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规模化畜禽养殖场粪便养分数据空间化表征方法 总被引:1,自引:0,他引:1
针对目前进行规模化养殖场粪便养分分配,主要以行政单元为单位将规模化养殖统计数据总量按农田面积简单分配,认为所有的农用地之间都是均匀的,而忽视了农用地块之间存在差异性的问题,利用GIS空间分析技术,结合农用地地块间的空间差异性以及规模养殖畜禽粪便作为肥料施用的特殊性,构建了规模化畜禽养殖统计数据空间化算法,并结合农用地最大养分负荷,实现从规模畜禽养殖统计数据到区域畜禽粪便养分供给的空间化转换,最后以福州市闽侯县上街镇为例进行了算法的实际应用。结果表明研究区农用地氮、磷最大养分负荷分别为169.994 kg/hm2和34.973 kg/hm2。无论是畜禽养殖粪便氮养分还是磷养分,都未超过算法设定的阈值。 相似文献
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区域专业化是现代农业发展的方向,比较优势是专业化的基础.通过对西部地区5种主要农产品在1990~2003年的比较优势和专业化程度的实证分析,表明西部地区主要农产品的专业化在比较优势的基础上逐步形成,提出了完善政府职能做好农业区域规划和在典型示范的基础上逐步引导农民走专业化生产的道路等建议. 相似文献
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Population-level impacts of insect herbivory on rare and endangered plants are poorly understood, being frequently suggested but seldom quantified. We compiled 37 studies from the primary literature encompassing 35 rare plant species and at least 63 insect herbivore species, and assessed patterns in the effects of insect herbivores on rare plant populations and vital rates. Only three studies directly quantified effects of insect herbivory on population size or growth rate, with the vast majority instead extrapolating from vital rates to population size. Few studies (eight) studied herbivory experimentally, and feeding guilds other than seed predators have been relatively neglected. Estimates of population-level impacts vary extremely widely, but for many rare plants insect herbivores cause major reductions in survivorship or fecundity or can even drive local extinctions. Four studies documented positive (plant-) density dependence in insect attack, suggesting that herbivores may have a stabilizing influence on plant populations and thus may play a role in regulating rare plant population size. Most reported herbivores of rare plants are oligophagous or polyphagous, but monophagous herbivores of rare plants do exist, and there was no detectable difference in impact among specialization classes. Attack on rare plants by escaped biocontrol agents can sometimes have significant population-level effects, but such cases appear uncommon. Because insect herbivory can strongly suppress rare plant populations or vital rates, we need to know much more about what ecological and evolutionary factors determine the population-level impacts of insect herbivores. We suggest several ways in which the results of such research could inform conservation practices for rare plant species – for example, the possibility of different management regimes for plants under attack by monophagous, oligophagous, and polyphagous herbivores. 相似文献
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《Journal of Crop Improvement》2013,27(1-2):405-436
SUMMARY Specialization is the foundation of contemporary agriculture, yet until the early decades of the 20th century, enterprise diversity was the norm. As agriculture has become more specialized in the intervening years, yields have increased dramatically, but so too have a range of economic, environmental, and health problems. This contribution presents evidence that specialization is an ecologically dysfunctional design for food production, a thesis which is supported by the predominance of problem-solving research in the contemporary literature. As demonstrated by Louis Bromfield in the 1940s and by organic and sustainable farmers today, the strategic integration of crops and livestock/ forage enterprises avoids many of the problems of specialization, while also capturing economic and ecological synergies denied to specialist producers. In addition to providing human foodstuffs, forage-based livestock production also offers a range of novel opportunities to channel natural processes to the service of humanity, from carbon sequestration and site remediation to non-chemical vegetation management. 相似文献
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新审计准则的颁布.现代风险导向审计模式的确立,都将促进我国会计师事务所行业专门化的发展.从审计服务供求两方进行经验分析,以验证中国审计市场是否需要专门化经营.结果显示,行业专门化水平的提高能够给事务所带来审计收费溢价,同时也能给投资者提供高质量的审计服务.另外,研究还发现,在我国审计市场,事务所行业专门化经营具有"非常快"(very fast)的学习效应,能显著提高审计质量,说明我们应当大力、广泛推广事务所的专门化经营,这也为我国事务所如何做大做强提供了有益的途径. 相似文献
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2009年,全国农民专业合作社蓬勃发展,呈现出数量增长快、带动农户多、产业分布广、服务内容宽等特征。2010年,农民专业合作社发展内涵不断丰富,规范化程度不断提高,“农超对接”步伐加快。创意农业产业将成为农民专业合作社的主战场。 相似文献
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从分析机关图书馆现状及特点入手,提出加强机关图书馆专业化建设是提高馆员素质,提升服务水平的有效途径,并以农业部图书馆为例,对机关图书馆如何围绕机关中心工作提供文献信息保障进行了探讨。 相似文献
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发展专业化农业小城镇是缩小城乡发展差距和解决城乡二元经济结构的有效途径,也是形成农业产业集聚的重要环节.长期以来,学界对专业化工业小城镇发展给予了大量的关注,而极少关注专业化农业小域镇的发展、首先分析了山东寿光专业化农业小镇的形成机理,接着总结了影响该地区的专业化农业小城镇形成的因素,最后得出了结论、 相似文献
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玉蜀黍赤霉致病力分化的研究 总被引:4,自引:0,他引:4
1984年从全国三个小麦赤霉病流行频率不同的地区采(征)集得77个病穗标样,经分离、鉴定,选取其中49个禾谷镰刀菌菌株(江苏省20个,黑龙江省19个,西北地区10个),在10个抗、感程度不同的冬小麦品种上进行致病力测定。结果表明:(1)各个地区内菌株间的致病力均存在显著差异,说明每个地区内的菌株均存在致病力分化;(2)茵株与品种间互作效应明显,但不宜划分为生理小种;(3)三个地区菌株的平均致病力以病害经常流行的江苏省菌株最强,少流行或不流行的黑龙江省和西北地区菌株为弱;(4)品种间抗病性存在显著差异。 相似文献