文档介绍：现代化农业——真正可持续性农业经营的生态影响和机遇 Modern Agriculture: Ecological Impacts and the Possibilities for Truly Sustainable Farming 1. 大约四十年前, 农业系统中的作物产量依赖的是内部资源、有机物的循环利用、内在的生物防治机制和将与模式。 Until about four decades ago, crop yields in agricultural systems depended on internal resources, recycling anic matter, built-in biological control mechanisms and rainfall patterns. 2. 农业产量虽然不高,但比较稳定。 Agricultural yields were modest, but stable. 3. 保证产量的方法是在某一地块的时空范围内多种几类作物, 以应对突发的虫害或恶劣的天气。 Production was safeguarded by growing more than one crop or variety in space and time ina field as insurance against pest outbreaks or severe weather. 4. 为取得氨肥, 采取轮换种植主要农作物和豆类的方法。反过来, 轮换种植可有效地破坏害虫、杂草、病害的生命周期, 从而抑制它们。I nputs of nitrogen were gained by rotating major field crops with legumes. In turn rotations suppressed insects, weeds and diseases by effectively breaking the life cycles of these pests. 5. 玉米带地区的普通农场主轮换种植玉米和包括大豆在内的几种作物, 而种植小粒谷物也是饲养牲畜的内在需求。大部分劳动由家庭成员完成, 偶尔会请几个帮手, 但不会从农场以外购买专用设备或服务。在此类农业系统中, 农业和生态的关系十分密切, 很少会出现环境退化的迹象。 A typical corn belt farmer grew corn rotated with several crops including soybeans, and small grain occasional hired help and so specialized equipment or services were purchased from off-farm sources. In these types of farming systems the link between agriculture and ecology was quite strong and signs of environmental degradation were seldom evident. 6. 但随着农业现代化的发展, 对生态法则的无视和践踏经常会打破生态——农业链。B ut