GROWTH, YIELD AND QUALITY OF GARLIC (Allium sativum L.) TO BLENDED NPS AND ZINC FERTILIZER RATES AT DEBRE BERHAN, CENTRAL HIGHLAND OF ETHIOPIA

Abstract

Garlic (Allium sativum L.) is the second most important and widely grown Allium crop in many regions of Ethiopia. However, the average bulb yield is low compared to the crop's potential yield due to several factors including lack of improved varieties, the occurrence of diseases and insect pests, lack of improved post-harvest technologies, poor agronomic and cultural practices and inappropriate use of fertilizer rates. Among these, inappropriate applications of macro- and micronutrient fertilizers are the major agronomic practices that tremendously reduce the yield of the crop. Using proper types and rates of fertilizer is one of the measures to increase the crop productivity in the region. Hence, a field experiment was conducted to evaluate the effects of blended NPS and zinc fertilizer rates on the growth, yield, and quality of garlic during irrigation time of 2022/23. The treatments consisted of factorial combinations of four rates of NPS fertilizer (0, 121, 242 and 363 kg ha-1) and four levels of Zn (0, 0.3, 0.6 and 0.9%). The experiment was laid down in a randomized complete block design with three replications using the garlic cultivar ‘Qundi’. Data on different phenological, growth, bulb yield and quality-related variables were collected and analyzed using R- software. The analysis of variance showed that most of the studied parameters were significantly affected by the interaction of the two factors. Accordingly, the study revealed that the combined application rates of 242 kg ha-1 NPS and 0.6% zinc resulted in the widest neck diameter (1.52cm), longest bulb length (4.98cm), widest bulb diameter (4.44 cm), longest clove length (2.61 cm), widest clove diameter (1.59cm), highest average bulb weight (44.63g), highest average clove weight (5.93 g), highest total bulb yield (14.89g), highest harvest index (87.41%), and highest percent dry matter content (43.18%). The average bulb weight, percent dry matter content and total bulb yield due to 242 kg ha-1 of NPS and 0.6% of zinc fertilizer application was increased by15.17, 24.12 and 39.94%, respectively, as compared to 242 kg ha-1 NPS without zinc application. In addition, the highest net benefit (Birr 1,606,330 ha-1) with an acceptable marginal rate of return (116.61%) was recorded from 242 kg ha-1 of NPS with 0.6% Zn rate application as xvi compared to the other treatments. Thus, it can be concluded that the combined application of NPS at a rate of 242 kg ha-1 and Zn at 0.6% rate could be recommended to enhance total bulb yield and quality of garlic in the study area and other similar agro-ecologies.