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Rotation of cover crops can greatly improve soil quality

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Green approach: Padraig Fahy harvesting Brussel sprouts at Beechlawn organic farm

Green approach: Padraig Fahy harvesting Brussel sprouts at Beechlawn organic farm

Green approach: Padraig Fahy harvesting Brussel sprouts at Beechlawn organic farm

This year has been declared the International Year of the Soils (IYS) by the UN. The IYS aims to be a platform for raising awareness of the importance of soils for food security and essential eco-system functions.

Farmers and growers are well aware of the crucial role that soil plays in ensuring good yielding crops. However, the connection between soil use and global food security, climate change mitigation and sustainable development tends to be neglected.

If current trends continue, the global population is projected to reach over 9.5 bn in 2050, and continue climbing to 11bn by 2100.

This will be accompanied by the growing worry of how we will feed this number of people. For organic farmers, soil health is a key component of good production and the simple slogan "healthy soil, healthy plants, healthy people" is often used to describe the practice of organic farming.

Much has been made in the past of the reduced yields under organic production methods, but the yield gap is decreasing.

More importantly, the lack of dependence on expensive inputs (both economic and environmental) is beginning to take centre stage.

Lilian O' Sullivan of Teagasc says that "the central role that soils occupy in production, means that meeting the challenges of food security relies on the knowledge and management of soils.

"Soils vary in their relative capacity to deliver functions, such as food production.

"Furthermore, agriculture cannot be intensified beyond the carrying capacity of soil (before irreversible damage occurs)," she said.

"The extent to which soils can support further intensification - critical to food security - relies on understanding what functions a soil type can support and its interactions with land-use management."

One thing that will be highlighted during IYS is the role that small farmers can play in maintaining soil quality and contributing to global food security.

Small farmers are the essential piece in the global food puzzle.

Policies

The UN Food and Agricultural Organisation (FAO) notes that while experts may have a tendency to ignore the small farmer's contribution, "the world's smallholders produce 70pc of the world's food on 25pc of the land."

In this IYS we must ensure that small farmers are supported by agricultural policies.

The use of cover or catch crops is one practical way in which farmers can enhance the soil and the commercial crops that follow.

These crops are collectively referred to as "green manures" by organic growers.

They are multi-functional, acting as a weed suppressant and fertility builder by adding nitrogen.

Many of these crops also possess the ability to improve soil structure and make nutrients more available to plants.

A more widespread adoption of cover crops could hugely enhance soil quality in Ireland.

Grace Maher is development officer with the IOFGA, www.iofga.org

gmaher @iofga.org

Case Study: Beechlawn Organic Farm

Padraig Fahy and Úna Ní Bhroin from  Ballinasloe certified Beechlawn organic farm with the IOFGA in 2002. They currently grow almost 20ac of organic vegetables and are renting more land for expansion.

Over the years Padraig has extended his use of cover crops or green manures and usually has 20-25pc of land under green manures by August or September.

"I will sow an over-wintering green manure such as winter vetch, crimson clover and Italian ryegrass in ground that I have taken out potatoes out of in August or September," he says.

"From May onwards, when brassicas and root crops are removed, I will sow Persian clover. This is generally topped four times during the growing season to make sure that it does not get too strong and become difficult to incorporate back into the ground," he says.

While green manures are an additional cost to growers, the benefits are obvious. "For me they are an important weed prevention strategy, but there are other benefits you do not see, such as a welcome break in cropping for the soil," says Padraig. "They also enhance soil biodiversity and fertility for the following crop.

"I have increasingly noticed that the crop that follows the green manure requires less inputs and labour, which offsets the initial cost of establishing the green manure."

Protected cropping is a significant aspect of the business at Beechlawn Farm, but establishing cover crops can be difficult in poly-tunnels as many of the high value crops such as tomatoes are not removed until September or October, making it too late to sow a cover crop.

Padraig is also looking at new cover crops such as Japanese oats and fodder radish to see what additional benefits they can bring to the cropping system at Beechlawn.

Indo Farming