Garlic (Allium Sativum L.) response to Nitrogen fertilizer rate and Intra-row spacing in Enderta Woreda, South Eastern Tigray, Northern Ethiopia

Abstract

Garlic (Allium Sativum L.) is one of the most ancient widely cultivated vegetable crop, and propagated by cloves and used for food medicinal purposes. However, its productivity is far below the demands. This is due low soil fertility; inappropriate planting density, and major diseases. A field experiment was conducted at Mekelle University Endayesus compus to study the effect of different nitrogen levels and intra- row spacing on yield and yield component of garlic during 2024 irrigation season using a local variety of garlic. The treatments consisted of four levels of nitrogen fertilizer (0,46,69 and 92 kg N ha -1), and three levels of intra- row spacing (5, 10 and 15 cm) arranged in randomized completely block design replicated three times each. Data were collected on plant growth, bulb yield and yield components and garlic rust diseases infestation level. The result showed that the different nitrogen rates significantly (P<0.01) affected garlic plant height, leaf length, leaf dry weight and marketable yield. Besides, intra row spacing significantly (P<0.05) influenced all garlic parameters except leaf number, clove number, and harvest index. Similarly, their interaction had significant effect on marketable yield and total bulb yield. The least and highest diseases severity and incidence percentages (4.1 &19.4) and (20 & 55%) was recorded from plots spaced at 5 & 15cm respectively. The highest 9 t ha-1 total bulb yield was recorded at 5 cm intra -row spacing and 69 kg of nitrogen fertilizer. The highest marketable yield of 8.1 t ha-1 was recorded from application of 46kg N spaced at 5 cm of intrarow spacing. Cost benefit analysis indicated that the highest (2,134,200) and lowest (1,162,533.34) ETB ha-1 net return was earned from 46 and 69 N ha-1 spaced at 5 and 15 cm intra row spacing respectively. The maximum marginal rate of return (8690%) was obtained from plots treated with 46 kg N and 10 cm intra row spacing. In garlic production, the application of nitrogen fertilizer at rates exceeding 92 kg ha-1, combined with an intra-row spacing of 15 cm, has been found to be uneconomical. Such practices not only result in excessive costs but also lead to diminishing returns in terms of yield. Based on these findings, it is recommended that farmers should reduce nitrogen fertilizer application to 46 kg N ha-1 and adjust the intra-row spacing to 10 cm. This rate of nitrogen and intra row spacing is expected to optimize fertilizer use efficiency, reduce unnecessary input costs, and enhance the overall profitability of garlic production.