Integrated Use of Farmyard Manure and NP fertilizers for Maize on Farmers’ Fields

Abstract

A study was initiated in 1997 to introduce the culture of supplementing low rates of NP fertilizers with farmyard manure (FYM) in the maize based farming system of western Oromia. The treatments were 0/0, 20/20, 40/25 and 60/30 kg N/P ha⁻¹ and 0, 4, 8, and 12 t FYM ha⁻¹ in factorial arrangement in a randomized complete block design with three replications. The experiment was conducted at Laga Kalla, Walda, Shoboka, Harato, and Bako Research Center using BH-660 hybrid maize. The FYM used for the experiment was well decomposed under shade and spot applied together with the P fertilizer at planting; N was applied in split form. The residual effects of FYM were investigated for Laga Kalla, Walda and Shoboka during the 1998 cropping season. Statistical analysis revealed that the N/P fertilizers and FYM significantly (p < 0.05) increased grain yield in all locations except for Walda in 1997. Interactions of FYM and NP fertilizer rates were significant (p ≤ 0.05) at all locations except for Shoboka. The application of FYM alone at rates of 4, 8, and 12 t ha⁻¹ produced average grain yields of 5.76, 5.61 and 5.93 t ha⁻¹, respectively, compared to 3.53 t ha⁻¹ for the control treatment in 1997. There were significant residual effects of FYM and NP fertilizers applied in 1997 on maize grain yields in 1998. Laboratory analysis confirmed that considerable amounts of macronutrients and small amounts of micronutrients were supplied by FYM. Based on the results of this study, the integrated use of properly managed FYM and low rates NP fertilizers could be used for maize production in the areas under consideration. Moreover, sole applications of FYM on relatively fertile soils like Walda and Harato are useful in maintaining soil fertility and are encouraging for resource poor farmers.