Words supplied by Ballance Agri-Nutrients
To mark World Soil Day on 5 December, Ballance Agri-Nutrients Forage Specialist and no-till advocate Murray Lane discusses soil loss prevention.
How does this year’s World Soil Day theme ‘Stop soil erosion, save our future!’ apply to farmers?
Over time soil is lost, even from pastoral situations, and our challenge is to keep soil and its microbes in place, growing soil at least as fast as we lose it. Cultivation and pugging both accelerate soil loss. When it’s loose, soil can be lost to the action of both wind and water. Accepting that cultivation’s necessary some of the time, for the most part no-till cropping’s a much better and very achievable option, leaving the soil undisturbed and reducing erosion losses.
From the soil’s point of view, there are very few situations where cultivation’s better than no-till, and by addressing soil loss, we also address phosphorus loss, as most phosphorus lost from land to water is bound to soil particles.
How does no-till reduce soil erosion?
The four key points for maintaining soil are: leave it undisturbed (uncultivated); always keep it covered (with crops or pasture); grow a variety of species; and incorporate animals into the system. Tillage involves disrupting the soil to prepare a seedbed for planting, leaving the soil surface bare, disturbing the soil structure, and making it more vulnerable to wind and water erosion. No-till on the other hand leaves the soil undisturbed, so it’s less vulnerable to erosion and pugging, water infiltration rate is unaffected, as are soil fauna.
Are there any other advantages of no-till farming?
No-till allows any type of land to be cropped quickly and efficiently. Less time is spent on the tractor, as no-till requires just two key operations, spraying and drilling. Soil structure isn’t affected, leading to less damage during grazing. Some New Zealand farmers are helicropping (a form of aerial no-tillage) hundreds of hectares with small seeded crops such as brassica. If these crops can be grown without even opening the gate, why are we still cultivating?
What no-till technology is available?
We’ve had no-till technology for 40 years now, and it’s continued to improve as knowledge and drill design improve. By the late 1980s no-till regrassing was standard. In the 1990s no-till cropping began to develop. Today all of the brassica crops (swede, kale, turnip, rape) plus clover, chicory and plantain, along with all pasture grasses and cereals can be established with no-till techniques.
Large seed crops such as maize can also be no-tilled. The idea is to modify the drill to manage the soil, rather than modify the soil so the (traditional) drill can perform effectively. The Foundation for Arable Research have 13 years of replicated trials in the Waikato growing maize crops comparing no-tillage, strip tillage and full cultivation, showing no-tillage crops yield the same as cultivated crops, and are better in drier seasons due to moisture retention. Plus the cost of cultivation’s saved, so there’s really no reason not to use it.
Do you have one take home message for readers?
No-tillage cropping’s a proven technology, used worldwide for all types of cropping, leaving the soil undisturbed, increasing water infiltration and reducing soil loss. The technology’s available in New Zealand, so if you value keeping your soil on the farm, perhaps it’s time for a change.