Michael Moodie1, Lynne Macdonald2 and Ray Correll3
1 Frontier Farming Systems, 7B Byrne Ct, Mildura, Victoria, 3500, www.frontierfarming.com.au, firstname.lastname@example.org
2 CSIRO Agriculture and Food, Locked Bag 2, Glen Osmond, SA, 5064
3 RHO Environmetrics, PO 366 Highgate, SA, 5064
Sub-optimal productivity is commonly reported for the deep sands that make up approximately 20-30% of the cropping soils in the low rainfall Victorian Mallee. Un-used water is evident despite an apparent absence of constraints commonly associated with sandy soils (e.g. non-wetting, acidification). Poor subsoil fertility and/or physical restrictions to rooting depth may be the primary constraints to production in deep Mallee sands. To explore the issues further, replicated trials were established across two sites, Ouyen (2017-18) and Carwarp (2018). These trials have investigated the interactions between physical disturbance (deep-ripping and/or rotary spading) and the incorporation of organic and inorganic inputs. Alleviating physical barriers to root growth through practices such as deep ripping and rotary spading are providing the most consistent yield increase on sandy soils in the Victorian Mallee, with yield benefits of up to 1.5 t/ha observed over two seasons. Spading of high nitrogen organic matter sources (vetch hay, chicken litter, compost) has also increased yield. Of the organic amendments, chicken litter has led to the highest cumulative grain yield response (2 t/ha across two seasons). This response from the application of chicken litter demonstrates the potential to improve crop yields by increasing the fertility of sandy soils.