变量技术及其在农业机械中的应用

精准农业是一套基于空间信息管理和变异分析的现代农业操作系统。精准农业的核心思想就是根据土壤性状和作物生长状况的空间差异，调节对作物的投入，一方面对耕地和作物进行定量的实时诊断，充分了解大田生产能力的空间差异；另一方面则以提高产量为前提，实施定位、定量的精确田间管理，     

敌敌畏熏蒸法防治小麦吸浆虫效果好

敌敌畏熏蒸法防治小麦吸浆虫效果好赵新建，赵建国（虞城县农技中心，虞城４７６３００）胡冰，赵军，高秀珍（虞城县气象局）（虞城县农业局）虞城县三在乡王庄村农民，采用敌敌畏熏蒸氏防治小麦吸浆虫，取得了显著效果。一、敌敌畏熏蒸法的优点１．灭虫增产效果显著。在...     

美洲斑潜蝇的物理防治

美洲斑潜蝇的成虫善于飞行,幼虫潜在叶内取食叶肉,仅留上下表皮,呈曲折蜿蜒的隧道。在菜田发生初期即可遍及全国,无一株幸免,防不胜防,严重时全园被毁。美洲斑潜蝇已经成为当今蔬菜的主要虫害之一。美洲斑潜蝇属于高度杂食性害虫,被害寄主多达36科,其中常见的有白菜、油菜、菠菜、豆角、芹菜、黄瓜、番茄等。为了防治美洲斑潜蝇,菜农往往采用多次、大剂量地喷施杀虫剂,成虫在喷施农药后迅速地飞走,待药效过后又飞回来继续危害。这样防治效果差,而且造成蔬菜大量农药残留,影响蔬菜品质。实验发现美洲斑潜蝇飞行的成虫具有趋黄性,我们充分利用…     

俄罗斯无刺大果沙棘种子育苗技术

俄罗斯无刺大果沙棘可用两种方法进行繁殖，即种子繁殖和营养繁殖，用种子繁殖虽不能保持品种的性状，却能得到５０％的雄株，这对于沙棘育种和造林是非常有利的。本文针对俄罗斯无刺大果沙棘的种子育苗技术环节进行了探讨。     

A low-threshold test ban is feasible

At present, nuclear explosions are limited by treaty to underground testing with yields of no more than 150 kilotons, and recently there have been renewed calls for further test restrictions. As part of these discussions, the U.S. Congress is considering bills that would legislate new limits to testing,whereas the Reagan Administration opposes such constraints. The editors of Science have asked two groups of participants in the debate to present their arguments for or against new limits to testing. Feiveson, Paine, and von Hippel argue for a treaty of indefinite duration between the United States and the Soviet Union, which includes the following provisions: (i) a ban on all testing outside a desiqnated site having known seismic properties; (ii)verification by means of on-site inspection and in-country seismic monitoring; (iii) unlimited testing below 1 kiloton at the special site; and (iv) an average of one test per year with a yield of up to 15 kilotons for ensuring reliability of the nuclear stockpile. MiUer, Brown, and Nordyke argue that a lowering of the present 150-kiloton threshold would be undesirable, and that new test bans would divert attention from a comprehensive approach to negotiated reductions in the nuclear and conventional arsenals of the United States and the Soviet Union.