Effect of biochar as inoculum carrier on the fertility of sandy soils

Increasing the fertility of sandy soils is a worldwide problem. A field experiment investigated the combination of two of fertility increasing methods, the application of biochar (BC) and a plant growth-promoting rhizobacteria inoculum in acidic and calcareous sandy soils from the temperate region. The treatments studied were BC alone; BC with inoculum; inoculum on BC carrier; and inoculum on conventional carrier at four dose levels. BC levels were 3, 15 and 30 t/ha. As a test plant maize was sown. Based on the chemical and biological changes observed in the soil, BC was the more decisive factor in the treatments. BC increased the pH and nitrification in acidic soil and the P and K availability in both soils. The survival of inoculated bacteria was better when it was added with BC. In acidic soil the small dose of BC inhibited arbuscular mycorrhizal fungal infection, probably due to its toxic organic contaminants. The growing season was extremely dry thus, the treatments did not affect maize yield, but the increase in total above-ground biomass showed that the combined application of BC and inoculum is more beneficial than their separate application. 

 

Acknowledgement: This work was funded by the Norway Grant HU09-0029-A1-2013 entitled “Combined application of biochar and microbial inoculant for deteriorated soils.”