【作者】 廖鸿昕；

【导师】 刘德林；

【作者基本信息】 湖南农业大学 ， 生物物理学， 2011， 硕士

【摘要】 蔬菜在人们的膳食结构中占据着相当重要的地位,绿色蔬菜、无公害蔬菜越来越被人们关注和重视。大棚蔬菜的硝酸盐含量远高于露天蔬菜,降低蔬菜硝酸盐的含量对提高蔬菜品质、保证人类健康有重大意义。蔬菜硝酸盐的积累与氮肥的施用有着直接的关系,本文采用常规方法与同位素示踪技术结合,研究了氮肥对蔬菜硝酸盐及品质的影响,氮素形态与蔬菜硝酸盐积累和分配的关系,结果表明：1.在减少20%的化学氮肥基础上,通过增施有机肥、配施微量元素、施用硝化抑制剂和脲酶抑制剂等农艺技术措施可降低蔬菜硝酸盐含量2.93%-22.05%,亚硝酸盐含量9.09%-53.17%；蔬菜硝酸盐积累过程中夏季蔬菜积累高峰早于冬季蔬菜,蔬菜后期硝酸盐含量比生长旺期有明显的降低；在同等氮肥条件下,施用有机肥、配施微量元素、硝化抑制剂和脲酶抑制剂等农艺措施能提高蔬菜Vc与可溶性糖含量,且蔬菜中的叶绿素SPAD值没有明显变化。第二章蔬菜为一种易富集硝酸盐的植物,硝酸盐在其体内的分布情况为茎大于叶,茎中硝酸盐含量为叶中1.5倍左右,Vc在蔬菜内的分布为叶大于茎,蔬菜根与叶中硝酸还原酶活性远大于茎。不同种类氮素对蔬菜硝酸盐的积累影响为：硝酸钠最大,硫酸铵次之,尿素与碳铵较小,蔬菜硝酸盐含量高的Vc含量也较局。第三章蔬菜中的硝酸盐主要来自源于土壤,达到80%以上,来自肥料部分的较少,仅为15%左右。蔬菜对土壤养分要求高,在蔬菜生产中应特别重视土壤部分硝态氮的减控,减少蔬菜对土壤硝酸盐的吸收,进而达到降低蔬菜硝酸盐的目的。4.施用尿素其肥料利用率达到42.67%,土壤残留氮素达到17.01%,均高于硫铵与硝酸钠,而尿素的损失率为40.32%,远低于硫铵52.67%与硝酸钠54.15%,这表明施用尿素有利于土壤氮素储量的保持和提高。更多还原

【Abstract】 Vegetables occupy a very important position on peple’s diets. Green and organic vegetables have been growing concern and attention. Nitrate content of greenhouse vegetables is much higher than that in the field. Reducing the Nitrate content of vegetables has a significant impact on improving the quality of vegetable and ensuring the health of human.The Nitrate accumulation of vegetables is directly related to Nitrogen fertilization.In this paper, conventional methods combined with the isotope tracer technique are used to research the fertilizer’s impact on nitrate and quality of vegetables, the relationship between nitrogen sources and nitrate accumulation、distribution of vegetables.The results are as follows:1. The results showed that:On the basis of 20% reduction of chemical fertilizer, it reduce2.93%-22.05% of the nitrate and 9.09%-53.17% of the nitrite content of vegetables through agricultural technical measures such as the combined application of organic manure,application of nitrification inhibitors and trace elements in urinary inhibitors;The nitrate accumulation peak of summer vegetables are earlier than winter vegetables,the nitrate content of the late period of Vegetable growth less than the period of rapid growth significantly; Under the same nitrogen, it increase the Vc and Soluble sugar content of vegetables and the chlorophyll SPAD values in vegetables change implicitly by using the organic fertilizer, distribution and application of microelements, nitrification inhibitor and urease inhibitor and other agronomic measures.2. Vegetables is an easy plant for nitrate accumulation. The nitrate content of vegetables in stem is about 1.5 times for leaf. The vitamin C content of vegetables in leaf is much higher than stems, meanwhile the nitrate reductases activity in roots and leaves is far outweigh the stems of Vegetables. Different types of nitrogen on the accumulation of nitrate in vegetables were as follows: sodium nitrate maximum, ammonium sulfate, urea and ammonium bicarbonate smaller.The more nitrate content in vegetables,the more content of Vc.3.more than 80% vegetables nitrate comes from soil, while less than 20% from the fertilizers.Vegetables demand is high of soil nutrients in vegetable production should be paid special attention in part of soil, reducing vegetables reduce control on the soil of nitrate, and then to reduce vegetables absorb the purpose of nitrate.4.When urea is added to soils, the rate of its fertilizer utilization has reached 46.27% and the rate of its soil residual nitrogen has reached 17.01%, which are higher than those of ammonium sulfate and sodium nitrate. The loss rate of urea is 40.32%, which is much lower than those of ammonium sulfate 52.67% and sodium nitrate54.15%.更多还原