Nutrient Balances for Australian Natural Resource Management Zones

The amounts of N, P, K, and S applied as fertilizers and removed as agricultural commodities were calculated using the Australian Bureau of Statistics (ABS) data for 2007-08 and 2009-10 for all Australian Natural Resource Management (NRM) regions.

The mass of P in commodities was 43 and 50% of the mass applied as fertilizers in 2007-08 and 2009-10 (with respective national net inputs of 190 and 170 kt P). Regions with (commodity P)/(fertilizer P) < 0.3 and >10 kt P net input in both years were Murray, Murrumbidgee, Lachlan, and Glenelg Hopkins. Nationally, the mass of K in commodities was 2.5 and 3.1 times the mass applied as fertilizers in 2007-08 and 2009-10 (with respective net exports of 196 and 256 kt P). Regions with > 10 kt K net export and (commodity K)/(fertilizer K) >10 in both years were Wimmera, Northern and Yorke. The mass of S removed in commodities was 49 and 62% of the fertilizer mass applied in 2007-08 and 2009-10 (with respective national net exports of 91 and 62 kt P). Strong net additions of S in both survey years occurred in South-East (SA), South-West (WA), and Glenelg Hopkins. Nitrogen balance depends on the method used to calculate biological N fixation. Simply using fertilizer amounts, regions with strong net input of N were Port Phillip and Westernport, West Gippsland, Hawkesbury-Nepean, Wet Tropics, and Condamine.

These balances will be contrasted with land management practices and soil test values, as well as the 1992-1997 Land and Water Audit. Future work will include biological N into the N balance and publishing the data on all nutrients surveyed. ANZ-16