Evaluation of sweet potato (Ipomoea batatas) based strip intercropping systems for yield, competition indices and nutrient uptake

摘要

Field experiments were conducted at Dumduma, Bhubaneswar, for three consecutive years (2006-2008) to assess the sweet potato based strip intercropping systems with respect to productivity, nutrient uptake, competition and economic parameters. Sweet potato (Ipomoea batatas L.) + pigeonpea [Cajanus cajan (L.) Millsp.] strip intercropping system recorded significantly higher root equivalent yield (13.53 t/ha) compared to other cropping systems except sole sweet potato. The total yield gain in sweet potato + pigeonpea system was 28.8% and 24.7% over sweet potato + rice (Oryza sativa L.) and sweet potato + ragi (Eleusine coracans L.) strip intercropping system. Root equivalent yield of sole sweet potato was significantly higher than the sole stand of other crops and strip intercropping systems except sweet potato + pigeonpea. Competition indices like land equivalent ratio (LER), area time equivalent ratio (ATER), aggressivity (A) and monetary advantage index (MAI) values were higher for sweet potato + pigeonpea strip intercropping system. Sweet potato appears more competitive than companion crops like rice or ragi. Partial competition ratio value of companion crops like maize (Zea mays L.) and pigeonpea had an edge over sweet potato in sweet potato + maize and sweet potato + pigeonpea strip intercropping systems. The uptake of N, P and K were observed to be more when sweet potato, maize and pigeonpea were included in the strip intercropping systems. The root equivalent yield and competition indices and economic parameters indicated that the strip intercropping of sweet potato with pigeonpea is biologically sustainable and economically viable.