Effect of variety and soil fertility management on performance of grain amaranth in different agro-ecological zones in Uganda

Abstract

Grain amaranth (Amaranthus spp.) is becoming an important crop in Uganda because of its nutritional value and potential grain yield. Since grain amaranth is a new crop, optimising its production requires adapted genotypes including optimum crop management practices. In this study, on-farm experiments were conducted in three agro-ecological zones represented by Kamuli, Nakasongola, and Apac districts; and one on-station experiment at Makerere University Agricultural Research Institute, Kabanyolo (MUARIK, Wakiso), to compare performance of grain amaranth varieties (Amaranthus hypochondriacus [cream] and Amaranthus cruentus [golden]) and determine influence of fertiliser application rate of (a) Urea at 0, 50, 100, 150 and 200 kg N/ha, (b) a composite fertiliser regime of urea and farmyard manure at 0:6, 25:6, 50:3, 75:1.5 and 100:0 kg N to tonnes of FYM/ha; on grain amaranth performance. Experiments were laid out as a randomised complete block design with a split-plot arrangement and replicated three times, for three seasons. Results from the single nitrogen fertiliser trial indicate that plant height, inflorescence height and grain yield of both varieties across all locations increased as more nitrogen was applied and maximum yield was achieved at fertiliser rate of 150kg N/ha. Results from the composite fertiliser trial show that maximum plant height, inflorescence height and grain yield were registered at a composite rate of 50KgN + 3 tonnes of FYM or 75kgN + 1.5 tonnes of FYM/ha for both varieties across study sites. Overall, grain amaranth performed better at MUARIK-Wakiso followed by Kamuli, Nakasongola and Apac. Also, cream variety performed better than golden variety in all locations regardless of fertiliser application rate.