See more from this Session: Managing Nutrients In Organic Materials and by-Products: II
Wednesday, October 19, 2011
Henry Gonzalez Convention Center, Hall C, Street Level
Commercial vegetable growers in Hawaii are largely dependent on imported synthetic fertilizers to reach yield targets. Growers are increasingly interested in finding locally available fertilizer alternatives that will reduce dependence on imported fertilizers. A series of field experiments were established on Maui with the aim of evaluating the nutrient supply capacity of a locally available commercial compost product (EKO) made from sewage sludge and green waste. The first set of experiments consisted of a 2X4 factorial with two compost treatments (0 and 33.5 T ha-1) and four rates of nitrogen (0, 84, 168, 336 kg N ha-1) with Maui sweet onion. The second set of experiments consisted of three consecutive crop cycles of sweet corn with two compost treatments (0 and 33.5 T ha-1) and two N rates (0 and 202 kg ha-1). At the 84 kg N rate, compost increased sweet onion yield by 31% increasing N rate beyond 84 kg with compost showed lower yield benefits. Repeated applications of compost eliminated the need for additional N fertilizer after the first cropping cycle in the sweet corn experiments. In addition, compost applications enhanced soil chemical and biological properties. The results suggest that EKO compost is a viable replacement for imported synthetic fertilizers on Maui.