Tim Weaver1, David Lester2, Michael Bell3, Bruce Haigh4, Stephen Harden4, Graeme Schwenke4.
1CSIRO, Locked Bag 59, Narrabri, NSW, 2390, firstname.lastname@example.org
2Department of Agriculture and Fisheries, Queensland. PO Box 2282, Toowoomba, QLD, 4350, email@example.com
3Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Gatton Campus, Gatton, QLD, 4343, firstname.lastname@example.org
4New South Wales Department of Primary Industries. 4 Marsden Park Rd, Calala, NSW, 2340, email@example.com
The depletion of phosphorus (P) in northern NSW and Queensland dryland cropping regions has resulted in a number of projects investigating the deep placement of P fertiliser and quantifying crop response (GRDC projects: UQ00063, UQ00078). One of these sites was established in January 2016 at Terry Hie Hie (northern NSW) with the implementation of deep placement treatments of P (0, 10, 20, 40, 80 kg/ha) ripped to a depth of 200 mm. The deep bands of P were applied in January 2016 with the intention to also examine differing widths of bands (side band, 33 cm, 66 cm). The inclusion of three widths of deep banded P is to determine the minimum distance the ripped bands can be spaced before a drop in crop response is detected. To study the effect of deep P on chickpea (Cicer arietinum) root architecture, clear polycarbonate tubes were installed under the plant line and between rows (passing through the deep P band) in the 33 cm banded treatment. A BTC-2 minirhizotron camera captured root images in August and November in 2016. Root tracing software was used to quantify root number, length, diameter and volume. The deep P bands had a significant effect on the root numbers, length, volume and root diameter. The root count number was higher under the plant line in August when compared to the tubes installed in the deep P band. However, the readings taken in November showed a higher number of roots in the deep P band.