Effect of poul try manure biochar on soil chemical properties and yield of Zea Maysl. cultivated on an Ultisol

Phosphorus (P) is a major chemical nutrient needed for plant growth. The objective of this research is to determine the effect of poultry manure biochar application on soil P as well as the performance of maize. This study was conducted at the Faculty of Sustainable Agriculture, Universiti Malaysia Sabah, and consisted of a phosphorus leaching study, a preliminary pot study and a field trial. Field planting was carried out for two cropping cycles (10 weeks per cycle) inside a net house using randomized complete block design (RCBD). Three poultry manure biochar rates (0, 7.5 and 15 t ha-1), two types of phosphate rock (Triple Super Phosphate and Egypt Rock Phosphate) and two phosphorus fertilizer rates (60 and 120 kg ha-1) were used for this research. For the soil, total N, pH, cation exchange capacity (CEC), total organic carbon (TOC), P, K, Ca and Mg were measured. For the maize, plant height, total dry matter, and estimated grain yield were measured. In the phosphorus leaching study, the application of biochar (10%) and phosphorus fertilizer (120 kg ha-1) showed a significant increase of Pin the soil which no interaction between the P and biochar. In the pot experiment, no significant main effect differences were observed for all the parameters except for biochar rate main effect on soil pH, CEC, total N, P and Mg. Similarly, there was no significant interaction effect between all the factors except for biochar rates and type of phosphorus fertilizer on mean maize height; for biochar rates and phosphorus fertilizer and for biochar rate with phosphate rock on total dry matter. In the field experiment, no significant Interaction was observed for all factors. However, there were significant differences for some soil chemical parameters for either the first or second crop except for soil TOC and K that showed significant differences for both crops. For leaf nutrient content, no significant interaction resulted between all the main factors for the first and second crops but significant differences resulted for some nutrients except for leaf phosphorus for both crops. There was a significant interaction between biochar rates and phosphorus fertilizer on mean maize height for both crops and for grain yield for the first crop. The addition of biochar can retain P in the soil due to adsorption as well as significantly increasing the soil N, K, Ca, Mg, pH, CEC and TOC. The addition of biochar at 15 t ha-1 generally improved the concentration of soil nutrients. The crop growth in terms of plant height, dry matter and crop yield increased significantly. Increasing the rate of biochar increased the nutrient uptake by maize, thus increasing the growth and productivity of the maize