| 题名 | 海河流域农田生态系统1990-2010年 氮平衡时空变化特征研究 |
| 作者 | 郑萌萌 |
| 学位类别 | 硕士 |
| 答辩日期 | 2014-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 郑华，肖燚 |
| 关键词 | 氮平衡 氮盈余强度 氮利用效率 农田生态系统 海河流域 nitrogen budget nitrogen surplus intensity nitrogen use efficiency agroecosystem Haihe Basin |
| 其他题名 | Study on the Spatio-temporal Characteristics of Nitrogen Budgets between 1990 and 2010 in the Agroecosystems of Haihe Basin, China |
| 学位专业 | 生物工程 |
| 中文摘要 | 氮肥过度施用是农业面源污染的主要原因之一，农田氮素平衡可以作为评价农田氮素损失引起环境风险的重要指标。本研究以海河流域为对象，分析了流域水环境状况及变化，基于流域县级农业统计数据、农田氮素平衡模型和 GIS技术，研究了海河流域农田生态系统 1990-2010年农田氮输入、氮输出、氮素盈余强度和氮素利用效率特征。结果表明： （1）1990-2010年，海河流域农田氮素输入强度由 238kg/ha增加到 420kg/ha，增加了 76%；其中，1990-2000年增加了 42%，2000-2010年增加了 25%。化肥氮输入强度由 149kg/ha增加到 310kg/ha，增加了 108%；其中，1990-2000年增加了 52%，2000-2010年增加了 37%。氮素输入总量由 31×108 kg增加到 54×108kg，增加了 74%；其中， 1990-2000年增加了 48%，2000-2010年增加了 17%。化肥输入总量由 19×108kg增加到 40×108kg，增加了 111%；其中，1990-2000年增加了 63%，2000-2010年增加了 29%。虽然氮素输入的速率趋缓，但是氮素输入总量和强度持续加大，流域潜在环境风险增加。 （2）1990-2010年，海河流域农田氮素输出强度由 149kg/ha增加到 261kg/ha，增加了 75%；其中，1990-2000年增加了 34%，2000-2010年增加了 31%。作物收获氮由 111kg/ha增加到 177kg/ha，增加了 59%；其中，1990-2000年增加了 26%，2000-2010年增加了 26%。氮素输出总量由 19×108 kg增加到 34×108kg，增加了79%；其中，1990-2000年增加了 42%，2000-2010年增加了 26%。作物收获氮的总量由14×108增加到23×108kg，增加了64%；其中，1990-2000年增加了36%，2000-2010年增加了 21%。随着氮素输入总量的增加，氮素输出的比例逐渐降低。 （3）1990-2010年，海河流域农田氮素盈余强度 (NSI)由 89kg/ha增加到159kg/ha，增加了 79%；海河流域农田氮素盈余总量由 11×108kg增加到 20×108kg。1990，2000，2010年，海河流域农田氮素利用效率分别为 0.46,0.42,0.42.其中 2000与 2010年氮素利用效率持平。氮素盈余强度不断加大，氮素利用效率尚未得到提高。 上述结果表明海河流域农田生态系统作物产量、氮肥施用强度增加的同时，环境风险也随之攀升，全面认识氮素平衡特征及其变化对于农业可持续发展和水环境污染防治具有重要意义。在不牺牲作物产量的前提下，建议采取以下措施提高氮素利用效率、降低氮素盈余强度，进而降低农田氮素损失的环境风险：结合本地土壤养分监测，优化化肥、有机肥施用比例；优化氮、磷、钾肥配比，提高作物对化肥的利用率；加大固氮作物品种的种植比例，降低化肥需求；通过教育、宣传等手段，提高农民对土壤肥力的认知水平。 |
| 英文摘要 | Excessive application of nitrogen fertilizer is one of the main reasons for agricultural non-point source pollution. The nitrogen balance can serve as an indicator of the environment risk resulting from nitrogen loss from agricultural land. To investigate the spatial-temporal change in agricultural nitrogen application and its potential threat to the environment of the Haihe Basin in China, this study constructed agricultural nitrogen balance model, calculated agricultural nitrogen input, nitrogen output, nitrogen surplus intensity(NSI), and nitrogen use efficiency(NUE)from 1990 to 2010 based on a database of county-level agricultural statistics and GIS technology. The results showed that as follows: (1)From 1990 to 2010, the nitrogen input intensity has risen from 238kg/ha to 420kg/ha,with a 76% increase for 1990-2010, a 42% increase for 1990-2000 and a 25% increase for 2000-2010.The chemical-N input intensity has risen from 149kg/ha to 310kg/ha,with a 108% increase for 1990-2010, a 52% increase for 1990-2000 and a 37% increase for 2000-2010.The total nitrogen input amount has risen from 31×108 kg to 54×108kg,with a 74% increase for 1990-2010, a 48% increase for1990-2000 and a 17% increase for 2000-2010.The total chemical-N input amount has risen from 19×108kg to 40×108kg,with a 111% increase for 1990-2010, a 63% increase for 1990-2000 and a 29% increase for 2000-2010.In spite of a lower growth rate with time, the input intensity and total input amount has continued to increase in the last 20 years and the environment risks have increased in the Haihe Basin. (2)From 1990 to 2010, the nitrogen output intensity has risen from 149kg/ha to 261kg/ha,with a 75% increase for 1990-2010, a 34% increase for1990-2000 and a 31% increase for 2000-2010.The nitrogen harvested by crop has risen from 111kg/ha to 177kg/ha,with a 59% increase for 1990-2010, a 26% increase for 1990-2000 and a 26% increase for 2000-2010.The total nitrogen output amount has risen from 19×108 kg to 34×108kg,with a 79% increase for 1990-2010, a 42% increase for1990-2000 and a 26% increase for 2000-2010.The total nitrogen amount harvested by crop has risen from 14×108kg to 23×108kg,with a 64% increase for 1990-2010, a 36% increase for 1990-2000 and a 21% increase for 2000-2010.The proportion of nitrogen harvested by crop has decreased as the total nitrogen input amount has increased in the Haihe Basin. (3)From 1990 to 2010, the nitrogen surplus intensity(NSI) has risen from 89kg/ha to 159kg/ha,with a 79% increase for 1990-2010; the total amount of nitrogen surplus has risen from 11×108kg to 20×108kg. The nitrogen use efficiency(NUE) was 0.46,0.42,0.42 in 1990，2000，2010,repectively,and those of 2000 and 2010 kept the same lower value. The nitrogen surplus intensity(NSI) has been intensified unceasingly, but the nitrogen use efficiency(NUE) has not been improved at the same time. The results above demonstrated that as the crop yields and chemical-N input intensity increased, the environmental risks kept climbing in the agroecosystems of Haihe Basin. It is of great significance to fully understand the characteristics of nitrogen balance and its change in the interest of a sustainable agricultural development and the prevention of environmental disruption. Without sacrificing crop yields, it is suggested that the following measures should be adopted to improve nitrogen use efficiency(NUE),reduce nitrogen surplus intensity(NSI).lessen environmental risks caused by nitrogen loss from farmland: optimize the types, volume, and proportions of fertilizers such as chemical fertilizer and organic fertilizer combined with local soil nutrient testing; optimize the proportion of N:P:K, raise the the amount of nitrogen absorbed by the crop; grow more nitrogen-fixing crop and reduce the demand for chemical-N; make knowledge of better soil fertility widely available among farmers by education and publicity. |
| 公开日期 | 2015-07-07 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/15631]  |
| 专题 | 生态环境研究中心_城市与区域生态国家重点实验室 |
| 推荐引用方式 GB/T 7714 | 郑萌萌. 海河流域农田生态系统1990-2010年 氮平衡时空变化特征研究[D]. 北京. 中国科学院研究生院. 2014. |
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