七十年代初,潍坊市各县(区)农作物施肥多偏重于氮素化肥,七十年代中后期磷肥的生产和施用量迅速增加,作物产量相应地大幅度提高;土壤养分构成逐步发生了变化,出现了大量元素与微量元素比例失调问题,影响作物产量的进一步提高。特别是在某些县(区)缺乏微量元素已成为发展农业生产的障碍因子。1983年全市范围内进行 In the early seventies, all counties (districts) in Weifang, with more emphasis on nitrogen fertilization, had more fertilizers for their crops. The production and application rates of phosphate fertilizer increased rapidly in the mid-to-late 1970s, and their crop yields increased dramatically. Their nutrient composition gradually changed , There has been a large number of elements and trace elements imbalance problem, affecting the further improvement of crop yield. In particular, the lack of trace elements in some counties has become an obstacle to the development of agricultural production. In 1983 within the city