Grain mineral contents in southeastern Australia

The values reported show considerable regional differences, with N, P, K, and S showing coefficients of variation (CV) of 18%, 20%, 14%, and 13%, respectively. However, within each region, the CV’s for N, P, K, and S were usually less than 5%. There were some important exceptions to this, with P in southern New South Wales and with P, K, and S CV’s for the North East and North Central regions of Victoria, although these values were derived from the smallest subsets within the data. Nutrient concentration for the macronutrients did not differ among the three sets of state means for N, P, K, S, and Ca, although there were significant regional differences for these nutrients. Contents of N, P, and S were not different between the two cultivars compared. Grain micronutrient concentration did differ between states and regions, except for state level Zn and Al contents. The data set analyzed does have a strong weighting to data from South Australia, so the “national” mean values presented are not indicative of the values across each agroecological zone. For all the nutrients tested, regional values differed significantly, suggesting that there is no universal value that can be used for a nutrient budget at regional or sub-regional (i.e. farm) level, rather that values should be based on data from that region. Cultivar and annual differences were not significant for P, S, Mg, or Na, so that a single regional value would seem appropriate for these nutrients. If the level of interest is in a national scale measure of nutrient balance, then the values reported would appear to be appropriate as there is no significant difference between the values at the state levels for the macronutrients.

In all regions, mean grain Zn levels are less than the 33 mg/kg target suggested as part of the HarvestPlus Zinc biofortification program. In the Lower Eyre Peninsula and the Victorian and South Australia Mallee, mean levels are around half the HarvestPlus target. IPNI also analyzed grain from other countries and Australian values were at the lower limits of grain from other countries such as Canada (48 mg/kg), Russia (27 mg/kg), and India (48 mg/kg). ANZ-01