Effect of Integrating Poultry Manure and Inorganic NP Fertilizers on Growth, Yield and Yield Component of Maize (Zea mays L.) at Ambo, Ethiopia

Abstract

Soil fertility decline is a major constraint to sustain higher agricultural production and productivity in tropical soils due to removal of crop residues from crop fields, low inherent soil fertility and the repeated suboptimal fertilization. A field experiment was conducted at Ambo University research farm, Ethiopia to investigate the effect of different levels of poultry manure (PM) and NP fertilizer rates on growth, yield and nutrient uptake of maize (Zea mays L.). The experiment consisted of eight treatments: control, 15 t ha-1 PM, 30 t ha -1 PM, 15 t ha-1 PM + 25% rec. NP, 15 t ha-1 PM + 50% rec. NP, 30 t ha-1 PM + 25% rec.NP, 30 t ha-1 PM + 50 % rec.NP and 100% recommended dose of NP fertilizer rates which were laid out in randomized complete block design (RCBD) with three replications. The results showed significantly (P<0.001) higher values of plant height, number of leaves per plant, leaf area, leaf area index, number of cobs per plant, cob girth, cob length, number of grains per cob, 1000-grain weight, dry biomass yield, harvest index and grain yield with the application of 30 t ha-1 PM plus 50% recommended NP fertilizer compared to both the absolute and standard controls. The highest maize grain yield (132.7q ha-1) was recorded for the treatment that received 30 t ha-1 PM combined with 50% recommended NP fertilizer. The lowest values of growth parameters, yield and yield components were recorded from the absolute control where no PM and chemical NP fertilizer were applied. Higher total N and P uptake was recorded with the application of 30 t ha-1 PM plus 50% recommended NP fertilizer. Correlation analysis indicated a positive relationship between grain yields and all growth and yield parameters. Moreover, the economic analysis showed higher net benefits from the application of 30 t ha-1 PM plus 50% rec. NP fertilizer rates. The integrated use of organic manure along with inorganic fertilizer improved the total nitrogen and phosphorus uptake.