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141.
贫困山区农户人力资本对生计策略的影响研究——以四川省凉山彝族自治州为例 总被引:1,自引:1,他引:0
人力资本是构建农户生计的关键要素,从人力资本视角探讨农户生计选择对于推动农户生计转型、实现乡村振兴具有重要意义。论文以西南贫困山区四川省凉山彝族自治州为案例区,采用2018年508个农户样本数据,应用回归模型,估算了人力资本对农户生计策略的影响。结果表明:人力资本是山区农户生计选择的重要影响因素,不同类型人力资本对农户生计策略的影响不同,且具有明显的空间差异。教育文化、健康状况对非农生计策略的选择具有正向影响,且高山区>二半山区>河谷区,健康状况对河谷区农户生计选择影响不显著;非农技能培训对非农生计策略选择具有显著的正向影响,且高山区>二半山区>河谷区;农业技能培训对非农生计策略选择具有负向影响,且高山区<二半山区<河谷区,但其对高山区农户生计选择并不显著;青壮年劳动力倾向于选择非农生计,务农人口老龄化问题严峻,高山区表现最为突出,二半山区次之,河谷区较不明显。最后,根据研究结论,探讨了人力资本、劳动力转移与乡村发展之间辩证关系及相关政策建议。 相似文献
142.
本文以西藏扎布耶盐湖卤水为研究对象,在夏季的大面积盐田中,记录了天然日晒蒸发过程中的卤水组分演化过程,分析了Li、B、K等组分的集散行为,为该湖卤水的综合利用提供了工业化参考数据。通过实验发现,扎布耶盐湖夏季卤水Li^ 富集较低,Li^ 浓度最高达到1.8g/L。Li^ 的析出较分散,在实验末期,固相Li2CO3析出达到高峰期,但Li2CO3的含量不超过4%。在实验后期,卤水中CO3^2-离子的浓度和卤水温度迅速升高,这是导致卤水中Li^ 快速析出的主要因素,蒸发后期,卤水中K^ 和B2O3迅速富集,母卤适于提取硼砂和钾石盐或硼钾盐。 相似文献
143.
1INTRODUCTIONDuetotiledecreaseoflandcoverandtheincreaseofwaterproofareasinurbandevelopment,itisclearthattherainwaterinfiltrationratewillreduceandtherunoft'volumewillincrease.Increasedrunoft'maycausetyequentfloodingandseveresedimentwashoutdownstream.Toavoidsuchadversedownstreameffects,storm-waterrunoft'andsedimentouttlowratemustbecontrolledusingdetentiontbcilitiesinInanynewcommunities.ThemainfunctionsofdetelltionpondsaretoreducepeakflowandcontrolthestreamlineandsedimentOutflowrate.Inperfo… 相似文献
144.
145.
Al-Zibdah Mohammad Oqaily Firas Al-Najjar Tariq Manasrah Riyad 《Ocean Science Journal》2008,43(1):9-16
Environmental qualities of coastal water and bottom sediment were assessed at Jordan's northernmost tip of Gulf of Aqaba to
evaluate possible impacts of the bordering fish pen cages in Eilat. Results showed significant differences between surface
and bottom water in the chemical and physical variables in the different months of the year (2004-2005). Chlorophyll a was
also significantly higher in bottom water when compared to that of the offshore water. Nitrate and ammonia were significantly
higher in bottom water than the surface water at each individual station. The upper 2 cm of sediment sample recorded higher
values of total phosphorus and organic matter. Seasonality affected the content of total phosphorus, organic matter, redox
potential and color especially at the sediment layer below 3 cm of the sediment core. The present investigation showed slight
modification of water and sediment qualities but no clear sign of eutrophication was observed. However, to maintain sustainability
of healthy environmental conditions at the northern tip of Gulf of Aqaba potentials of any possible environmental risks arising
from the fish farms or any other coastal investment should be carefully considered. 相似文献
146.
凡纳对虾(Penaeus vannamei Boone)高产养殖试验 总被引:4,自引:0,他引:4
1999-2001年3a的高产试验结果显示,在符合一定条件的虾塘中和恰当的管理下,在广西沿海进行凡纳对虾(Penaeus vannamei Boone)的集约化养殖是可行的,在平均放苗密度约74尾/m^2时,凡纳对虾的平均单位产量可达到7224.35kg/hm^2。在一定的放苗密度范围(27-81尾/m^2)和养殖期限(99-139d)内,对虾单产与放苗密度和养殖天数正相关,蛋白质水平为35%的配合饲料可以满足集约化养殖的凡纳对虾的需要。 相似文献
147.
The theory on the cyclic adaptation between society and ecosystems sheds new light on the evolution and internal structure of human–environment systems. This paper introduces the risk index(RI) and adaptation capacity index(ACI) to evaluate the rural human–environment system. An evaluation index system for the adaptability of rural human–environment systems is configured in the context of climate change and policy implementation. On this basis, the stages, features, dominant control factors, and evolution mechanism were examined vis-à-vis the adaptability of the rural human–environment system in Darhan Muminggan Joint Banner from 1952 to 2017. The main results are as follows:(1) The evolution of the rural human–environment system can be divided into three stages, namely, the reorganization and rapid development stage(1952–2002) with population, cultivated land, livestock and degraded grassland increasing by 260%, 13%, 134% and 16.33%, respectively. The rapid to stable development stage(2003–2010) with population increasing by 2.8%; cultivated land, livestock and degraded grassland decreasing by 2.3%, 13.6% and 10.7%, respectively. The stable to release stage(2011–2017) with population, cultivated land, livestock and degraded grassland decreasing by 2.6%, 0.2%, 10.6% and 3.8%, respectively.(2) With the passage of time, the ACI of the rural human–environment system first increased slightly(–0.016–0.031), followed by a slight decline(0.031–0.003), and culminating in a rapid increase(0.003–0.088). In terms of spatial patterns, adaptability is high in the middle, moderate in the north, and low in the south.(3) The evolution of adaptability in the rural human–environment system was mainly controlled by the per capita effective irrigation area(22.31%) and the per capita number of livestock(23.47%) from 1990 to 2000, the desertified area(25.06%) and the land use intensity(21.27%) from 2000 to 2005, and the per capita income of farmers and herdsmen(20.08%) and the per capita number of livestock(18.52%) from 2010 to 2007.(4) Under the effects of climate change and policy interventions, the cyclic adaptation of the rural human–environment system was propelled by the interactions between two kinds of subjects: farmers and herdsmen on the one hand and rural communities on the other hand. The interaction affects the adaptive behavior of the two kinds of subjects, which in turn drives the cyclic evolution of the system. As a result, the system structure and functions developed alternatively between coordinated and uncoordinated states. Small-scale adaptive behaviors of farmers and herdsmen have a profound impact on the evolution of the rural human–environment system. 相似文献
148.
研究了湛江东海岛3种不同养殖模式虾池弧菌对抗菌药物的耐药性,并对虾池水域环境的水温、盐度、DO、pH、叶绿素a、DOC、无机氮、无机磷、硅酸盐、细菌总数和弧菌数量变化进行了监测和评价。结果表明,调查的三个虾池的弧菌对万古霉素产生耐药性,高位新池和传统精养池的弧菌对利福平产生耐药性,对其他抗菌药尚未形成耐性,3个虾池的弧菌对恩诺沙星和氯霉素高度敏感,传统精养池和天然虾池的弧菌对复方新诺明、庆大霉素、TMP和环丙沙星高度敏感;在水平差异上,高位新池的弧菌比传统精养池和天然虾池对12种抗菌药更具耐药性,同时多重耐药菌株在高位新池中出现,可能与虾苗来源和配合饲料中添加了抗菌药物有关。水质监测结果表明,养殖过程中,虾池水域环境逐渐富营养化,无机氮和Chla超过富营养化阈值,细菌总数增加;两个精养池的水体富营养化程度高于天然虾池;调查期间的弧菌数量在对虾发病的感染剂量阈值范围之内,尚无弧菌病害发生的潜在危险。 相似文献
149.
WANG Lin WANG Weida GONG Zhaoguo 《中国海洋大学学报(英文版)》2006,5(4):363-367
1IntroductionPopulation growth has created escalating pressureson our resources(natural,humanandsocial)onlocal,regional,and global scales.These pressures negativelyi mpact the natural environment,our communities andthe quality of our lives.In the face of … 相似文献
150.
新疆宜农后备土地资源划分与评价 总被引:11,自引:0,他引:11
由于土地资源的不断开发,新疆宜农后备土地资源的面积不断减少,土地开发条件越来越差,造成一些土地开发以后成为低产田或无灌溉水源而弃耕,使非常有限的土地开发资金浪费。为了使新疆宜农后备土地资源开发有计划、有重点、有目的、分阶段的顺利进行,更好的发挥新疆宜农后备土地资源开发的经济效益,必须研究清楚新疆现阶段宜农后备土地资源的数量、质量、与分布。以现阶段新疆宜农土地资源开发利用技术水平和农业生产技术水平及所产生的经济效益为基础,参照新疆水资源和土地开发资金,注重对生态环境的保护,兼顾农林牧业共同发展的方针,划分出新疆现阶段宜农后备土地资源。 相似文献