On-farm farmers participatory evaluation of intensification of rice (Oryza sativa)ricefallow system with vegetables in summer under humid tropical irrigated lowlands

An on-farm field experiment was conducted in 24 farmers fields in randomized block design with 5 treatments. Introduction of vegetables, viz. Vellayani Jyothika, yardlong bean (Vigna unguiculata L. ssp. sesquipedalis), Arka Anamika okra (Abelmoschus esculentus L.), Saubhagya oriental pickling melon (Cucumis melo L. var. conomon) and Arun amaranth (Amaranthus tricolor L.) in summer fallow of traditional double crop Uma rice (Oryza sativa L.) in a humid tropical irrigated lowland was attempted during 200913 at Pathanamthitta, Alapuzha and Kottayam districts of Kerala. System yield, soil-nutrient balance and economics of the systems were compared. Ricerice yardlong bean system could realize higher productivity and profitability. Recycling of yardlong bean residues back into system could add to actual N and K gain and overcome actual P loss observed in soil. Rice-grain-equivalent yield of ricericeyardlong bean was the highest (35.39 t/ha), followed by ricericeamaranth (28.65 t/ha). The lowest ricegrain-equivalent yield was recorded from ricericefallow (10.63 t/ha). Ricericeyardlong bean had better sustainable-yield index (0.62), system productivity (96.96 kg/ha/day), land-use efficiency (91.79%), appar- ent nutrient-use productivity (118 kg/kg N, 221 kg/kg P O and 177 kg/kg K O), net returns ( 252 103/ha), sus- 2 5 2 tainable-value index (0.40), system profitability ( 751/ha/day) and net returns per rupee invested (1.95) than the other systems. Soil-nutrient balance under ricericeyardlong bean showed gain of 39 and 47 kg/ha of N and K respectively.