More efficient nitrogen utilization through wool pellet and soil inoculation

Abstract

In recent years, many alternative bio-waste-based fertilizers have been proven to have a beneficial effect on plant nutrition. These also include wool pellet, whose comprehensive evaluation of synergistic effects on plant development and soil biological activity is still a limited field of investigation. To address this, we explored the potential of combining soil inoculations and N-rich wool pellet as ecologically sound alternatives to N fertilizers. In a pot experiment, we investigated the effect of Azotobacter vinelandii, the Trichoderma harzianum T34, and wool pellet, individually and in combination, on the growth and nitrate uptake of the test plants, as well as on the biological activity and permanganate-oxidizable carbon of the sandy soil with low organic matter content. The combination of T. harzianum + wool pellet showed the highest biological activity and permanganate-oxidizable carbon content, while the untreated control plants exhibited the lowest values. The treatment combination of wool pellet and A. vinelandii exhibited the highest nitrate uptake by plants. Measuring the concentration of photosynthetic pigments, net photosynthesis, transpiration rate, stomatal conductance, and total dry biomass, we found that the treatments led to a significant improvement in the photosynthetic intensity of lettuce plants. These results suggest that wool pellet served as a significant source of N and that their biological activity plays a key role in improving plant parameters. Moreover, the combination of microbial inoculants and wool pellet effectively increases N use efficiency in plant growth.