Validation of organic management in cassava intercropped in coconut plantation in the humid coastal tropics of Kerala, India

Abstract

Crop diversification and alternatives like organic farming assume importance for sustainable food production, especially during climate change. Besides, organic farming enables environmentally benign and clean food production. Cassava, an important food-cum-nutritional security crop with diversified uses in feed and industrial sectors, is a common intercrop in coconut plantations. On-station field experiments at ICAR-Central Tuber Crops Research Institute (ICAR-CTCRI), Thiruvananthapuram conclusively proved that organic management promoted productivity, tuber quality and soil properties in cassava. Cost-effective technologies were also developed, which required large scale field validation. Hence, a field experiment was conducted under Network Project on Organic Horticulture during 2015-2017 at the Research Farm, ICAR-Central Plantation Crops Research Institute, Kasaragod, to validate the ICAR-CTCRI developed organic farming technologies in cassava under intercropping in an organically raised mature coconut garden. Three varieties of cassava (Sree Vijaya, Vellayani Hraswa and H-165) were tested under four production systems viz., traditional, conventional, integrated and organic, and replicated thrice in split-plot design in a 48-year-old coconut (var. Kera Keralam) garden. Organic and conventional practices were equally efficient in crop growth, yield, tuber quality and soil chemical properties. Averaging over the years, yield under organic management was 76 per cent of conventional farming. The domestic and industrial varieties of cassava performed similarly under the different production systems, with almost the same yield reduction (24%) under organic over conventional management. The organic technology package comprising farmyard manure, green manure cowpea, cassava crop residue and biofertilizers, resulted in significantly higher available N in soil and improvement in P, K, Mg, Mn and Zn contents in cassava tubers. However, cassava var. Vellayani Hraswa under an integrated production system resulted in the highest net income (` 1,97,830 ha-1) and B:C ratio (1.99) when intercropped in coconut.