New balanced nitrogen and potassium for cassava after common practices in Malaysia

NurulNahar, E.¹, Noor Ismawaty, N.²* and Mohd Rani, A.³

Abstract
Cassava is one of the most important food crops and is known to be the highest producer of carbohydrates among staple crops. Crop genetics, planting practices, and productivity have evolved over the last decade. New, high-yielding cassava varieties may have different nutrient requirements compared to older ones. Reevaluating fertiliser rates enables adjustments to new farming practices and more efficient nutrient utilisation. Hence, we studied the effects of three rates of nitrogen and potassium (0, 100, 200 kg/ha) on the growth and yields of two cassava varieties (Sri Kanji 2 and Sri Pontian) under clay and peat soils. A randomised complete block design with two replications was used. In Serdang (clay soil), nitrogen did not influence the fresh root yield. In Pontian (peat soil), an increase in nitrogen significantly increased fresh root yield, of which 200 kg N/ha produced 97.4 t/ha, followed by 100 kg N/ha (47.4 t/ha) and 0 kg N/ha (22.6 t/ha). Potassium (K) significantly increased cassava fresh root yield from 0 kg/ha (55.3 t/ha) to 200 kg/ha (71.2 t/ha) by 28.8%. There was no difference between 0 kg K/ha and 100 kg K/ha (61.4 t/ha). The fresh root yield of Sri Kanji 2 (65.2 t/ha) was slightly higher than Sri Pontian (60.1 t/ha) by 8.5% but did not differ. For optimum yield and to avoid nutrient depletion for long-term cassava cultivation, the rates (N: P2O5:K2O) of 100:50:100 and 200:100:200 for clay and peat soil are recommended.

Keywords: cassava, starch production, root yield, nutrient, Manihot esculenta

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