Population dynamics and growth of Galinsoga ciliata in relation to method of cultivation, crop type and altitude

Population dynamics and growth (dry-matter yield) of Galinsoga ciliata (Raf in.) Blake a serious weed in hill agroecosystem of Meghalaya was studied fo r two years in radish (Raphanus sativus L.) and maize (Zea mays L.) fields under slash and burn agriculture (jhum) and tenace cultivation situated at high and low altitudes of Meghalaya, northeast India. Two to three seedling cohorts were recruited in the crop fields at the low altitude, while at hi gh altitude seedlings were recruited invariably in three successive cohorts . Seedling emergence in the first cohort was significantly higher than in t he second and/or third cohort. Associated crop, method of cultivation and a ltitudinal variation significantly influenced seedling recruitment and surv ivorship and half lives of cohorts of G. ciliata.