14 / INSIGHT
SOIL MANAGEMENT AND REGENERATION
FIGURE 1: RHIZOSPHERE OF A LEGUME WITH NITROGEN FIXING BACTERIAL ROOT NODULES
Dr Brian Murphy explores the challenges facing soil conservation and the role compost can play in soil improvement
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oil is a valuable natural resource that performs vital ecosystem functions. It cleans our air and water; it provides us with food and materials for shelter and clothing. Without soil, life as we know it would not exist. Just like air and water, it is part of our planet’s life support system. Our soil is a huge sink for carbon, holding two to three times more carbon than the atmosphere and more carbon than all the world’s forests combined. Soil carbon sequestration offers a tangible way of mitigating climate change. The soils of our gardens, roadsides and green spaces are vital havens for biodiversity. So why do we seem to take soil for granted?
CHALLENGES FACING SOIL Soil is vulnerable to erosion, compaction, pollution, desertification, urban development, intensive agriculture and climate change. The equivalent of 30 football pitches of fertile soil is estimated to be lost globally every minute. Soil organic matter, which is vital to soil health, is decreasing in soils across Europe (Bellamy et al. 2005) [1]. A 2017 report from Panagos et al. [2] estimated that European countries are losing up to €1.25 billion annually in agricultural productivity due to soil erosion and loss. Loss of biodiversity is also a serious challenge, which is directly related to how we manage soils. In the EU, we have a water framework directive and an air quality directive, both positive directives to protect our water and our air. A soil framework directive was proposed in 2006 but was scrapped in 2014 due mainly to a blocking minority of the UK, France, Germany, Austria and the Netherlands. The soil framework directive must be revisited, given the importance of food security and the climate crisis. It is also disappointing that there is no mention of the soil's potential to actively sequester carbon in the Irish Government's Climate Action Plan. Currently, Irish legislation and environmental enforcement are such that soil stripped from a greenfield site before development is classified as waste material or at best, a by-product, imposing strict limitations on its reuse. The reality is that vast amounts of fertile soils are ending up in landfill or filling a hole in a soil recovery facility. This situation does not follow the principles of a circular economy.
NATURALLY DRIVEN SOLUTIONS On a positive note, these problems have solutions. Many farmers, growers and soil scientists are already instigating changes to conserve and improve soil health. Conservation agriculture, regenerative agriculture and biological farming
Spring 2020 / www.horticultureconnected.ie / HORTICULTURECONNECTED
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