Effect of integrated rice-fish-azolla farming system on weed management in lowland rice fields

Abstract

Field experiments were conducted at Annamalai University Experimental Farm, Annamalai Nagar during samba (Aug. -Jan.) and Navarai (Jan. -Apr.) seasons of 1995-96 to study the effect of component enterprises of an integrated rice farming system on weed control. Enterprises like fish culture (grass carp. Ctenopharyngodon idella (val.)@ 1 fish per m², in trenches occupying 15 per cent of rice area) and Azolla culture (Azolla microphylla @ 0.5 kg per m²) were compared independently and in combination with rice as the main enterprise, each with and without the butachlor 1.5 kg ha-1. The results revealed that integration of azolla and fish culture as component enterprises in rice farming along with the herbicide (butachlor) performed significantly superior in respect of weed control (weed control index of 61.85 and 65.11 per cent), grain yield of 4.45 t ha-1 and 4.4 t ha-1 during first and second season, respectively and net return of Rs. 58413 ha for two seasons.