Soil nutrient budgets of Australian natural resource management regions Robert Edis, Robert Norton and Kithsiri Dassanayake

Melbourne School of Land and Environment, The University of Melbourne The International Plant Nutrition Institute

Nutrient Imbalances – a big part of the challenge in an open system

Vitousek et al., 2009, Science

Recovery Efficiency in Produce

The issue here •  ANLWA 2001 published REp

–  Data in this study was collected 1994-96 – most recent information!?!?

–  Some P balances done more recently •  Gourley – Dairy farms; Cordell – Continental; Wong &

Weaver (2011) – farming systems in WA 2011 –  Update the ANLWRA data.

WA SA Vic Tas NSW Qld

N +/~ ~/- - + ~/+ ~/-

P ~/+ ~ -/~ + ~/- -

K - - - ~ - -

S +/~ ~/+ ~/+ + ~/+ -/~

Farm gate surveys of P balance for major industries (Weaver and Wong 2011)

Approach & data sources

•  ABS data 2007-08 & 2009-10 @ NRM regions –  Inputs and outputs land management and agricultural

commodities –  32-35 k farm businesses surveyed (out of about 135-141 k in

total), over 53 NRM regions

•  Fertiliser sales data from the Fertiliser Industry Federation of Australia (FIFA)

–  Data at state level only

•  For each NRM, Recovery efficiency in agricultural products estimated

–  RE = Σ(Nut density * Product) / (Nutrient applied + Nutrient fixed) –  Balance = (Removal – Application)/area

Some (!) assumptions

•  Livestock nutrient exports (milk, meat) based on stock numbers in region and state production statistics

•  Nutrient concentrations in commodities as for NLWRA •  Imported feed not directly included (important for dairy-

rich regions) •  Animal manures assumed to be from external sources

(manure or animal feed) •  Where ABS survey lumps fertiliser data (eg ammonium

phosphates; triple and double super; muriate or sulphate of potash), weighted average based on FIFA sales data used.

•  “All other manufactured fertilisers” not included

National P fertiliser sales

P balance intensity

(kg P (P in - P out)/ha ag land)

P balance (kg)/ha any fertiliser applied  Murrumbidgee (NSW)   10   12  Glenelg Hopkins (Vic)   10   12  South (TAS)   9   10  Goulburn Broken (Vic)   11   10  Lachlan (NSW)   10   10  North (TAS)   9   9  Port Phillip and Westernport (Vic)   9   9  Murray (NSW)   10   9  East Gippsland (Vic)   9   9  Kangaroo Island (SA)   ?   8  Hunter-Central Rivers (NSW)   6   8  North West (TAS)   7   7  West Gippsland (Vic)   7   6  North East (VIC)   7   6  Central West (NSW)   7   6  Murray Darling Basin (SA)   7   6  North Central (Vic)   7   6  Northern and Yorke (SA)   7   6  Mallee (Vic)   6   5  Adelaide and Mount Lofty Ranges (SA)   3   5  

South East (SA)   6   5  Southern Rivers (NSW)   6   5  Northern Rivers (NSW)   5   5  

K balance intensity

(kg K (K in - K out)/ha ag land)

S balance intensity

(kg S (S in - S out)/ha ag land)

N balance intensity – fertilisers only

(kg N (N in - N out)/ha ag land)

Sugar cane regions

kg N/ha kg P/ha kg K/ha kg S/ha Burdekin All removed -0.5 -0.2 -1.0 -0.2

All returned 0.1 -0.1 -0 0 Mackay WS All removed -4.7 -0.8 -16 -2

All returned 5.5 0.9 1.3 0.3 Burnett Mary All removed 0.55 -0.4 -5.5 -0.7

All returned 4.7 0.3 1.8 0.6 Wet Tropics All removed -0.6 -0.1 -0.9 -0.1

All returned 0.2 0.1 0.5 0.2

Change in calculated balance (over all land used for agriculture) if all cane removed or returned

Comparison with NLWRA 1992-1996

Discussion and Conclusions •  Strong consistently positive phosphorus balance for many

regions, even in areas without highly P sorbing soils. Most striking are the regions of southern NSW, SW Victoria and Tasmania.

•  Strong consistently negative potassium balance, even in areas without high indigenous available K. Most striking are the regions of southern NSW and SW Victoria

•  Even without including BFN some NRMs are in positive N balance; Port Phillip and Western Port; West Gippsland; Hawkesbury Nepean; Condamine. N balance in sugarcane producing catchments dependant on