Effects of Poultry Manure and Cropping Systems on Chemical Properties and Productivity of Ultisol in Umudike, Southeastern Nigeria

Abstract

Problems of maintenance of soil properties and sustainability of crop yield have led to increased use of organic manure. Poultry manure (PM) at 0, 5, 10 and 15t/ha was used for this study as organic amendments on chemical properties and productivity of an Ultisol in Umudike, southeastern Nigeria. Topsoil (0-20cm) samples collected from Michael Okpara University of Agriculture, Umudike farm before planting and after harvesting sole maize (SM), sole okra (SO) and maize-okra intercrop (MO) were used to determine soil properties. The properties determined were organic matter (OM), pH, available phosphorus (AP), total nitrogen (TN), exchange properties (Ca, Mg, K, Na), exchange acidity (EA), micronutrients (Fe, Cu, Zn) and particle size distribution. Fresh maize cob (FMC), weight and fresh okra pod (FOP) weight were measured. The experimental design was a split plot in a randomized complete block design (RCBD) replicated thrice. The PM was the sub-plot treatment while the cropping system (CS) was the main-plot treatment. Data generated were subjected to analysis of variance (ANOVA) and differences between means were detected by Fisher’s least significant difference (F-LSD) at 5% probability level (P£ 0.05). Correlation and regression (by the method of Little and Hills) were used to determine relationship among soil properties. The soil texture was loamy sand. Improvements in soil properties and crop performance due to PM application were significant (P£ 0.05) compared to the control. However, at 5t/ha, TN (0.39%), Mg (1.38cmol/kg) and EA (2.08 cmol /kg) were not significantly different from the control (0.31%, 1.36cmol/kg and 2.13cmol/kg). Regression of organic matter and pH showed that organic matter accounted for 25.4% reduction in acidity. The correlation of pH with Ca and Mg indicated a positive significant (P£ 0.01) relationship (r = 0.585) and (r = 0.501), respectively. Compared to the control, poultry manure application significantly (P£ 0.05) increased fresh maize cob and fresh okra pod weights, as sole or intercrop. At 10t/ha poultry manure, fresh maize cob weight from sole maize plots increased by 63.3% above the control, whereas fresh okra pod from sole okra plots increased by 149.8%. These results suggest that application rate of 10t/ha poultry manure will enhance the chemical properties and production of maize and okra in Ultisols in Umudike