三峡库区紫色土坡地—桑树系统土壤养分及微生物活性特征研究

发布时间：2018-05-13 02:31

本文选题：桑树-坡地系统 + 三峡库区　；参考：《西南大学》2014年硕士论文

【摘要】：随着人口的持续增长,粮食与食品需求不断增加,资源开发与利用强度逐年增强,由此导致农业面源污染逐年加重。目前,农业面源污染已在全球范围内引起土壤与水污染,我国农业面源污染的形势极其严重,其污染源主要有三类,分别是化肥、畜禽粪尿和农药。农业面源污染因为其独有特性,已成为当今世界环境污染治理最为棘手的难题之一,因此探索行之有效的防控措施,遏制农业面源污染,对培肥地力,保持水土,减轻生态破坏和环境污染具有十分重要的理论和现实意义。坡地-桑树系统,因植物自身的机械阻拦作用、吸收作用与系统内土壤抗侵蚀环境(提高土壤的抗冲性、覆盖度、减缓坡度等)的改善,使其不仅能很好地保持坡地水土,还能显著地减轻农业面源污染物对土壤与水体的危害。本研究以三峡库区上游及库周丘陵区的紫色坡耕地为对象,从流域角度把坡地-桑树系统作为一种控制农业面源污染的坡地复合生态农业技术。本文共设一个对照,四个处理,分别为横坡垄作(CK)、两带等高桑+横坡垄作(T1)、三带等高桑+横坡垄作(T2)、四边桑+等高桑+横坡垄作(T3)、四边桑+横坡垄作(T4)。系统、定量化地研究其控制农业面源污染物N、P的效应、微生物数量及生物量的活性,综合评价桑树-坡地系统经济-土壤质量效益,为控制区域农业面源污染优化技术的推广提供科学依据,对保护流域水环境安全,推动区域经济-环境协调发展具有重要的理论与实践意义。研究取得以下结果： 1在各榨菜季、间歇季、玉米季三季中,因为温度、湿度、桑带长势、作物类型等因素,土壤氨氮含量与不同季节中的温度、湿度、光照强度、光照时间等存在相关关系。在T1、T2、T3、T4四个处理中,土壤速效磷、速效钾含量与各处理呈显著正相关；全氮含量与各处理呈极显著正相关。此外,在各养分之间进行相关分析得到,碱解氮与速效钾呈极显著正相关关系、土壤全氮含量与土壤全磷和速效磷含量呈显著正相关关系、土壤速效磷与土壤pH呈极显著负相关关系。综合得到,在四个不同处理中,对土壤全氮含量影响很大,出现极显著相关关系；其次则是对土壤速效磷和速效钾含量影响较大,出现显著相关关系。除此之外,本试验中各坡地-桑树系统的其他土壤养分差别不大,与处理间的相关关系不显著。 2在各处理间,对土壤径流水拦截效益数T3和T4处理最为明显,T1和T2处理则因为桑树长势等问题对土壤径流水拦截效果不明显。各处理对土壤径流水养分影响较大,尤其是对土壤径流水氮素含量呈现极显著负相关关系,即各处理已经有效的拦截了土壤径流水携带的养分,保护了土壤养分的蓄积。但各处理对微生物数量、生物量的影响不大,更则细菌与处理表现出显著负相关关系,这使得试验设计初衷与试验结果相悖,得到这一结果是出自试验的客观存在还是试验过程中的偶然现象,值得进一步研究加以论证。此外,各处理作物营养吸收也差别不大,与处理间均未表现出相关关系。 3经过经济产值和土壤质量评价后得到：在各处理中,从作物经济角度分析得到T3处理亩产值最高,为3863.21元/亩,其次是T1处理,为3599.08元/亩,T2和T4处理经济效益最低,分别为3575.96元/亩和3465.55元/亩。而从土壤养分综合指标评价得到,T4土壤质量最优,IQI值为0.657；其次是T1处理,IQI值为0.624；再者是T3处理,IQI值为0.590,T2处理土壤综合评价值IQI最低,仅为0.430。各处理经济效益和生态效益评价得到,T1处理经济产值和土壤质量均处于各处理中上水平；T2处理则表现均不占优势；T3处理经济产值最优,但土壤质量仅优于T2处理；而T4处理虽然经济产值最低,但土壤质量最优。为平衡经济产值和土壤质量均衡发展,从试验结果得到各处理中T1处理为最佳。综上所述,科学合理地优化和评价坡地-桑树系统,提高其生态、经济、综合效益,不仅能控制农业面源污染,更能提高土地生产力,有益于当地生产。同时,桑带种类及空间结构、经营管理技术等相关基础技术理论对坡地-桑树系统有极大影响,尤其是如何根据不同坡度、土层深度等地形因子并结合气象资料,合理地设计桑带间带间距等相关基础技术理论研究应进一步加强。
[Abstract]:With the increase of population , food and food demand are increasing year by year , resource exploitation and utilization intensity increase year by year . The pollution source of agricultural surface source has become one of the most difficult problems of pollution control in the world .

This study is based on purple slope cultivated land in the upstream and reservoir of the Three Gorges Reservoir area . The slope - mulberry system is used as a slope compound ecological agriculture technique for controlling agricultural surface source pollution .

The content of ammonia nitrogen in soil was correlated with the temperature , humidity , illumination intensity and illumination time in different seasons .
The results showed that the total N content of soil was positively correlated with the content of total phosphorus in soil and the content of available phosphorus in soil .
Secondly , there was a significant correlation between the content of available phosphorus and available potassium in soil . In addition , there was no significant difference in other soil nutrients in the soil - mulberry system in this experiment , but the correlation between treatments was not significant .

2 In the treatment room , the treatment of soil runoff water interception benefit number T3 and T4 is the most obvious , and the treatment of T1 and T2 is not obvious to the soil runoff water interception effect because of the long potential of mulberry trees .

3 After the evaluation of economic output value and soil quality , the yield of T3 treated per mu was highest , 3863.21 yuan / mu , followed by T1 treatment , 3575.96 yuan / mu and 3465.55 yuan / mu , respectively .
followed by T1 treatment with an IQI value of 0.624 ;
In addition , T3 treatment , IQI value of 0.590 , T2 treatment soil comprehensive evaluation value IQI is the lowest , only 0.430 . The economic benefit and ecological benefit evaluation of each treatment , T1 treatment economic output value and soil quality are in each treatment level ;
T2 treatment was not dominant ;
T3 deals with the best economic output value , but the soil quality is better than T2 treatment .
While T4 treatment is the lowest with the lowest economic output value , the soil quality is the best . In order to balance the economic output value and the development of soil quality equilibrium , the T1 treatment in each treatment is the best from the experimental results .

To sum up , scientifically and reasonably optimize and evaluate the slope - mulberry system , improve the ecological , economic and comprehensive benefits , not only can control the agricultural surface source pollution , but also improve the land productivity and benefit the local production .

【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：S158.3;S154.3

【参考文献】