若尔盖地区主要覆被类型浅层土壤持水量和有机碳关系研究

为探究若尔盖地区浅层土壤持水量和有机碳关系,以若尔盖地区主要覆被类型(沼泽化草甸、非沼泽化草甸和天然林地)浅层(0~20 cm)土壤为研究对象,分析其有机碳和水分特征,探究土壤有机碳含量和最大持水量关系。结果表明:3种覆被类型浅层土壤总孔隙度、最大持水量和有机碳含量均存在明显差异,其中,沼泽化草甸土壤最大持水量最高(2592.46 g·kg^(-1)),是非沼泽化草甸和天然林地的4.0和1.9倍;沼泽化草甸土壤有机碳含量(416.11 g·kg^(-1))约为非沼泽化草甸和天然林地的4.2和2.7倍;若尔盖地区浅层土壤最大持水量与有机碳含量呈极显著正相关关系(R^(2)=0.92,P<0.01),每一种覆被类型土壤水碳也均呈极显著正相关关系;3种覆被类型浅层土壤水碳拟合曲线斜率范围为4.11~7.43,天然林地最大,依次为非沼泽化草甸和沼泽化草甸。研究揭示该地区天然林地土壤最大持水量对有机碳含量变化最敏感,沼泽化草甸土壤水碳关系相对稳定。研究结果对科学判断全球变化背景下区域碳水功能评估提供数据基础。

云南甜樱桃产业发展现状及建议

近年来,云南甜樱桃产业发展迅速,已初具规模。为正确引导云南甜樱桃产业的健康持续发展,在深入云南各甜樱桃种植基地进行调研、了解甜樱桃的生产现状的基础上,分析了云南省甜樱桃产业发展中存在的问题,通过对种植地和市场的分析和文献查阅,结合甜樱桃栽培所需的生态条件,针对云南甜樱桃产业发展中存在问题提出了对策及建议。

Distribution and development strategy for Jatropha curcas L. in Yunnan Province, Southwest China

Yunnan Province is the main distributing area ofJatropha curcas L. This plant is abundant in several drainage areas of the dry-hot, dry-warm and sub-humid valleys in the south subtropical area of Yunnan Province. The seeds that were picked from trees blossoming between April and May and fructifying between September and October will have large seed yield and fine quality. For developing bio-diesel stock forest ofJ. curcas in areas with adaptive climate, seeding measures for afforestation should be taken and techniques on breeding, fast-growing, and high-yielding plantation cultivation are very important.

Floral display and breeding system of Jatropha curcas L.

Plant flowering and breeding characteristics are important for us to understand the reproduction of plant populations. In this paper, we studied the reproduction characteristics of Jatropha curcas in Yuanjiang County （23°36＇1＇4, 101°00＇E）, Yunnan Province. The plant produces flowers in dichasial inflorescences. Normally, the flowers are unisexual, and male and female flowers are produced in the same inflorescence. Only a few male flowers are produced in an inflorescence, and fruits are produced only through pollination between different flowers from the same or different plants. By the treatments of emasculation, bagging and artificial pollination in this experiment, there were few but same fruit set ratios when the inflorescences were emasculated, bagged, or bagged with net, except artificial pollination treatments, which showed that Jatropha curcas could produce fruit through apomixis but not wind pollination. When the inflorescences were unbagged, unemasculated and with free pollination treatments, or bagged, emasculated and with artificial cross-pollination treatments, or unbagged, emasculated and with free pollination treatments, there were many fruits produced. It showed that Jatropha curcas shows outcrossing, is self-compatible, and demanding for pollinators. Normally, the male flowers open first and a few flowers bloom in one day in a raceme. These flowers last a long time in bloom. However, a large number of female flowers open from the third to the fifth day, with some female flowers opening first in a few raceme. This shows a tendency to promote xenogamy and minimize geitonogamy.

金沙江流域干热河谷土壤肥力特征及其影响因素

【目的】探明特殊生境土壤肥力的环境影响因子,为金沙江干热河谷植被恢复和生态治理提供基础和决策依据。【方法】在金沙江干热河谷上、中、下游共设置47个样地,通过野外调查、土壤采集和室内分析,对比研究其表层土壤肥力特征及其环境影响因子。【结果】①金沙江干热河谷上、中、下游土壤肥力受气候、植被等环境因子影响,上游土壤肥力特征优于中、下游,中游土壤肥力状态最差;②金沙江干热河谷土壤肥力受植被类型的影响较大,其中天然林土壤孔隙度、有机质、全氮、全磷含量等显著(P<0.05)高于稀树灌草丛,人工林土壤肥力在整体上也优于稀树灌草丛;③金沙江干热河谷海拔升高使环境温度降低、湿度增大、植被从稀树灌草丛向人工林和天然林逐渐过渡,导致土壤孔隙度和养分含量等土壤肥力特征随海拔升高而显著(P<0.05)提升;④金沙江干热河谷受光照、水分等条件影响,阴坡土壤肥力状况优于阳坡。【结论】金沙江干热河谷土壤肥力受不同区段、植被类型、海拔和坡向等环境因子的影响,其土壤肥力状态存在一定程度的区域差异。因此在金沙江干热河谷植被恢复和生态治理的实践中,应根据不同区段、植被类型、海拔、坡向等环境条件制定相应的植被恢复管理方案,这样才能获得更好的植被恢复效益。