Development of Protocol for Custom Mixed Fertilizers for Elephant Foot Yam under Intercropping in Coconut Gardens of the Two Agro- Ecological Units of Kerala

Abstract

Root and tubers are the third most important food crops constituting either the staple or subsidiaryfood for about one fifth of the world population. Elephant foot yam (EFY) (Amorphophallus paeoniifolius(Dennst).Nicolson) is a highly potential tropical tuber crop and an ideal intercrop for the coconutgardens of Kerala especially in Agro Ecological Unit (AEU) 9 (South central laterites) and AEU 3(Onattukara sandy plain) having laterite and sandy soil types. This paper narrates the protocols designedfor the development of nutrient mixtures comprising of major, secondary and micronutrients for EFYintercropped in coconut gardens known as ‘custom mixed fertilizers’. It is a mixed multi nutrientcarrier whose sources are from inorganic and organic origin which are formulated through specificsystematic process of granulation and satisfies the nutritional demands of the crop, specific to agroecology, soil type and plant need designed taking into account the farmers nutrient managementstrategy also. The present study for the formulation of the custom fertilizer for the two AEU’s includedthe optimization of all required nutrients based on the weighted average of the soil data of the twoAEU’s comprising of 43 (AEU 3) and 161 (AEU 9) panchayats followed by validation of the optimumfixed through nutrient omission and nutrient level plot techniques for both major, secondary andmicronutrients as field experiments in farmers plots and on station. Based on the survey on farmers’nutrient application strategy, tuber yield, plant nutrient contents, total plant uptake, pre and post soiltest data, parameters like nutrient requirement, % contribution from soil, fertilizer use efficiency andnutrients to be applied through fertilizers were arrived. By fitting these parameters in soil test cropresponse and response curve approaches, the rate/ grades of component nutrients for the custommade fertilizers and their levels of application for the two AEU’s were designed. The three gradesdesigned were tried in two rates in five locations of the two AEU’s with eight treatments (includingpackage of practices and farmers’ practice) replicated thrice in randomized block design.