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A change from cropping to pasture During the early settlement history of the Border Rivers and Gwydir catchments, change of land use consisted of turning woodlands and native pastures to cropping land. Soils capable of being ploughed were ploughed, and often with spectacular crops as a result. Agricultural productivity has been largely responsible for the wealth of this region.

Part of this success was that the soils were generally much higher in organic matter, open structured and high in essential plant nutrients when the land was first put to the plough. Many of the lighter soils across the Border Rivers and Gwydir catchments were only moderately fertile and not highly productive under cropping. Many years of cropping lead to a cycle of ever decreasing returns on cropping systems due to loss of organic matter, soil compaction and loss of soil fertility. In addition, a legacy of sheet, rill and gully erosion and sometimes dryland salinity developed.

Scenes like this are common in some of the older cropping areas: bare, hard set soil exposed to erosion.Photo: Border Rivers-Gwydir CMA, 2007.

Case Study: ‘Emohta’, Upper Bingara Norm Armstrong, and his wife Nell, moved “over east” from Western Australia and purchased their property ‘Emohta’ in 2003. When they bought ‘Emohta’ it had been run for a very long time as a sheep property with high stocking rates. This had left it “hammered for resources”, as Norm puts it. Groundcover was nearly zero across the farm; there had been “too many mouths and too many feet per acre”. Many of the lower sloping areas of the property had a long history of growing oats for winter feed. Soil surfaces were very hard, surface soil structure was non-existent and major soil nutrients were depleted.

‘Emohta’ covers 2300 hectares and is in the Mackenzies Flat sub-catchment of the Gwydir River. This is a high plateau area south east of Bingara that drains to the west through steep hills onto the lowlands of the Bingara Valley. The “flashiness” of run-off from this sub-catchment has caused streambank erosion and sedimentation of creeks in sub-catchments below.

Location of case study and the sub-catchment.

Soil Management:Conversion from Cropping to Pasture

Case study area:Mackenzies Flat sub-catchment

Moree

Garah

Boomi

Guyra

Uralla

Yetman

Bellata

Ashford

Bingara

Bonshaw

BundarraCobbadah

Mungindi

Inverell

Warialda

Kingstown

Gravesend

Deepwater

Boggabilla

Glen Innes

TenterfieldCroppa Creek

Collarenebri

N

‘Emohta’

The Armstrong’s decided quickly that a change in management at ‘Emohta’ was necessary to turn things around and move towards sustainability. They decided to change from continuous sheep to rotational cattle grazing for a start. Clearly, cropping for winter oats on much of the property was not sustainable, so the Armstrong’s decided to investigate returning cropping land to perennial pastures in the longer term.

The Border Rivers-Gwydir Catchment Management Authority (CMA) assisted with these changes as part of an overall property plan. ‘Emohta’ was subdivided to allow for a more controlled grazing regime. Watering points were provided in each new paddock by installing troughs.

Rudosol (40 cm deep and very stony)Photo: SoilFutures Consulting Pty Ltd, 2010.

Poor soil surface cover after winter oats at ‘Emohta’ in 2007.Photo: Border River-Gwydir CMA

Soil types at ‘Emohta’ The soils at Emohta are generally very shallow and geologically quite old. An inspection of soils on the property showed the hills were dominated by shallow and stony Rudosols (Lithosols) (very rocky or gravelly soils) whilst the larger valley flats tended to have deeper Chromosols and Sodosols (Red-Brown Earths and Solodic Soils). Many of the lower sloping areas with Rudosols had been extensively cropped, leaving them in a structurally poor state, and producing little, even if left to re-colonise with native pastures.

After nearly a century of sheep grazing and cropping in the flatter areas, topsoils on ‘Emohta’ have become structureless not allowing much water penetration and encouraging high run-off.

When starting with such hostile conditions for plant growth, a “blank slate” approach is often the answer. The introduction of improved, vigorous subtropical pasture species helps to create more favourable conditions for plant growth. Pasture varieties such as Bambatsi Panic, Green Panic, and Consol Love grass are well suited to this situation. They are all robust, deep-rooted perennial tussock grasses, which are very successful at exploiting deeper soil resources compared with the pioneer voluntary native grasses which grow in the area. Along with appropriate winter legumes such as sub clovers and attention to soil nutrition, they can provide an immense quantity of feed for stock. They tend to produce biomass for prolonged periods of time, owing to their ability to access deep soil moisture.

A Brown Sodosol, typical of the deeper soils on ‘Emohta’. Note the bleached nature of the topsoil and the white lime pieces in the subsoil. Photo: SoilFutures Consulting Pty Ltd, 2010.

SoilFutures Consulting Pty Ltd

Good pasture management, where one third is grazed off, one third is trampled and one third still standing, encourages strong pastures with extensive root growth and retention of mulch, which will turn into soil organic matter over time. This type of management helps open up hard topsoils and re-form natural soil structures, essential for effective water penetration and soil moisture retention. Healthy soil conditions encourage nutrient cycling through plant roots, and in turn, promoting better pasture growth.

The Sodosols on ‘Emohta’ generally have very silty topsoils which settle hard after prolonged cultivation or heavy grazing. These are underlain by structured clays, which often have a good store of lime but also often have high sodium levels that can cause dispersion. This is good in a dam when you want to hold water, but not so beneficial when it causes waterlogging in pastures. Good pasture management on these soils can mix the sharp soil horizon boundaries, offsetting the waterlogging effects of sodicity and to cycle lime to the surface where it can aid in soil structure development and organic matter build-up.

A plan in action The Armstrong’s actions based on their property planning include:

• conversion of much of their prior cropping land to deep rooted perennial pastures;

• paying attention to soil nutrition as pastures evolve. Phosphorus nutrition is important as well fed legumes make protein rich grasses;

• splitting up of larger paddocks for controlled grazing and inclusion of 8 new dams and 23 new troughs;

• use of pasture cages to monitor and evaluate how paddocks compare in terms of gross pasture production;

• fencing off the creek and taking some of the steeper rocky lands out of production to be managed for conservation purposes;

• keeping at least 75% ground cover in all native and improved pastures which is crucial to the success of this grazing system; and

• seeking advice from different sources of expertise in the catchment which has been crucial.

Norm is committed to maintaining a sensible stocking rate. He says that putting in the infrastructure was the start, not the end. It was a start that needed to be made to make ‘Emohta’ both environmentally and economically viable.

Having commenced conversion of cropping to pasture with assistance from the Border Rivers-Gwydir CMA, Norm is convinced he will continue on in this way and aims to restore most of the cropping land on the

property to permanent pasture. Oats have their place in a grazing system and are great whilst they are there, but the land under oats produces nothing for the rest of the year. Good pastures on the other hand, supply feed more consistently rather than in a big burst.

Norm’s use of pasture cages, which show how much grass can grow through a season, indicates how productive each new paddock on the farm is. Photo: SoilFutures Consulting Pty Ltd, 2010.

Planting pasturesPlanting pastures is like planting a crop. There are many things to consider such as moisture profiles and species selection. Norm’s paddocks were prepared for a spring sowing following the end of the oats, with herbicide to control weeds and allow for some soil moisture to build up. Sowing was done with a no-till pasture planter, which allowed for minimal disturbance of soil, and placed seed at exactly the right depth in the soil. Most improved and native species need to be sown very shallow and some, like Consol Love grass, even require some access to light to germinate properly.

Despite months of no rain and shallow soils, some of the perennials established in 2007 like this Bambatsi Panic tussock here continue to produce new growth. Photo: SoilFutures Consulting Pty Ltd, 2010.

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SoilFutures Consulting Pty Ltd

Costs involvedNorm said that the Border Rivers-Gwydir CMA had helped with funding for implementing his property plan and also contributed towards pasture establishment. The cost of pasture establishment has been very high so far and includes mostly his own time and money to achieve what he has to date.

Norm says that the establishment cost is quite high (greater than $120/ha) but once a system is in place and established, input becomes maintenance cost plus time. For every successive year the pro-rata reduces.

What does it mean for the catchment?When the Armstrong’s purchased ‘Emohta’ it was shedding most of its water to the creek, along with loads of sediment and nutrients which cause environmental problems downstream. Even with the current drought conditions, the potential for erosion has been greatly decreased by the huge increase in groundcover achieved through conversion from cropping to pasture, along with the introduction of rotational grazing across the property.

In time, as soil structure improves, water infiltration to the soil will increase, and the creek, which runs through the property, may well begin to flow as it used to. Rainwater will infiltrate more deeply into soils and recharge local fresh groundwater, supplying a more constant and fresh water supply to the greater catchment than it has in the past. Sediment delivery to the creek, responsible for damage to deep pools and sedimentation of properties lower in the catchment, will be minimal. As flows return to normal, permanent

deep holes tend to mend themselves and the creek flows should be much longer rather than destructive and flashy.

What lessons have the Armstrong’s learned?Norm says that if he were to undertake the project again, he would take more time to collect as much information as possible and spend more time on self-education before “jumping in with boots and all.” One comment he made is that “drought doesn’t happen with no stock” and he has learnt that he probably wouldn’t run as many head. A rotational grazing system is great but it will fall over like any other if pushed too hard.

Norm also learned that cattle markets are as much a pasture management tool as any other in his tool box. Removing stock earlier will enhance production of pasture when a season breaks meaning he can get stock back onto the place quicker. Destocking earlier allows for stock to be re-introduced earlier at the end of a drought. Drought seldom breaks across the country all at once. Exploring markets beyond the local markets helps when sourcing cattle for a reasonable price when a drought breaks.

Focusing on pasture production and soil health rather than cattle production has lead to a better production system which, in the long term, will pay dividends.

Norm Armstrong 3 years after pasture establishment during a severe drought. He now has high ground cover levels and even some growing plants despite the lack of moisture. Photo: SoilFutures Consulting Pty Ltd, 2010.