植被作用下土质覆盖层渗透特性的现场试验

通过现场试验监测了3种不同覆盖层的内部水分运移过程,研究了不同植被对覆盖层防渗性能的影响。首先在室外自然环境中修建了3种覆盖层场地,分别是无植被裸土覆盖层、狗牙根草覆盖层（须根系植被）、香根草覆盖层（直根系植被）。在亚热带潮湿气候条件下培育一年,选择降雨量和蒸发量较大的7~9月份实时监测了3种覆盖层内部不同深度处的体积含水率和基质吸力。研究发现,香根草的存在使得覆盖层的渗透系数增大,从而减弱了覆盖层的防渗性能;相反,狗牙根草降低了覆盖层的渗透系数,从而增强了覆盖层的防渗性能。这主要是因为须根类根系（狗牙根草根系）和直根系（香根草根系）对土体中水分运移的影响不同。监测结果显示,在覆盖层较浅的位置（如5 cm深度处）土体内的含水率主要受降雨和蒸发的影响,有无根系对此处的含水率变化影响较小。在覆盖层深处（如50 cm处）,只有香根草覆盖层还受降雨和蒸发的影响,而狗牙根草覆盖层和裸土覆盖层深处含水率基本没有变化,这说明了香根草覆盖层根系影响了覆盖层深处,而狗牙根草根系只对覆盖层浅处有影响。     

Slow restoration of soil microbial functions in an Acacia plantation established on degraded land in Thailand

Deforestation diminishes the ecological services that a forest provides (e.g., flood prevention). To restore such services, reforestation is often utilized. The full restoration of the original forest ecosystem, however, can take several decades. The present study was conducted to identify the missing key components for rehabilitation of a degraded plot of land in Thailand on which Acacia trees were planted 18 or 19 years ago. Canopy spectral and soil physicochemical profiles of the Acacia plantation plot showed more advanced rehabilitation than in the soil microbial functions, as represented by soil dehydrogenase activity and community-level physiological profiles, when compared with those of a natural evergreen forest. The slower restoration of the soil microbial functions was thought to: (1) be attributed to the loss of certain microbes that played important roles in the evergreen forest soil, and (2) restrict the restoration of the entire forest ecosystem which was found to be still progressing towards a full restoration of the land’s original conditions. Finally, possible measures for further rehabilitation of the ecosystem were discussed.     

Kinetics of nitroreductase-mediated phytotransformation of TNT in vetiver grass

The effectiveness of vetiver grass in removing 2,4,6-trinitrotoluene (TNT) and the involvement of nitroreductase (NR) enzyme in TNT degradation in vetiver has been documented in our earlier studies. The present study was designed to optimize the parameters influencing NR enzyme-mediated TNT transformation in vetiver. The current study is the first report of detailed kinetic examination of NR enzyme induced by TNT in vetiver. Results show that NR activity in vetiver root increased with exposure time as well as with initial TNT concentration, showing a first-order reaction kinetics at lower and a second-order reaction kinetics at higher TNT concentrations. Nitroreductase activity was higher in shoot compared to root in all TNT treatments. Increasing concentration of TNT resulted in a significant increase in the NR activity in shoot. Very high increase in the shoot NR activity indicates a faster root-to-shoot translocation of TNT. The optimum range of the factors influencing NR-mediated TNT transformation and the kinetic parameters were determined, which will be crucial for the application of vetiver for phytoremediation of TNT-contaminated systems.     

Geochemical Evaluation of Soil Quality in Menyuan County of Qinghai Province北大核心CSCD

青海省门源县内林草地面积大于44万公顷,耕地仅不到4.2万公顷,林草地资源丰富。2016年在门源县地区开展了1：25万土地质量地球化学评价工作,是青海省首次在大面积林草地区开展1：25万土地质量地球化学调查工作,具有较好的示范作用。通过评价土壤养分、土壤环境等级划分了土壤质量地球化学综合等级,结果表明：门源县土壤质量一等优质土壤占比92.4%,二等良好土壤占0.8%,三等中等土壤占5.6%,四等差等土壤占0.9%,五等劣等土壤占0.3%。通过项目实施可服务门源县土地资源管理,为门源县土地规划利用、农业种植结构调整及生态环境治理等提供依据,助力门源县绿色有机农畜产品输出地建设。     

The efficiency of vegetative buffer strips in runoff quality and quantity control

In recent years, nonpoint source pollutions, caused mostly by surface runoff, have become a subject of interest. Vegetative buffer strips contain a special plant species being passed by the flow before getting into the water bodies. The main aim of the present study is to evaluate the impact of three different types of vegetative buffer strips to reduce the surface water pollutants including sediment, nitrate and phosphate. The experiments were carried out using the experimental plots with the dimension of 1 × 10 m² as well as the artificial runoff with a flow rate of 1.65 L s^?1 during a year. The results of this study showed that the vegetative buffer strips reduced the runoff volume by 35–90%, sediment concentration by 42–94%, nitrate concentration by 35–88% and phosphate concentration by 28–95%. According to the results, the vetiver grass has a high efficiency in runoff pollutants control; but, due to the probability of creating the concentrated flow among the bushes of vetiver grass, it is strongly recommended to use a resistant plant with a density and uniformity similar to the turf grass and consistent to climatic conditions of the study area along with the vetiver grass. Also, periodic cutting the plants is as an effective strategy to deal with the role of vegetative buffer strips as a source of nutrients and sediment.     

基于遥感和景观分类的北京市裸露农田分析和治理对策

基于遥感影像的决策树分类,结合土地利用图,将北京市农业地表覆盖划分为春玉米、冬小麦、果园、林木苗圃、牧草地、设施农业和畜禽饲养地。考虑海拔、坡度和土壤质地三个因子将北京市分成10个景观区,在景观分区和不同农业用地基础上划分出39类农业景观单元。利用基于遥感影像计算的归一化差异植被指数,结合实地调查验证,分类出北京市冬春季裸露农田。结合景观分类,分析了不同景观单元冬春季地表裸露情况。结果表明：2007—2008年冬春季裸露农田共8.05×104 hm2,主要分布在延庆盆地、密云水库北岸和城区边缘的近郊农业区;海拔和土地利用方式对裸露情况影响较大,其中山区春玉米和平原果园裸露情况绝对面积较大,分别占到总裸露农田面积的40%和17%,牧草地、林木苗圃与设施农业地裸露程度较高。基于不同景观单元裸露程度,结合绿肥种植、保护性耕作、生草覆盖等裸露农田治理方法,探讨了北京市农业产业和景观一体化建设策略。     

The use of vetiver grass (Vetiveria zizanioides) in the phytoremediation of soils contaminated with heavy metals

Recent research has shown that phytoextraction approaches often require soil amendments, such as the application of EDTA, to increase the bioavailability of heavy metals in soils. However, EDTA and EDTA–heavy metal complexes can be toxic to plants and soil microorganisms and may leach into groundwater, causing further environmental pollution. In the present study, vetiver grass (Vetiveria zizanioides) was studied for its potential use in the phytoremediation of soils contaminated with heavy metals. In the pot experiment, the uptake and transport of Pb by vetiver from Pb-contaminated soils under EDTA application was investigated. The results showed that vetiver had the capacity to tolerate high Pb concentrations in soils. With the application of EDTA, the translocation ratio of Pb from vetiver roots to shoots was significantly increased. On the 14th day after 5.0 mmol EDTA kg⁻¹ of soil application, the shoot Pb concentration reached 42, 160, 243 mg kg⁻¹ DW and the root Pb concentrations were 266, 951, and 2280 mg kg⁻¹ DW in the 500, 2500 and 5000 mg Pb kg⁻¹ soils, respectively. In the short soil leaching column (9.0-cm diameter, 20-cm height) experiment, about 3.7%, 15.6%, 14.3% and 22.2% of the soil Pb, Cu, Zn and Cd were leached from the artificially contaminated soil profile after 5.0 mmol EDTA kg⁻¹ of soil application and nearly 126 mm of rainfall irrigation. In the long soil leaching experiment, soil columns (9.0-cm diameter, 60-cm height) were packed with uncontaminated soils (mimicking the subsoil under contaminated upper layers) and planted with vetiver. Heavy metal leachate from the short column experiment was applied to the surface of the long soil column, the artificial rainwater was percolated, and the final leachate was collected at the bottom of the soil columns. The results showed that soil matrix with planted vetiver, could re-adsorb 98%, 54%, 41%, and 88% of the initially applied Pb, Cu, Zn, and Cd, respectively, which may reduce the risk of heavy metals flowing downwards and entering the groundwater.     

基于果园牧草间作的石漠化综合治理效益评价

开展石漠化综合治理效益评价,对于石漠化综合治理模式的优化和改进至关重要。文章以贵州兴义市南盘江镇田房村为研究对象,分析热带果树+覆盖作物措施的石漠化综合治理效益。通过调查兴义市南盘江镇田房村治理前（2014年）和治理后（2017年和2020年）的农业产业结构、产业资源发展、经济效益和生态效益,利用冗余分析(RDA)和结构方程建模(SEM)评价了田房村石漠化治理的综合效益。结果表明:通过将耕地转变为园地（芒果和澳洲坚果间作牧草或绿肥）,综合治理6年后,该示范区农业产业结构、产业资源发展、经济效益和生态效益均呈现向好趋势;除了农/林草面积比和农产品商品产值两个观测变量,农业产业结构和产业资源发展与经济效益和生态效益之间观测指标均呈显著相关;果园用地比重、务工劳动力比重、务工贡献率、农产商品化产值、农/林草面积比5个变量是引起经济效益和生态效益变化的重要驱动因子;石漠化治理能耦合生态环境与产业资源的协调发展,同时实现生态恢复和经济增收。热带果树+覆盖作物相结合综合治理石漠化是该村生态恢复和经济增收的有效措施。研究结果为喀斯特石漠化综合治理提供了依据。      

国土整治生态修复中的农业景观生物多样性保护策略

随着生态文明建设成为国家发展战略,国土整治修复需要更多生态科学和技术的支撑.农业景观生物多样性是重要的自然资源,为人类可持续发展提供了重要的生态系统服务,并提供了应对气候变化等风险的途径.本文分析了我国农业景观生物多样性保护及其对国土整治生态修复的重要性,国土整治生态修复中农业景观生物多样性保护面临的挑战,并总结了欧盟...     

不同土地管理和利用方式喀斯特坡地养分和碳库管理指数的差异

文章选择环江喀斯特农业生态试验站坡地,设计封育、种植玉米、种植牧草、火烧、刈割和刈割除根6种处理方式,测定了不同处理下坡地土壤养分含量、有机碳、易氧化碳含量和碳库管理指数。结果表明,不同处理下土壤养分含量、有机碳含量和碳库管理指数均存在明显差异。土壤全氮、全磷、碱解氮、速效钾、有机碳和易氧化碳含量随土壤人为干扰的增大而减小,种植玉米、种植牧草和刈割除根处理由于人为干扰较大,上述指标显著低于封育和火烧处理。土壤全钾和速效磷含量均以种植玉米处理最高,而刈割处理最低。土壤缓效钾含量以封育最高,种植玉米和种植牧草处理次之,而刈割处理最低。与封育相比,各处理土壤碳库管理指数均显著降低,其中种植玉米和火烧处理最低,并显著低于其他各处理。此外,土壤全氮、全磷、全钾、碱解氮和有机碳含量随坡位的升高而降低。在喀斯特生态脆弱地区,自然封育有利于土壤养分和碳库管理指数的保持和提高。随着土壤人为干扰的增大,土壤养分含量和碳库管理指数下降。     

Human development is linked to multiple water body impairments along the California coast

To elucidate relationships between land cover and water quality along the central California coast, we collected monthly samples from 14 coastal waterway outlets representing various degrees of human development. Sites were distributed between three salinity categories, freshwater, estuarine, and marine, to better understand land cover-water quality relationships across a range of coastal aquatic ecosystems. Samples were analyzed for fecal indicator bacteria (FIB), dissolved nutrients, stable nitrogen isotopes in particulate organic matter, and chlorophylla (chla). Sediment samples from 11 sites were analyzed for the concentration of the anthropogenic organic contaminant perfluorooctane sulfonate and its precursors (ΣPFOS). While the data indicated impairment by nutrient, microbial, and organic contaminants at both agricultural and urban sites, the percentage of agricultural land cover was the most robust indicator of impairment, showing significant correlations (p<0.05) to FIB, nutrient, chla, and ΣPFOS levels. FIB densities were strongly influenced by salinity and were highest at sites dominated by agriculture and urbanization. Nutrient levels and chla correlated to both agricultural and urban land use metrics as well. Positive correlations among FIB, nutrients, chla, and ΣPFOS suggest a synergy between microbial, nutrient, and organic pollution. The results emphasize the importance of land management in protecting coastal water bodies and human health, and identify nutrient, microbial, and organic pollution as prevalent problems in coastal California water bodies.     

基于主成分和模糊C-均值聚类算法的农业水资源高效利用综合分区

基于农业生态系统环境要素、水的资源属性、水资源的高效利用内涵、生产力水平、土地利用方式、种植结构及种植模式等因子,选取构建农业水资源高效利用综合分区的指标体系(16个定量指标、4个定性指标),采用主成分分析和模糊C-均值聚类算法为区划方法,对川中丘陵区进行量化分区。研究结果将川中丘陵区16个地级市和一个县级市(简阳)分为农业水资源较低利用区、农业水资源低效利用区、农业水资源中等利用区、农业水资源高效利用区和农业水资源较高效利用区5个区,这对南方季节性干旱区水资源利用规划有较强的借鉴作用。     

Population growth and its spatial distribution as factors in the deforestation of Nang Rong, Thailand

Frontiers constitute a major source of global land cover change hot spots, with forests and grasslands being converted into agricultural uses. As such, frontiers provide an opportunity to see how people manipulate the land and their lives in the context of social, cultural and environmental constraints. This paper examines frontier settlement and land cover change in Nang Rong district, Northeast Thailand for the last half century. It uses a Cellular Automata (CA) model to explore the land cover consequences of alternative patterns of settlement in a setting where people establish dwelling units in nucleated villages and work agricultural plots that surround villages. Forested land around the center of a village is converted into agricultural uses in an inverse relationship to the distance from the village center, but frequently modified by biophysical conditions. Land at the center of the village may be reforested after the village is established as a source of shade as well as fruit and other products. Model variation in land cover change is more sensitive to the spatial reach of village households than their temporal reach, suggesting the important role that technology plays in how villagers travel to their fields (walking versus motorized transit).     

承德自然资源综合地质调查工程进展与主要成果

为积极探索地质调查支撑服务生态文明建设和自然资源管理的新举措、新机制,丰富地质调查工作转型升级的实践经验,2017年以来,中国地质调查局先后组织实施了“承德市生态文明示范区自然资源综合地质调查” 项目和工程。通过需求对接、野外调查与勘察、室内评价与编图等系列工作,初步取得了一批重要成果和认识: ①基本查清了承德市水、土、地质遗迹、生态等自然资源禀赋特征和环境本底条件,提出了矿山地质环境、林草湿地等地质问题及潜在风险; ②从自然资源与历史文化综合调查评价、全域生态文化旅游新格局打造和林果业种植结构优化等方面,探索了自然资源综合调查的地质支撑服务模式; ③基本查明了地质建造对农业和生态格局的控制关系,据此提出了耕地资源和植树造林的优选区域; ④以双滦区为例,探索了地表基质层的分布特征,为宜林、宜耕、宜草提供了理论基础; ⑤提出了基岩山区矿泉水成因模型和土地资源数量、质量、生态“三位一体”的调查评价工作方法。该工程取得的初步进展及成果为承德市国土空间规划和用途管制、生态保护与系统修复、生态文明建设和自然资源管理等提供了科技支撑。     

基于镉污染风险的湖南省龙山县百合种植区安全区划

湖南省龙山县作为我国重要的百合生产基地县之一,其土壤却存在一定程度的镉(Cd)污染风险。同时,百合作为一种食药同源的植物,其食用和药用的质量安全标准不一致。因此,在龙山县提出百合种植区安全区划具有重要意义。笔者等在龙山县耕地采集326件表层土壤样品和70件百合样品(配套根系土样),在分析土壤及百合中Cd的含量和土壤中氧化物、有机质、pH等指标的基础上,探讨Cd生物有效性的影响因素,并据此建立百合Cd生物富集系数预测模型,结合土地质量地球化学调查数据预测耕地的百合Cd含量,给出百合种植区安全区划及建议。结果表明,研究区土壤存在Cd污染风险,百合具有质量安全问题。研究区Cd的生物有效性受到土壤CaO、S、P、K₂O含量和土壤pH的共同影响。与多元线性回归模型相比,随机森林模型能够更好地预测百合Cd生物富集系数。百合种植区安全区划显示,研究区食用百合优先种植区、药用百合优先种植区、药用百合次级种植区、结构调整种植区面积占比分别为1.49%、92.71%、2.88%、2.92%,建议大力开发药用百合农产品。该研究成果将Cd污染风险耕地的安全利用与食药同源农产品的质量安全有...     

基于镉污染风险的湖南省龙山县百合种植区安全区划

湖南省龙山县作为我国重要的百合生产基地县之一,其土壤却存在一定程度的镉（Cd）污染风险。同时,百合作为一种食药同源的植物,其食用和药用的质量安全标准不一致。因此,在龙山县提出百合种植区安全区划具有重要意义。笔者等在龙山县耕地采集326件表层土壤样品和70件百合样品（配套根系土样）,在分析土壤及百合中Cd的含量和土壤中氧化物、有机质、pH等指标的基础上,探讨Cd生物有效性的影响因素,并据此建立百合Cd生物富集系数预测模型,结合土地质量地球化学调查数据预测耕地的百合Cd含量,给出百合种植区安全区划及建议。结果表明,研究区土壤存在Cd污染风险,百合具有质量安全问题。研究区Cd的生物有效性受到土壤CaO、S、P、K2O含量和土壤pH的共同影响。与多元线性回归模型相比,随机森林模型能够更好地预测百合Cd生物富集系数。百合种植区安全区划显示,研究区食用百合优先种植区、药用百合优先种植区、药用百合次级种植区、结构调整种植区面积占比分别为1. 49%、92. 71%、2. 88%、2. 92%,建议大力开发药用百合农产品。该研究成果将Cd污染风险耕地的安全利用与食药同源农产品的质量安全有效衔接,完善了受污染耕地安全利用的工作方法,为推动龙山县百合产业发展提供了科学依据。     

Why do smallholders plant biofuel crops? The ‘politics of consent’ in Mexico

Recent studies have addressed the social and environmental impacts of biofuel crops but seldom the question as to why rural producers engage in their production. It is particularly unclear how governments worldwide, especially in middle-income countries such as Brazil, Thailand, and Mexico, could enroll so many smallholders in biofuel cropping projects. Conventional views see yields and economic returns as main drivers for smallholder participation in biofuel production but ignore the role played by power and politics. This paper analyses the rapid biofuel expansions (oil palm, jatropha) in the southern Lacandon rainforest in Chiapas (Mexico) and their partial failure (jatropha) from a political ecology perspective. Our findings indicate that biofuel expansions in this region not only occurred for productive reasons, but also because biofuel programmes provided prospects for political gains through strengthened rural organisations. In contrast with emphasis on state coercion and local resistance—common in political ecology—the biofuel expansion relied, in this case, upon a ‘politics of consent’ in which both the state and rural organisations, albeit in a power-laden relationship, sought to achieve their own goals by supporting the planting of biofuel crops. These findings suggest the need to rethink how particular approaches within political ecology apply Gramsci’s notions of power and hegemony and, more broadly, to consider the importance of politics in explaining why certain forms of agricultural production become dominant.     

日本岩垂草在岩溶山地的生态效益研究

本文首次在岩溶山地生态重建中引进优质草种——日本岩垂草(Lippianodiflora (L.) Greene),通过对其盖度、根系特征、径流量和抗侵蚀能力的研究,探讨其在岩溶山地的生态效益,寻求修复岩溶地区脆弱生态系统的途径,并为日本岩垂草在岩溶山地种植推广提供依据。试验表明,日本岩垂草对降低地表径流量收效明显,在种植了3个月后,地表径流量已经由110mm下降到42mm,下降了62%;抗侵蚀能力强,在同样的雨强和降雨量情况下,其侵蚀量只是传统耕地的5.60%~5.83%;根系生长速度快,密度大,数量多,种植90d时盖度已达100%。实验证明,日本岩垂草具有优秀的生态修复和生态美化能力,能够有效地改善岩溶地区脆弱的生态状况。      

农业地质环境调查成果在农产品认证中的应用

在简介农业地质环境调查和中国农产品认证现状的基础上,论述了农业地质环境调查成果可为无公害农产品、绿色食品和有机食品的产地认证提供有益的补充,特别是在有机食品的产地认证中可发挥独特作用.结合萧山大青梅原产地保护认证的实践,阐明了通过农业地质环境调查建立农作物的原产地地质模型,可为原产地的地域划定提供科学依据,也可为扩大优质农作物的种植面积和调整农业产业结构提供基础资料.     

重庆南川区石漠化分布特征及其坡地利用模式分析

利用2004TM遥感影像,并结合地质、水文气象、土地利用图等,研究了重庆南川区石漠化的分布特征。结果表明,南川区石漠化分布具有如下特征:地层岩性上,石漠化集中发育在中生界三叠系嘉陵江、飞仙观、雷口坡组和下古生界奥陶系马家沟组碳酸盐地区的纯灰岩与其他灰岩和白云岩互层分布区中;气象水文上,石漠化集中分布在中部槽坝年均温为10~16℃、年降水量大于1200mm的地区;地形高程上,轻度石漠化和中度石漠化主要分布在海拔800~1200m之间,重度石漠化主要分布在600~800m之间,极重度石漠化主要分布在500~600m之间;土地利用上,轻度和中度石漠化主要分布于灌木林地中,重度以上石漠化则主要见于旱地。根据研究区石漠化的发育和分布特点,建议平缓坡地(<5°)推行稻田保护性耕作和加强无公害农产品基地建设;较缓坡地(5°~15°)发展农耕和种植园区;较陡坡地(15°~25°)种植藤本植物(金银花)、经济林果和生态林草;陡峻坡地(>25°)应长期封山育林,重点发展水源林和景观林。