【作者】 周细红；

【导师】 荣湘民； 曾清如；

【作者基本信息】 湖南农业大学 ， 植物营养学， 2007， 硕士

【摘要】 为考察硫脲对我国典型土壤理化性质和酰胺态氮转化的影响，为硫脲在我国农业上的应用提供科学依据，进行了本项目的研究。本文采用室内模拟和盆栽试验方法，研究了不同酸碱性质土壤中尿素配施硫脲后，硫脲对氮素转化及NH₃挥发的影响以及硫脲对3种酸性土壤理化性质的影响，并针对湖南典型土壤类型，研究了尿素配施硫脲后对玉米幼苗生长的影响。试验结果表明：1．硫脲是一种有效的脲酶抑制剂和硝化抑制剂，不仅延缓了红菜园土中尿素的水解，且使其水解后释出的氨在土壤中得到了更多和更长时间的保持，5mmol．kg^-1硫脲较不施硫脲处理的NH₃挥发减少35％。在冲积菜园土中，硫脲由于其强的硝化抑制效果，导致尿素在碱性土壤中氮素的NH₃的挥发损失明显，1mmol．kg^-1硫脲处理的NH₃挥发是不施硫脲处理的3倍，5mmol．kg^-1硫脲的NH₃挥发为施氮量的20．1％，重要的是至试验结束时其仍然有NH₃释放。因此硫脲不适宜在碱性北方土壤中和尿素配施。2．在交换性Al含量高的酸性红壤中，单施硫脲1周可使土壤pH有小幅度上升，且随着硫脲浓度的增加而增加。单施硫脲对土壤交换性Zn浓度影响不显著，但能显著增加土壤交换性Al、Mn、Cu的浓度。2种土壤中单独施入硫脲7周，土壤pH始终维持在稍高于不施肥料土壤的pH水平上，随时间的变化不显著，表明在没有其它氮肥存在时，硫脲在土壤中能稳定存在，不易分解。硫脲与尿素配施后有效地抑制硝化作用，推迟或延缓土壤的酸化过程；硫脲与尿素配施后短期内土壤pH上升幅度略大于单施尿素。红壤有效Al含量随着土壤pH值变化而变化，硫脲与尿素配施所引起的土壤pH的短期和长期效应间接地降低了红壤Al元素的有效性。红壤有效Mn的含量随着硫脲用量增加而显著升高，硫脲配施尿素时由于硫脲的用量不同而使红壤有效Mn的含量呈两个变化趋势：1mmol．kg^-1硫脲用量产生的短期效应是红壤有效Mn的含量高于单施尿素的土壤，长期效应是红壤有效Mn的含量低于单施尿素的土壤；5mmol．kg^-1硫脲与尿素配施后红壤有效Mn的含量在试验周期中一直远高于单施尿素的土壤。3．砂培时，2．5mmol．kg^-1用量的硫脲对玉米苗产生毒害；土培时，在交换性Al含量高的酸性红壤上2．5mmol．kg^-1用量的硫脲对玉米苗产生毒害。1mmol．kg^-1硫脲与尿素配施入红壤2周时有效地降低了玉米植株中Al的含量而增加了玉米根中Mn的含量，将导致玉米锰毒的产生。更多还原

【Abstract】 The purposes of this investigation were to study the influence of thiourea on the . physico-chemical properties of Chinese typical soil and transformation of urea nitrogen, and provide scientific basis on the application of thiourea as in agriculture. The urea and thiourea which were fertilized in different acid-alkaline soils influenced the transformation of nitrogenous sources, volatilization of NH₃ and the physico-chemical properties of three different acidic soils conducted through laboratory simulation and static test on the growth of maize seedling in Hunan typical soil. The results indicated that:1. Thiourea was effective urease inhibitor and nitrification inhibitor which can delay the hydrolysis of urea in Hunan red acid soil and lead NH3 to more stability. Compared to the controls, the volatilization of NH₃ decrease 35% when the concentration of thiourea was 5 mmol.kg^-1 in soil. Due to the strong effect of nitrification inhibition, fertilization of thiourea can lead NH₃ to volatilizing evidently in Beijing soil which was alkalinity soils, the volatilization of NH3 from soil fertilized 1 mmo.kg^-1 thiourea was three times more than the control, and the volatilization quantity of NH₃ from soil fertilized 5 mmol.kg^-1 thiourea was 20.1% of total nitrogen fertilization quantity and NH3 still released at the end of this experiment. As a result, the thiourea can not be fertilized with urea in alkalinity soils.2. In red acid soil which contained a large number of exchangeable Al, the pH value of soil fertilized thiourea increased after one week, and which increased with the increase of thiourea concentration. The concentration of exchangeable Zn was not influenced evidently in soil fertilized thiourea, but thiourea can increase the concentration of exchangeable Mn, Cu. After seven weeks, the pH value of two soils fertilized thiourea maintained slightly higher than the level of which can not fertilized thiourea. The results present that thiroureas can exist stably in soil which do not fertilize other nitrogen sources. The thiourea fertilized with urea can inhibit nitrification evidently, delayed acidification in soil and increase the pH value of soil which increased more quickly than the soil fertilized urea lonely. The concentration of exchangeable Al changed with changing of the pH value in red soil, so the pH value of soil influenced by the fertilization of thiourea and urea decreased the availability of Al in red soil. The concentration of exchangeable Mn increased with the increase of fertilized thiourea evidently, and two trends of the exchangeable Mn concentration changed with the different amount of thiourea combined with urea in red soil were that: when fertilized 1 mmol.kg^-1 thiourea, the concentration of exchangeable Mn was higher than the concentration from the soil fertilized urea lonely in short term, but lower in long term; when fertilized 5 mmol.kg^-1 thiourea, the concentration of exchangeable Mn was higher than the concentration from the soil fertilized urea lonely in whole experiment period.3. 2.5 mmol.kg^-1 thiourea can lead the maize seedling poisoned when which planted in sand, and the same phenomenon was also still observed in red soil contained a large number of exchangeable Al. 1 mmol.kg^-1 thiourea fertilized with urea decreased the content of Al in maize seedling and increased the content of Mn after two weeks in red soil, which led maize seedling poisoned by Mn.更多还原