农村社区发展的资金问题：—Ⅱ，农村社区金融组织的构成

农村社区经济发展中农村金融领域的多元化构成是极为重要的，可借鉴国外农村社区金融组织发展的经验，形成中国农村社区金融的新构成。以国家银行、农业开发银行为主体，大集体的农村信用社和小集体性农村合作银行为辅，发展农村的商业信用，引导农村民间借贷为手段，从而形成新的构局。     

江河源区的湿地退化现状与驱动力分析

在描述江河源区1986-2000年15年间江河源区湿地的动态变化情况的基础上,分析了导致江河源区湿地退化的自然因素和人为因素,指出气候变化和江河源区自身脆弱环境的相互作用固然是江河源区湿地退化的主要原因,但是近十几年来日趋加剧的人类活动对湿地退化起到了推波助澜的作用。     

草地土壤微生物多样性影响因子

草地土壤微生物多样性是当前草地生态学研究热点之一, 本文主要综述非生物因素、人类活动、生物因素3方面对草地土壤微生物多样性的影响, 分别从土壤温度、土壤水分、土壤pH、放牧、开垦、施肥、植被类型、植物多样性、群落结构、外来入侵植物、植物根际等方面具体阐述这些因素变化对土壤微生物多样性产生的影响, 并在此基础上探讨草地土壤微生物多样性研究未来的发展趋势, 为深入研究草地对外界因子的响应机制和适应对策及管理提供科学依据。     

2000—2020年西藏“一江两河”地区人类活动对植被覆盖变化的影响

[目的] 探究西藏“一江两河”(雅鲁藏布江、年楚河和拉萨河)地区人类活动对植被覆盖变化的影响机制,为该区开展山水林田湖草沙冰一体化保护与修复工程实施提供理论依据和科学指导。 [方法] 基于2000—2020年归一化植被指数、土地利用数据、生态工程数据和气象数据,利用GIS技术、残差分析、slope趋势分析和M-K检验等方法,研究“一江两河”地区人类活动对植被覆盖时空变化的影响机制。 [结果] ①2000—2020年研究区植被NDVI总体呈增加趋势,但表现出显著的空间差异性,NDVI增加区主要集中在河谷两岸。 ②2000—2020年人类活动对NDVI正向影响区主要集中在雅鲁藏布江和拉萨河等河谷地带,负向影响主要分布在拉萨市区及其周边地区,分布较少,以正向影响为主导。 ③不同土地利用类型对植被覆盖变化的影响程度不同,草地和灌丛对NDVI变化的贡献率最大,两者共达到92.8%,其中城镇和森林面积急剧增加,城镇生态系统增加面积主要由农田和草地生态系统转入,森林和灌丛生态系统主要由草地和荒漠生态系统转入。 ④生态工程林是研究区NDVI增加主要原因之一,生态工程林面积变化与NDVI变化率、残差变化率均呈极显著正相关关系,同时生态工程林能够较好地解释残差变化。 [结论] 人类活动是西藏“一江两河”地区地表植被覆盖变化的重要促进因素,适度的生态工程对植被恢复有重要作用。     

吉林省实施中央财政森林生态效益补偿综合效益评价

本文介绍了重点公益林实施中央财政补偿制度的一般情况和主要经验和做法。从生态、社会和直接效益方面,分析、评价了实施补偿后重点公益林产生的效益。     

Deltamethrin induced alterations of hematological and biochemical parameters in fingerlings of Catla catla (Ham.) and their amelioration by dietary supplement of vitamin C

The present study was carried out to investigate the sub-lethal toxicity of technical grade deltamethrin (a synthetic pyrethroid) of concentration 1.61 μg/L (1/3rd of 96 h LC₅₀) on hematological and biochemical parameters of catla (Catla catla) fingerlings and its amelioration through dietary vitamin C. The deltamethrin exposed fishes were fed with different levels of supplemented vitamin C such as 50, 250, 500 and 1000 mg/kg diet to see its ameliorating effect by assaying hematological parameters viz. total erythrocyte count (TEC), total leukocyte count (TLC), hemoglobin content (Hb), total serum protein, albumin, globulin, albumin–globulin ratio and biochemical parameters such as lactate dehydrogenase (LDH), acetylcholine esterase (AChE), alanine amino transferase (ALT), aspartate amino transferase (AST), total adenosine triphosphatase (ATPase), magnesium adenosine triphosphatase (Mg²⁺-ATPase) and sodium potassium adenosine triphosphatase (Na⁺, K⁺-ATPase) activities. The finding of this study showed that deltamethrin had negative effect on the hematological and biochemical parameters of Catla catla. The experimental group, which was exposed to deltamethrin and fed with normal diet showed significantly lower values (P ? 0.05) of all parameters studied except ALT activity. This might be due to possible disruption of hematopoiesis and proteosynthesis. However, the fish fed with varied concentration of vitamin C in diets neutralized the toxic effect of deltamethrin, as evidenced by significantly lowered hematological and biochemical response. Vitamin C @ 1000 mg/kg diet was the most effective in amelioration of harmful effect of deltamethrin on hematological and biochemical parameters of catla fingerlings. The result suggests that vitamin C can be effectively used to neutralize the toxic effect of deltamethrin on catla.     

农业生产活动对黄土高原丘陵沟壑区坡地土壤水分动态的影响

通过在坡度为20°耕地和荒草坡面对降水、土壤水密集观测,结合模拟降雨实验,从降雨入渗、蒸散发等过程分析讨论了影响黄土高原丘陵沟壑区坡地土壤水分动态的主要因素。结果表明:1)降雨入渗量△S主要受控于雨强和降雨量,坡耕地的入渗量随着雨强增加而衰减的速度快于荒坡,坡耕地有利于中等雨强大雨的下渗,雨强增大时两坡面的降雨转化率逐渐接近,且植被的再分配作用凸显,甚至使短历时暴雨时坡耕地的入渗速度低于荒坡,长历时的大、暴雨或连续降雨利于深层入渗,坡面耕作或在裸地上种植冰草后降雨转化率增约50%;2)7月～10月上旬为土壤水补给期,土壤水分在枯水年及平水年处于负平衡,在丰水年获得补给,最终以蒸散发消耗;3)荒地主要耗水层在20cm,耕地土壤水分活跃层及作物主要耗水层延伸至30cm。总体上,农作物增大蒸散发量、增加土壤水分利用深度,农业生产活动对减少降雨径流、增加土壤水资源量、强化水分小循环有重要作用。     

行商园林里的涉外活动

广州十三行是清政府指定专营对外贸易的半官半商组织。行商们借助垄断地位获得巨额财富,营建了许多大型私家园林。行商园林里发生了许多涉外活动:政府对外交涉;定期供外商人员散心游赏;平时接待应酬外国要员及其家属;西方先进器物在此试用或展示等等。行商园林成了中西文化、科技和国务商务交流、碰撞的前沿地,在中国园林史上具有某种划时代的特质。     

The role of NGOs in improving social forestry practice: Do they promote livelihood, sustainability and optimal land use in Bangladesh?

The encroachment rate in forests in Bangladesh is high and increasing — accelerated by rural poverty and the demand for dwelling space and forest products — causing environmental degradation as well as loss of forest cover and productivity. The forests are managed by the Forest Department, although a substantial area of marginal land belongs to other semi-public agencies including Roads and Highways and the Water Development Board. This marginal land has been left unused or underutilized. In contrast, nongovernmental organizations have an appropriate accessibility and technology disseminating ability to utilize this land in reducing poverty and enhancing rural livelihood, and have been highly active and successful in rehabilitating encroached forests. NGOs have added a new dimension to forest management, which has ensured community participation and protection of the forests, both planted and natural. This study evaluates the social forestry activities of four large NGOs, namely BRAC, Proshika, Caritas and CARE-Bangladesh, as well as national social forestry activities. By adopting a common partnership between public and private authority, property right conflicts have been resolved and rural livelihoods enhanced, and scope has been created for utilizing marginal land. The NGO partnership has been effective in reducing poverty and improving livelihoods. As an outcome of this common partnership, 33,472 km of roadside planting and 53,430 ha of reforestation activities have been carried out during the last two decades.     

杉木-山苍子-作物复合经营模式土壤肥力的研究

通过对杉木-山苍子(A)、杉木-山苍子-黄豆(B)、杉木-山苍子-烟叶(C)及对照的纯杉林土壤生物学活性、土壤化学性质、土壤结构、孔隙组成和水分性状等研究,结果表明:模式B、C表层土壤结构性状变差,土壤营养元素含量下降,土壤生物学活性减弱,但底层土壤熟化程度提高。为了维持幼林地土壤肥力,模式B、C应适当降低耕作强度,缩短间种年限,同时适当增加N和P肥使用量。模式A具有良好的改良土壤能力,是南方林区优良的杉木混农模式。