Land management practice trendsin Western Australia’s broadacre

cropping industries

LAND MANAGEMENT PRACTICE TRENDS IN WESTERN AUSTRALIA’S BROADACRE CROPPING INDUSTRIES2

IntroductionBroadacre cropping (includes cereals, oilseeds, lupins, sugar cane, legumes, hops, cotton, hay and silage) is an important industry in Western Australia, contributing over $3.1 billion (more than 50 per cent) of the gross value of agricultural production of the state, and almost 8 per cent to the gross value of Australia’s agricultural production in 2009–10 (ABS 2011). According to national land use mapping, about 8.4 million hectares (3 per cent) of the total area of the state was cropped in 2005–06 (ABARE–BRS 2010; Figure 1).

Improving soil condition is important to agricultural productivity and the quality of ecosystem services provided to the community from rural lands. Wind and water erosion, soil carbon rundown and soil acidification processes reduce the land’s ability to provide clean air and water and productive soils, protect biodiversity and maintain the resilience of the landscape to climate change, whilst producing food and fibre. The impact on soil condition of some land management practices used in the broadacre cropping industry is summarised in Table 1.

Caring for our Country—the Australian Government’s $2 billion flagship natural resource management initiative—is funding projects in the sustainable farm practices national priority area under the improving management practices and landscape scale conservation targets. These projects provide information to farmers in the broadacre cropping, dairy, horticulture and beef cattle/sheep industries about land management practices that will help improve soil condition and contribute to maintaining a healthy environment.

By 30 May 2012, $448 million had been approved for projects across Australia to improve soil and biodiversity management practices on farm. On farm practice change is being monitored using the biennial Australian Bureau of Statistics (ABS) Agricultural Resource Management Survey (ARMS), which surveys 33 000 of Australia’s 135 000 agricultural businesses (farmers). Results are reported at the national, state and natural resource management region levels (ABS 2009).

Table 1. Cropping management practices expected to improve soil condition.

Table 1

Practice Increases carbon Reduces wind

erosion riskReduces water

erosion riskReduces soil

acidification risk

No cultivation apart from sowing Indirectly Y Y N

Crop residue left intact Y Y Y Indirectly

Soil pH testing Indirectly Indirectly Indirectly Y

Soil nutrient testing N N N Y

Lime or dolomite applied to reduce soil acidity

Indirectly Indirectly Indirectly Y

LAND MANAGEMENT PRACTICE TRENDS IN WESTERN AUSTRALIA’S BROADACRE CROPPING INDUSTRIES 3

Cropping industry profileAccording to ABS estimates, in 2009–10 Western Australia had 7590 broadacre cropping businesses, a decrease of more than 14 per cent since 2007–08. During this time the area of broadacre crops decreased by about 10 per cent.

In 2009–10 the average age of managers of Western Australian crop businesses was 53 years; on average they had managed their holdings for 25 years and farmed in their local region for 31 years. An estimated 25 per cent of crop businesses (1901) had a Landcare group member.

Land management practicesCaring for our Country provided project funding to encourage farmers to better manage ground cover by reducing tillage and increasing crop residue retention, to test lime soils regularly and to build soil carbon. Funding has complemented the activities of state agencies, industry and community groups. Data from the ABS 1995–96, 2000–01 and 2010–11 agricultural censuses (which surveyed all agricultural businesses)

and the 2007–08 and 2009–10 ARMS help track trends in adoption of these practices. The percentage of farmers reporting using particular practices can exceed 100 where more than one method (such as crop residue retained in some areas, burnt in others) is used on a holding.

Figure 1. Western Australian cropping regions, 2005–06. Source: ABARE–BRS (2010).

Figure 1

LAND MANAGEMENT PRACTICE TRENDS IN WESTERN AUSTRALIA’S BROADACRE CROPPING INDUSTRIES4

Figure 2. Percentage of businesses in Western Australian natural resource management regions using different cultivation intensities to prepare land for broadacre crops, 2007–08, 2009–10 and 2010–11. The 2007–08 numbers include businesses preparing land for pasture.

Figure 2

Tillage practicesFarmers have been encouraged to move to one-pass sowing systems to reduce the risk of soil loss through wind and water erosion, lower greenhouse gas emissions and improve water use efficiency. The number of broadacre cropping businesses in Western Australia using no cultivation apart from sowing when preparing cropping land is estimated to have increased from 59 per cent to 74 per cent between 2007–08 and 2009–10 (Figure 2); this declined to 62 per cent in 2010–11. Longer-term ABS data (not shown) indicate that the current number of broadacre cropping businesses in Western Australia using no cultivation when preparing cropping lands is almost one and a half times greater than in 1995–96.

All six natural resource management regions experienced an estimated increase in the percentage of broadacre cropping businesses using no cultivation apart from sowing from 2007–08 to 2009–10, followed by a generally small decrease from 2009–10 to 2010–11. The biggest decreases occurred in the Swan (from 69 per cent to 32 per cent), South Coast (from 72 per cent to 61 per cent) and South West (from 62 per cent to 40 per cent) regions (Figure 2).

Statewide, the area prepared for crops and pastures without cultivation apart from sowing is estimated to have increased from 79 per cent to 88 per cent between 2007–08 and 2010–11, with the biggest increase (from 75 per cent to 88 per cent) in the South West region (Figure 3). The area prepared without cultivation increased in Western Australia from 41 per cent to 88 per cent between 1995–96 and 2010–11 (Figure 4).

LAND MANAGEMENT PRACTICE TRENDS IN WESTERN AUSTRALIA’S BROADACRE CROPPING INDUSTRIES 5

Figure 3. Percentage of crop area in Western Australian natural resource management regions prepared by broadacre cropping businesses using different cultivation intensities, 2007–08, 2009–10 and 2010–11. The 2007–08 numbers include areas prepared for pasture. Results were not publishable for the South Coast (2007–08) region.

Figure 3

Figure 4

Figure 4. Percentage of crop area in Western Australia prepared by broadacre cropping businesses using different cultivation intensities, 1995–96 to 2010–11. The 2007–08 numbers include areas prepared for pasture.

LAND MANAGEMENT PRACTICE TRENDS IN WESTERN AUSTRALIA’S BROADACRE CROPPING INDUSTRIES6

Figure 5. Percentage of broadacre cropping businesses in Western Australian natural resource management regions using different crop residue management practices, 2007–08, 2009–10 and 2010–11.

Figure 5

Crop residue managementRetaining residues between crops not only affords protection from soil loss through wind and water erosion, but also helps improve soil organic matter (soil carbon). Between 2007–08 and 2010–11 the number of farmers estimated to be retaining crop residues in Western Australia increased from 49 per cent to 55 per cent (Figure 5). This number remained stable or increased in all natural resource management regions except the Rangelands. Longer term ABS data indicate that almost twice as many broadacre cropping businesses in Western Australia retained crop residue after harvest in 2010–11 than did in 1995–96.

Between 2007–08 and 2010–11, the area where crop residue was retained after harvest was estimated to have increased from 72 per cent to 78 per cent in Western Australia, with the greatest increases in the Swan region (from 35 per cent to 55 per cent; Figure 6). Statewide since 1995–96 the area of crop residue retention was estimated to have increased from 42 per cent to 78 per cent (Figure 7).

LAND MANAGEMENT PRACTICE TRENDS IN WESTERN AUSTRALIA’S BROADACRE CROPPING INDUSTRIES 7

Figure 6

Figure 7

Figure 7. Percentage of crop area in Western Australia reported by broadacre cropping businesses with different crop residue management practices, 1995–96 to 2010–11.The 1995–96 numbers include the area where pasture stubble was managed.

Figure 6. Percentage of crop area in Western Australian natural resource management regions reported by broadacre cropping businesses with different crop residue management practices, 2007–08, 2009–10 and 2010–11.

8 LAND MANAGEMENT PRACTICE TRENDS IN WESTERN AUSTRALIA’S BROADACRE CROPPING INDUSTRIES

Managing soil acidityIt is estimated that about half of Australia’s agricultural land has a surface soil pH of less than or equal to 5.5, which is below optimum for extremely acid-sensitive agricultural crops, and below the optimal level to prevent subsoil acidification (National Land and Water Resources Audit 2001). Where soil acidity moves further down the soil profile, damage may be irreparable. Very acid soils are unlikely to support good ground cover, increasing the risk of soil loss through wind and/or water erosion and reducing input to soil carbon.

It is estimated that about 84 per cent of Western Australia’s cropping land has a high risk of soil acidification, 8 per cent is at moderate risk and 8 per cent at low risk (Figure 8, Table 2). Areas at high risk are where the soil pH is low, the soil has a low capacity to buffer against pH decreases, and the dominant (current and/or past) agricultural practices are highly acidifying.

Regular testing of soil pH and applications of lime and/or dolomite can be used to manage surface soil pH. Testing soil nutrient levels to better match fertiliser applications to crop requirements can also help slow soil acidification. It was estimated that the number of broadacre cropping businesses in Western Australia undertaking pH and nutrient testing declined slightly between 2007–08 and 2009–10; from 40 per cent to 38 per cent for pH testing and from 39 per cent to 37 per cent for nutrient testing (Figure 9).

Increases in the proportions of farmers testing soil pH and soil nutrients occurred in the Northern Agricultural and South Coast regions; the largest estimated increases occurred in the Northern Agricultural region (from 43 per cent to 50 per cent) and (from 42 per cent to 50 per cent) respectively (Figure 9).

Estimated decreases in soil pH testing and soil nutrient testing occurred in four of the six natural resource management regions; the greatest decreases in the proportion of farmers testing soil pH occurred in the Avon region (from 49 per cent to 40 per cent) and soil nutrient testing (from 48 per cent to 39 per cent; Figure 9).

The number of cropping businesses in Western Australia applying lime and/or dolomite to their holdings to manage soil acidity increased from an estimated 33 per cent to 40 per cent (Figure 10) between 2007–08 and 2009–10. Longer term data for cereal businesses (a major component of the cropping business category which excludes cotton, rice, sugar, oilseeds and pulses), show that an estimated 8 per cent applied lime or dolomite in 1995–96, increasing to 43 per cent by 2009–10 (Figure 11). Western Australian broadacre crop farmers applied 969 934 tonnes of lime and 61 014 tonnes of dolomite to their holdings at rates of 1.19 and 0.89 tonnes per hectare respectively in 2007–08 (Table 3).

Low risk (%) Moderate risk (%) High risk (%)

Avon 8 8 84

Northern Agricultural 2 7 91

Rangelands 74 6 20

South Coast 18 12 70

South West 5 7 88

Swan 0 12 87

Total 8 8 84

Table 2. Estimated percentage of cropping area at risk of soil acidification. Source see Figure 8.

Table 2

LAND MANAGEMENT PRACTICE TRENDS IN WESTERN AUSTRALIA’S BROADACRE CROPPING INDUSTRIES 9

Figure 8. Western Australian cropping areas with low, moderate and high risks of soil acidification. This figure was produced by intersecting cropping (dryland and irrigated) from Land use of Australia 2005–06 (ABARE–BRS 2010) with the soil acidification risk map prepared by Wilson et al. 2009.

Figure 8

Figure 9

Figure 9. Percentage of Western Australian broadacre cropping businesses undertaking pH and soil nutrient testing, 2007–08 and 2009–10.

LAND MANAGEMENT PRACTICE TRENDS IN WESTERN AUSTRALIA’S BROADACRE CROPPING INDUSTRIES10

Figure 10

Figure 11

Figure 10. Percentage of broadacre cropping businesses in Western Australia applying lime or dolomite to their holdings, 2007–08 and 2009–10.Results for businesses applying lime, lime sand or limestone were not publishable for the Rangelands (2007–08). Results for businesses applying dolomite were not publishable for the Rangelands (2007–08 and 2009–10) or the Northern Agricultural (2009–10) and Swan (2009–10) regions.

Figure 11. Percentage of cereal (excluding rice) businesses in Western Australia applying lime or dolomite to their holdings, 1995–96, 2000–01 and 2009–10. 2009–10 data are slightly different from that for Figure 10; there is no direct comparison between cereal cropping businesses and total broadacre cropping businesses.

LAND MANAGEMENT PRACTICE TRENDS IN WESTERN AUSTRALIA’S BROADACRE CROPPING INDUSTRIES 11

ConclusionsThe data suggest that good progress is being made in reducing tillage and increasing crop residue retention in most regions. Reducing tillage and increasing crop residue retention could be expected to reduce the risk of soil loss through wind and water erosion and increase soil carbon. Increasing acidification across

much of Western Australia’s cropping areas remains a significant risk. With more than 92 per cent of all cropland in Western Australia at moderate to high risk of acidification, regular testing needs to be increased and where needed, liming of cropping soils, especially in the Avon, Northern Agricultural, South West and Swan regions.

Table 3

Table 3. Rates of lime and dolomite application by Western Australian broadacre cropping businesses on their holdings, 2007–08. np not publishable.

Tonnes (t) of lime applied

Lime application rate (t/ha)

Tonnes (t) of dolomite applied

Dolomite application rate

(t/ha)

Western Australia 969 934 1.19 61 014 0.89

Avon 381 193 1.07 23 425 0.85

Northern Agricultural 115 632 1.28 2 044 0.53

Rangelands np 0 np 0

South Coast 203 734 1.22 29 305 0.98

South West 195 897 1.28 5 070 0.78

Swan 73 478 1.44 1 171 1.09

LAND MANAGEMENT PRACTICE TRENDS IN WESTERN AUSTRALIA’S BROADACRE CROPPING INDUSTRIES12

This document is provided under a Creative Commons Attribution 3.0 Australia (http://creativecommons.org/licenses/by/3.0/au/) licence. Unless otherwise stated, all images in the publication are copyrighted by their original owners. Thanks to Jodie Mewett and Justyna Paplinska, Australian Bureau of Agricultural and Resource Economics and Sciences, for data analysis. This publication (and any material sourced from it) should be attributed as Barson, M 2013 Land management practice trends in Western Australia’s broadacre cropping industries, Caring for our Country Sustainable Practices fact sheet 33, Department of Agriculture, Fisheries and Forestry, Canberra.

© Commonwealth of Australia 2013

ReferencesABARE–BRS 2010, Land use of Australia 2005–06, version 4, Australian Bureau of Agricultural and Resource Economics–Bureau of Rural Sciences, Canberra.

ABS 2009, Land management and farming in Australia, 2007–08, cat. no. 4627.0, Australian Bureau of Statistics, Canberra, available at abs.gov.au/AUSSTATS/abs@.nsf/allprimarymainfeatures/C3FC0BDD85E571DBCA2578B50011D983?opendocument.

ABS 2011, Value of agricultural commodities produced, Australia 2009–10, cat no. 7503.0, Australian Bureau of Statistics, Canberra.

National Land and Water Resources Audit 2001, Australian agriculture assessment 2001, vol. 2, Commonwealth of Australia.

Wilson, P, Baldock, J, Grundy, M, Jacquier, J, Griffin, T, Moody, P, Chapman, G, Hall, J, Maschmedt, D, Crawford, D, Hill, J & Kidd, D 2009, Identification of land with a risk of acidification, CSIRO Sustainable Agriculture Flagship, report prepared for Caring for our Country, available at nrmonline.nrm.gov.au/catalog/mql:2560