Farmers’ perceptions of sorghum production constraints and Striga control practices in semi-arid areas of Tanzania

The objectives of this study were to investigate constraints affecting sorghum production and farmers' approaches of Striga management in the semi-arid regions of Tanzania. Focus group discussions based on a semi-structured questionnaire and observations following transect walks were used for data collection. Only 35%, 15%, and 10% of the farmers from Igunga, Kishapu, and Meatu districts, respectively, reported growing newly released varieties. The major constraints affecting sorghum production in the study areas included Striga infestation, drought, storage pests, damage by birds, a lack of access to improved varieties, and a lack of access to production inputs, such as fertilizers, insecticides, fungicides and herbicides. Hand weeding, crop rotation, fallowing, intercropping, and organic manure application were the most common practices of farmers for reducing Striga infestations, but most farmers (79.7%) had little knowledge of the best recommended Striga management practices. About 65% of the farmers did not use fertilizers and herbicides for soil fertility improvement and weed management, respectively, creating favourable conditions for Striga infestation. A systematic breeding programme aiming at improving sorghum varieties for Striga resistance, including farmers' preferred traits, should be designed and implemented to increase the adoption of these new varieties by the farmers.     

铜仁市农业生态环境的脆弱性及可持续发展

铜仁市地处喀斯特地貌山区,农业生态环境极为脆弱,给农业可持续发展带来很多不利影响。铜仁市农业生态环境脆弱性是喀斯特自然作用和人为活动作用的结果,据此阐述其环境整治和农业可持续发展的途径及相应的发展模式。     

作为学科与专业的“农学”之历史反思与体系再构——以农业生态学作为新农学的核心理论科目

现代农学学科的形成源于欧洲工业革命主导的实验科学归纳论思维, 取得农业产量巨增的同时, 却破坏了农业可持续性赖以维持的自然基础。随着农业可持续发展战略目标的日益清晰, 农学学科及其教育体系的重构也日益迫切。联姻生态学, 建立以“农业生态学”为核心科目的新农学理论体系, 并据此调整和拓宽“作物栽培学”、“耕作学”、“作物遗传育种学”等农学分支学科的研究领域; 建立以“农业生态系统管理”为核心的新农学应用体系, 以融合现代生物工程、生态工程、信息工程和材料工程技术; 也意味着我国“古代”演绎论和西方“近代”归纳论携手为实现“现代”可持续农业(低碳农业)提供一条可行的途径。     

农业生态系统安全性预警与预警系统的建立

分析农业生态系统面临的威胁,提出农业生态系统进行安全性预警必要性,探讨了预警指标、模型和预警类型的选择和及农业生态预警系统建立等研究状况。预警指标的选择主要考虑受人类直接或间接影响后而容易发生退化的因子,主要有土壤肥力质量指标和土壤环境质量指标等;模型在生态安全预警研究中具有预测、解释和推断功能,在不同预警指标中将会采用不同的模型;预警的类型包括对农业生态系统恶化的程度和状态,趋势,速度等预警;WebGIS技术的运用为建立包括不同尺度和时间的预警,单项因子预警信息、子系统预警信息和系统总体预警提供了有力的技术支撑。     

河北省中南部农业环境承载力研究

以环境承载力理论为基础,建立了河北省中南部5地区的农业环境承载力指标体系,并用综合加权的方法进行评价分析,与理想指数和警戒指数进行比较.对区域的生态因素、抗灾能力和农用化学物质施用强度进行定量分析,以表征该区可持续发展的能力.     

我国农业生态问题的成因与对策

阐述农业生态危机的成因和我国目前主要的农业生态问题,提出解决农业生态问题的基本对策。     

黄塔小流域农业生态系统景观特征探析

应用GIS、RS和GPS现代技术研究了黄塔小流域农业生态系统景观特征;并从地形因素、基岩和母质、人类活动方面分析其对黄塔小流域景观生态系统的影响。     

Raising organic: An agro-ecological assessment of grower practices in California

As the organic food sector has grownand changed to become more mainstream, large-scaleconventional growers have entered into organicproduction. While it is increasingly clear that notall organic farms are self-sufficient small scaleunits that practice poly-cultural agronomy and sell inlocal marketing venues, there still exists apresumption that there are clear lines between thesmall scale ``movement' farmers who followagro-ecological agronomic ideals and the relativelylarger and partly conventional newcomers who do not.This paper addresses a specific empirical issue, whichis the extent to which California organic farmerspractice the techniques of ecological farming. Itillustrates that while there are some distinctdifferences in practices between larger and/orpart-conventional (i.e., mixed) growers and smallerand/or all-organic growers, it also shows that inalmost all cases, practices fall quite short ofagro-ecological ideals. By examining in more depth howgrowers follow particular agro-ecological principles,the paper also demonstrates that key variations arerelated to variables separate from scale. Some ofthese variables are geographic, ranging frombiophysical and climatic opportunities andconstraints, to regional norms and institutionalsupport. Mostly, however, variation is related to cropspecificities and the availability of efficacioustechnologies to deal with crop-specific problems. Thisso-called technology barrier crucially depends on howorganic is defined, and thus suggests the importanceof organic rules and regulations in shaping thepractices of organic production.     

农业生态系统安全性预警与预警系统的建立

分析农业生态系统面临的威胁，提出农业生态系统进行安全性预警必要性，探讨了预警指标、模型和预警类型的选择和及农业生态预警系统建立等研究状况。预警指标的选择主要考虑受人类直接或间接影响后而容易发生退化的因子,主要有土壤肥力质量指标和土壤环境质量指标等; 模型在生态安全预警研究中具有预测、解释和推断功能，在不同预警指标中将会采用不同的模型；预警的类型包括对农业生态系统恶化的程度和状态，趋势，速度等预警；WebGIS技术的运用为建立包括不同尺度和时间的预警，单项因子预警信息、子系统预警信息和系统总体预警提供了有力的技术支撑。     

用生态学思维重构传统农学学科: 以农业生态系统管理作为核心应用科目

传统农学体系源于近代实验科学浪潮,并在工业革命巨大成就的推动下不断细分,失去对农业生态系统的整体把握。导致人类重新面临粮食安全(农业生态系统破坏引发的生产力衰退)和食品安全(农业环境破坏导致食物污染物残留)的双重危机。在我国,传统农学不论作为学科还是专业都属于生态系统以下的生物组织层次,是现代化石农业带来的生产和环境问题的根源。因此,农学学科及其专业教育体系的再构极为紧迫。作者提出以农业生态学为核心理论科目,以农业生态系统管理为核心应用科目而重构传统农学学科和教育体系。本文重点探讨了农业生态系统管理的基本框架和技术选择,并深入讨论了农业生态系统管理科目的内涵、外延及其发展前景。