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61.
以甘肃省临夏州东乡族自治县和宁夏回族自治区西吉县的实地调查资料为基础,总结了西北地区东乡族、回族聚居县乡村庄空心化的特点,分析了"男工女耕"、"男耕女牧"状况下留守妇女从事农牧业生产经营的困境,研究了留守妇女参与农牧业合作社的路径。本研究结果对提高东乡族、回族留守妇女的组织化程度,解决留守妇女面临的生产经营困难,进而增加其家庭收入,维护西北民族地区的农村政治与社会稳定,促进生态文明建设,有理论参考和实际价值。 相似文献
62.
We up-scaled the APSIM simulation model of crop growth, water and nitrogen dynamics to interpret and respond to spatial and temporal variations in soil, season and crop performance and improve yield and decrease nitrate leaching. Grain yields, drainage below the maximum root depth and nitrate leaching are strongly governed by interaction of plant available soil water storage capacity (PAWC), seasonal rainfall and nitrogen supply in the water-limited Mediterranean-type environment of Western Australia (WA). APSIM simulates the interaction of these key system parameters and the robustness of its simulations has been rigorously tested with the results of several field experiments covering a range of soil types and seasonal conditions in WA. We used yield maps, soil and weather data for farms at two locations in WA to determine spatial and temporal patterns of grain yield, drainage below the maximum root depth and nitrate leaching under a range of weather, soil and nitrogen management scenarios. On one farm, we up-scaled APSIM simulations across the whole farm using local weather and fertiliser use data and the average PAWC values of soil type polygons. On a 70 ha field on another farm, we used a linear regression of apparent soil electrical conductivity (ECa) measured by EM38 against PAWC to transform an ECa map of the field into a high resolution (5 m grid) PAWC map. We then used regressions of simulated yields, drainage below the maximum root depth and nitrate leaching on PAWC to upscale the APSIM simulations for a range of weather and fertiliser management scenarios. This continuous mapping approach overcame the weakness of the soil polygons approach, which assumed uniformity in soil properties and processes within soil type polygons. It identified areas at greatest financial and environmental risks across the field, which required focused management and simulated their response to management interventions. Splitting nitrogen applications increased simulated wheat yields at all sites across the field and decreased nitrate leaching particularly where the water storage capacity of the soil was small. Low water storage capacity resulted in both low wheat yields and large leaching loss. Another management option to decrease leaching may be to grow perennial vegetation that uses more water and loses less by drainage.Paper from the 5th European Conference on Precision Agriculture (5ECPA), Uppsala, Sweden, 2005 相似文献
63.
通过引种造林,对J172柳等5个柳树良种进行了不同区域抗寒、抗风力对比试验,结果表明:J172柳、J194柳抗寒、抗风力强;J369柳和青冈柳次之;准葛尔柳根据其生长特性,在高寒阴湿地区抗性明显好于其它品系。 相似文献
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A computer‐based water budget technique was developed considering the land gradient [{vertical interval between two adjacent field bunds (levees)=20 cm} ÷ the distance between the bunds] and paddy field bunds (viz. 16, 18, 20, 22, 24 cm) in its formulation for computing daily runoff from coastal paddy areas in India. The inputs used in the water budget technique consist of limited meteorological data that are easily available in India. The water budget technique was validated with the modified curve number method and the measured data collected during 2001 in a coastal paddy area of Orissa (east coast of India close to Bay of Bengal), India and its superiority was found. In most of the cases (barring a few events of 16 cm and 18 cm paddy field bunds for the water budget technique), statistically both methods differed significantly from each other while generating daily runoff. The estimate of the surface drainage coefficient (the amount of excess surface runoff water to be drained from the crop field during a 24‐hour period) for a 5‐year return period was computed as 100 mm day−1 (taking the 22 cm paddy field bund) and 109 mm day−1 in case of the water budget technique and modified curve number method, respectively. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
66.
后备牛蛋白质营养需要研究进展 总被引：2，自引：0，他引：2
为培育优质泌乳奶牛,研究不同生理阶段后备牛日粮的最佳蛋白质水平。采用生长比较试验、消化代谢试验和屠宰试验研究蛋白质水平对后备牛的影响。结果表明,①0～2月龄哺乳期犊牛,代乳粉中粗蛋白水平22%为宜;②3～4月龄断奶犊牛,开食料中粗蛋白水平20%最佳;③8～10月龄后备母牛,在日粮消化能为13.17MJ/kg时,粗蛋白水平约12%,蛋白能量比为37.9:1(g/Mcal),可满足ADG为0.9kg/d时的生长需要。结论,蛋白水平对后备奶牛的生长发育非常重要。 相似文献
67.
以陕西省榆林市红石峡迎宾服务区的规划设计为例,借鉴九寨沟、武当山及华山华麓三大景区迎宾服务区的成功模式,归纳了红石峡旅游景区门户空间营造的设计原则,使门户空间规划设计符合其在整个景区所占的地位、所起的作用,满足其在景区中所具有的功能及所提供的服务。 相似文献
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70.
本文以群众杨、合作杨为对照,对以I-69、欧洲黑杨、美洲黑杨、小叶杨、箭黑杨、青杨等为亲本的23个杂种无性系,进行了生长性状和材性性状分析。各无性系的树高、胸径、材积均差异极显著。6-7年生树高和胸径的遗传力均很高。随着树龄的增大,生长性状的遗传力增大,受较强的遗传力的控制。各无性系间木材密度差异极显著,最大者较对照群众杨提高了23.5%,无性系间纤维长度差异极显著。ZJ-2和ZJ-10较对照群众杨高出10.9%,通过综合评分法,从23个无性系中,选出6个无性系,分别为:ZJ-7、ZJ-2、ZJ-3、ZJ-10、ZS-8和L910-140。这几个无性系生长性状和材性性状均优良,可以与群众杨、合作杨等品种平行推广应用。 相似文献