EPA - Ireland's Environment, An Integrated Assessment - 2020

Chapter 5: Land and Soil Land and Soil 1. Introduction Our soils and land are precious resources that need to be managed carefully. They have a variety of uses including food production, forestry, development of national and commercial infrastructure, housing and leisure activities. Policies and practices linked with land and soils can directly impact on biodiversity, climate change, air quality and our aquatic environment. Sustainable land use and spatial planning are therefore extremely important. This chapter summarises the functions of soils and the main land cover and land use types in Ireland and examines the current trends in land cover change. 2. Functions of Soils Healthy soils that are properly managed support farming and environmental protection. Soils consist of a biologically active, complex mixture of weathered minerals, organic matter, organisms, air and water. They form over long periods of time and are limited resources needing careful management. Our soils, land use and landscape are shaped by natural processes and human interventions. About a quarter of all living species, such as fungi, bacteria and insects, live in our soils. Healthy soils provide us with clean air, food and water. They also support plant and animal growth and provide the foundations for human habitats, buildings and infrastructure. They provide important ecosystem services including agricultural food production, flood alleviation, water filtration and storage, carbon sequestration, pollution control and development of pharmaceuticals. Many widely used antibiotics have come from soil. Penicillin, for example, came from a fungus ( Penicillium ) found in soil. Seven of the United Nations Sustainable Development Goals have direct links to soils, while a further two depend indirectly on healthy soils (Tóth et al. , 2018). Carbon stored in soils plays an important role in maintaining soil functionality, in water and air quality and in climate change. Proper land use management is essential to prevent carbon stored in soil from being released into the atmosphere and further contributing to greenhouse gas emissions and climate change. Measured in pH units, the acidity or alkalinity of soil plays a role in supporting its fertility. The increased use of lime is resulting in increased levels of soil fertility, leading to better soil pH management (Teagasc, 2019). Teagasc has indicated that the optimal soil pH for agriculturally productive grasslands is at or above pH 6.3. This optimal soil pH leads to improved grass yields and more efficient application of fertilisers. In the period from 2017 to 2019, 57 per cent of Teagasc soil samples had an optimum pH (Simo et al. , 2019). This was a significant improvement on the value of 34 per cent for the period from 2014 to 2016. Before deciding on what constitutes ‘optimal’ soil pH, or indeed other soil parameters such as nutrient levels, it is wise to decide the best primary use for a piece of land. The parts of the country with higher levels of agricultural productivity are generally the areas with productive soils, a conducive climate and a history of agricultural intensification. Many other areas support land that is better suited to providing low or modest levels of agricultural productivity, coupled with other hugely valuable services such as high nature value farming. Such services include supporting biodiversity, delivering wildlife habitats for pollinators and others, and providing for carbon sequestration and storage, better water quality or water attenuation. In the coming years, farming support schemes will be targeted at these areas of high nature value farmland, with lots of semi-natural habitats. Land management can then be better planned across a range of services and not solely focused on agricultural production. Teagasc has indicated that targeted improvements in soil quality should lead to better nutrient uptake from applied fertiliser and organic manures. Fewer losses of nutrients to water and air should, in turn, result in reductions in agriculture-related emissions to water and air. 99