Capturing the potential Managing the risks

1. RIGHT INPUTS FOR BEST OUTCOMES

Take-home messages
• Manage for least cost (ie low risk) not for maximum profit in 2008
• Concentrate resources and efforts on the reliable, low risk paddocks.
• Poorly performing paddocks should be left out of the cropping programme in 2008.
• Control summer weeds early.
• Production in paddocks with good soil fertility will still perform well even with very low rates of fertiliser applications.
• Soil test paddocks for informed management decisions where histories are not known.
• Low cost options exist for managing most nutrient deficiencies with fertilisers – make use of them in 2008.

Managing for least cost rather than most profit

Due to the exceptionally poor run of seasons for most districts over the last few years, many farm businesses are under severe financial pressure. This means for many of those businesses that their 2008 programme can not be conducted in a way that the manager would normally choose. The emphasis for these businesses will be to reduce their costs as much as possible (ie minimise their risk) rather than attempt to maximise profit. There are many ways in which farm businesses can reduce their costs without severely handicapping their potential to generate income.

Paddock Selection

A risk minimisation programme starts with paddock selection. Paddocks should be grouped into three categories: 1. Definitely will seed, 2. Will seed with a good start to 2008 and 3. Will seed only if there is a great start.
Paddocks in category 1. are the bread winners. These are the paddocks which always produce the best outcomes for the farm. This is because they are dominated by a soil type which suits the environment, they have low weed and disease burdens and reasonable soil fertility. Collectively this means that they can produce reliable income with least effort and cost. The 2008 programme must concentrate resources on these paddocks by seeding them first with high value cereals in most cases. Dry seeding is an option for many of these paddocks. However, break crops should also be considered in a couple of these paddocks because there must be some paddocks again in this category for 2009. Since these paddocks will be the first seeded in the programme, they are also those which could be considered for early grazing by stock if necessary. However, the stock must be removed early to ensure best chances for grain production.
Category 2. paddocks should be the next seeded. Due to this delay, the higher weed burdens in these paddocks can be at least partially controlled with low cost knock downs prior to seeding. These paddocks should be seeded with cereals and their end use should remain flexible, ie they could be used for grazing, hay production or grain depending on how the spring develops.
Category 3. paddocks are the high risk, high cost paddocks and should only be seeded if the break in 2008 is exceptional. These paddocks have poor soils and/or high weed or disease burdens and are a major liability for the business in 2008. If they are to be cropped, inputs must be kept to an absolute minimum.

Summer weed control

For those districts which have received significant summer rain, summer weeds should be controlled early. Although this may appear to be a risky operation for the business because the full benefits are uncertain at the time (this depends on the pattern of subsequent summer rainfall events), the pay-offs can be handsome. Without follow up summer rain, an early event may still result in little stored water for the crop in 2008 but the gains in seeding efficiency from better trash flow etc can still recoup a major part of the costs of summer weed control. With late summer events or multiple events, even modest amounts of stored water can pay for the cost of timely summer weed control many times over (see highlight box for an example).

Summer weed control should always be early. Do not rely on stock to do the job unless they are in a category 3 paddock. They can be used in a mop up operation but primary control in categories 1 and 2 should be with herbicides. Although summer weed control is best achieved when conducted under high delta-T conditions, if conditions deteriorate before the job is finished it is probably better to continue with adjusted applications (eg higher water rates, higher chemical rates, at night) than stop (because there may not be another chance to get the weeds while they are still small).

Stored water

Stored water from the previous summer/autumn has probably been under valued in southern Australia as a resource for crops. Although most of crop production in southern Australia relies on in season rainfall, stored moisture can be very important in dry years and can be the difference between success and failure of a crop (unfortunately many growers have seen stark evidence of this in the last couple of years). This stored water, which is deeper in the profile, is used very efficiently by crops. However, be aware that even though controlling summer weeds early, high residue cover and reduced tillage systems will all help store and conserve water in the profile, our hot low humidity summers can still completely deplete the root zone of our shallow soils of any moisture under some circumstances.

Fertiliser management

Farmers have several options for minimising outlay in fertilisers without severely comprising production potential. This is probably just as well because a near doubling in price of most fertilisers over the last twelve months is certainly focussing the mind of all managers and advisers on ways to cut corners with fertiliser use.
Firstly, 2008 is a year to exploit previous good histories of fertiliser use. For phosphorus and several trace elements (notably zinc and copper), previous applications can have good residual benefits. Make use of these in 2008 by substantially reducing rates of these nutrients where previous histories are good. Fertilise only for production in 2008, do not apply extra for crops or pastures to use in 2009 or to further boost soil reserves. Reserves of P can be determined in a soil test but trace element status can really only be determined from paddock records of prior applications.
Never has it been more important to undertake soil tests to determine current soil fertility levels. If good records of previous fertiliser use exist and prior soil tests have been taken, more soil tests in 2008 can be avoided. Otherwise, minimum fertiliser rates and choices can only be sensibly estimated with soil reserves as part of the background information. Production in paddocks with high reserves of fertility will not fall off a cliff if fertiliser rates are cut back severely, even to as low as none.
In situations where phosphorus fertiliser is deemed to be necessary (and this is still going to be the majority of paddocks in 2008), ie will return a good profit, this fertiliser should be placed with or near the seed at sowing. This is the most efficient way of applying P fertiliser to broadacre crops. P fertiliser should not be broadcast prior to seeding in 2008 because this approach is only justified in situations where soil P reserves are high and dressings are designed to maintain those reserves – in 2008 simply do not broadcast those paddocks and use the money saved on other inputs which will return better profits.
Keep nitrogen rates to a minimum early in the season. One advantage with N nutrition is that timing of application is not critical. In cereals, N can be applied as late as the crop running up and still be very effective at boosting production and returning a profit. Exploit this feature in 2008 by avoiding early applications and allowing for strategic applications later in the year when a better feel for the season may have developed.
Rates of N of up to 15 kg N/ha can be applied very efficiently in high analysis fertilisers (MAP or DAP) at seeding for almost no cost (because most managers and advisers cost MAP and DAP for their P content, which makes the N component effectively free). It is any extra N above this first 15 kg/ha which should be “saved” until later in the season.
Trace element deficiencies should be managed with a foliar spray or seed dressing in 2008. Foliar or seed dressing treatments are the cheapest option to meet the needs of the 2008 crop but will not provide any residual benefits for subsequent crops or pastures. If the seed dressing option is taken, the budget should also allow for a foliar spray because the seed dressing may not be sufficient to completely protect the crop if the deficiency is severe. If a paddock has a sound and recent history of zinc or copper, consider not using any of those nutrients in 2008. Using seed from a soil type which does not suffer from the trace element deficiency in question, will produce similar benefits to a commercial seed dressing. If this seed needs to come from another property, be aware of weed and cost consequences of such an approach compared to the cost of a commercial dressing.

Nigel Wilhelm
SARDI, Waite Research Precinct

0407-185501.