Soil ph and microbial properties as affected by integrated use of biochar, poultry manure and urea

Abstract

Background and Objective: The use of biochar, a charred organic material, is becoming a sustainable technology that leads to the improvement of highly weathered tropical soils. A study was conducted at the Teaching and Research Farm of the University of Calabar to compare the effects of integrated use of Biochar (B), Poultry Manure (PM) and urea on the pH and microbial properties of soil-grown with Amaranthus cruentus. Materials and Methods: A total of 15 treatments consisting of a sole and combined use of biochar, poultry manure, urea and control were fitted on a randomized complete block design with 3 replications. The organic amendments were applied 2 weeks before sowing while urea was applied 2 weeks after sowing. Composite soil samples (0-15 cm) were taken before and after the experiment for pH and microbial analysis. Results: Soil pH was raised from a strongly acidic level to values ranging from 5.73-6.8 (moderately acid-slightly acid, respectively) pH level after the experiment with the highest obtained in Full B+½PM amended soil. The fungal population was maximum in PM (sole and combinations) (18×103-20×103 CFU g-1) and minimum in sole biochar and control (×-10×103 CFU g-1). The bacterial population exhibited a similar trend with the maximum value in PM (sole and combinations) (98×106-148×106CFU g-1) and minimum in control (×-36×106CFU g-1). Conclusion: This suggests that biochar addition alone did not cause any apparent alteration to the microbial population and diversity compared to its complementary use.