Response of Cassava to Potassium Fertilization in a Tropical Sandy Typic Paleustult Amended with Burnt Rice Husk for Two-Consecutive Years

Abstract

ABSTRACT A tropical sandy Typic Paleustult soil has low fertility status with low nutrient retainability. A field experiment was carried out in a farmer field, northeast Thailand for two-consecutive years (2018–2019). Split plot design with four replications was employed with main plot consisting of five rates (0, 3.125, 6.25, 12.5 and 25 t/ha) of burnt rice husk (BRH) and subplot comparing six rates (0, 25, 50, 75, 100 and 125 kg K2O/ha) of potassium (K) fertilizer. Amending the soil with 12.5 t/ha of BRH promoted the significantly highest fresh tuber yield (FTY) of 29.31 t/ha in the first crop and all amended plots significantly gave better FTY than did non-amended plot in the latter crop. Cassava significantly produced the highest FTY when received 125 kg/ha of K2O in both growing seasons. In the second year, the addition of 25 t/ha of BRH along with 125 kg/ha of K2O interactively gave the highest FTY which was 99.7% greater than that of the plot received no BRH nor K fertilizer. The waste, with increasing rates, evidently stimulated more N, P and K uptakes in all plant parts while N uptake in tuber and K in all plant parts were increased by increasing K fertilization. Two-consecutive year application of BRH significantly improved available P, K, Mg, Zn and Cu contents in the topsoil.