我厂甜菜产区历史悠久。由于耕作制度的落后,病虫害逐年加重,造成单产不高,总产不稳的生产局面。造成产量、含糖、效益三低的主要原因是:亩保苗率低,一般平均在2500——3000株,比要求的4000株低37.5——25％;一般都采用四 My factory beet producing area has a long history. Due to the backward farming system, pests and diseases are aggravating year by year, resulting in a production situation in which yields are low and the total output is unstable. The main reasons causing the low yield, sugary benefit and low profit are as follows: the seedling protection rate of mu is low, generally averaging 2500 to 3000 strains, which is 37.5 to 25% lower than the 4000 strains required; generally, four