Effect of organic and inorganic fertilizer on yield and chlorophyll content of maize (Zea mays L.) and sorghum Sorghum bicolour (L.) Moench)
The effects of amending soil with organic (poultry manure) and inorganic fertilizer on yield and chlorophyll content of maize (Zea mays L.) and sorghum (Sorghum bicolour (L.) Moench) was carried out at the Teaching and Research (T&R) Farm of the Obafemi Awolowo University, (O.A.U.) Ile - Ife, Nigeria. The experiment was a randomised complete block design (RCBD), laid out in a split-plot arrangement in the second cropping season of year 2001 and 2002. There were four sources of fertilizer for soil amendment: inorganic fertilizer (IF), mixture of inorganic fertilizer and poultry manure (IFPM), poultry manure (PM) and control (C) (no fertilizer or manure treatment). Each fertilizer source supplied 54 kg N plus 25 kg P2O5 and 25 kg K2O5/ha. There were significant variability and diversity observed on the two crops due to treatments. Grain yield was highest in sorghum (3.55 kg/ha) and maize (2.89 kg/ha) under IFPM followed by IF treatment for maize (2.33 kg/ha) and PM treatment for sorghum ((3.37 kg/ha). Sorghum and maize had the highest dry matter of 72.3 g/plant and 71.0 g/plant under IFPM at harvest. The effects of PM on the dry matter of sorghum (68.1 g/plant) and maize (61.7 g/plant) were not significantly different (p = 0.05) from that of IF (sorghum 66.1 g/plant, maize 58.7 g/plant). Sorghum also had the highest leaf area (LA) (2752.9 cm2/plant) and total chlorophyll content of 3.28 mg/g under PM while maize on the other hand had the highest LA (1969.5 cm2/plant) and total chlorophyll content of 2.63 mg/g under IFPM. In both maize and sorghum, the lowest chlorophyll content occurred in control plot. Drought tolerance measured as percentage chlorophyll stability index (CSI%) was highest under control plots in both crops.