Soil, the all-important moisture reservoir

Knowing plant available moisture at plant-rooting depths is key to understanding yields you will get from crops. This is important advice from farmer Peter Conlan, who has a wealth of experience growing crops including wheat, sunflower, flax and oilseed rape in diverse countries such as Australia, Ukraine and Russia

Water is the limiting factor holding crop yields back, Mr Conlan finds; but he does not recommend irrigating to take yields to their genetic potential as it adds in a risk factor that the return on investment might not be good enough.

“As growers, we need to grow to their maximum economic yield, which is not necessarily the maximum yield the crop could achieve,” he says.

For example, if there is 200mm of water at depths of 1m, this means there is enough water in the soil to achieve a minimum sunflower yield of 1.4t/ha without irrigation, he says. That allows you to budget for selling that amount of crop. The crunch factor is not the numbers of tonnes of crop sold, but the difference between the money received and total costs.

“We have to be economically sustainable; if you are unable to make a profit and give a good commercial return to the land-owner, you go out of business and lose the land.”

This means fine-tuning to make sure all inputs are put to maximum use; for example, he recommends growers to look at the long-term forecast for rain before applying nitrogen (N) to cereals at GS31, just when they are at the tillering stage. 

“Think about the availability of moisture needed to take your crop to 100 per cent yield, and whether that is feasible. If you believe you will only make 50 per cent as water is limited, then apply the appropriate amount of N for that – putting on excess N which is not taken up by the plant is a waste of resources and money.” 

Premiums for higher protein levels required for bread-making wheat do not compensate for the extra N inputs 80 per cent of the time, he believes, so he does not aim for this market. Nevertheless, he adds, sometimes the wheat does reach the necessary protein levels, winning premium which is pure profit as no extra inputs have been made. 

For Mr Conlan, being able to move away from applying N would be ideal, and he has been considering using cover crops which will fix their own supply from the air, such as crimson clover. His challenge, however, is that it can be difficult to find such supplies as it is mostly only available in mixes.

Of course, getting planting right is crucial, and Mr Conlan opts for a no-till regime using a Canadian-built seeder (drill) with tines. “If the recommended seeding rate for sunflower is 90,000/ha, you can halve this as the crop will compensate, develop bigger heads and achieve the same yields as those drilled at higher rates.

“Crops with a bit more space have more room to develop and absorb sunlight for photosynthesis; so again, you are saving on costs so your rate of return is higher.”

With winter wheat and oilseed rape, crops need to go in in September to get well-enough established before soil temperatures drop away in the Autumn. 

“Ideally it needs to get to tillering before winter.” Of course, there are some areas with easier climates to deal with than others, he says, adding that the area of Ukraine near the Black Sea is more difficult for crops to cope with as it is the last place to get snow cover and the first to lose it. 

Moving on to discuss machinery, he stresses the importance of purchasing a seed-drill which will last at least twenty years. 

“You need to keep the number of moving/wearing parts to a minimum so you keep maintenance costs down,” he advises. 

As a result, he does not use a precision planter – which would be a higher investment which may only end up achieving five per cent extra yield, so seed density at planting is his only variable. He has also minimised the number of hours his tractors work a year, going from 1500 hrs/tractor/year to just 400, saving on tractor wearand-tear, diesel, man-hours – and carbon footprint. 

Fields are treated with glyphosate and then drilled within 24 hours with N and P, fertiliser is applied in March and a herbicide in late March. The only other activity is harvesting, he says.

“Where possible it is always better to follow the principles of controlled traffic farming (CTF), so you avoid creating compaction pans.” Mr Conlan believes in keeping things simple, following rotations such as two wheat crops, one flax, sunflower plus oilseed rape if seasons allow.

“Many of the most profitable farms across the world are in lowrainfall areas; they have learned to be efficient and use all their inputs in the most efficient way to make sure they can make a profit.”