Improved phosphorus fertilisation efficiency of wood ash by fungal strains Penicillium sp. PK112 and Trichoderma harzianum OMG08 on acidic soil

Abstract

Effective recycling of phosphorus (P) remains a critical issue in sustainable agriculture. Wood ash represents valuable soil amendment and potential source of P for agriculture, but its solubility and subsequent P-fertilisation efficiency is extremely low. This study tested fungal inoculants (Penicillium sp. PK112 and Trichoderma harzianum OMG08) applied alone and in combination with wood ash on P-limiting acidic soil to determine if they can improve P-nutrition in maize. Wood ash alone did not have any significant P-fertilising effect. Application of both inoculants, when combined with wood ash, led to significant increment of plant-available P content in soil, increased P uptake by maize plants and consequently to higher production of maize shoot biomass. Both inoculants suppressed overall microbial activity in soil as determined by the activity of dehydrogenase, alkaline phosphatase and microbial P content. Only T. harzianum led to higher activity of soil acid phosphatase. This study demonstrated that tested strains may be co-applied with wood ash to improve its P-fertilisation efficiency. The positive influence of inoculants on P availability was mainly due to stronger acidification of rhizosphere and decreased content of microbial P. However, both effects seemed to be hindered by the P sorption capacity of the soil in the case of inoculation without wood ash. Such findings may lead to development of novel formulations of recycled fertiliser products and boost nutrient recycling in agriculture.