Soil acidity restricts plant growth mainly due to the toxicity effects of Aluminium (Al) and Manganese (Mn). Deficiencies of Molybdenum (Mo), Nitrogen (N), Phosphorus (P), Calcium (Ca) and Magnesium (Mg) can also occur in acid soils. In Western Australia, Al toxicity is most prevalent on acid soils whilst Mn toxicity is relatively minor. However, in Eastern Australia, acid soils more commonly cause Mn toxicity in crops (Slattery et al. 1999; Uren 1999; Gazey and Davies 2009). Insoluble Al is abundant in most soils, but under acid conditions (pHCaCl2 less than 4.5) some forms of aluminium are solubilised to release Al3+ and Al(OH)2+, ions that are highly toxic to roots and bacteria.

Aluminium toxicity inhibits cell division and reduces root elongation of plants. Such effects on root growth not only impair nutrient acquisition by crops but may also exacerbate drought by restricting access of roots to sub-soil water storage. This project will investigate the tolerance of wild Cicer accessions to low pH and sandy soils. These accessions then have potential to be included in the chickpea breeding program specifically to target acid sands including the areas where lupins are currently grown in Western Australia, providing growers additional pulse crop options to improve profitability of farming systems.