农田生物多样性与害虫综合治理

在现代农田生态系统中 ,人类为了满足自身的需要 ,通常把自然界的植物群落改造成大面积种植单种特定的作物 ,人为地排除其他植物种类的竞争以提高作物的产量。由于单一化的作物不断取代自然植被 ,降低了农田的物种和生境多样性 ,结果导致农田生态系统的不稳定和害虫问题的更加恶化。影响农田生物多样性的因素很多 ,如地理位置、气候类型、环境条件、作物品种、种间关系、人类的栽培活动等。根据现有的生态学原理和研究成果 ,人类可以通过采用适当的措施来恢复和强化农田生物多样性 ,提高天敌的控制潜能 ,减少害虫发生的可能性 ;这些措施包括合理安排混作的时空格局 ,通过轮作进行间断性耕种 ,对多年生作物采用地面覆盖植被 ,利用不同品种以提高作物的遗传多样性 ,等等。在设计农田生物多样性的管理策略时 ,必须同时考虑当地气候、地理 ,植被 ,作物 ,土壤等因素的变化 ,因为在特定的生境条件下 ,这些因素可能增加或减少害虫发生的机会

Biodiversity and integrated pest management in agroecosystems

In modern agroecosystems, natural plant communities are usually modified to meet the special needs of humans with a specific species of cultivated crop over vast area, and other species of plants are artificially excluded for improving the crop yield. The instability of agroecosystems, which is manifested as worsening of most insect pest problems, is increasingly linked to the expansion of crop monocultures in place of the natural vegetation, thereby reduction of species and habitat diversity in the fields. Agricultural biodiversity may be affected by many factors, such as geographical location, climatic types, environmental variables, crop varieties, interspecific relations and cultivated activities, etc. Based on current ecological principles and research results, higher natural enemy and lower insect pest potentials can be expected through restoration and enhancement of the agricultural biodiversity which may be well done in the manners of rational arrangement of mixing crops in time and space, discontinuity of monoculture in time through rotation, ground cover vegetation in perennial crop systems, high genetic diversity using variety mixtures, and so on. In the planning for a biodiversity management strategy in agroecosystems, however, local variations in climate, geography, vegetation, crop and soil must be taken into account because these variables might increase or decrease the potential for pest development under certain habitat conditions.