ABSTRACT

Litter production, litter decomposition, nutrient cycling pathways and maize production were undertaken for 12months (January 2009 - December 2009) in an Entandrophragma cylindricum agroforestry- based ecosystem at Onne, Rivers State, Nigeria. The dry season months of November, December, January, February and March 2009 gave significantly higher leaf litterfall (508.80- 1070.20 kg ha'1) than the rainy season months of April - October, 2009 (118.67- 507.28 kg ha '*) . Total leaf litter decomposition (100.00%) of soilincorporated leaf litter was obtained at the 20th week after litter placement (WALP). Soil incorporated leaflitter had significantly higher decomposition percentages (69.49%) than the soil-surface placed litter (57.79%). Leaf litter half lives of the soil-surface placed and soilincorporated leaf litter were 9.90 and 6.91 WALP respectively. Total decomposition (100.00%) for fresh leaf of E. cylindricum was obtained at the 12th WALP for soilincorporated method. Soil-incorporated fresh leaf had significantly higher decomposition percentages (84.08%) than the soil-surface placed litter (67.38%). Fresh leafhalflives ofsoilsurface placed and soil-incorporated methods were 5.08 and 0.40 WALP respectively. No significant difference existed between leaf litter decomposition and the fresh leaf decomposition rates. In the precipitation pathways, stemflow and rainfall gave significantly the highest and the least pH, N, P, K, Na, Ca, Mg, Organic matter Organic Carbon, Fe nutrients contents. The precipitation pathways were in the following significant order: stemflow > throughfall > rainfall. The application of 4.0 or 2.0 t ha'1 poultry manure, or 1000kg NPK 15: 15: 15 fertilizer rates, more significantly improved maize yield than the 500 kg ha’1 NPK15:15:15 and the control treatments (with either no inorganic fertilizer or poultry manure) within and outside the E. cylindricum agroforestry farm. The 500 kg ha'1 and 1000 kg ha’1 NPK 15: 15: 15 treatments which had statistically similar maize plant height values gave significantly the highest plant height results. The two levels of poultry manure were statistically similar and significantly higher than maize plant established without inorganic fertilizer or poultry manure within or outside the E. cylindricum agroforestry farm. The maize plant within the E.cylindricum agroforestry farm without inorganic fertilizer or poultry manure treatment gave significantly higher plant height value than the maize plant established outside the plantation without any rate ofNPK15: 15: 15 or poultry manure.