Germination of Maize as Affected by Rates and Time of Poultry Manure Application.
S. Agyenim Boateng, Soil Research Institute, Academy Post Office, Kwadaso-Kumasi, -, Ghana
There have been recent complaints of poor germination and burning of seedlings from farmers using Poultry Manure (PM) to cultivate maize in the forest zone of Ghana. This study was conducted to investigate the causes of these problems. PM in a semi-decomposed state and containing 11% water content in rates of 0,2,2x2(split),4,6, and 8 pm t/ha was used in a field trial to study the effect on maize. Treatments of recommended mineral fertilizer and 2 t pm/ha plus one-half mineral fertilizer rates were included. Two weeks after sowing it was observed that increasing the amount of the pm applied decreased the germination of the maize seeds. With 4 and 6 t PM/ha, the germination rates were 74% and 68% respectively of the control and at 8 t/ha, the control plot had twice the number of young maize plants. No negative effect was observed with the lower rates and the mineral fertilizer. A satellite experiment was, therefore, set up to delineate the causes of this observation. PM rates of 0,2,4,8 and 12 t/ha were applied to maize seeds sown either in contact with the manure or away from the manure,and either on the day of manure application or six days later. The results showed that higher rates of PM applied at a time had negative effects on maize germination. Temperatures of 34C and above, ammonium concentration of above 1500 ppm and eC of above 5 mS/cm were found to be responsible for the detrimental effects. In order to reduce those effects in the forest zone of Ghana, it is confirmed that direct contact with seeds should be avoided; and recommended that a minimum period of one week after manure incorporation should elapse before sowing (in fact, three weeks is preferred); and that if maize seeds would have to be sown within one week of manure incorporation, the rate should not exceed 2 t/ha applied at a time.