农业污染对土壤的危害及防治措施

伴随着我国经济的高速增长,环境问题也日益突出,特别是环境污染和生态破坏日益严重。城市环境问题日益得到重视,而农村的环境保护与治理相对来说是一个薄弱环节,农村环境也正日趋恶化。农村环境污染的加剧和农业生态环境的破坏,已成为制约我国农村经济健康发展的因素之一,农业减排势在必行。结合农村实际情况,本文从环境保护的角度阐述了农业生产过程中几种典型（农药、化肥、农作物秸秆）的污染及其对农田土壤造成的危害,同时针对化肥污染和农业污染提出了防治措施。     

基于eDNA的硅藻群落时空异质性及生态健康评价

近年来,环境DNA技术广泛应用于水生态生物多样性监测,如何基于环境DNA数据建立河流生态健康评价方法是当前研究的热点.拟开发基于环境DNA的分子硅藻指数来指示人类活动影响下的河流生态健康状况.首先通过环境DNA技术监测了沙颍河流域春秋两季硅藻群落组成和结构变化,解析了春、秋两季群落的驱动环境因子;进一步比较了4种基于环境DNA宏条形码数据的计算策略(OTU-分类、OTU-无分类、ASV-分类和ASV-无分类),构建了适合于评估沙颍河流域生态健康状况的分子硅藻指数.结果表明:①硅藻群落结构存在季节性差异,其中Discostella pseudostelligera、Nitzschia amphibia和Diatoma vulgaris等类群是区分春、秋季硅藻群落季节差异的主要因素;②重金属Mn、Fe和TN (总氮)是影响春季硅藻群落结构变化的主要环境因子,COD和Cu是影响秋季硅藻群落结构变化的主要环境因子;③在4种计算策略中,基于OTU-无分类数据计算的硅藻指数更好地反映了环境梯度变化;硅藻指数显示,沙颍河流域生态健康状况在时间上秋季优于春季,而在空间上上游优于下游.综上,通过eDNA技术监测了沙颍河春、秋两季硅藻群落,构建了沙颍河流域分子硅藻指数,促进了环境DNA技术在河流生态健康评价中的应用.     

Governance of seed and food security through participatory plant breeding: Empirical evidence and gender analysis from Syria

This paper presents the findings of a study on the governance of seed conducted in the framework of a participatory plant breeding (PPB) programme, based on a multi‐year inquiry with a panel of ten Syrian households. The study assessed the interactions between governance regimes regulating the rights to access and control genetic resources at international and national level, compared to the actual ability of the respondent women farmers to access and control the seed of varieties they co‐developed with the PPB programme. The paper argues that gender equal access to seed can “optimally” contribute to enhancing household food security in small scale farming. The paper also argues that to support a gender‐equal access to seed in the respondent households legislation needs to explicitly protect the rights of women farmers to access and share the benefits of genetic material and draw from empirical evidence of the actual access to and control of seed at ground level.     

Can environmental compensation contribute to socially equitable conservation? The case of an ecological fiscal transfer in the Brazilian Atlantic forest

ABSTRACT

Regions of high biodiversity often coincide with regions of poverty and conservation can imply economic and social costs for poor resident populations. Environmental compensation is considered a tool to reduce socio-environmental conflict, improve the equity of conservation and promote sustainable development. The intricacies of specific socio-ecological systems may determine how compensation payments are interpreted locally to produce outcomes. This research examines the social perceptions of an ecological fiscal transfer which intends to compensate the local public administration for the substantial costs of conservation in a hotspot of biological and social diversity in the Brazilian Atlantic forest. In this context we explore whether financial compensation (1) influences local perceptions of the conservation regime, (2) contributes towards the reconciliation of human-conservation conflicts and (3) triggers any meaningful socio-economic improvement that would counter the local costs of conservation. Results show that environmental compensation is not widely recognised as effectively benefiting the community. Local authorities consider compensation insufficient to enact a sustainable development agenda. Environmental compensation could play an important role in a policy mix for socially equitable conservation by being explicitly linked to community benefits, especially to fostering local livelihoods. The collaboration of actors operating across multiple governance levels may improve the institutional capacity of local actors to produce effective outcomes.     

Spatial and long-term variability of soil loss due to crop harvesting and the importance relative to water erosion: A case study from Belgium

The harvest of crops such as sugar beet (Beta vulgaris L.), potato (Solanum tuberosum L.), leek (Allium porrum L.) and carrot (Daucus carota L.) causes soil loss from arable land because soil adhering to the crop and soil clods that failed to be separated by the harvesting machine, are exported from the field together with these harvested crops. These soil losses can be of the same order of magnitude as soil losses caused by water erosion processes, but are often neglected in soil erosion research. In this article we developed a methodology to investigate the spatial and long-term (1846–2004) variability of soil loss due to crop harvesting (SLCH) in Belgium and the spatial distribution of the importance of SLCH relative to soil losses caused by water erosion processes in Flanders. The study is based on long-term time series of soil tare data of crop processing factories and area and crop yield statistics. Until the middle of the 20th century, potato and roots and tubers grown as second crop, had the largest share in the SLCH-crop growing area in Belgium. Sugar beet gained importance from the end of the 19th century onwards and has now, of all SLCH crops, the largest growing area. We could estimate that, partly due to increasing crop yields and the mechanisation of the harvesting process, SLCH per hectare of cropland increased from 0.4 Mg ha⁻¹ year⁻¹ in 1846 to 2.4 Mg ha⁻¹ year⁻¹ in the 1970s and early 1980s. Since then mean annual soil losses decreased again to 1.8 Mg ha⁻¹ year⁻¹ in 2004. It was assessed that total yearly SLCH in Belgium rose from more than 575,000 Mg in the middle of the 19th century to more than 1.7 × 10⁶ Mg in the 1970s and early 1980s, while current SLCH values are 1.4 × 10⁶ Mg. We estimated that since 1846, more than 163 × 10⁶ Mg soil was exported from cropland in Belgium through this erosion process, which corresponds to 109 hm³ or an average soil profile truncation of 1.15 cm. Average sediment export from cropland in Flanders was 3.7 Mg ha⁻¹ year⁻¹ in 2002, of which 46% was due to SLCH and 54% was due to water erosion processes. The relative importance of SLCH varied, depending on the agricultural region, between 38% and 94%.     

Growth of non-English-language literature on biodiversity conservation

English is widely recognized as the language of science, and English-language publications (ELPs) are rapidly increasing. It is often assumed that the number of non-ELPs is decreasing. This assumption contributes to the underuse of non-ELPs in conservation science, practice, and policy, especially at the international level. However, the number of conservation articles published in different languages is poorly documented. Using local and international search systems, we searched for scientific articles on biodiversity conservation published from 1980 to 2018 in English and 15 non-English languages. We compared the growth rate in publications across languages. In 12 of the 15 non-English languages, published conservation articles significantly increased every year over the past 39 years, at a rate similar to English-language articles. The other three languages showed contrasting results, depending on the search system. Since the 1990s, conservation science articles in most languages increased exponentially. The variation in the number of non-English-language articles identified among the search systems differed markedly (e.g., for simplified Chinese, 11,148 articles returned with local search system and 803 with Scopus). Google Scholar and local literature search systems returned the most articles for 11 and 4 non-English languages, respectively. However, the proportion of peer-reviewed conservation articles published in non-English languages was highest in Scopus, followed by Web of Science and local search systems, and lowest in Google Scholar. About 20% of the sampled non-English-language articles provided no title or abstract in English; thus, in theory, they were undiscoverable with English keywords. Possible reasons for this include language barriers and the need to disseminate research in countries where English is not widely spoken. Given the known biases in statistical methods and study characteristics between English- and non-English-language studies, non-English-language articles will continue to play an important role in improving the understanding of biodiversity and its conservation.     

Modeling the Impacts of Farming Practices on Water Quality in the Little Miami River Basin

Since intensive farming practices are essential to produce enough food for the increasing population, farmers have been using more inorganic fertilizers, pesticides, and herbicides. Agricultural lands are currently one of the major sources of non-point source pollution. However, by changing farming practices in terms of tillage and crop rotation, the levels of contamination can be reduced and the quality of soil and water resources can be improved. Thus, there is a need to investigate the amalgamated hydrologic effects when various tillage and crop rotation practices are operated in tandem. In this study, the Soil Water Assessment Tool (SWAT) was utilized to evaluate the individual and combined impacts of various farming practices on flow, sediment, ammonia, and total phosphorus loads in the Little Miami River basin. The model was calibrated and validated using the 1990–1994 and 1980–1984 data sets, respectively. The simulated results revealed that the SWAT model provided a good simulation performance. For those tested farming scenarios, no-tillage (NT) offered more environmental benefits than moldboard plowing (MP). Flow, sediment, ammonia, and total phosphorus under NT were lower than those under MP. In terms of crop rotation, continuous soybean and corn–soybean rotation were able to reduce sediment, ammonia, and total phosphorus loads. When the combined effects of tillage and crop rotation were examined, it was found that NT with continuous soybean or corn–soybean rotation could greatly restrain the loss of sediments and nutrients to receiving waters. Since corn–soybean rotation provides higher economic revenue, a combination of NT and corn–soybean rotation can be a viable system for successful farming.     

张家界国家森林公园不同土壤类型土壤动物群落的初步调查研究

2000年8月对湖南省张家界国家森林公园森林土壤进行了土壤动物调查，获各类动物1972个，分隶属于4门8纲24目，其中螨类和弹尾类为优势类群，双翅目和膜翅目为常见类群。初步研究表明，森林旅游对土壤动物类群和个体数目都有较大的影响。     

农业生态系统中杂草资源的可持续利用

杂草是农业生态系统中对农作物的生长和产量产生重要影响的伴生植物。杂草具有耐不良环境、生长快、繁殖力强等优良特性,是重要的生物资源。可利用杂草的优良基因作为农作物遗传改良的基因供体,利用其有用成分开发中医药,利用植物他感效应进行害虫生物防治,可开发成观赏植物,可作为先锋物种进行生态恢复、改良环境、促进养分循环、保护土壤微生物等。杂草的化学防除是导致杂草资源丧失的重要因素,寻找既利于杂草资源保护又不影响农作物生长的防除途径、杂草资源数据库的创建、杂草资源有益基因的发掘和开发利用,是杂草科学今后应加强的研究方向。     

三峡水库初期蓄水对消落带植被及物种多样性的影响

通过对173 m蓄水后三峡水库消落带内植物群落的调查,运用CCA法对消落带植物群落进行排序,研究了消落带植物群落特征和物种多样性格局,分析了消落带植被的变化及其环境解释。结果表明:三峡库区消落带共记录58科175种植物。狗尾草、马唐、小蓬草、狼杷草、稗、酸模叶蓼、苍耳、双穗雀稗、狗牙根等为优势种。一年生植物为消落带优势生活型。共记录54个群落类型,其中灌丛群落5个,草本植物群落49个。CCA排序表明,三峡水库消落带植物主要分布在坡度平缓、底质较细、高程较高的消落带上部区域。在消落带内,物种多样性和一年生植物比例随高程上升而增加。消落带植物组成特征和物种多样性格局与水淹干扰强度在空间上的变化一致。长期的冬季水淹、剧烈的水位变动以及退水季节的高温伏旱等环境因素是影响消落带植被组成的重要因素。