BIOMASS AND PRODUCTIVITY OF WEEDS IN A FALLOW PERIOD AT GUJAR TAL MARGIN, INDIA

This paper deals with biomass accumulation and net primary productivity pattern in a fallow period of a lake margin agroecosystem. The slight slopping margin of present study site was characterized into two ecological zones, i.e. upper and lower from top up-land to lower region near water margin. Maximum biomass of dominant weed Cynodon dactylon (Linn) Pers. and ‘rest (other) weeds ’ were 190.55 and 265.22 g m-2 in upper zone in September. In contrast, in the lower zone of study site, peak value of biomass of dominant plant C. dactylon and ‘rest weeds ’ were 67.91 and 178.84 g m-2, respectively in June as lower zone was inundated from first fortnight of July to September, 2008. Maximum percentage contribution of the weed (C. dactylon) was 54.00 and 59.15 % in March and ‘rest weeds ’ was 74.49 and 75.15 % in April, 2008 in the respective upper and lower zones. Maximum productivity values of respective dominant weed (C. dactylon) and ‘rest weeds ’ in upper zone were 2.07 and 2.51 g m-2 day-1 in July. In contrast, in the lower zone of the study site peak productivity values of respective dominant weed (C. dactylon) and ‘rest weeds ’ were observed 1.36 in June and 1.23 g m-2 day-1 in October. Total productivity values in two respective zones upper and lower zones varied between 330.59 and 140.17 g m-2 per eight month. Analysis of variance in standing biomass of plant species was found significant p<0.05 in upper zone and p<0.01 in lower zone. Key words: Biomass, productivity, fallow land, weed, lake margin