Crop-weed dynamics, nutrient uptake, and soil microclimate in elephant foot yam under conservation agriculture

Conservation agriculture (CA) is a sustainable option to adapt to climate change. Weed management is one of the most important challenges faced by CA. Information on CA in cropping systems involving elephant foot yam (Amorphophallus paeoniifolius (Dennst.) Nicolson), an important tuber crop, is lacking. Hence, this study aimed to determine the effect of CA in elephant foot yam on crop-weed dynamics, nutrient uptake, and soil microclimate. Field experiments were conducted in randomized block design over two seasons at ICAR-Central Tuber Crops Research Institute, Thiruvananthapuram, Kerala, India, in elephant foot yam (var. Gajendra) intercropped with banana (var. Robusta) with five treatments viz., conservation organic, conservation chemical, conventional chemical, existing conventional [package of practices (POP) as control], and existing organic package. The weed flora was dominated by broad-leaved weeds. By the fourth month, conservation chemical practice reduced the weed density by 58.8% and weed biomass by 55% over existing POP. The total biomass production and its partitioning to corms, uptake of nitrogen (N), phosphorus (P), and potassium (K), crop growth rate, corm bulking rate, and harvest index of elephant foot yam did not differ significantly under conservation or conventional practices but were higher in conservation chemical practice. The N, P, and K physiological efficiencies were higher in conventional chemical treatment. The soil microclimate was improved, with higher soil CO2 flux and soil moisture in conservation organic or organic plots. The study proved that conservation practices involving reduced tillage, residue retention, and use of herbicides was a viable alternative in banana + elephant foot yam system.