摘 要

在生产栽培竹林过程中，为了追求高产，化肥的施用量大大增加。导致竹林中的有机氮、总氮等在土壤中大量积累，而且土壤的理化性质发生变化。在降雨过程中，盈余的氮营养元素易随径流进入水体，不但降低了氮肥施用的经济效益，还会导致水体面源污染等环境问题。本研究通过模拟试验，研究生物炭添加（设置10 t/ha和20 t/ha施用量）技术与植被缓冲带技术耦合对竹林氮流失的减控效果进而优化现有的减控竹林氮流失的工程技术。研究结果表明：

单独添加生物炭量对土壤的氮流失减控效果呈正相关，径流中总氮的含量分别减少了32.4%、50.1%。随着生物炭添加量的增加，土壤中氮的固持能力也增加。在经过缓冲带处理过的径流中有机氮和总氮的含量分别减少了14.6%和12%。而经过联用技术处理过后的径流中有机氮的含量减少了67.1%，总氮的含量也减少了67.5%。

综上所述，添加生物炭、设置植被缓冲带均可以有效减少集约经营竹林的氮径流损失，其中联用技术的减控效果最为有效。而只采用植被缓冲带体系对阻控竹林氮流失的影响在此次实验中效果不明显。

关键词：联用技术；减控；生物炭；缓冲带；氮径流损失

Combination technique of biochar application and buffer strip on reducing nitrogen runoff losses from intensive bamboo forest soil

ABSTRACT

In the process of producing bamboo forests, the amount of chemical fertilizer has been greatly increased in pursuit of high yield. Lead to the accumulation of organic nitrogen and total nitrogen in the soil, and the physical and chemical properties of the soil changed. In the process of rainfall, the surplus nitrogen nutrient elements are easy to enter the water with the runoff, which not only reduces the economic benefits of nitrogen fertilizer application, but also leads to environmental problems such as non-point source pollution. This study through the simulation test, the research of biochar added (set 10 t/ha and 20 t/ha fertilizer) technology and vegetation buffer technology coupled to bamboo nitrogen loss reduction and control effect and control optimization of reducing nitrogen loss of bamboo existing engineering technology.The results show that:

Addition of biochar amount was positively related to soil nitrogen absorption, the content of total nitrogen in runoff were reduced by 32.4%, 50.1%.With the increase of biochar content, the retention of nitrogen in soil increased.Organic nitrogen and total nitrogen were reduced by 14.6% and 12%, respectively, in buffer treated runoff. The amount of organic nitrogen decreased by 67.1% and the total nitrogen content decreased by 67.5%.

To sum up, adding biochar and setting buffer belt can effectively reduce the nitrogen loss of bamboo forest with intensive management, and the control effect of combined technology is more effective and obvious. The effect of vegetation buffer system on nitrogen loss in the control bamboo forest was not obvious in this experiment.

Key words：Hyphenated technique；Reduction and control；biochar；buffer belt；Nitrogen runoff loss

目 录

1 前言 1

1.1国内外研究现状背景 1

1.2研究目的及意义 2

1.3研究内容及创新 2

2 材料与方法 3

2.1 试验处理 3

2.2分析指标 3

2.3 试验过程 4

3 结果与分析 5

3.1不同技术对竹林土壤径流中铵态氮的减控效果 5

3.2不同技术对竹林土壤径流中硝态氮的减控效果 6

3.3 不同技术对竹林土壤径流中有机氮的减控效果 8

3.4不同技术对竹林土壤径流中总氮的减控效果 9

4 结论及总结 12

4.1生物炭的添加对减控各种形式氮流失量的影响 12

4.2设置缓冲带的必要性 12

4.3联用技术的优势 12

4.4 不足及展望 13

5 致 谢 14

参考文献 15

1 前言

1.1国内外研究现状背景

我国是世界上使用化肥最多的国家之一，基于国情，我国农村地区还将会持续使用化肥以达到增产增收的目的。但是由于落后的经营方式，使得化肥的利用效率极低，氮肥利用率普遍低于30%、磷肥利用率普遍低于15%^[1]。其中大部分未经利用的氮磷养分会通过渗漏或地表径流流失到地下水和地表水中，最终进入河流湖泊。不合理的田间管理方式会造成耕地大量的养分流失，如过量施肥、肥料地表撒施、雨前施肥等。通过改善田间管理方式不仅能显著提高肥料的利用率，而且有效降低流失量^[2]。

随着产业结构的调整，竹林经济林栽培的集约化程度越来越高。为了获得高产高效，不仅仅是提高肥料的投入，还需要在过程处控制氮素的流失。而氮素的流失更会造成农业的面源污染^[3]。一般认为面源污染的发生需要两个充要条件：污染源的发生和污染物的迁移。只有当污染源和污染物的迁移条件共存时才会发生面源污染。因此，我们可以通过减少面源污染物的源头发生和控制污染物的迁移来控制面源污染，从而实现氮素污染的影响缩小，从流失过程处减控氮的流失。