Agroforestry – an opportunity for soils and climate
Worldwide, about ten million hectares of agricultural land are lost to farming every year. Intensive farming causes a global decline in humus content and ultimately leads to the degradation of valuable soil. The Food and Agriculture Organisation has long warned that if we continue as we have been doing, there will only be enough arable land for about 60 harvests. Agroforestry systems as a form of sustainable and site-adapted agriculture can counteract these developments, regenerate soils and thus secure our livelihood.
Until the 19th century agroforestry was an integral part of agriculture. It was only with the increasing mechanisation of cultivation that trees became more and more of a nuisance and had to give way to machinery. The effects can be seen from afar - increasingly sandy, nutrient-poor soils, exposed to all kinds of weather without protection and rendered useless for growing food.
Modern agroforestry systems are a combination of trees and arable crops and/or animal husbandry, making conscious use of the interactions between the different crops.
Agroforestry - protecting, preserving and regenerating soil
The advantages are obvious: the protective trees improve the microclimate on the arable land and evaporation is significantly reduced. The rows of woody plants considerably reduce water and wind erosion. This makes it easier to cope with longer periods of drought. Targeted management measures train trees to develop roots up to 35 metres deep, which serve as water and nutrient pumps. The root system also prevents the discharge of substances into surface waters. It absorbs pollutants from deeper soil areas and thus reduces the average nitrate concentration in groundwater by more than 120 times.
Foliage falling from the trees, dead fine roots and root excretions increase soil fertility. The cultivation of arable crops at different altitudes also makes more extensive use of solar radiation, thus increasing the photosynthetically active area. The result: more biomass and higher and more stable yields.
Benefits for climate, people and animals
In addition to the important advantages for the arable land, agroforestry systems can play a role in climate protection in the coming years that should not be underestimated. Not only trees, but also intact soils in forests are important CO2 reservoirs. They also provide habitats for numerous animals and plants and thus preserve biodiversity. The trees provide shade and generally improve the quality of life by beautifying the landscape.
Systems with agroforestry are also beneficial from an economic point of view: through product diversification, harvest losses in one arable crop can be offset by another. An improved nutrient and energy balance considerably reduces the use of fertilisers and plant protection products. Work peaks are better distributed over the year, as the management of woody plants in agroforestry systems is regularly in the winter months.
Contra Agroforst - What's wrong with forest in the field?
Indeed, agroforestry does not only have advantages. The comparatively high establishment costs and the relatively high effort involved in cultivation may argue against a switch from pure arable farming to agroforestry. The long-term capital and land commitment resulting from the relatively slow growth of woody plants, in contrast to arable crops, must also be considered. Combined with other efficiency-enhancing, sustainable methods of land management, however, the disadvantages of agroforestry can be clearly buffered. Humic substance-based soil conditioners, for example, increase yields, save water and fertiliser and guarantee better soil and plant health.
The development of arable soils described above and the global challenge posed by climate change in the coming years require a rethink at all levels. The advantages of agroforestry systems for soil development, the climate and thus for mankind should therefore be included and given special weight in a cost-benefit calculation. Used wisely, systems such as agroforestry offer a real opportunity for agriculture - one of many paths to a future fit for grandchildren.
Agroforestry systems are eligible
Recently, a small enquiry by the Left Party to the Federal Government revealed that agroforestry systems are in principle eligible for support under EU law. What do you think of the idea of planting rows of trees in your field? Do you also see the advantages of agroforestry for soil conditions and plants or do you fear the loss of valuable land for cultivation?