New amendments for sandy soils

Crop productivity is generally lower on sandy soils than on loam and clay soils under the same environment and technology. Sandy soils cover over 11 million hectares of agricultural land in southern Australia. The focus of most research to improve performance of sandy soils is on their limited capacity to supply water and nutrient resources to the roots of crops.

While sandy soils vary across a continuum, they have a number of distinctive limitations including poor pH buffering capacity, low biological activity, low water holding capacity, high water repellence, and a high susceptibility to compaction. These all combine to limit crop production.

This project proposes that step changes towards high performance sandy soils will come from permanently raising their reactive surface area, with added clay or recalcitrant organic matter or both. The project will design a long-term, multi-site field program for improvement of sandy soils with clay and organic amendments. The results should help farmers to manage their sandy soils more productively.

Previous research has shown that doubling production on these soils can be achieved but that the mechanisms are poorly understood. Due to the high potential for benefit to growers, it is important to understand ameliorative processes to identify the most cost effective treatments.