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51.
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隐性知识是图书馆的宝贵资源.本文在解析隐性知识涵义和特点的基础上,阐述了图书馆隐性知识的作用,分析了图书馆隐性知识管理存在的障碍,提出了图书馆隐性知识挖掘的基本策略. 相似文献
53.
结合中国社会的实际情况,电子商务作为知识密集型服务,其发展之制约因素分为外部和内部两类,本文深入剖析电子商务发展中国内环境、电子商务业务中个人消费者、传统企业以及电子商务企业存在的知识管理方面的弊端,以引发相关部门、企业及个人的思考. 相似文献
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M. De Vos L. Che V. Huygelen S. Willemen J. Michiels S. Van Cruchten C. Van Ginneken 《Journal of animal physiology and animal nutrition》2014,98(4):609-619
Selection for hyperprolific sows, as a means of increasing litter size and profit, has resulted in an increased number of low‐birthweight (LBW) piglets. These LBW piglets might suffer from increased morbidity and mortality during the early neonatal period. In addition, they show reduced growth performance, meat and carcass quality, which leads to an important economic loss for the farmer in the post‐natal period. Therefore, nutritional interventions can be undertaken to prevent and rear LBW piglets. In the first part of this review, the preventive strategies at the sow level will be discussed. Approaches in preventing LBW piglets are to optimize the intrauterine environment via supplementing the sow during gestation. In the second part of this review, the interventions at the piglet level will be described. To increase the survival and growth rates of LBW piglets, one must focus on ensuring adequate colostrum and milk intake. Interventions include supplementing piglets, split nursing, split weaning and cross‐fostering. Additional interventions increasing the probability of optimal post‐natal food intake will be discussed. 相似文献
56.
草地土壤肥力及其营养管理的必要性 总被引:3,自引:0,他引:3
介绍了草地土壤肥力的来源,土壤基本养分对草地生产的作用,草地植物与动物对养分的需求量及缺乏症状,说明了加强草地营养管理以及维持草地生态系统营养平衡的重要性,指出增强对土壤肥力和营养管理是提高草地生产能力、保证草地生态系统平衡、保障草地可持续利用的关键技术措施。 相似文献
57.
Élvis da Silva Alves Lineu Neiva Rodrigues Fernanda Laurinda Valadares Ferreira 《Journal of Agronomy and Crop Science》2023,209(1):176-187
Soil evaporation constitutes a major pathway of water loss in agriculture. Understanding its dynamics in the face of drying and soil cover is fundamental to improve both simulation models and the sustainability of production systems. Thus, the objective of this study was to estimate soil evaporation as a function of drying and percentage of soil cover. Three experiments were carried out in three different periods. In each of the periods, in parallel and in an adjacent area, an experiment was carried out to evaluate the influence of weighing micro-lysimeter (ML) height on the estimation of direct soil evaporation. The experiments were installed with a completely randomized design. For the experiments that measured evaporation as a function of cover, the treatments consisted of six different percentages of cover of the internal area of the ML (0%, 10%, 25%, 50%, 75% and 100%), with four replicates, using artificial plants to cover the soil. The experiments that estimated evaporation as a function of ML height were conducted with eight repetitions and three different ML heights (100, 200 and 300 mm). It was observed that the accumulated evaporation up to 25 days after wetting was 52% and 53% lower in micro-lysimeters with 100 mm height, compared to those with 200 and 300 mm height, respectively, for all experiments. The new model developed to calculate soil evaporation as a function of the days after wetting and percentage of soil cover showed excellent performance (NSE > 0.95). 相似文献
58.
The quality of service provided by the provincial Irrigation Department (DGI) to the Water Users Associations (UA), and subsequently by the UA's to the related water users, is based on the provincial water law. The intended volume of water being delivered per considered period further depends on the water availability and on the (crop irrigation) water requirements. The Service Level (SL) compares the intended water supply with the water supply that would be required to supply the entire irrigable area with sufficient water. As soon as the intended water delivery pattern is set, the measured actual delivery can be assessed against the intention. Several performance indicators are used in this context. Based on the assessment of the Water Delivery Performance Ratio and the Overall Consumed Ratio recommendations are made on changes which can be made to improve water use and reduce problems of waterlogging. 相似文献
59.
Yujiao DONG Fanwen ZENG Jiang YUAN Guangbin ZHANG Yuanxue CHEN Xuejun LIU Padilla HILARIO Tusheng REN Shihua LU 《土壤圈》2020,30(6):863-873
The hilly area of Southwest China is a typical rice production area which is limited by seasonal droughts and low temperature in the early rice growth period. A field experiment was conducted on three typical paddy fields (low-lying paddy field, medium-elevation paddy field, and upland paddy field) in this region. Nitrogen (N) treatment (180 kg N ha-1 year-1) was compared to a control treatment (0 kg N ha-1 year-1) to evaluate the effects of integrated rice management (IRM) on rice growth, grain yield, and N utilization. Integrated rice management integrated raised beds containing plastic mulch, furrow irrigation, and triangular transplanting. In comparison to traditional rice management (TRM), IRM promoted rice tiller development, with 7-13 more tillers per cluster at the maximum tillering stage and 1-6 more tillers per cluster at the end of tillering stage. Integrated rice management significantly increased the rice aboveground biomass by 34.4%-109.0% in different growth periods and the aboveground N uptake by 25.3%-159.0%. Number of productive tillers significantly increased by 33.0%, resulting in a 33.0% increase in grain yield and 8.0% improvement of N use efficiency (NUE). Grain yields were significantly increased in all three paddy fields assessed, with IRM being the most important factor for grain yield and productive tiller development. Effects of paddy field type and N level on N uptake by aboveground plants were reflected in the rice reproductive growth period, with the effects of IRM more striking due to the dry climate conditions. In conclusion, IRM simultaneously improved rice yield and NUE, presenting a valuable rice management technique in the paddy fields assessed. 相似文献
60.
Gunter Wriedt Marijn van der Velde Alberto Aloe Fayçal Bouraoui 《Agricultural Water Management》2009,96(5):771-789
We present a pan-European irrigation map based on regional European statistics, a European land use map and a global irrigation map. The map provides spatial information on the distribution of irrigated areas per crop type which allows determining irrigated areas at the level of spatial modelling units. The map is a requirement for a European scale assessment of the impacts of irrigated agriculture on water resources based on spatially distributed modelling of crop growth and water balance. The irrigation map was compiled in a two step procedure. First, irrigated areas were distributed to potentially irrigated crops at a regional level (European statistical regions NUTS3), combining Farm Structure Survey (FSS) data on irrigated area, crop-specific irrigated area for crops whenever available, and total crop area. Second, crop-specific irrigated area was distributed within each statistical region based on the crop distribution given in our land use map. A global map of irrigated areas with a 5′ resolution was used to further constrain the distribution within each NUTS3 based on the density of irrigated areas. The constrained distribution of irrigated areas as taken from statistics to a high resolution dataset enables us to estimate irrigated areas for various spatial entities, including administrative, natural and artificial units, providing a reasonable input scenario for large-scale distributed modelling applications. The dataset bridges a gap between global datasets and detailed regional data on the distribution of irrigated areas and provides information for various assessments and modelling applications. 相似文献