Evaluation of Azolla As Biofertilizer for Vegetable Production on Alluvial Soil in West Kalimantan, Indonesia.

In order to achieve food security in Indonesia, it is recommended to enhance self-sufficiency of households by diversifying locally-available food. Therefore, each household is expected to grow vegetables in their backyard. One approach to intensify vegetable production is through locally-grown fertilizer. The Azolla-Anabaena symbiosis can provide N for vegetable production through biological nitrogen fixation. The aim of this study was to evaluate the potential for use of Azolla pinnata as fertilizer on red spinach and radish production on Inceptisols in West Kalimantan, Indonesia as compared to commonly-used fertilizers. The experimental design was a Randomized Complete Block Design with three replicates. Treatments were an unfertilized control, urea at 50 kg ha^-1, chicken manure at 5 t ha^-1, Azolla at the urea N rate, and Azolla at the manure N rate. Treatment means were compared using the honestly significant difference Tukey adjusted post hoc test (n=3, P<0.1). Manure had the highest yield in both crops. In spinach production, manure was comparable in yield to urea; whereas there were no significant differences in radish yield. The highest leaf N content of spinach was found in the manure treatment; however, it was not significantly dissimilar to urea, control, or Azolla applied at the urea rate. The highest bulb N content of radish was in Azolla applied at the manure N rate, although there were no differences among N fertilizer treatments. The highest nitrogen use efficiency (NUE) in spinach was in the urea treatment and there was no N fertilizer effect on NUE in radish. Nevertheless, the highest NUE in radish was Azolla at the urea N rate. Manure also showed a significant effect on radish height. In summary, the radish did not respond to any fertilizer treatment, and Azolla was not as effective as urea or manure at increasing spinach yield on alluvial soil.

Key Words

locally-grown, Azolla, vegetable, alluvial