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1.
针对龟石灌区农业用水效率低下、浪费严重等问题,提出了节水措施,分析了节水改造的潜力与效益。灌区水资源优化配置与合理利用,提高灌溉水利用率和水分生产率,富余水量用于城市供水及发电,提高单位水量的价值不仅是必要的,而且是灌区发展的必由之路。  相似文献   
2.
A field experiment was conducted to find out the critical physiological stages of irrigation schedules inducing better growth, physiological efficiency and seed yield potential of berseem ( Trifolium alexandrinum L., Var. S-99-1). For this purpose eight irrigation treatments were made comprised of four treatments of three irrigation (W1, W2, W3 and W4), three treatments of four irrigation (W5, W7 and W8) and one treatment of five irrigation (W6) at various physiological stages i. e. regeneration, flower initiation, full bloom, seed initiation and advance seed development stage.
Thus based on the experimental results the physiological role of watering in berseem seed production could be discussed as:
With-holding of irrigation either at regeneration or at full bloom stage developed potential water stress in plants as indicated by high proline content of irrigation treatments — W4, W1 and W7; and further brought out disturbance on the formation of carotene, synthesis of water soluble sugar and translocation of sugar towards reproductive organs during grain development stage. These stresses adversely affected the plant growth and flowering behaviour. The irrigation at seed initiation stage increased the seed yield. Continuous irrigation did not appear to be useful. Thus it can be concluded that irrigation at three critical physiological stages i. e. regeneration, full bloom and seed initiation was found to be essential for obtaining potential seed yield of berseem.  相似文献   
3.
Abstract. The repeated application of pig slurry to agricultural soils may result in an accumulation of salts and a risk of aquifer pollution due to nitrate leaching and salinization. Under Mediterranean conditions, a field experiment on a sandy loam soil (Typic Xerofluvent) was performed with maize (Zea mays) in 1998, 1999 and 2001 to study the effects of applying optimal (P1) and excessive rates (P3) of pig slurry on soil salinization, nitrate leaching and groundwater pollution. The rate of pig slurry was established considering the optimal N rate for maize in this soil (170, 162 and 176 kg N ha?1 for 1998, 1999 and 2001, respectively). Pig slurry treatments were compared to an optimal N rate supplied as urea (U) and a control treatment without N fertilizer (P0). The composition of the slurries showed great variability between years. Mean NO3? leaching losses from 1998 to 2001 were 329, 215, 173 and 78 kg N ha?1 for P3, P1, U and P0 treatments, respectively. The amount of total dissolved salts (TDS) added to the soil in slurry application between 1998 and 2001 was 2019 kg TDS ha?1 for the P1 treatment and 6058 kg TDS ha?1 for the P3 treatment. As a consequence, the electrical conductivity (EC) of the slurry‐treated soils was greater than that of the control soil. The EC correlated significantly with the sodium concentration of the soil solution. Over the entire experimental period, 2653, 2202 and 2110 kg Na ha?1 entered the aquifer from the P3, P1 and P0 treatments, respectively. The P3 treatment did not significantly increase grain production in 1999 and 2001 compared with that achieved with the optimal N rate treatment (P1). This behaviour shows the importance of establishing application guidelines for pig slurry that will reduce the risk of soil and groundwater pollution.  相似文献   
4.
本文提供了三因素随机区组试验结果统计分析的 BASIC 程序,可进行方差分析、计算标准差、判定差异显著性。该程序输入输出方式简单,容易掌握。  相似文献   
5.
介绍并分析宁陕县城区及周边地区“8.29”惨遭洪水、泥石流袭击,生态环境遭到严重破坏的情况,提出了城区生态环境方面存在的问题,同时在规划设计方案中运用生态治理技术,以工程造林的方法,探求城区生态环境建设的新模式。  相似文献   
6.
本文对会计电算化发展中存在的一些问题提出了对策与建议,并针对财会工作的自身特点,从程序控制和制度控制两个方面阐述了电算化会计信息下的内部控制方法。  相似文献   
7.
施肥和灌溉对蔬菜品质影响的研究进展   总被引:5,自引:0,他引:5  
综述了蔬菜品质的内涵及施肥、灌溉对蔬菜品质影响的研究进展。综合前人研究结果可以看出,适量增加施肥量通常可改善蔬菜商品品质,并可提高蔬菜产品中蛋白质、游离氨基酸、有机酸等营养物质指标的含量,但过量施肥则常导致总糖、可溶性糖、抗坏血酸等营养成分含量的降低,并可导致卫生品质及风味品质的降低。合理灌溉可以有效提高蔬菜各种品质指标,但对于许多果菜类而言,适当控制浇水量则有利于营养品质的提高。通常情况下,施肥与灌溉对蔬菜产品品质的影响结果受土壤基础肥力、肥料种类及其配比、蔬菜种类、产品成熟度等因素的影响较大。  相似文献   
8.
节水灌溉对葡萄及葡萄酒质量的影响   总被引:7,自引:0,他引:7  
张振文  李华  宋长冰 《园艺学报》2002,29(6):515-518
 研究了不同灌溉方法对葡萄生长发育、浆果品质和葡萄酒质量的影响。结果表明, 节水灌溉显著改善了土壤结构, 增加了深层土壤的根系密度; 提高了果汁糖含量, 降低了酸含量和全盐含量, 改善了pH 值; 提高了葡萄酒的感官质量, 酒体丰满, 香气浓郁, 滋味更好; 年灌溉用水量3825 ~ 4800m3# hm-2, 比常规灌溉节水36%。  相似文献   
9.
With a 2 millions of tons production, France is the second country in the European Union to produce durum wheat. Durum wheat production requires high grain nitrogen concentration. Irrigation and nitrogen fertilization must be managed simultaneously to maximize grain yield and also avoid low protein concentration and environmental impacts. To help advisors and farmers to better manage together these two agricultural operations and to develop innovative managements, developing a biodecisional model is an interesting possibility. However, knowledge is still missing on how farmers already managed these operations and how these two operations are linked. We developed the conceptual model for the decision part of this computer model. We performed a survey of 28 farmers conducted over the five French production areas investigating a diversity of growing conditions to identify the set of possible constraints and farmers' decision rules. To analyze the survey, we first used a general inductive approach on individual cases and then built a conceptual model of the decision with a bottom-up approach. We identified four decision sequences for fertilization (N splitting, choice of N fertilizer, rate of application, fertilization triggering) and five for irrigation (irrigation period, anticipated number of irrigation cycles, irrigation cycles organization, irrigation triggering and irrigation cycle specificities). For each operation, the first three decision sequences refer to strategic decisions. The other decision sequences refer to tactical decisions. Coupling this model with a crop model could provide guidelines for managing durum wheat in the current climatic and economic changing context.  相似文献   
10.
草业科学专业本科生科研能力培养途径探索   总被引:1,自引:0,他引:1  
从草业科学专业本科生科研能力现状出发,结合学校实际,对本科生科研能力培养途径进行了探索,阐释了本科生科研能力培养的必要性,分析了本科生科研训练、本科生导师制、科研助理、自选试验探究学习和毕业论文实习对本科生科研能力培养的效果,并就存在问题提出了解决对策。旨在提升本科生科研能力,为培养草业科学专业高素质人才提供保障。  相似文献   
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