Agroforestry – an opportunity for soils and climate
Worldwide, about ten million hectares of arable land are lost every year. Intensive agriculture causes a global decline in humus content and ultimately leads to the degradation of valuable soil. The Food and Agriculture Organization (FAO) has long warned that there will only be about 60 harvests left if we continue as before. Agroforestry as a form of sustainable and location-adapted agriculture can counteract these developments, regenerate soils and thus secure our very livelihood.
Agroforestry was an integral part of agriculture until the 19th century. It was only with the increasing use of technology in cultivation that farmers started to think of trees as unwanted obstacles that had to give way to agricultural machines. The consequences are visible from afar – increasingly sandy, nutrient-poor soils that are exposed to all weathers without protection and have become unusable for the cultivation of food.
Modern agroforestry combines tree planting with arable crops and/or animal husbandry, consciously utilizing the interactions between the various crops.
Agroforestry protects, preserves and regenerates the soil
The advantages are obvious: the protective trees improve the microclimate on the arable land and the evaporation is significantly reduced. The rows of trees considerably reduce water and wind erosion. This makes it easier to cope with longer periods of drought. Targeted tree management prompts trees to develop roots up to 35 meters 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.
Deciduous waste, dead fine roots and root excretions increase soil fertility. The cultivation of plants of different heights also makes more extensive use of solar radiation and thus increases the photosynthetically active area. The result is more biomass and higher and more stable yields.
Advantages for climate, humans and animals
In addition to the important advantages for arable land, agroforestry systems are a factor in climate protection that should not be underestimated. Not only trees, but also intact forest soils are important CO2 stores. They also provide habitats for numerous animals and plants and thus preserve biodiversity. The trees provide shade and improve the quality of life in general by beautifying the landscape.
Agroforestry is also economically advantageous: by diversifying products, crop losses in one crop can be offset by increased crop growth in another. An improved nutrient and energy balance considerably reduces the use of fertilizers and pesticides. Manpower is more evenly distributed throughout the year, as the trees are regularly cultivated during the winter months.
Contra Agroforestry – what speaks against it?
In fact, agroforestry does not only offer advantages. The comparatively high establishment costs and the relatively high effort involved in management may argue against conversion. The long-term commitment of capital and land through the relatively slow growth of woody plants, in contrast to arable crops, should also be considered. Combined with other efficiency-increasing, sustainable methods of soil management, however, the disadvantages of agroforestry can be significantly buffered. Humic acid based soil conditioners, for example, increase yields, save water, increase fertilizer use efficiency and guarantee better soil and plant health.
The development of arable soils described above and the global challenge posed by climate change require a rethink at all levels. The advantages of agroforestry for soil development, the climate and thus for humans should therefore be included in a cost-benefit analysis and given special weighting. If used wisely, agroforestry offers a real opportunity for agriculture – one of many paths towards a future suitable for grandchildren.