Tropical eggplant (Solanum melongena L.) production with a buffelgrass (Pennisetum ciliare L.) living mulch system in Hawaii

This research was conducted to determine if a living mulch polyculture system, designed for mitigating non-point source pollution, is also a viable crop-production system in a tropical island ecosystem. Two field experiments were conducted in Hawaii to compare the yield of eggplant in a buffelgrass (Pennisetum ciliare L.) living mulch system with the yield of eggplant in a conventional monoculture bareground system. In the first experiment, eggplant grown in chemical suppressed living mulch treatment plots produced over 100% higher yields than the conventional treatment plots, due to higher mite (Tetranychus cinnabarinus Boisduval) infestation levels in the conventional monoculture plots. Soil moisture levels were higher within the living mulch treatments than in the conventional treatment. Hand labour times recorded to maintain a weed-free status were significantly greater in the conventional treatment plots due to the greater weed densities established in the exposed between-row spaces. The establishment of a buffelgrass living mulch increased microbivorous nematode populations, but only had a variable influence on plant-parasitic nematode populations. In the second experiment, the conventional monoculture treatment had a significantly higher early yield, but was not significantly higher than the suppressed living mulch treatments in the final cumulative yields. Eggplant yields from the mechanical and chemical-suppressed living mulch treatments were significantly higher than in the unmanaged living mulch treatment. This research supports the living mulch system as a viable production system with integrated benefits of pest management and land stewardship for tropical island ecosystems.