| 题名 | 灌淤土中氮肥的转化和淋洗研究 |
| 作者 | 王平 |
| 学位类别 | 硕士 |
| 答辩日期 | 2001 |
| 授予单位 | 中国科学院．中国科学院新疆生态与地理研究所．土壤学． |
| 导师 | 田长彦，中国科学院新疆生态与地理研究所 张福锁，中国农业大学 ， |
| 关键词 | 灌淤土 |
| 中文摘要 | 本研究采用化学分析、室内土壤培养试验、渗漏池渗漏试验和不同作物田块调查相结合的方法，系统研究了氮肥在灌淤土(渭干河流域)中的转化过程和淋洗现状及其影响因素。通过本研究，掌握了灌淤土中氮肥的转化过程和淋洗现状，并对其进行评价，主要结果如下：1.尿素态氮的比色测定方法研究改进后的测定方法对尿素态氮的检测有回收率高、重复性好、反应快速和成本低的优点，适合于大批量样品的测试。2M NaCL-PMA同时适用于硝态氮、亚硝态氮和铵态氮的浸提测定。2.氮肥在灌淤土中的转化及其影响因素温度对尿素态氮转化速度有显著的影响，温度从15 ℃上升到25 ℃，尿素的水解速率由2.07ug·g~(-1)·hr~(-1)上升到4.5lug·g~(-1)·hr~(-1)，温度系数Q_(l0)达到2.18；长效尿素的水解速率由1.28ug·g~(-1) hr~(-1)上升到2.41 ug·g~(-1)·hr~(-1)，温度系数Q_(l0)达到2.04；水分对尿素态氮转化速度有显著的影响，土壤含水量在20％-28％之间时，水解速度基本稳定在1.75 ug·g~(-1)·hr~(-1)左右，当含水量在12％时，水解速度下降至1.57 ug·g~(-1)·hr~(-1)左右；培养192小时后氨挥发量表现为PU>U>LU。3.硝态氮的淋洗及其影响因素在354mm的灌水量条件下，高施氮量(480 kg/hm~2N)的处理，土壤中硝态氮可被淋洗至180-220cm的层次，而中施氮量(240kg/hm~2N)和低施氮量(120kg/hm~2N)未发生明显的淋洗。大量灌水(900mm)的条件下，部分硝态氮被淋出了140cm的土体；中量灌水(600mm)的条件下硝态氮可被淋洗到80-100cm处，从累加淋洗的角度看，经过几个生长季的连续灌溉，这部分氮素最终会被淋失；低量灌水(300mm)的条件下，土体中未发生明显的硝态氮淋洗无植被(棉花)覆盖能够显著的增加O-140cm土体硝态氮的淋洗，在4月至11月期间，硝态氮随着每一次灌水向下淋洗；而有植被(棉花)的条件下，几乎没有发生硝态氮的淋洗；在有植被条件下0-140cm土体内硝态氮的累积量为57kg/hm~2N；而无植被的条件下累积量高达165kg/hm~24.渭干河灌区不同种植方式下土壤硝态氮的淋洗现状调查在自然条件下，荒地土壤剖面硝态氮主要分布在土壤表层O—20cm，40cmm以下很少，不存在硝态氮的淋洗损失问题。小麦—玉米轮作方式下，小麦收获后，土壤剖面上硝态氮含量较低，由上至下略有升高；1m—2.8m硝态氮有一定累积。植棉条件下，盛蕾期0-60cm土体硝态氮累积量较高，是硝态氮淋洗的危险期；吐絮期由于植株的吸收，0-60cm土体硝态氮含量很低，向下有硝态氮的累积，总累积量在252kg/hm~2N-379kg/hm~2N。由于过量施氮和灌水，造成新和县郊菜地土壤硝态氮在0—280cm土体中大量积累，在7个调查田块中1m土体累积量平均为252kg/hm~2 N，接近一季蔬菜的需氮量，0—280cm土体累积量平均为588.4kg/m~2。已对浅层地下水构成严重威胁；施氮量越高土体中硝态氮积累量也越高。渭干河灌区排渠水硝态氮含量不高。有79.1％的样品硝态氮浓度低于5mg/L，只有8.3％的排渠水含量略高于国家饮用水标准。By chemical analysis, plot experiments and field investigation N-fertilizer transformation and nitrate leaching and factors influence it has been studied in Xinjiang anthropogenic-alluvial soil. The result showed as follows: 1 Colorimetric Determination of Urea in Soil The colorimetric method of Douglas&Bremner has been used to determine urea in soil, and we found that some improve measurement are effective. The result of our experiment showed as follows: 1. KCL can be replaced by NaCL; 2. The quantity of H_3PO4 can be reduce to a half by modify the procedure; 3. The 2M NaCL-PMA solutions satisfactory for determination for exchangeable ammonium, nitrite, and nitrate as well as of urea. 2. Study on transformation of different nitrogen fertilizer in anthropogenic-alluvial soil. In this study, We investigated the transformations of three N fetilizer (urea, diammonium orthophosphate, long-lasting urea) in Xinjiang anthropogenic-aUuvial soil, and the effected factors such as temperature, moisture. The result showed as follows: l.It's about 4days that all Urea-N transform into NH_4-N at 15 ℃ and 20%water treatment. Long-lasting urea can prolong the time about 4days; 2. The effects of soil water condition on urea hydrolysis rate is evident. The rate is about 1.75 ug·g~(-1)·hr~(-1) at soil water condition range from 20% to 28%. The rate reduce to 1.57 ug·g~(-1)·hr~(-1) at 12% soil water condition; 3. Ammonia volatilization increased in an order of diammonium orthophosphate, urea, long-lasting urea. 3 Nitrate leaching and factors influence it The higher annual rates of N application (480kg/ha) can cause NO_3-N move down to 180-to 220-cm depth under 354 mm irrigation and leaching is not evidence at middle N rate (240kg/ha) and lower N rate (120kg/ha). Part of fertilizer NO_3-N was leaching out of 140cm soil profile at high irrigation (900mm), while 600mm of irrigation water can cause NO_3-N move down to 80- to 100-cm and leaching has not oecurrent under 300mm irrigation water. Maintaining a crop on the soil can significantly reduce nitrate leaching. 4 Crop rotation in relation to movement of nitrate nitrogen through soil profile Nitrate leaching has not occurrent in the wild field. After crop harvest the total amount of NO_3-N in the soil profile is lower. High nitrate accumulation was found in 0-60cm soil layer during cotton buddling stage and then reduced by crop root sorption in Boll-opening stage. High nitrate-nitrogen accumulation was found in vegetable field. There was an average accumulation of 252kg/ha N in a 1M deeps profile and average accumulation of 588.4 kg/ha N in 0- to 280-cm soil layer. It may impose hazards on underground water. |
| 语种 | 中文 |
| 学科主题 | 农学 |
| 公开日期 | 2010-11-12 |
| 页码 | 共55页 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.xjlas.org/handle/365004/8290]  |
| 专题 | 新疆生态与地理研究所_中国科学院新疆生态与地理研究所(2010年以前数据) |
| 推荐引用方式 GB/T 7714 | 王平 . 灌淤土中氮肥的转化和淋洗研究[D]. 中国科学院．中国科学院新疆生态与地理研究所．土壤学．. 2001. |
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