Throw away the textbooks

25 Mar 2012

Indulge me. Just one more reflective blog on Australian farming.

Tree ferns recovering from bush fireThe picture of the tree fern recovering from a wildfire is a metaphor for the resilience of the Australian countryside and agriculture. Perhaps the area of the least resilience is the small rural communities and towns. These are obviously suffering and there are many local initiatives to try and keep them in business, including promoting tourism and as a place to do business.

The problem is rural depopulation. Not only has agriculture become dramatically more labour efficient, but many farmer families, particularly those with children, have now moved to relatively large towns with good schools. So it is the farmer who commutes to work during the growing season, staying in the farmhouse when the long hours are required.

The more meetings I attended, and the more farmers I met, made me review my understanding of the management of risk in determining input levels. The risk of getting it wrong is fairly low in areas where the rainfall is typically either relatively high or relatively low.

In low rainfall areas, farmers are still reluctant to throw much at the crops, even when soils are moist at the time when inputs may theoretically increase yields. This is because of the high chance of a ‘dry finish’. In this situation, additional inputs can reduce yields if they have encouraged larger crop canopies leading to more moisture loss earlier in the season.

Risk management is at a premium in those areas where it is more likely that there may be sufficient moisture to keep the crop actively growing until ripening. Getting it right is crucial, because exploiting the good years and minimising losses in the bad years is critical to the long-term economic viability of these farms.

Since my first blog from Australia there has been too much rain in Queensland, New South Wales and Victoria in particular; between 240 and 400 mm of rain in a week. We only just got out of a small town in Northern Victoria in time; having to drive through shallow water on perhaps the only route still open.

In one way, this is good news as the soils will have high moisture reserves when sowing starts in late April. But, it is also bad news because waterlogging will result in nitrate leaching and denitrification. Soil mineral nitrogen is the major source of nitrogen for most Australian cereal crops and too much rain will have diminished this valuable resource. This only goes to prove the old adage that the weather is never perfect for farming.

The Australians have studied the availability of soil mineral nitrogen in detail, because of its importance. They reckon that between 40-50% of it in the rooting zone is taken up by the crop. Our RB209 and some other UK recommendation systems assume that there is 100% take-up of soil mineral nitrogen. I regretfully have to admit that a review of around 60 NIAB TAG trials in wheat suggests that the Australians have got it right (this once!!!).

Finally, I’ve previously listed the potential threats to Australian crops. Not only is it the weather (drought, heat and frosts) but an array of pests. One morning, we actually drove through a small flight of locusts, and find out that they can easily block car radiators.

There are a couple of pests I’ve previously not mentioned. Earwigs and millipedes are severely damaging seedling crops in some areas. The textbooks say that they should not but since when have Australian pests read the textbooks.