Improving Yield and Economic Benefits of Garlic (Allium sativum L.) Through Integrated Use of Organic and Inorganic Fertilizers on Different Soil Types

Abstract

Soil fertility depletion is among the major impediments to sustained crop productivity because of limited application of fertilizers in Ethiopia. Crops yield  can be enhanced through balanced application of inorganic and organic soil nutrients. Thus, field experiment was conducted to investigate the effect of  chicken manure (CM) with reduced levels of inorganic nitrogen (N) and phosphorus (P) fertilizers on garlic growth, yields and economic benefits at  Debrezeit Agricultural Research Centre on two soil types (Andosols and Vertisols) in 2013/14 cropping season. The treatments consisted of factorial  combinations of three levels each N (0, 46, 92 kgha^-1), P (0, 20, 40 kgha^-1) and CM (0, 10, 20 tha-1); which were laid out in randomized complete block  design with three replications at each site. The analysis result showed that there was a significant main effect of N, P, CM and soil type on the evaluated  growth and yield traits in the experiments. Effect of the manure on growth and yield of garlic bulb were significantly higher on both soils than the mineral  NP fertilizers but the highest bulb yield of garlic was recorded from Vertisols than from Andosols. The applied fertilizers interacted and  significantly influenced the yield attributes of garlic on both soils. The highest bulb yield was obtained with the application of 46 kg N ha^-1, 40 kg P ha^-1  and 20 t CM ha^-1 on Andosols and with the application of 46 kg N ha^-1, 20 kg P ha^-1 and 20 t CM ha^-1 combination on Vertisols. There was a yield  advantage of 110% and 139% due to these two combinations over the lowest yield obtained from the control plot on Andosols and Vertisols, respectively.  Application of fertilizers at the combination rates of 46 kg N ha^-1, 20 kg P ha^-1 and 20 t CM ha^-1 significantly improved bulb yield by 57% on Vertisols than  the yield produced on Andosols. Moreover, the mean bulb yield produced on Vertisols was higher by 21% compared to that of Andosols. In addition,  the higher economic yield and marginal rate of return was obtained by the application of 10 t CM ha^-1 along with 46 kg N ha^-1 and 20 kg P ha^-1  on Andosols. Thus, application of 10/20 tha^-1 CM saved the recommended levels of N and P fertilizers by 50%, without reducing the bulb yield and  economic benefits of garlic.