Agronomic consequences of vegetative groundcovers and reduced nitrogen applications for banana production systems

Abstract

Banana production in the north Queensland region of Australia represents 90% of the total production in Australia. However, in this region banana plantations are constrained by the need to protect environmentally sensitive areas such as the Great Barrier Reef, climatic impacts such as cyclones, high labour costs and soil-borne diseases. To overcome the constraints and improve the resilience of banana production systems, innovations are required, particularly regarding the management of the soil. Field experiments were established comparing vegetative groundcover, primarily pinto peanut (Arachis pintoi), to bare soil, and three nitrogen application treatments: 350 kg N ha-1 crop-1, 180 kg N ha-1 crop-1 applied as urea and 180 kg N ha-1 crop-1 applied as urea treated with 3,4-dimethyl pyrazole phosphate (Entec), a nitrification inhibitor. The agronomic aspects of banana production systems were determined by measurements of plant height, leaf emergence, bunch generation intervals and bunch characteristics. Additionally, measurements of leaf chlorophyll and nutrients were used to determine if management was restricting nutrient uptake. The first banana crop had reduced vegetative growth and an increased generation interval with the vegetative groundcover treatment compared to bare soil. Similarly, reduced N application reduced vegetative production of bananas and the Entec N treatment reduced bunch weight. However, fertiliser use efficiency was doubled in the lower N treatments relative to application of 350 kg N ha-1 crop-1. In the second crop, a reduction in the vegetative growth of bananas was again observed with lower N treatments, no significant differences in bunch weight was recorded. For banana producers to adopt agro-ecological production practices, penalties in vegetative plant growth need to be overcome, or benefits other than production need to be revealed, such as increased disease suppression.