Agronomic and Economic Benefits of Garden Organics Compost in Vegetable Production

Abstract

Little research has been carried out on the agronomic and economic value of compost produced from garden organics for vegetable production. A field experiment was established in Camden, near Sydney, Australia (i) to evaluate the effect of the compost on vegetable production (ii) and to evaluate the economic returns from using compost in vegetable production. A total of five vegetable crops were grown and the results indicated that a once only application of compost at an agronomic rate of nitrogen (125 t/ha) produced similar or higher vegetable yields than that of current farmer's practice. For four of the five crops grown, yield was similar, and for one of the crops (capsicum), compost treatment yielded 21% higher than that of the farmers' practice. In addition to soil health benefits, using compost at this rate also resulted in considerable saving of chemical fertilisers. Over the period of the experimental trial, there was a 36% saving in urea as well as 100% saving in P and K fertilisers. For the Mixed treatment (compost at half rate and supplemented by chemical fertilisers), vegetable yield was similar to that of the farmers' practice for the first four crops but this declined to only 64% of that of the farmers' practice for the final crop of leek. Benefit cost analyses showed that for the vegetable compost trial, application of compost provided a benefit cost ratio (BCR) of 1 after five vegetable crops, indicating that this practice was very close to breaking even. On the other hand, BCR of Mix treatment (compost at half rate and supplemented by inorganic fertiliser) was negative due to significant yield decline after growing four crops.