Effect of phosphorus-enriched biochar and poultry manure on growth and mineral composition of lettuce (Lactuca sativa L. cv.) grown in alkaline soil

The use of pyrolysis products of manures gives positive effects on soil fertility, crop productivity and soil carbon sequestration. However, effects depend on soil characteristics, plant species and the raw material from which the biochar is derived, and some negative effects of biochar have been reported. The objective of this study was to evaluate the effectiveness of poultry manure (PM)-derived biochar on the growth, and P, N, K, Ca, Mg, Fe, Zn, Cu and Mn concentration of lettuce (Lactuca sativa L.) plant. The treatments as follows: control, 20g/kg poultry manure (PM), 20g/kg phosphorus-enriched poultry manure (PM+P), 10g/kg Biochar (B), 10g/kg Biochar+P (B+P). Application of biochar and PM significantly increased lettuce growth, and P-enriched forms of PM and biochar gave the higher growth. PM has no significant effect on the N concentrations but biochar and, P-enriched PM and biochar treatments significantly increased N concentrations. Phosphorus concentration of the lettuce leaves significantly increased by PM and biochar treatments. Plant K concentrations were also increased by PM and biochar, and their P-enriched forms. Leaf Ca and Mg concentrations were lower in Biochar and B+P treatments than that of PM and PM+P treatments. Compared to control and PM treatments, biochar applications reduced Fe, Zn, Mn and Cu concentrations of the lettuce plants. The results of this study indicated that application of biochar to alkaline soil is beneficial for crop growth and N, P and K nutrition, but it certainly reduced Fe, Cu, Zn and Mn nutrition of lettuce.