The term agroforestry system refers to a form of land use, in which trees and shrubs are combined with arable crops and/or livestock on the same land in order to benefit from the ecological and economic interactions[1]. There is a wide range of possibilities for different system designs regarding species composition and management. Agroforestry systems can be subdivided into Silvoarable Systems (woody plants with arable crops), Silvopastoral Systems (woody plants with animals, →Silvopastoral Agroforestry Systems) and Agrosilvopastoral Systems (woody plants with animals and arable crops) [2].
The idea of agroforestry systems is to make use of the potential synergies between the (now often strictly separated) land use forms of animal husbandry, animal feed production and arable farming, horticulture, viticulture as well as fruit growing, thus increasing yields and protecting the soil. At the same time, firewood, animal feed, fruit and construction timber should be produced on one and the same area.
Agroforestry systems provide positive external effects on the environment. One example is the inclusion of trees in cultivation systems, which can contribute to the purification of the groundwater by reducing nitrogen leaching into the groundwater[3]. In addition, agroforestry systems provide diverse habitats for animals, fungi and plants, and thereby increase biodiversity in agricultural regions compared to conventional farming systems[4]. The trees in the agroecosystems help to bind more carbon above and below ground in the long term (CO2 sink), to promote humus formation and to provide protection against erosion by wind and water[5]. The increasing weather extremes caused by climate change can be compensated by agroforestry systems. For example, temperature extremes are reduced by shading. If agroforestry systems are not combined with organic farming practices, at least the use of agrochemicals and fertilizers can be greatly reduced, by improving nutrient utilization and closed nutrient cycles as well as by increasing resilience to pests[6].
By allowing trees to break down nutrients that arable crops would not be able to break down on their own[7], agroforestry systems achieve higher overall productivity through these synergy effects and thus higher yields per hectare compared to monoculture systems[8]. The product range is expanded (also in comparison to the ®Forest Garden concept[9]) and thus, for example, wood can be sold as a sustainable energy feedstock. A particular advantage of including trees in agriculture is the aesthetic effect of this cultural landscape. This plays a major role in promoting the social acceptance and appreciation of the system. [10]
Agroforestry systems are among the oldest forms of land use worldwide. Based on pollen findings, agroforestry systems can be dated back to as long as 1300 years ago.[11] Traditional economically important forms of land use, which have been widely used in Europe (and in Germany), include, for example, lopping fodder trees for the production of animal feed, hollow log beekeeping for the production of honey, pannage (rearing pigs in woodland areas), the combination of fruit growing and pasture, as well as hedgerow management systems such as the North German 'Knicks' [12]. While the specialization of land use has increased since then, it was only about 40 years ago that these agroforestry techniques found their way from traditional indigenous knowledge into science, and are thus increasingly gaining appreciation[13]. Modern agroforestry systems were only developed in the 1970s and 1980s in response to environmental and food crises[14].
Agroforestry is practiced worldwide on approximately 1 billion hectares in a wide variety of forms[15]. The spectrum includes Forest Garden systems and Shifting-Cultivation in the tropics, aquacultures in mangrove forests and energy wood systems, which are particularly widespread in Central Europe[16]. Agroforestry systems are generally considered in the EU regulation concerning the 'Common Agricultural Policy'. However, they are not yet clearly recognized and defined as an independent form of land use in German legislation. As a result, only a few forms of agricultural subsidies following the EU regulation are available in Germany. These forms are 'orchard meadows with grassland use', 'landscape features' or 'short rotation coppice'[17].
With regard to existing disadvantages, advocates of agroforestry systems point to the higher costs required for its establishment and management[21]. The amount of work involved is also higher than in other systems. The long-term capital tie-up due to the slow-growing trees and shrubs can be a problem. The joint use of resources (light, nutrients, water) of woods and arable crops as well as the shared space for growth can have negative effects on plant growth apart from the advantages described above.
The low acceptance of agroforestry systems by conventional farmers to date may disadvantageously impact their expansion. Little knowledge of the agroforestry systems and a lack of trust in their productivity are some of the hurdles for its application by farmers[22]. Awareness raising and conversion support for farmers may be necessary.
[1] Nair, P. K. R. (1985). Classification of agroforestry systems. In: Agroforestry Systems, 3(2), pp. 97–128. https://doi.org/10.1007/BF00122638
[2] Toensmeier, E. (2016): The Carbon Farming Solution - A Global Toolkit of perennial Crops and Regenerative Agriculture Practices for Climate Change Mitigation and Food Security
[3] Brown, S. E. et al. (2018): Evidence for the impacts of agroforestry on agricultural productivity, ecosystem services, and human well-being in high-income countries: A systematic map protocol. Environmental Evidence, 7(1), p. 24. https://doi.org/10.1186/s13750-018-0136-0
[4] Reeg, T. et al.(2009): Agroforstsysteme aus Sicht des Naturschutzes. In: Anbau und Nutzung von Bäumen auf Landwirtschaftlichen Flächen, pp. 301–311. https://doi.org/10.1002/9783527627462.ch27
[5] Quinkenstein, A.et al. (2009): Ecological benefits of the alley cropping agroforestry system in sensitive regions of Europe. Environmental Science & Policy, 12(8), pp. 1112–1121. https://doi.org/10.1016/j.envsci.2009.08.008
[6] ibid.
[7] Smith, J. (2010): Agroforestry: Reconciling Production with Protection of the Environment A Synopsis of Research Literature.
[8] Brown, S. E. et al. (2018): Evidence for the impacts of agroforestry on agricultural productivity, ecosystem services, and human well-being in high-income countries: A systematic map protocol. Environmental Evidence, 7(1), p. 24. https://doi.org/10.1186/s13750-018-0136-0
[9] Haack, M., Engelhardt, H., Gascoigne, C., Schrode, A., Fienitz, M. & Meyer-Ohlendorf, L. (2020): Sozial-ökologische Transformation des Ernährungssystems: Nischen des Ernährungssystems. German Environment Agency, Dessau-Roßlau.
[10] Brookfield H. and Padoch C. (1994): Agrodiversity. Environment 36(5): 7-11, pp. 37-45.
[11] Konold, W., & Reeg, T. (2009). Historische Agroforstsysteme in Deutschland. In: Anbau und Nutzung von Bäumen auf Landwirtschaftlichen Flächen pp. 313–324. https://doi.org/10.1002/9783527627462.ch28
[12] ibid.
[13] Brookfield H. and Padoch C. (1994): Agrodiversity. Environment 36(5): 7-11, pp. 37-45.
[14] Nair, P. K. R. (2009): An Introduction to Agroforestry.
[15] Nair, P. et al. (2010): Carbon Sequestration in Agroforestry Systems. Advances in Agronomy, 108, pp. 237–307. doi.org/10.1016/S0065-2113(10)08005-3
[16] Gruenewald, H. et al. (2007): Agroforestry systems for the production of woody biomass for energy transformation purposes. Ecological Engineering, 29(4), pp. 319–328. https://doi.org/10.1016/j.ecoleng.2006.09.012
[17] Böhm, C. et al. (2017): Wie können Agroforstsysteme praktikabel in das deutsche Agrarförderrecht eingebunden werden? In: Böhm, C. Bäume in der Land(wirt)schaft – von der Theorie in die Praxis. Tagungsband mit Beiträgen des 5. Forums Agroforstsysteme. Senftenberg, BTU Cottbus, pp. 7-16.
[18] Mazi Farm—Farming for the Future (2018). https://www.mazifarm.com (20.02.2020)
[19] AFINET - Agroforestry Innovation Networks (n.d.). http://www.eurafagroforestry.eu/afinet/ (20.02.2020)
[20] World Agroforestry | Transforming Lives and Landscapes with Trees (2019). http://www.worldagroforestry.org/ (20.02.2020)
[21] Agroforst (2018): Pro und Contra Agroforst. 06.12.2019. https://agroforst-info.de/chancen/ (20.02.2020)
[22] Kaeser, A. et al. (2011): Agroforstwirtschaft in der Schweiz. 2(3), pp. 28–133.
