation Techniques on N Distribution of Different N- fertilizer in Soil and Tomato Plants in Greenhouse

Effects of irrigation techniques on N distribution of diffferent N-fertilizers in soil and tomato plants were studied by micro-plot planting experiment in grennhouse. The results showed that inorganic N mainly existed in the form of NO3--N, while NH4+-N only occupied small amount during the whole growing period. Whatever drip irrigation or furrow irrigation, in 0~100cm soil layer, the NH4+-N content was stable at a lower lever of less than 6mg kg-1, and was slight affected by different irrigation and fertilization; in 0~20cm soil layer, NO3--N content maintained much higher. The NO3--N content could move to lower soil layers in furrow irrigation, while drip irrigation will not influence distribution of NO3--N in or below 40-60cm soil layer. For NO3--N fertilizer, it's more easier to move to the deep soil layer with the irrigation water than NH4+-N fertilizer and NH2-N fertilizer. No significant effects of irrigation techniques on the distribution ratios of 15N among the fruits, stems and leaves had been observed. Among the above-ground parts, fruit contained the highest 15N, then followed the leaves. The stem contained the minimum 15N. In terms of 15N distribution ratio, there is no difference among the fruit, stem and leave in both irrigation techniques with average ratio of 2.9∶1∶1.6.