Effects of Poultry Manure and Plant Population on Soil Properties and Agronomic Performance of Sweet Maize (Zea mays L. saccharata Strut)
Donatus Felix Uwah, Cynthia Chinenye Ogar, Roseline Joseph Akpan

Abstract
A two-year field experiment was conducted during the late planting seasons from September to December of 2011 and 2012 on the acidic soils at Uyo and Calabar, to evaluate the effects of four rates of poultry manure (PM) (0, 5, 10 and 15 t/ha) in factorial combinations with four plant populations (PP) (57,142, 66,666, 80,000 and 100,000 plants/ha) on soil chemical properties and agronomic performance of sweet maize (Zea mays L. saccharata Strut). The treatments were fitted into a randomized complete block design with three replications. The application of PM significantly (P≤ 0.05) raised soil pH, organic matter (OM) content, total N, available P, exchangeable K, Ca, Mg and the effective cation exchange capacity (ECEC) status of the soil. The exchangeable acidity (EA) of the soil was reduced by more than two-fold in the two cropping seasons. The highest plant density (100,000 plants/ha), registered the lowest values for soil pH, OM and residual soil N, P, K, Ca, Mg and ECEC in both locations compared with other population densities. The 15 t/ha PM rate maximized sweet maize growth attributes, total dry matter (TDM) and grain yields and also hastened days to 50% tasselling and silking. On average over the two seasons, the application of 5, 10 and 15 t/ha PM rates increased TDM and grain yield by 9.11, 57.29 and 77.67%; and 52.32, 117.18 and 144.28% respectively, compared with the 0 t/ha PM rate. The highest PP registered the maximum leaf area index and the lowest TDM production whereas, the 66,666 PP maximized TDM, weight of grains/ear, 1000-grain weight, ear and grain yields in the two-seasons. Averaged over the seasons, the 66,666 plants/ha density out-yielded the 57142, 80,000 and 100,000 plants/ha densities by 56.05, 18.41 and 29.55% respectively, in terms of total grain yield. Plant population of 66,666 plants/ha in combination with 10-15 t/ha PM is therefore recommended as appropriate for late season sweet maize production in the south eastern Nigerian environment.

Full Text: PDF