Effects of integrated use of organic and inorganic fertilizers on soil properties, yield and yield components of maize (zea mays l.) on the nitisols of pawe district, northwestern Ethiopia

Abstract

Maize (Zea maize) is a major cereal crop in Pawe District; however, the current yield is decreased due to low soil fertility status by continuous cultivation, limited use of organic and inorganic fertilizers, erosion, and leaching. Hence, a field experiment was conducted at Pawe research station during 2020 cropping season to determine the effects of integrated use of Farmyard manure (FYM) and nitrogen fertilizer (urea) on soil physico-chemical properties, yield and yield components of maize on Nitisols. Factorial combination of four levels of FYM (0, 5, 10 and 15 t ha-1) and four levels of Nitrogen (0, 34.5, 69, and 103.5 kg ha-1) were laid out in Randomized Complete Block Design (RCBD) with three replications. Soil samples were taken before treatment application and after harvesting, and selected soil physicochemical properties were analyzed following laboratory standard procedures. Samples of FYM were also taken and analyzed to determine its quality. All collected soil data, phenological, yield and yield components of maize data were analyzed by using SAS software (version 9.4). Before treatment application, soil result showed that the study site was clay in texture, moderately acidic (5.32), low in BD (1.25), total N (0.139), AvP (9.24) and exchangeable (Exc.) Na (0.195), moderate in OC (1.90), Exc. Mg (2.67) and K (0.52), and high in CEC (27) and Exc. Ca (12.39). The analyzed FYM (pH=7.53, OM=9.34, C: N ratio=6.61) were suitable, had high nutrient contents and were well matured for application. After crop harvest the soil analysis of variance showed that the soil pH, OC, TN and AvP was affected significantly (p<0.05) by the main effects of N fertilizer, and the soil BD, pH, OC, TN, AvP, CEC and Exc. cations (Ca, Mg and K) was also affected significantly (p<0.05) by the main effects of FYM. The combined applications of FYM and N fertilizer were significantly (p<0.05) affected the soil pH, OC, CEC and Exc. Ca. The highest maize grain yield (GY) (10,035.8 kg ha-1) and thousand-grain weight (TGW) (415.97gm) were obtained from the application of 10 t ha-1 FYM with 69 kg ha-1 N, but grain yield was at par with the applications of 69 kg N with 15 tons FYM; 103.5 kg N combined with 10 and 15 tons ha-1 FYM. However, the lowest GY (4534.1kg ha-1), TGW (299.47gm) and above ground biomass yield (AGBY) (15.17 t ha-1) were recorded from the control treatment. The highest AGBY (25.83 t ha-1) was obtained from the interaction effect of 103.5 kg ha-1 N +15 t ha-1 FYM, but statistically at par with the combined applications of 69 kg N with 10 and 15 tons FYM; 103.5 kg N with 10 tons FYM per hectare. All yield component parameters were positively correlated with the grain yield of maize. The combined applications of 10 t ha-1 FYM and 69 kg ha-1 N was the most recommended and economically feasible for maize production and soil fertility improvements on the Nitisols of the study area, which provided the net benefit of (81,258.7 ETB ha-1) with an acceptable MRR of (497.96%).