Soil indicators respond to changes in banana plantation management

Abstract

The north Queensland region of Australia produces over 90% of Australia's bananas. However, to maintain its importance as a banana-growing region, producers are seeking innovative methods to manage their plantations in order to protect environmentally sensitive areas, reduce impacts from climatic events and suppress soil borne diseases. The development of a healthy soil is an aspiration sought to address these constraints, using indicators based on soil physical, chemical and biological parameters. From 2012 to 2015, 86 soil samples were received for analysis from different banana management scenarios; conventional (53), newly planted fields (15), and Ecoganic production (18). Ecoganics is a farmer certification program that combines environmental management systems with sustainable production practices. A stepwise-discriminate analysis was used to determine a minimum set of soil parameters required to discriminate between management systems. Ten soil parameters: fluorescein diacetate hydrolysis rate (FDA), nematode enrichment and channel indices, B/(B+F) ratio (bacterivorous nematodes relative to bacterivorous and fungivorous nematodes), nematode diversity, and abundance of Fu2 fungivorous nematodes, Om4 omnivorous nematodes, Ba1 and Ba3 bacterivorous nematodes and abundance of the plant-parasitic nematode Helicotylenchus multicinctus were required to separate the different banana management systems. However, the separation of banana management groups had a 19% error, with the leave-one-out validation model confusing Ecoganic bananas with conventional bananas 22% of the time. The results confirmed that crop management has considerable effects on soil biology. The use of soil indicators can guide farm management decisions to implement practices most likely to overcome banana production constraints.