【作者】 熊国华；

【导师】 林咸永； 章永松；

【作者基本信息】 浙江大学 ， 植物营养学， 2004， 硕士

【摘要】 近年来，农业生产上大量施用化肥而忽视有机肥投入的现象非常普遍，这不仅降低了肥料的利用率和施用效益，加剧土壤养分失衡，在保护地栽培条件下易造成严重的盐害，而且污染地下水，降低蔬菜品质，影响蔬菜的可持续生产和生态环境安全。尽管施肥措施对菜园土壤环境质量和蔬菜品质的影响已有许多的研究报道，但以往的大部分报道都偏重于单一肥料对蔬菜品质和土壤生态环境的影响，而对于不同肥料配施尤其有机肥和化肥配施方面的研究相对较少。因此，弄清有机肥和化学肥料配合施用对土壤中氮的转化、积累和迁移以及对蔬菜品质的影响，对于提高菜园土壤生态安全和蔬菜品质是十分重要的。因此，本文拟采用菠菜和苋菜为材料，通过室内培养试验、土培试验和土柱淋洗试验等，研究钾与不同氮源（尿素和有机肥）配施对菠菜品质及菜园土壤环境质量的影响，从而为保护蔬菜产地的生态环境和生产优质安全的蔬菜提供科学依据。主要结果如下： 1．室内培养试验结果表明，尿素与双氰胺配施延缓硝化作用的进行，有效地降低土壤中NO₃^-—N的积累和维持较高的土壤NH₄⁺—N含量，而尿素配施有机物料对土壤NO₃^-—N和NH₄⁺—N含量的影响与单施尿素处理间没有显著差异。土壤铵态氮含量随施钾量的增加而增加，而硝态氮含量则呈下降趋势。土壤速效钾和缓效钾含量随着供钾水平的提高而显著增加，并且配施有机肥时土壤速效钾和缓效钾含量也有所提高。钾对土壤脲酶和转化酶活性没有明显的影响，但是配施有机物料处理的脲酶和转化酶活性显著高于单施尿素或尿素配施DCD。不同氮源供应条件下，土壤的pH值在培养的前7d没有显著差异，但在培养后期土壤pH值大小顺序为：尿素+DCD＞尿素+鸭粪≈尿素+猪粪＞尿素，钾肥施用量增加，土壤pH值也有所上升。在培养初期，有机肥与尿素配施土壤电导率值略高于单施尿素，但在培养7d后，单施尿素处理的EC显著高于其它处理。 2．土柱淋洗试验结果表明，淋洗液中硝态氮的浓度在前35d内随着淋洗次数的增加而提高，在35d以后则逐渐下降，淋洗液中铵态氮的浓度则随着淋洗次数的增加而下降。尿素配施有机物料或DCD能够降低硝态氮、铵态氮和无机氮的总淋失量及淋洗液的EC值，提高了淋洗结束后土壤铵态氮和硝态氮含量及淋洗液pH值。供钾也可明显降低硝态氮和无机氮的总淋失量，并且提高了淋洗结束后土壤铵态氮和硝态氮含量及淋洗液的pH值及EC值。本试验结果表明尿素与有机肥或DCD配施能够减轻土壤养分的淋失和对地下水污染的风险。 3 土培试验结果表明，供钾降低了土壤中硝态氮含量，而对铵态含量没有明显的影响。尿素与双氰胺配施延缓了硝化作用的进行，能有效地降低土壤中NO₃^-—N的积累和维持较高的土壤NH₄⁺—N含量，而尿素配施有机物料对土壤NO₃^-—N和NH₄⁺—N含量的影响与单施尿素处理间没有显著差异·添加有机物料处理的土壤脉酶和转化酶活性、土壤速效钾和缓效钾含量以及土壤pH值显著高于单施尿素处理，但却降低了土壤电导率.土壤速效钾、缓效钾含量及土壤电导率和pH值随着施钾水平的提高而增加，但钾对土壤脉酶和转化酶活性没有明显的影响.钾与不同氮肥种类配施对菠菜生长的效果因培养时间而异，在追肥初期尿素和有机肥配施处理的菠菜生物星显著高于单施尿素处理，但随着追肥时间的延长，各处理的生物旦差异变小.在同一氮肥种类供应条件下，菠菜单株鲜重随施钾量的提高而显著增加。尿素和有机物料或双佩胺配施处理可以明显降低菠菜体内的硝酸盐和亚硝盐含量，能够在一定程度上提高维生素C和粗蛋白含星及硝酸还原醉活性.菠菜体内维生素C和粗蛋白含最及硝酸还原酶活性随着钾肥用最的提高而增加，植株体内的硝酸盐和亚硝盐含量则随钾供应水平的提高而降低.本试验结果表明，合理施用钾肥、尿素与有机物料或双橄胺配施能够显著改善土壤环境质量和蔬菜品质. 4.土培试验结果表明，尿素与双佩胺配施能够有效地降低第2季疏菜收获时土壤中硝态氮含从和保持较高的饺态氮含最，而尿素配施有机物料处理对第2季蔬菜收获时土壤N场一N和NH’+一N含最的影响与单施尿素没有显著差异.供钾提高了土壤中钱态氮含嫩而降低了土壤硝态氮含量。添加有机物料处理在第2季蔬菜收获时土壤中速效钾和缓效钾含量高于单施尿素和尿素配施双佩胺处理，供钾则显著地增加了土壤中速效钾和缓效钾含星。在不同氮源的处理在第2季蔬菜收获时土壤中的EC值人小顺序为:尿素>尿素+鸭粪>尿素+猪粪>尿素+Dco，pH值的变化趋势则相反.供钾处理也提高了土壤的电导率和pH值.施用钾肥、尿素与有机物料或OCD配施能够提高第2季作物芜菜体内硝酸还原酶活性，降低了硝酸盐和亚硝盐的含量，并且增加觅菜的生物量、可溶性糖（D CD除外）、维生素C和粗蛋白含最.以上结果表明，施用有机肥不仅能提高当季疏菜品质和土壤环境质量而且能够提高第2季疏菜品质和土壤环境质星。更多还原

【Abstract】 In the past few years, the role of organic fertilizer in agronomic practices has long been replaced by chemical fertilizer. It has also brought about some unfavourable results. Besides the impairment of soil environmental and vegetable quality in protected field, this practice also caused a decline in soil productivity through excessive soil erosion, nutrient runoff, imbalanced nutrient, and deteriorated soil chemical properties. Much work has been done and a wide range of techniques have been developed and put into practice to improve soil environmental and vegetable quality, especially the effect of application single fertilizer in vegetable field. However, little information is available on the effects of combined application of potassium with urea and organic manure on soil environmental and vegetable quality. It is very important to understand the combined application of potassium with urea and organic manure management on nitrogen transformation and accumulation, and improve vegetable and environmental quality. Therefore, the objective of this study is to gain some information, by using incubation experiment, pot experiment and soil column leaching experiment, on soil environmental and vegetable quality in spinach and Amaranthus hypochondriacus as affected by combined application of types of nitrogen fertilizers under different K supply levels. The results are summarized as follows:1. The results from the soil incubation experiment showed that lower NO3--N content and higher NH4+-N content in soil was observed in the treatment of combined application urea with DCD, but addition organic manure to urea did not show notable effect on NO3-N and NH4+-N content in soil. The contents of available and slowly available potassium in vegetable soil significantly increased with the higher of potassium, and application organic manure combined with urea higher than that of single urea treatment. The soil urease and invertase activity was significantly higher in combined application of organic manure with urea than that of single urea or urea with DCD treatments, but insignificant difference was found among different potassium levels. The treatment did not have notable effect on pH within earlier seven days of incubation period, but pH of the vegetable soil in later incubation stage varied: U+DCD >U+DM U+PM>U, and pH of the soil was enhanced by the increase of potassium application. The soil electrical conductivity was higher in organic manure with urea than that of single urea within seven days, but higher soil electrical conductivity was observed in single urea treatment in later stage.2. In soil column leaching experiment, the NO3- concentration of leachate increased with the increase of leaching times within earlier thirty-five days, and decreased with the increase leaching times after thirty-five days, but the NH4+ concentration of leachate decreased with the increase of leaching times. Combined application of urea with organic manure or DCD distinctly decreased total amount of NO3-N, NH4+-N and inorganic nitrogen leached, and electrical conductivity of leachate, while enhanced NO3-N and NH4+-N contents, and pH of leachate in vegetable soil after leaching. Potassium supply not only increased pH, EC of leachate, and NO3-N and NH4+-N accumulation in soil after leaching, but also decreased the total amount of NO3-N and inorganic nitrogen leached. It is evident that combined application of urea with organic manure or DCD could effectively decrease nutrient leaching and the risk of nitrate pollution to underground water.3. It was found in the pot experiment that NO3-N content in soil was gradually decreased with the increase of potassium concentration, but NH/-N content was not obviously affected. Combined application of urea with DCD reduced NO3-N content in soil and maintained higher content of NH4+-N due to the inhibition of nitrification by DCD, but addition of organic manure did not have notable effect on NO3-N and NH4+-N content in vegetable soil in comparison with the treatment of urea. Urea combined with org更多还原