Response of garlic (Allium sativum L.) to nitrogen and phosphorus under irrigation in Lasta district of Amhara Region, Ethiopia

Crop production under irrigation systems is under pronounced challenges resulted in low yield in Lasta district of Amhara region for many reasons among which no or inefficient application of the major nutrients (nitrogen and phosphorus) took considerable share. Hence, a field experiment was conducted to study the effect of nitrogen (N) and phosphorus (P) on the growth and bulb yield of garlic at Lasta district Kechin Abeba irrigation scheme in 2013 and 2015. The treatments were arranged in a factorial combination of three rates of N (0, 46, 92, kg ha−1) and four rates of P (0, 23, 46, 69, kg P2O5 ha−1) in a randomized complete block design in three replications. All triple supper phosphate (phosphorus source) was applied at transplanting whereas urea (nitrogen source) was applied in two splits (half at transplanting and the other half at 45 days after planting). Irrigation water was applied uniformly to all plots in furrow every 6 days. Agronomic data were collected and analyzed using SAS software and significant treatment means were separated using least significant difference at 5% level of significance. The effect of nitrogen and phosphorus was significant on plant height and bulb yield. Application of 92 and 46 kg P2O5 ha−1 increased bulb yield by 48.3% compared to the control and the partial budget analysis shows applying nitrogen and phosphorus at rate of 92N and 46 P2O5 kg ha−1was economically dominant over the other treatments. Therefore, application of 92N and 46 P2O5 kg ha−1is an optimum rate for garlic production at Lasta District, Kechin Abeba irrigation scheme and similar agro-ecologies