The morphology and development of Lotus uliginosus and Trifolium subterraneum under Pinus radiata canopy in southern Chile

A split-plot experiment was conducted in southern Chile to study the effects of tree cover and level of fertilizer application at establishment on the morphology and development of the legumes Lotus uliginosus and Trifolium subterraneum, when sown in conjunction with Festuca arundinacea as the companion grass. Trees were 13-year-old Pinus radiata, spaced at 4 × 12.5 m intervals and with a mean canopy diameter of 4.8 m. At 150 days after sowing the total area of Lotus leaves and length of Lotus stems/plant were not affected by tree cover. Individual plants had fewer stems but they were longer. For Trifolium, despite large increases in individual petiole length and leaf area, total petiole length and leaf area/plant were reduced by tree cover because of a reduced number of petioles/plant. At 275 days after sowing, the number and weight of Lotus components/ha was not affected by tree cover, although companion grass development was reduced. By 640 days the number and weight of Lotus components/ha was reduced but only to the same degree as the companion grass. Trifolium plant development, and in particular seed yield, was affected by tree cover at 275 and 640 days and to a greater extent than Lotus or the companion grass. A high level of fertilizer application at establishment induced a greater development of both legumes at 275 days, but by 640 days the effects were much reduced. It is concluded that both Lotus uliginosus and Trifolium subterraneum respond to tree cover by increasing stem length and leaf area, but that in situations with low soil fertility, the development of Lotus is less affected by tree cover than Trifolium. This revised version was published online in June 2006 with corrections to the Cover Date.     

Combination of cacao with other plantation crops: an agroforestry system in Southeast Bahia,Brazil

Brazil accounts for about 20% of the world production of cocoa, and about 95% of cocoa produced in Brazil is from the southeastern part of Bahia State. Traditionally, cacao is grown in monoculture (though under the shade of various other species). But various crop combinations involving cacao have recently been undertaken by the farmers with encouragement from Brazilian government.As a part of the crop diversification programme in the traditional cacao growing areas and their surroundings, extensive areas are being planted to other plantation crops, mainly clove and rubber and, to some extent, coconut too. Crop combinations have been adopted in some of these new plantings and cacao is an important component of most of such combinations. Whereas several other crops are combined with clove trees, cacao is usually the only species grown with mature rubber trees. Young rubber trees are, however, interplanted with a number of other species. Productive coconut areas are found mostly in sandy soils along the coast so that there is little intercropping. However, scattered farms are found where coconuts are underplanted with guarana, black pepper, cacao, cashew, etc. as done commonly in other parts of Northeast Brazil.     

Determining transpiration coefficients of Sahelian vegetation barriers

Vegetation barriers along contour lines are an appropriate measure for runoff management. An essential element of their design is minimisation of competition for water between the agricultural crop and the vegetation barrier. This requires the evapotranspiration of the vegetation barrier to be known. In 1998 FAO (the Food and Agricultural Organisation of the United Nations) presented a method to estimate the evapotranspiration of natural vegetation. The method includes a dual crop coefficient approach, distinguishing soil evaporation and canopy transpiration. The transpiration coefficient can be obtained from either the LAI (leaf area index) or the fractional ground cover. This paper reports the results of a study conducted in Burkina Faso in 1998. Transpiration coefficients of three vegetation barriers were obtained by directly measuring transpiration and soil evaporation during the mid-season growing stage. Measured values were compared with those obtained from the FAO estimation method, using both the LAI and the ground cover approach. In most cases the FAO approach overestimated the transpiration coefficient. To overcome overestimation FAO proposes a reduction factor based on the stomatal resistance of vegetation with high stomatal control. This factor is difficult to obtain, however, and complicates the relatively simple method of estimation. Even if this reduction factor is taken into account, an overestimation of transpiration coefficients when using the LAI approach should still be acknowledged.This revised version was published online in November 2005 with corrections to the Cover Date.     

居民庭园植物配置中使用园艺作物的价值探讨

对庭园中由于种植园艺作物而在保护农业生物多样性、经济、环保以及居民的保健功能等方面所产生的价值进行探讨,提出应打破当前在居民庭园中植物配置方面的模式化设计,建设具有田园风光的自然生态庭园。     

有机肥和覆盖处理对（木柰）果品质及贮藏性的影响

不同有机肥（豆饼、猪粪、鸡粪、绿肥）、地面覆盖（生草覆盖、地膜覆盖）处理对（木柰）果实品质的影响。试验结果表明：有机肥处理能提高（木柰）果可溶性固形物（TSS）、总糖、总酸含量和固酸比以及果实耐贮性，有机肥处理中以豆饼施用效果最明显；猪粪、鸡粪其次；豆饼、猪粪和鸡粪还能有效减少果面黑斑和果肉木栓化。覆盖处理中以地膜覆盖提高果实品质的效果较明显，但对果实的耐贮性影响不大。有机肥提高（木柰）品质和耐贮性的效果较覆盖处理好。     

Trends in land cover change and isolation of protected areas at the interface of the southern boreal mixedwood and aspen parkland in Alberta, Canada

The Beaver Hills region of central Alberta is located at the interface of the southern boreal mixedwood forest and the aspen parkland, an area now dominated by agriculture, urban and industrial development. Increasing anthropogenic land cover will eventually isolate remaining natural habitats currently protected in parks and reserves. This paper analyzes land cover and land cover change (LCC) in the Beaver Hills moraine and surrounding areas using a structured hierarchical satellite imagery classification applied to Landsat Multi Spectral Scanner and Thematic Mapper from 1977, 1987, and 1998. Our goal was to quantify deforestation and habitat fragmentation trends and then discuss how this information could be used to develop a conservation approach that will protect current areas against further habitat loss. We found that the rate of deforestation in the lands surrounding the moraine was similar to the broad trend at the southern periphery of the Canadian boreal forest region: annual rate of change in forest cover was −0.82%/year. However, in the Beaver Hills there was a net gain of +0.61%/year, due to regeneration of low quality agricultural lands. All fragmentation indices used indicated an increase in forest fragmentation. We designed a network of protected areas and remaining large forest patches, based on the UNESCO-MAB biosphere model. Our results underline concerns regarding the increasing isolation of national parks and biological reserves in Canada.     

云南樟,新樟,细叶香桂,银桂的抗冻性研究

冷冬是影响云南省樟树生产的重要原因之一。经低温处理云南樟、新樟、细叶香桂、银桂4种植物的离体新鲜叶片后,用电导法测定叶片浸提液电介质渗出率,并计算各植物的半致死温度。根据半致死温度,就能合理布局云南省云南樟、新樟、细叶香桂和银桂的生产。     

济源市草本油料作物资源及开发利用

在介绍济源市地理气候特点的基础上,着重介绍了济源市草本油料作物9科13个种的主要形态特征、经济价值,并根据目前草本油料作物生产现状,从形成规模化种植、加强科学研究、建立深加工基地、注重综合性开发四方面对其进一步开发利用提出了建议,以期促进济源市的草本油料作物生产和经济发展.     

基于MODIS与AMSR-E数据的雪被产品合成及精度评价

摘要：利用2002年10月1日-2008年3月31日青海省Terra/MOD10A1和Aqua/MYD10A1每日雪被产品,合成了MODIS五日积雪分类图像（MOYD_5D）,结合AMSR E五日雪水当量产品（AE_5D）,利用用户自定义合成算法合成五日积雪分类图像AEMD_5D。根据气象台站的雪情数据,对比分析MOYD_5D、AE_5D和AEMD_5D这3种积雪产品的积雪分类精度（Sa）。结果表明,1）当积雪深度为1~3 cm时, MOYD_5D、AE_5D和AEMD_5D的积雪分类精度分别为17.5%、49.8%和23.2%;2）积雪深度为4~6 cm时,MOYD_5D、AE_5D和AEMD_5D的Sa分别为46.2%、55.1%和56.9%;3）雪深为7~9 cm时,MOYD_5D、AE_5D和AEMD_5D的Sa分别为58.6%、78.5%和78.6%;4）当雪深≥10 cm时,MOYD_5D、AE_5D和AEMD_5D的Sa分别为66.7%、82.2%和84.1%。合成产品AEMD_5D对积雪分类精度有所提高,对于牧区雪灾监测及评价具有重要的应用价值。