【作者】 马雪姣；

【导师】 王殿武；

【作者基本信息】 河北农业大学 ， 土壤学， 2003， 硕士

【摘要】 针对蔬菜生产中水氮投入过量造成蔬菜品质下降、地下水硝酸盐含量超标，水、肥资源的浪费以及给人体健康造成的潜在性威胁的实际情况，以油菜和芫荽为研究对象采用模拟土柱、盆栽和田间微区试验相结合方法系统监测了蔬菜生育期内硝酸盐含量的动态变化以及收获后不同土层土壤硝态氮的残留量，研究了水氮对蔬菜硝酸盐累积的影响及对土壤硝态氮残留的效应。研究结果表明： 油菜和芫荽体内硝酸盐含量在生育期内的动态变化为旺盛期＞成熟期＞苗期，根据蔬菜硝酸盐积累规律选择合适的采收期，油菜和芫荽的合适采摘期分别为油菜出苗后40d左右和芫荽出苗后45d左右。 土壤中0～100cm硝态氮积累量随着施氮量的增加而增加，随着灌水量的增加而降低。在一定的施氮量下，硝态氮的积累峰值随着灌水量的增加而下移，150mm灌水量下田区试验和模拟土柱试验0～100cm土体内硝态氮的积累峰值分别出现在0～30cm和50～70cm；250mm灌水量下分别出现在40～60cm和60～80cm；350mm灌水量下田区试验中0～100cm土体硝态氮没有出现峰值，而模拟土柱试验在80～100cm则有明显的积累。另外油菜的生物量在低施氮量下，过量的灌水可使油菜有减产的趋势，水分利用效率下降；芫荽的生物量随着施氮量和灌水量的增加而增加，但是当施氮量超过一定的值后，随着施氮量的增加其增加幅度呈降低的趋势。油菜和芫荽体内粗蛋白含量在一定的氮肥用量范围内随着施氮量的增加而增加，但是当施氮量高于270kg／hm~2时，增施氮素可降低蛋白质的合成。 油菜和芫荽体内的硝酸盐含量随着施氮量的增加和灌水量的降低而升高。氮肥用量和植株体内硝酸盐含量回归分析显示出两者间存在显著相关关系，结合对土壤中硝态氮淋溶及蔬菜产量和品质的进一步研究，确立了本地区的合理灌水量和施氮量：保护地和露地油菜的合理灌水量为250mm，施氮量分别为101.0kg／hm~2、222.5kg／hm~2，芫荽的合理灌水量为250mm，最高施氮量为171.6kg／hm~2。 本研究将蔬菜-土壤系统中最重要的水分和氮素相结合，探明了蔬菜-土壤系统中硝态氮积累规律，为蔬菜生产上推荐水氮合理施用量提供了重要理论依据。更多还原

【Abstract】 It is a serious issue that water and nitrogen input rates are unreasonable high in vegetable production in china, which may increase nitrate accumulation in vegetable and ground water contamination. In result, these will be harmful to people’s health. The objectives of this paper which based on column % pot and micro-plot experiments were to compare the effects of different water and nitrogen supply strategies on nitrogen leaching in the soil profile and nitrate accumulation in vegetable as a base for the N and water recommendations in vegetable production. The results are as follows:The nitrate contention of rape and coriander at full growth varied from seedling stage to maturing stage which is vigorous growth stage >maturing stage >seedling stage. We should choose the optimum stage: rate and coriander are 40d and 45d after coming out respectively. Vegetable nitrogen contention and nitrogen leaching in soil were strongly affected by water and nitrogen supply in the experiments. Nitrate content of rape and coriander increased with higher nitrogenous fertilizer application and lower water supply. Nitrogen leaching in the soil increased with higher nitrogenous fertilizer application and water supply in column and micro-plot experiments, especially on higher irrigation and higher nitrogenous fertilizer. There was little nitrogen leaching when N application was below 135 kg/hm2, but N use at a rate of 270 kg/hm2 increased nitrogen leaching in the soil.Water and nitrogen are two important factors which strongly affect vegetable growth. There were no significant differences in marketable yield between irrigation at rate of 250mm and 350mm and among N use more than 135kg/hm2, which means that much water and nitrogen fertilizer could be saved using irrigation treat 250mm and nitrogenous fertilizer with 135kg/hm2to obtain higher yield.The effect of N application rate on quality of rape and coriander was studied, the results showed that application of certain amounts of N fertilizer increased the content of protein, but high N rates reduce content of protein.The health of human body, economic benefit, environment, should be considered in order to define the reasonable applying fertilizer. The economically optimal usage of nitrogen are 101.02kg/hm2 for rape in protect soil 222kg/hm2 for rape in land, 171kg/hm2 for coriander and irrigation are 250mm.respectively, which can improved vegetable quality , yield and less nitrate residues in the soil profile.更多还原