Effectiveness of organic-/bio-fertilizer supplemented with chemical fertilizers for improving soil water retention, aggregate stability, growth and nutrient uptake of maize (Zea mays L.)

In this study, an organic-fertilizer was prepared by composting fruit and vegetable wastes in a locally fabricated unit and enriching, it with N applied at the rate of 147 g kg(-1) compost. This "organic-fertilizer" was also used as a carrier for PGPR strain, Pseudomonas fluorescens biotype G (N-3) containing ACC-deaminase to formulate a bio-fertilizer. The organic- and/or bio-fertilizers were applied at 300 kg ha(-1) to maize in pots/plots supplemented with 0, 88 or 132 kg ha(-1) urea-N. A basal dose of P and K (100 and 50 kg ha(-1), respectively) was applied to all pots/plots. Results of two-years' pot and field trials revealed that the organic-fertilizer supplemented with 88 kg ha(-1) N was equally effective compared to full dose of N-fertilizer (175 kg ha(-1)) in improving root weight, fresh biomass, and ear and grain yields of maize. However, bio-fertilizer supplemented either with 88 or 132 kg N ha(-1) significantly increased the growth and yield of maize over full dose of N-fertilizer and exhibited superiority over organic-fertilizer. Organic-/bio-fertilizer application significantly enhanced N and P uptakes while substantially reducing the rate of water loss from the soil and increased aggregate stability. Results may imply that organic waste could be composted into value-added soil amendment by enriching/blending it with N and PGPR containing ACC-deaminase activity. The novelty of this approach is that the organic- or bio-fertilizer was used at a low rate Oust 300 kg ha(-1)). Moreover, this strategy could also be useful to protect our environments against threat posed by organic wastes.