Identifying gender aspects of new irrigation management policies     

Margreet Z. Zwarteveen 《Agriculture and Human Values》1998,15(4):301-312

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农户稀缺感知、超采认知对地下水灌溉用水效率的影响——基于河北地下水超采区457个农户调研数据     

刘维哲  王西琴 《中国生态农业学报》2021,29(5):929-936

华北地区由地下水超采造成的环境问题日益严重,农业作为主要用水部门,亟须提高灌溉用水效率,减少水资源浪费。本文基于2019年对河北地区457户使用地下水进行灌溉的农户调查数据,采用随机前沿模型对灌溉用水效率进行测算,进一步在参照相关研究基础上重新构建农户水资源稀缺性感知和地下水超采认知测度的指标体系,在控制个人和家庭特征、生产特征基础上,实证分析农户稀缺感知和超采认知对灌溉用水效率的影响。研究结果显示:农户平均灌溉用水效率值为0.59,主要分布区间为0.40～0.80,具有较大提升空间;稀缺感知中水量感知、水位感知和稀缺预期对农户用水效率具有显著正向影响,超采认知中地下水超采危害认知和压采环保认知对用水效率提升具有促进作用;务农年限和受教育程度同用水效率正相关,相较于自有土地,流转土地具有更高的用水效率,耕地细碎化和灌溉设施距离过远则显著降低用水效率。因此,大力提升农户相关认知水平、推进土地流转和完善设施建设等措施将有助于提高河北地区灌溉用水效率。  相似文献   

关中-天水经济区粮食生产的生态成本研究     

李建丽  李晶 《水土保持通报》2013,(4):85-89

以关中-天水经济区各市区为研究对象,依据水土流失的相关理论,运用生态学和经济学思想并结合遥感影像进行估算,采用主成分方法对粮食生产过程的生态成本和直接生产成本进行了研究。研究结果表明,关中天水地区粮食生产的生态成本最高已经达到0.8元/kg,直接生产成本约为1.45元/kg,总成本约为2.25元/kg,已经接近粮食的出售价格2.56元/kg。水土流失对于关中-天水地区粮食的生态成本具有重要影响,种子费用和机械费用过高是制约粮食生产成本过高的关键因素。高成本低收益的情况会极大地削减农民种植粮食的积极性。因此,在今后的种植过程中,应当充分利用农业资源,加大科技投入,扩大种植规模,降低生产单位粮食的生态成本。  相似文献   

施钾对甜叶菊糖苷跃变期生理指标和产量品质的影响          下载免费PDF全文

张靖  谢忠清  贾蕊鸿  刘强  王祎  赵玺  张亚萍 《寒旱农业科学》2023,(2):148-154

为提高河西绿洲灌区甜叶菊产量和品质,提升该区甜叶菊市场竞争力。以谱星6号为试验材料,比较了不同施钾水平(K2O 0、60、90、120、150 kg/hm2)对甜叶菊糖苷跃变期生理指标以及产量品质的影响。结果表明,不同施钾处理下,甜叶菊整个糖苷跃变期叶片各生理指标含量达到峰值的时间有所不同,叶片SOD活力、含钾量均在现蕾前5 d达到最高,可溶性蛋白、SPAD值、含氮磷量、总苷含量以及叶片干物质量在现蕾初期达到最高,POD活力、可溶性糖含量在现蕾后5 d达到最高,以上各指标均以施用K2O 120 kg/hm2处理表现最佳。其中总苷含量最高,达128.4 g/kg,较不施钾肥增加14.19%;产量也最高,达7 007.64 kg/hm2,较不施钾肥增加57.24%;净收益达5.26万元/hm2,比不施钾多3.40万元/hm2。通过甜叶菊叶片理化指标与产量品质的相关性分析,以上各生理指标与产量品质均呈现显著或者极显著的正相关关系。在当地甜叶菊生产中施用K2O 120 kg/hm2,且在现蕾初期采摘叶片可获得较好收益。  相似文献   

多作物种植结构和灌溉水量优化模型及算法研究     

欧定华  夏建国  张莉  赵智 《中国生态农业学报》2013,21(12):1515-1525

在综合考虑作物灌溉水量、种植面积、水分生产函数、产量反应系数、水分敏感指数等因素基础上, 以实现灌区作物总产量最大为目标函数, 建立了多作物种植结构和灌溉水量优化分解协调模型, 设计了改进实码遗传算法与分解协调迭代算法相结合的模型求解算法, 并利用中国科学院盐亭紫色土农业生态试验站多年试验数据, 运用上述模型和算法对玉米、小麦联合种植的种植结构、灌溉水量以及玉米、小麦灌溉制度进行了优化计算。结果表明: 产量反应系数大的作物分配的灌溉水量和种植面积大, 且随灌溉水量增加其增产速度越快; 当作物某些生育阶段灌水前的潜在腾发量与可供利用水量的差值相差不大时, 水分敏感指数大的作物生育阶段获得灌溉水量较多, 反之, 即使水分敏感指数大的作物生育阶段也有可能分配不到更多的灌溉水量。这一结果与作物产量反应系数的几何意识、边际效益递减规律等理论以及节水增收初衷相符合, 充分说明模型在实现灌区有限水资源在多作物间和各作物生育阶段优化分配的同时, 实现了灌区多作物种植结构优化, 具有较强推广价值。改进实码遗传算法克服了传统实码遗传算法计算精度低、易早熟、求解结果不能严格满足等式约束等缺陷, 能够搜索到严格满足约束条件的模型最优解, 表明该改进实码遗传算法在解决这类包含等式和不等式约束的最优化问题上具有一定应用价值。分解协调迭代算法能使模型在允许迭代误差范围内收敛, 能够获得使模型整体效果较为理想的最优解, 表明分解协调迭代算法在求解复杂大系统优化问题上具有很好的应用前景。  相似文献   

Uncertainties and values in European aquaculture: communication, management and policy issues in times of “changing public perceptions”     

M. Kaiser  S.M. Stead 《Aquaculture International》2002,10(6):469-490

The hypothesis that forms the basis of debatefor this paper is that in order for theEuropean aquaculture industry to achieve itsgrowth potential in terms of consumer andpublic acceptance then it must establishparticipatory fora that adopt open andtransparent discussions on the current andfuture issues surrounding sustainabledevelopment. Fundamental to this goal iseffective communication of easy-to-digestinformation. Also, interested parties should begiven the option to be involved in thedevelopment of recommendations.This paper recommends among others the followingmeasures:Full adoption of the Integrated Coastal Zone Management Strategy, based on a multidisciplinary framework and extended peer-reviews;More openness and debate, including the broadening of perspectives, regarding the issues of sustainability and food safety;The wider use of various participatory mechanisms on different levels, e.g. through national consensus conferences.  相似文献   

Aquaculture and its role in Integrated Coastal Zone Management     

S.M. Stead  G. Burnell  P. Goulletquer 《Aquaculture International》2002,10(6):447-468

The workshop, Aquaculture and its role inIntegrated Coastal Zone Management held inOstende, Belgium in April 2001, aimed to provideinformation to help develop recommendations forwise management of aquaculture in coastal andmarine environments. This paper focuses on thetwo main objectives of the workshop, 1) to aidthe development of stronger interdisciplinarycommunication between the natural and socialsciences and to improve the utility ofavailable scientific information and knowledge;and 2) to promote new perspectives on thesustainable use of coastal areas and naturalresources. The paper also summarizes thedebates following each of the three workshopthematic sessions: aquaculture and ICZM;socio-economic and political dimensions;developing sustainable production systems; andidentifies the key recommendations that may beapplied to the formulation of policy onintegrated aquaculture management in coastaland marine environments.  相似文献   

Differing body size between the autumn and the winter–spring cohorts of neon flying squid (Ommastrephes bartramii) related to the oceanographic regime in the North Pacific: a hypothesis     

Taro Ichii  Kedarnath Mahapatra  Mitsuo Sakai  Denzo Inagake  Yoshihiro Okada 《Fisheries Oceanography》2004,13(5):295-309

The neon flying squid (Ommastrephes bartramii), which is the target of an important North Pacific fishery, is comprised of an autumn and winter–spring cohort. During summer, there is a clear separation of mantle length (ML) between the autumn (ML range: 38–46 cm) and the winter–spring cohorts (ML range: 16–28 cm) despite their apparently contiguous hatching periods. We examined oceanic conditions associated with spawning/nursery and northward migration habitats of the two different‐sized cohorts. The seasonal meridional movement of the sea surface temperature (SST) range at which spawning is thought to occur (21–25°C) indicates that the spawning ground occurs farther north during autumn (28–34°N) than winter–spring (20–28°N). The autumn spawning ground coincides with the Subtropical Frontal Zone (STFZ), characterized by enhanced productivity in winter because of its close proximity to the Transition Zone Chlorophyll Front (TZCF), which move south to the STFZ from the Subarctic Boundary. Hence this area is thought to become a food‐rich nursery ground in winter. The winter–spring spawning ground, on the other hand, coincides with the Subtropical Domain, which is less productive throughout the year. Furthermore, as the TZCF and SST front migrate northward in spring and summer, the autumn cohort has the advantage of being in the SST front and productive area north of the chlorophyll front, whereas the winter–spring cohort remains to the south in a less productive area. Thus, the autumn cohort can utilize a food‐rich habitat from winter through summer, which, we hypothesize, causes its members to grow larger than those in the winter–spring cohort in summer.  相似文献   

温室移动喷灌机关键部位研究进展     

高星星  张俊峰  曾凡琮  刘海  庞雄斌  周朝 《安徽农业科学》2014,(15):4934-4937

近年来温室产业发展迅速,温室内移动喷灌机市场随之扩大。对国内外温室内自走式移动喷灌机的轨道结构形式、喷灌机供水方式、移跨装置等关键部位的研究状况进行了表述,对各种结构形式的特点进行了比较,总结了目前温室内移动喷灌机的发展趋势,为后续开展相关研究工作提供参考。  相似文献   

洞庭湖生态经济区乡村人—地—业耦合协调度时空分异     

刘畅  曾毅  蔡雪琪  赵旷纬 《农学学报》2022,12(5):77-84

乡村是由人口、土地、产业等核心要素有机组合而形成的复杂巨系统。为了探究乡村人—地—业之间的互动关系,本研究基于洞庭湖生态经济区县域面板数据,选取“人口—土地—产业”乡村发展三要素,通过构建耦合协调度评价指标体系,运用耦合协调度模型深度刻画洞庭湖生态经济区乡村人—地—业耦合协调发展的空间分异特征。结果表明,洞庭湖生态经济区乡村人口、土地、产业各子系统发展水平总体呈现差异较大、不均衡的特点;大部分县域乡村人—地—业发展处于协调耦合阶段,形成以洞庭湖生态经济区东部岳阳市发达区域为核心并以圈层的形式逐渐向外扩散的空间格局,呈整体水平逐年上升的趋势;耦合协调度呈现勉强协调、初级协调、中级协调和良好协调4个类型,乡村人—地—业耦合协调度在整体上呈现出由初级协调向中度协调发展的逐年上升特征。  相似文献