我国土地辽阔,国土的大部处于温带、暖温带和亚热带地区。在悠久的农业历史过程中,我国在农业生产上栽培着多种的农作物种和品种,形成了世界上最大最古老的作物资源中心之一,同时,在技术上素有精耕细作的传统。在实现农业现代化的技术革新中,对于有助干提高农作物产量和改善其品质的化学控制等新技术,农业工作者一向给予很大重视。我国的大部农业区(除了青藏高原和很少的寒温带外),农业生长期的热量条件都较 Our country has vast land and most of the territory is in temperate, warm temperate and subtropical regions. In the course of a long history of agriculture, China has cultivated a great variety of agricultural species and varieties in agricultural production, forming one of the largest and oldest crop resource centers in the world. At the same time, it is technically known for its intensive and intensive tradition. In technological innovations in the modernization of agriculture, agricultural workers have always placed great emphasis on new technologies such as chemical control that help to improve crop yields and improve their quality. Most of China’s agricultural areas (except the Qinghai-Tibet Plateau and very few cold temperate), the agricultural conditions of the heat are more