砂田甜瓜套作向日葵系统的养分利用研究

2010—2013年在庄浪县进行的砂田甜瓜套作向日葵系统的养分利用研究的结果表明,无论在甜瓜的初花期、座果期、膨大期套作食葵或油葵,套作系统比单作明显提高了作物的吸氮量、吸磷量和吸钾量。氮吸收量比单作增加50%~59%,磷吸收量比单作增加12%~41%,钾吸收量比单作增加33%~68%。     

差不嘎蒿茎叶解剖特征及其与气候因子的关系

差不嘎蒿（Artemisia halodendron）是我国东北部重要的防风固沙植物,本研究利用石蜡切片法观察内蒙古不同地区差不嘎蒿的叶片和茎解剖结构,运用方差分析方法比较不同地区差不嘎蒿解剖结构间的差异性,以逐步回归得出影响解剖数量特征的主导气候因子。结果表明：差不嘎蒿叶为等面叶,表皮细胞为1层,栅栏组织呈环栅型,排列紧密,维管束发达;茎表皮细胞为1层,外韧无限维管束,环状排列,髓发达;来自于北部的呼伦贝尔沙地的差不嘎蒿叶上表皮角质层和茎皮层厚度显著高于科尔沁沙地,髓直径和茎导管直径也有类似趋势;差不嘎蒿栅栏组织厚度、茎筛管直径随生长季降水的减少而增加,叶上表皮角质层、髓直径、茎导管直径随有效温度的减少而增加,表现出对水分和温度的适应性变化。研究结果为本种在不同气候条件下的生态适应性研究提供基础资料。     

浑善达克沙地东部地区天然水体的水化学组成及其控制因素

浑善达克沙地东部地区位于内蒙古高原,其天然水体为淡水。利用原始型Durov三线图对其天然水体进行水化学分类,结果表明,地表水水化学类型属于碳酸氢盐组,而地下水属于碳酸氢盐组、混合组和硫酸盐组多种类型。天然水体样品在Gibbs图中的分布表明,岩性控制是形成该地区天然水体水化学组成的主要因素,这种情况不同于我国西部和中部沙漠由于蒸发强烈而受控于蒸发-结晶作用的天然水体。天然水体的离子比例关系表明,地下水中蒸发盐岩和硅酸盐岩的风化程度较高,而碳酸盐岩风化程度低,这可能是由于地下水的水-岩作用时间长、二氧化碳供给不充分引起的;相反,由于水-岩作用时间短、二氧化碳供给充分,地表水中蒸发盐岩和硅酸盐岩的风化程度较低,而碳酸盐岩风化程度高。     

Wind erosion and sand accumulation effects on soil properties in Horqin Sandy Farmland,Inner Mongolia

Rain-fed agriculture is widespread in Inner Mongolia, northern China, where wind erosion of farmland is very common because of sandy soil and dry, windy weather. However, very little is known about the effects of wind erosion on soil physical and chemical properties in this region. A field experiment was conducted in sandy farmland, where erosional and depositional gradients were established to evaluate the effects of wind erosion and leeward sand accumulation on soil texture, nutrient content, soil water, and soil temperature. The research showed that long term wind erosion could result in significant soil coarseness, infertility and dryness. Severe erosion reduced clay by 59.6%, organic C by 71.2%, total N by 67.4%, total P by 31.4%, available N by 64.5%, available P by 38.8%, and average soil water content by 51.8%, compared with non-eroded farmland in the study region. The sand fraction (particles > 0.05 mm), pH and ground-surface temperature increased by 6.2%, 3.7%, and 2.2 °C, respectively. Accumulated sand also caused a decrease in nutrients and soil water content. Under severe sand accumulation, clay was reduced by 2.0%, organic C by 19.3%, total N by 21.7%, total P by 13.7%, available N by 52.5%, and average soil water content by 26.6%. The sand fraction, pH, available P, and ground-surface temperature increased by 0.2%, 0.9%, 5.8% and 2.8 °C, respectively.     

冀东梨园主要昆虫种群调查及其防治

调查了化防程度较高及不用药梨生产园的主要昆虫种群构成,并从多样性指数、种间相遇机率和均匀度等对昆虫多样性指标进行了分析.结果表明:化学防治梨园的昆虫多样性指数较低,很少使用农药的梨园昆虫多样性指数相对较高,但生态系统健康程度较低.     

Trends in natural resource use and prospects for sustainable resource management in Kenya's Arid and Semiarid Lands

This paper describes the environmental problems facing the development of Kenya's Arid and Semiarid lands (ASAL) today. The problems arise because of a rapidly declining resource base in the ASAL as a result of overexploitation and misuse, following basic land use conflicts. The extent of the overutilization or resource damage is not well known and varies a great deal from one agroecological zone to another and from resource to resource in the ASAL; those most affected include: soil, water, range, forest, livestock and wildlife. As a result of increased population growth in the ASAL, these resources are under stress. This paper argues that many of the environmental problems in the ASAL cannot be solved if the development programme does not address the needs of the people who live in the ASAL. There is a need to shift the objective of ASAL development from a preoccupation with economic growth and the idea that the ASAL should make a contribution to GNP through interregional trade and export to sustainable development that enables the communities in the ASAL to support themselves at as good a standard of living as possible. The last part of this paper outlines a strategy to promote such sustainable development.     

浑善达克沙地飞播区不同恢复阶段植物群落结构动态变化

为研究浑善达克沙地飞播区不同恢复阶段植物群落结构动态变化,揭示飞播后浑善达克沙地植被恢复的特点和变化规律,于2013—2017年在浑善达克沙地11个飞播区进行了植被调查试验,并从功能型角度出发,结合对应分析、关联度分析以及Mann-Kendall趋势分析等数据分析方法探讨了飞播区植被恢复的阶段性以及各功能型植物在群落中的地位和作用。结果显示:浑善达克沙地飞播区19 a恢复时间共分为3个恢复阶段,且飞播后,伴随恢复时间的推移,乔木、灌木半灌木、多年生杂类草、一/二年生杂类草、多年生豆科牧草、多年生禾草、一/二年生禾草7个功能型植物间的相互依赖程度逐渐减弱;随着恢复年限的增加,群落的稳定性逐渐增大。不同恢复阶段,植被恢复的主导功能型并不唯一,可在不同阶段进行适时管理,从而使植物群落的演替阶段和整体发展趋势更有利于退化沙地的植被恢复与重建。     

沙地樟子松人工林碳储量研究

以科尔沁沙地樟子松人工林为研究对象,分别实地测定了造林10年、18年、25年和30年樟子松人工林树木生物量、枯落物生物量、草本生物量和根系生物量,并研究了各碳库碳储量动态变化特征.结果表明:樟子松各器官平均碳含量为48.12%;随着林龄的增大,除了林下草本碳库碳储量减小外,樟子松地上部分碳库、枯落物碳库、根系碳库及土壤...     

榆林沙区盐渍化土地水盐运动规律研究

本文根据实测资料,分析了定边县周台子乡东梁村水盐运动的变化特征,结果表明,该区全年处于积盐状态,由于季节的不同,积盐差异较大,盐分的表聚性强;该区土壤盐分含量还表现出随地形不同而变化,地势高,地下水位低,土壤盐分含量低,随着地势的降低,地下水位升高,土壤盐分含量也随着增加。     

浑善达克沙地野生花灌木资源及其园林应用评价

通过对浑善达克沙地野生花灌木资源调查,筛选出野生花灌木44种,隶属于10科,17属;在对其观赏类型和园林用途进行初步分析的基础上,就该地区花灌木今后的引种方向和保护措施提出建议。