Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Plant Protection submitted time 2018-07-18 Cooperative journals: 《广西植物》
Abstract： Many natural ecosystems have been suffering from degradation across the world. Karst ecosystems are known for susceptibility and sensitivity to disturbance. So far, little information is available on the characteristics of vegetation communities suffering from different levels of degradation in Karst areas. Therefore, this study investigated species composition, community structure and species diversity of vegetation communities suffering from different levels of degradation in Karst areas. The results showed that: (1) There were significant differences in species composition and life form composition of communities suffering from different levels of degradation. Numbers of plant families and species were highest in potential degraded communities. Along degradation, tree species gradually reduced and ultimately disappeared. The proportion of shrubs increased first and then decreased. The proportion of herbal increased gradually along degradation. (2) There is a total of 217 vascular plant species belonging to 86 families and 165 genera across 45 explored plots, and Euphorbiaceae, Meliaceae, Rosaceae, Verbenaceae, Gramineae, Nephrolepidaceae were the dominant species. Along degradation, the important values of dominant species gradually decreased, i.e., their dominance in the community gradually weakened while the important values of the companion species gradually increased. (3) Community structure tended to simplify along degradation, as density, height and coverage of community decreased. (4) There were significant differences in species diversity indexs of arbor, shrub and herb layers of communities suffering from different levels of degradation. The species richness index, Shannon-Wiener index and Simpson index decreased along degradation. In sum, characteristics of vegetation community substantially changed along degradation, which has important implication for further studies on degradation and vegetation restoration in Karst areas.
Subjects: Biology >> Botany submitted time 2018-05-02 Cooperative journals: 《广西植物》
Abstract：为研究香蕉-粮肥兼用绿豆间作模式（简称蕉肥间作）下微喷灌对蕉园土壤水氮动态及香蕉产量的影响，试验设置4种不同灌溉定额处理：MSI2（900 m3·hm-2）、MSI3（1 350 m3·hm-2）、MSI4（1 800 m3·hm-2）、MSI5（2 250 m3·hm-2），以不灌溉和清耕栽培为对照。结果发现：蕉肥间作下绿豆生长期间各灌溉处理土壤棵间蒸发量均呈不同程度的下降，香蕉清耕栽培MSI0土壤棵间蒸发量呈上升趋势。随着灌水量的增加，香蕉棵间蒸发量逐渐增高，MSI5棵间累积蒸发量最高达385.6 mm，分别比MSI2、MSI3、MSI4高12.2%、7.6%、4.9%，导致灌溉水利用效率降低。微喷灌处理提高表层土壤含水量，MSI2、MSI3、MSI4和MSI5处理0-30 cm土层含水量显著高于MSI0和 MSI1，在30 cm以下，土壤含水量开始递减。微喷灌还改善土壤耕层结构，提高土壤有效氮。以MSI2处理土壤三相比（2:1:1）较为理想，MSI3处理表土层有效氮含量最高。MSI4处理产量高达48 218 kg·hm-2，MSI3处理蕉果含糖量高达25.67%。因此，蕉肥间作下通过微喷灌方式，适量灌溉有利于提高香蕉产量和改善品质。
Hits
Hits
Downloads
Comment