Paper Title
IMPROVING LEAF NUTRIENT CONCENTRATIONS AND MINERAL COMPOSITION OF SWEET POTATO WITH BIOCHAR AND POULTRY MANURE COMBINATION IN DEGRADED SOILS

Abstract
Abstract - Field experiments were conducted over two growing seasons (2019 and 2020) at two degraded soils to assess the impact of biochar (B), poultry manure (PM), and their combined application on the leaf nutrient concentrations and mineral composition of sweet potato. A randomized complete block design with a factorial layout and three replications was employed. Each year, the experiment comprised various combinations of biochar (0, 10.0, 20.0, and 30.0 t ha−1) and poultry manure (0, 5.0, and 10.0 t ha−1) in a 4 × 3 factorial layout. The findings revealed that both the individual application of biochar (B) and poultry manure (PM) and their combined application significantly enhanced the leaf nutrient concentrations and mineral composition of sweet potato storage roots. Notably, there were significant interactions between biochar and poultry manure (B × PM) in terms of leaf nutrient concentrations and mineral composition, indicating the potential of biochar to enhance the efficiency of poultry manure utilization and improve nutrient utilization from poultry manure. The highest leaf nutrient concentrations and mineral composition of sweet potato were observed when applying a combination of 30.0 t ha−1 biochar and 10.0 t ha−1 poultry manure (B30+ PM10) at both sites. Conversely, the control group exhibited the lowest leaf nutrient concentrations and mineral composition. These findings suggest that the combination of biochar and poultry manure has the ability to improve the leaf nutrient concentrations and mineral composition of sweet potato storage roots, which can have positive implications for human health in severely degraded soils. Keywords - Degraded Soils, Biochar, Leaf Nutrient Concentrations, Mineral Composition, Poultry Manure, Sweet Potato.