Pragmatism rules crop management
GroundCover™ Issue: 102 | Author: Emma Leonard
“Livestock produce 15 per cent of my income, so they can take up no more than 15 per cent of my time.”
This pragmatic attitude is characteristic of David Giddings’s approach to his mixed-farming enterprise in Lower Eyre Peninsula.
Fifteen years ago, with father Graham, the farm was refenced to land potential – old fencelines were removed and cropping paddocks laid out to provide large areas as regular in shape as possible. In the intervening years they have increased the farm size by about 40 per cent, but they have stuck to their philosophy.
Consequently, any scrub or creek lines have been taken out of the productive area. The 2500 Merino ewes are run on just over 750 hectares of land that is never cropped, as it suffers from waterlogging and salinity. The remaining 2000ha are sown to a 50:50 rotation of wheat and canola.
While cropping makes up the lion’s share of the business, livestock and pasture production are a passion for David.
The cell grazing system comprises 40 paddocks of 5ha to 15ha distributed across five cells. Sets of paddocks radiate from a single watering point, and across the five cells the carrying capacity is 5000 dry stock equivalent (DSE) of ewes or ewes and lambs. After weaning, the lambs are set-stocked and fed pasture and supplements to finish them rapidly.
“The sheep are moved to the next paddock in the cell after a few days, depending on the time in the season and the pasture growth,” David says.
“The aim is to accumulate feed in winter but as growth increases in spring the sheep just have time to nip the top off the pasture, to delay seed set and to also ensure it keeps growing for as long as possible.”
In the spring, when the pasture is growing rapidly, ewes are grazed on a paddock for about a day before being moved to the next, not returning to that paddock for another 30 days. In winter and early spring the sheep will remain in a paddock for a maximum of three days and will not return for 90 days. Over summer, the sheep also have access to stubble.
This high stocking rate is achieved by the cell grazing and underpinned by David’s use of annual and perennial pasture mixes.
The annual component is supplied by a mixture of regenerating ryegrass, barley grass, balansa clover and subclover. Historically, the perennial component has been supplied by tall wheat grass, especially on saline soils, and lucerne. However, two years ago David started planting chicory into the mixed pasture sward.
“The perennials help me extend the period of green feed. The lucerne kicks in as soon as we have a summer or autumn rain event, while the chicory and tall wheat grass grow well in late spring/early summer. Overall, perennials are providing more feed and extend the period of useable green feed by about a month.”
The pasture combination is producing large quantities of dry matter and David aims to maintain full soil cover throughout the year to protect the soil and minimise weed germination.
The whole livestock system is low input. David only holds about 100 round bales on hand for cold, wet periods in the winter. Fertiliser and herbicide inputs are minimal, with most of the nitrogen coming from fixation by the balansa clover and lucerne. On average, each year 100 kilograms/ha of single superphosphate is applied to all pastures prior to the break of the season.
Inputs may be a little more intense on the cropping enterprises but the streamlined systematic approach is continued.
A wheat/canola rotation is sown across the cropped hectares, with several varieties grown to spread maturity dates and workload.
“With my two workmen we have chosen to have a tight seeding program, working around the clock to sow the 2000ha in about 10 days.”
Avoiding herbicide resistance in his dominant grass weed, annual ryegrass, has been a driver behind David’s choice of rotation.
Ten years ago the land was divided with a third sown to lupins, a third sown to canola and a third sown to wheat. This meant that grass herbicides were being used across two-thirds of his rotation. Consequently, David decided to move to a 50:50 wheat/canola rotation to reduce grass herbicide use to 50 per cent of the rotation.
“Running a no-till, no-burn operation means my weed control is highly reliant on herbicides and I have to make the best use of the chemistry available.”
His intensive use of canola has made blackleg management a focus equal to the avoidance of herbicide resistance. Due to the intensity of canola production, David is unable to adopt the recommended 500-metre separation between each new canola crop and the previous season’s stubble.
However, he implements all the other control practices, including growing three or four varieties with good blackleg resistance, using fungicide and sowing early. Now that the blackleg resistance group ratings are available, he uses these in order to choose varieties with different resistance genes from the previous season’s canola.
In 2013, David is returning lupins to the rotation on the poorer soils with a bleached subsoil. A rotation containing three different crop types will help reduce his risk and his reliance on high levels of nitrogen inputs.
2013 will also see the implementation of a full controlled-traffic system based on 4m wheel spacing. The choice of 4m rather than the more common 3m wheel centres was determined by his self-propelled sprayer/windrower.
“I feel this wheel spacing will be simpler and ultimately safer, especially for the harvester.”
He is working on implement unit widths of 10.5m for the disc seeder, windrower and harvester, while the boomspray is 32m.
The implement unit width was partly based on the fact that it is hard to achieve an even spread of stubble beyond 10.5m and fertiliser beyond 30m.
David also wants to have as little investment in machinery as possible, without compromising timeliness and productivity.
“I will run only one tractor, which will pull the seeder, fertiliser spreader and chaser bin. The self-propelled sprayer/windrower unit and harvester are the only other engines I require.”
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