有效群体 meaning in Chinese

effective population

In planting ratoon sugarcane , " four early " : ploughing soil so as to loose sugarcane sprout , applying fertilizer during seedling so as to provide necessary nutrition for growing early and rapidly , early thinning out and singling seedling with shelling sear leaves so as to insure available populations and ventilation , controlling diseases and pests so as to ensure sugarcane seedling orderly , full and healthy
宿根蔗突出“四早”管理，即早破垄松蔸，促进蔗蔸萌发；早施苗肥，促进蔗苗早生快发，保证养分有效供给；早间苗、定苗，及时剥除枯脚叶，确保甘蔗有效群体和田间通透性；早防治病虫，保证苗齐、苗全、苗匀、苗壮。