Residual Effects of Red Gram [Cajanus cajan (L.) Millsp.] on Growth, Yield and Quality of Fodder Maize (Zea mays L.)

Abstract

Background: Bio-recycling of crop residues is contemplated as an environment friendly soil enrichment and conservation practice that sustains agricultural productivity in the long run. Legume residues are privileged by the unique nitrogen fixing capacity and rhizospheric properties that enhance soil fertility, thereby reducing the need for chemical nutrient inputs. The present study was conducted to evaluate the residual effect of red gram on fodder maize cultivated as succeeding crop in the southern laterites of Thiruvananthapuram district, Kerala, India. Methods: The field experiment to assess the effect of red gram residue incorporation on the growth and yield of fodder maize was carried out in the Instructional Farm, College of Agriculture, Vellayani, Kerala during June - August 2019. Fodder maize (African tall) was sown in the plots after incorporation of crop residues of red gram varieties (APK 1 and Vamban (Rg) 3) grown under different planting geometry (40 cm x 20 cm and 60 cm x 30 cm) and NPK doses (40:80:40, 30:60:30 and 20:40:20 kg NPK ha-1) and compared with the package of practices recommendation and in randomized block design (RBD) replicated thrice. Result: Significantly higher quantities of red gram residues were realised and incorporated in the treatments involving a planting geometry of 40 cm x 20 cm and an NPK dose of 40:80:40 kg NPK ha-1 in both varieties used, Vamban (Rg) 3 and APK 1 (T7 and T1). Nutrient contents in the residues and decomposition in T1 and T7 resulted in the maximum additions in soil, available N, P and K status and dehydrogenase activity. Evaluation of the residual effects of the legume on fodder maize revealed the significantly highest growth and yields in maize raised with chemical fertilizers as per package recommendation and, among the residue incorporated treatments, maximum plant height and fodder yields were recorded in the treatment in which residues of Vamban (Rg) 3 raised at 40 cm x 20 cm spacing and fertilised with 40:80:40 kg NPK ha-1 were incorporated, on par with variety APK 1 raised under same management practice. The green fodder yield with residue incorporation was 80-90 per cent that under chemical fertilizer managed treatment. Among the quality parameters, crude protein (9.30%) was the highest with chemical fertilizer application while carbohydrate content (66.23%) was the lowest.