Microsatellite Marker Based Assessment of Genetic Diversity among Cultivars, Landraces and Wild Relatives in Rice

India being the primary center of origin for rice had a very large treasure of local land races, most of which are out of cultivation today. The exact genetic potential and their differences from commercial varieties and the magnitude of heterogeneity still present in them are not well catalogued. Hence the need to characterize the available land races has become imminent in the modem day concept of crop improvement （Rezai and Frey, 1990）. The present study addresses the utility of SSR markers in divulging the genetic relationships at molecular level among the major component factions office gennplasm viz., local cultivars, land races and wild species collected from a wide range of agro-geographical regions of Indian subcontinent.     

关于上一轮县级土地利用总体规划中土地利用变化及生态环境效应的思考 ——以重庆市丰都县为例

基于重庆市丰都县1996年、2004年土地利用现状与2010年土地利用总体规划数据，运用特尔斐法、层次分析法、定量分析法，对丰都县1996—2004和1996—2010土地利用变化及生态环境效应进行对比定量分析研究。结果表明：（1）土地利用格局均发生了明显变化，耕地、未利用土地减少，园地、林地、水域、交通用地增加；（2）土地利用变化引起的生态环境质量变化均呈改善趋势，其主要原因是退耕还园、还林，以及未利用土地的开发利用；（3）规划与实施土地利用变化及生态环境效应差异太大；（4）土地利用总体规划与实际土地利用变化一致性很差，缺乏科学性和严肃性；（5）对规划土地利用变化引起的生态环境改善重视不够。最后提出新一轮土地利用总体规划修编的建议。     

陆稻抗旱性主要指标的研究

在大田栽培水分子缺条件下，对３个陆稻品种的部分抗旱指标进行了测定，分析在正常供水与水分胁迫两种条件下的生理反应差异，从而对其抗旱性鉴定进行了探讨。结果表明，水分胁迫下的叶片游离脯氮酸含量，可溶性糖含量，叶细胞膜透性，组织相对含水量，离体叶片失水百分率，根冠比等都可作为陆稻抗旱性鉴定指标，并应用以上指标采取模糊隶属法对３个品种的抗旱性进行了综合评价，合江５号属全期弱抗品种，东陆１号全期中抗品种，推广     

浅析南方丘陵地区土地平整中的表土问题及对策

土地平整工程是土地整理项目的核心内容,但是,南方丘陵地区土地平整中出现不科学的工程措施导致的表土破坏的潜在问题却一直没有引起重视。在此,针对南方丘陵地区土地整理中土地平整工程的特点及现状,总结土地平整从规划设计到项目实施表土保护问题并进行分析,提出加强表土保护的相应措施。     

冶河流域径流减少的驱动因素分析

分析了1970—2000年滹沱河的重要支流——冶河流域径流减少的主要驱动因子气候和地表覆被的变化趋势及其对流域径流的影响。结果表明，30年来，流域降水量减少，流域内的年平均气温上升并达到显著水平。流域1995年有林地和高覆盖草地所占面积同20世纪80年代相比大幅减少，林地和草地的质量有所下降，到了2000年有所回升；流域内农田的有效灌溉面积逐年增加。同时流域的径流量发生了明显变化：年均流量自1966年以来不断减小，尤其是80年代以后下降趋势更明显。以致上游长年有水河流部分河段出现了不同程度的断流。     

坡地赤红壤不同利用模式对土壤磷和酶的影响

试验采用广东东莞花岗岩发育的坡地赤红壤为样品进行研究表明 :在坡地赤红壤的 4种利用模式中 ,旱地种植花生 ,荔枝可以有效地改善土壤的酸性 ,提高土壤肥力 ;提高土壤Al-P和Fe -P的含量 ,减少O -P的所占的比例 ,提高坡地赤红壤磷酸盐的有效性 ;增加土壤表层的脲酶和蛋白酶的活性 ,可能使土壤的磷酸酶的活性降低     

土地利用方式对黄土丘陵土壤CaCO_3含量及分布的影响

本文以具有典型黄土丘陵特征的砖窑沟流域为例,对该流域梁峁地主要土壤类型上不同土地利用方式下0～200cm层土壤剖面CaCO3含量进行了分析。结果表明:土壤CaCO3含量耕地>林地>荒草地;耕地土壤CaCO3有明显的累积层,累积深度约在20～100cm之间;林地累积层深度约在20～60cm之间;而荒草地无明显累积层。这种现象与一般干旱半干旱地区不同。     

Regrowth forests on abandoned agricultural land: A review of their habitat values for recovering forest fauna

Human land use has modified the structure and function of terrestrial landscapes throughout much of the world, with cropping and livestock grazing the major drivers of landscape change. In many tropical, sub-tropical, temperate and Mediterranean regions, regrowth forests regenerate naturally on abandoned agricultural land if human disturbance declines. With the exception of some tropical forest literature, the broader ecological and conservation literature has largely ignored the potential of regrowth forests to facilitate passive landscape restoration and the recovery of fauna communities in fragmented agricultural landscapes. This paper addresses this deficiency by reviewing the available global evidence of fauna recovery in regrowth forest from 68 papers, identifying the main gaps in current knowledge, and providing directions for further research. The majority of reviewed studies focus on regrowth in tropical regions, which often contain large areas of mature forest. Species’ utilisation of regrowth forest is highly variable and is particularly influenced by land-use history, an important determinant of the structural and compositional characteristics of regrowth forests. While site-scale (<1 ha) forest structure and floristic diversity were frequently studied, only 11 studies considered the spatial configuration and context of habitat patches and just two studies explicitly considered landscape structure. Based on this review, six key research questions are posed to direct future research on this important issue. We conclude that a broader perspective of the role of regrowth forest in the landscape is required if we are to realise the potential benefits of regrowth forest for passive landscape restoration and fauna conservation and recovery.     

Assessing the perceived utility of wood resources in a protected area of Western Tanzania

To identify factors associated with interest in gaining access to protected wood resources in western Tanzania, I collected demographic, socio-economic and wood-use data for 240 households in three villages bordering Katavi National Park. Interest in accessing the protected wood resources was not associated with fuelwood needs, and did not fall along ethnic or demographic lines. Instead, logistic regression analysis identified material and land wealth as variables that increase households' interest in accessing wood resources in the Park, whereas intent to move in the near future and the interaction of material and land wealth were negative influences. These results suggest that resource-use interests are largely dependent upon expected individual gains, which vary according to household needs and ability to process resources for potential local sale or trade. This study considers the importance of distinguishing between people's conservation attitudes and their interest(s) in using specific resources, emphasizing the need to recognize intra-community variation in use interests.     

Landsliding related to land-cover change: A diachronic analysis of hillslope instability distribution in the Sierra Norte,Puebla, Mexico

This study examines mass movement associated with land use change, particularly deforestation, from multiple perspectives. The significance of such understanding is related to the degree of impact landsliding may cause on human settlements and economic activities, and on forest ecosystems. In this paper, the distribution of hillslope instability in the Sierra Norte, Puebla, Mexico is addressed by means of a diachronic analysis, which involves the development of vegetation indexes, as well as vegetation fragmentation derived from Landsat-5 (TM) and Landsat-7 (ETM+) satellite images from 1989 and 1999, respectively. The time period was chosen to compare vegetation cover conditions prior and after the extreme October 1999 rainfall event that triggered hundreds of slope failures in the study area. Results suggested there was a significant vegetation reduction from 1989 to 1999, which was strongly expressed by an increase of 809 km² of bare surfaces. Additionally, areas with highest vegetation density (91–100%) decreased considerably, from 1245 to 363 km², resulting in a net vegetation reduction of 70%. Furthermore, it was possible to highlight that landslide concentration was much higher on surfaces that were bare and had low vegetation density (0–50%), representing 85% of hillslope instability, than on surfaces having a greater density of vegetation cover. Land use change and land degradation are precursors to environmental hazards, such as mass movement events, that pose serious threats to regional population distributions and economic vitality.