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991.
Abstract. Sustaining soil fertility under agricultural intensification and expansion onto marginal lands is a significant challenge in the Nepalese Middle Mountains. In a detailed watershed study it was shown that the overall soil fertility is poor, forest soils display the poorest conditions as a result of biomass removal, and sustaining agriculture is questionable due to the transformation from traditional to multiple cropping systems. Parent material is a significant factor influencing low phosphorus status while insufficient inputs create deficiencies in total carbon, nitrogen and bases. A nutrient budget model was developed to assess inputs, redistribution and losses relative to soil fertility. Yield, input and management data obtained from farm interviews, and soil analysis data were used in the calculation of nutrient budgets. Results from modelling indicate declining soil fertility under rainfed agriculture, forest and rangelands, and marginal conditions under irrigated agriculture subject to intensive cultivation. Nutrient deficits were relatively low for irrigated rice-wheat systems, which benefit from nutrient inputs via sediments and irrigation waters, but the introduction of triple cropping showed greater deficits. Nutrient balances were most critical under rainfed maize production where 94% of the farms were in deficit. Current shortages of organic matter make elimination of nutrient deficits problematic but improvement of composting, biological N-fixation and fertilizer efficiency and reducing erosion were found to be potential options. 相似文献
992.
浅谈我院图书馆期刊的管理 总被引:1,自引:0,他引:1
陶明玉 《农业图书情报学刊》2008,20(9)
分析了漳州城市职业学院图书馆期刊管理存在的问题,并提出了建立合理的期刊管理模式,准确定位与形成特色,充分开发期刊资源,加强期刊管理人员队伍的业务素质建设等建议. 相似文献
993.
南京奶业 (集团 )公司扭亏为盈 ,并取得骄人业绩的启示是 :企业正确定位 ;实行企业 (集团 )经营的公司型运作方式 ;实行低成本扩张和品牌战略 ;引进国外先进技术设备 ,走与国际奶业接轨的发展道路 ;改善产业结构 ,实行多元化经营。 相似文献
994.
Fengshui forests, very popular among the ethnic minorities in the rural areas in Guizhou Province of China, have spiritual symbolic meanings and are strictly managed. This paper examines the nature, history, local perceptions and management of fengshui forests in two Buyi villages in the Guizhou Province. With their long history, the fengshui forests are perceived to provide good wishes, security, unity, fortune, wealth and health to the local communities. Fengshui forests act as a form of “community based nature reserve” which maintains the health of natural forests, especially hydrological features and prevention of soil erosion. Cunguimingyue (Folk Regulation and Customs) is the primary local normative mechanism that maintains the fengshui forests in a good condition. The lessons learnt from local fengshui forest management needs to be incorporated in for contemporary China's forest policy formulation as these forests play an important role in rural livelihoods. 相似文献
995.
996.
试验应用现代体外循环技术,实施完全心肺转流的低温体外循环,首次在我国兽医临床建立了28只犬低温体外循环实验模型。探索适用于小动物心脏直视手术的体外循环手术操作、心脏停搏与复苏、体外循环灌注管理的技术方法。研究表明,选择右侧第4肋间进胸,从右心房施行前后腔静脉插管及升主动脉根部置供血管是简便易行的手术通路。采用部分晶体液与全血作预冲液,体外转流维持中度血液稀释(平均2368±327%),最低温度控制26℃左右(平均2614±077℃),血流复温至36℃左右(平均3597±068)开放升主动脉,转流中灌注压维持50~90mmHg(平均72±13mmHg),灌注流量80~100mL·kg-1·min范围,是低温体外循环下开展犬心内直视手术成功的基本保障。采用冷晶与冷温血停搏液不同灌注。结果显示,冷温血停搏液联合灌注组心脏自动复跳率最高,并且复跳迅速,心搏有力,正性肌力药应用剂量小,复跳后辅助循环时间明显低于冷晶停搏液灌注组(P<005)。 相似文献
997.
998.
供应商管理库存(VMI)是一种在用户和供应商之间的合作性策略。通过策略选择、实施目标分析及协议制定三个角度分析研究,设计实施的南方液压公司VMI模式全程方案,可有效提升南方液压公司的库存管理水平。 相似文献
999.
We investigated the tolerance to weed harrowing of four spring barley varieties and examined the possible interactions between varietal weed suppressive ability and two nutrient levels. Tolerance was defined as the combined effect of crop resistance (ability to resist soil covering) and crop recovery (the ability to recover in terms of yield). The weed harrowing strategy was a combination of one pre‐ and one post‐emergence weed harrowing. In terms of yield, the four varieties responded significantly differently to weed harrowing and the response depended on nutrient level. At the lower nutrient level, weed harrowing caused an increase in yield of 4.4 hkg ha−1 for a strong competitor (cv. Otira), while there was no effect on yield at the higher nutrient level. For a weaker competitor (cv. Brazil), weed harrowing caused no change in yield at the lower nutrient level, whereas yield decreased by 6.0 hkg ha−1 at the higher nutrient level. There were marked differences between the weed suppressive ability of the four varieties when not harrowed, with less pronounced but significant differences when harrowed. Weed harrowing did not change the weed suppressive ability of a variety. Varieties that are tall at post‐emergence harrowing and have increased density after pre‐emergence harrowing, are the ones that benefit most from weed harrowing. 相似文献
1000.
林权改革对集体林可持续经营的影响——以辽宁丹东为例 总被引:1,自引:1,他引:0
在创建集体林可持续经营评价体系基础上,采取定性要素赋值、数据标准化、层次分析法求权重等方法,计算出综合评价指标指数。再根据收集的数据,通过改革前后均值的显著性分析以及改革后综合评价指数、相关要素变化趋势分析,得出如下结果和结论:①林权改革对集体林可持续经营具有明显的促进作用,集体林可持续经营指数改革后比改革前上升了0.0454;②林权改革对集体林生态、经济、社会三个子系统可持续的影响程度有明显的差异,对集体林经济可持续影响最为显著,对集体林社会可持续的影响为其次,对集体林生态可持续的影响最小;③林权改革对集体林可持续经营的促进作用,随着时间的推移,越来越明显。 相似文献