Tillage can do more on sustainability and environmental footprint

Tillage farming has a reasonably good profile in terms of its environmental impact. It has lower greenhouse gas emissions, very low ammonia emissions, it is essential for certain species of birds and generally has much better nutrient use efficiency than intensive grassland. But still our crop production systems are far from perfect.

We see costs increasing continuously, not so much because of price increases, but rather because of our dependency on simple and convenient short-term solutions.

Our system of farming has frequently allowed problems to develop, such as resistance development or the proliferation of a new weed, and then we seek yet another chemical solution. But where does this all end?

Benefits of winter cover

One of the major lessons of recent years has been the benefits that having autumn crop covers brings to a tillage system. Whether we call it a cover or catch or green manure is irrelevant.

Many growers have discovered the benefits in springtime of having plants growing in a field over the winter and that having a soil profile full of actively growing roots makes it much easier to break up than a slumped soil.

The use of catch crops is not an optional extra for grain growers

Slumping is where a soil is tightened by time and weather, where the fine particles created by bashing the soil with rain are washed down into the profile. This makes it wetter in spring and much more difficult and expensive to cultivate.

The use of catch crops is not an optional extra for grain growers. They are an important element for soil health and add the capacity to capture carbon as organic matter in our worn soils. This is one definite area where we can do better as tillage farmers and if we are to be financially rewarded for this carbon capture, then that is a further benefit.

Having plant covers in situ over winter does two main things for our soils. The presence of foliage reduces damage to soil caused by beating rain. And plant roots help keep the soil open and friable.

One other thing that might be said here is that killing off winter cover after 1 December reduces the benefits it can bring

As well as these two benefits, such crops also help minimise nutrient leaching and enable additional carbon capture, both of which are proportionate to the amount of dry matter production and so are related to planting date.

One other thing that might be said here is that killing off winter cover after 1 December reduces the benefits it can bring.

Leaving these plants grow in situ for longer will provide ongoing protection to the soil against rain until much later in spring. Eventually growers will recognise that they can drill directly into those loose friable seedbeds without prior cultivation, adding further savings.

Soil fertility

Soil fertility levels in tillage land leave scope for additional nutrient application, especially in the form of organic manures. Worn tillage soils have considerable potential in surplus manures that are causing management issues in other enterprises. If such opportunities were promoted, this could present an opportunity for further reduction in national nitrous oxide (a GHG) and ammonia emissions.

Having more natural nutrient recycling in the soil means higher plant yields, less fertiliser used and more yield

The higher the basic fertility we have in our soils the better that is for crop productivity. This normally comes through the recycling of organic matter, but if that plant material is not in the soil to begin with, then nutrients cannot be released. Having more natural nutrient recycling in the soil means higher plant yields, less fertiliser used and more yield per unit of applied fertiliser.

Biodiversity

With biodiversity set to be increasingly important, there is scope for us to do more in tillage. This could be via that poor corner or wet bottoms that never yield well, or it could be headland strips of wild flowers that act to increase both the diversity of plants in an area and also the associated insects (bees, etc) which live off them.

Having more plants, flowers and insects should inevitably lead to increased bird numbers.

Tillage crops do provide seeds on stubbles for seed-eating species

While tillage cropping is essential for some bird species, such as the barn owl and the yellow hammer, we must also recognise that the weed-free crops which we need for ease of management are a limitation to biodiversity. Having more crops is an advantage in this regard.

Tillage crops do provide seeds on stubbles for seed-eating species. These also feed rodents, which are food for owls etc. However, desiccated stubbles provide a pretty sterile environment.

Water quality

Buffer zones are well established in tillage cropping and are obligations for fertilisers and pesticides. Tillage farmers are obliged to not cultivate or plant within 2m of an official watercourse and all pesticides carry an official buffer zone requirement next to water.

As for fertiliser, virtually all modern high-capacity spreaders are fitted with headland spreading devices which significantly limit the likelihood of fertilisers being spread into waterways to cause pollution.

For growers who practice both these measures, there is not much more that can be done, other than to reduce the level of inputs. Further technological developments will help in time.

However, liquid fertiliser could be used close to sensitive water bodies and frequent stale seedbeds on headlands would, in time, reduce the requirement for herbicides along by waterways.