Shifting from monocultural use of land and forest to mixed crops, agroforestry systems and mixed forests
What's the measure?
Shifting from monocultural agriculture & forestry to mixed crops, agroforestry systems and mixed forests.
How can it be implemented?
The knowledge about positive effects of restructured cultivation systems is available, the main point is to implement it. Helpful measures are the shifting of subsidies to mixed crops or subsidies for the conversion. Farmers* must be taught how to use mixed crops and agroforestry systems and thus also how to avoid synthetic fertilizers and pesticides. This must take place with as few barriers as possible. The farmers must be equipped with new tools
How does the measure save CO2 (how much)?
In monocultural agriculture, large amounts of fertilizers and pesticides are necessary to compensate for poor crop rotation and susceptibility to pests. The production of fertilisers and pesticides generates large quantities of greenhouse gases (GHG). The very energy-intensive production of one tonne of nitrogen fertiliser requires about two tonnes of crude oil. This could be saved if pests are counteracted by mixed crops and leaching out the soil through adequate crop rotation and crop protection years. Monocultures are also used because their uniform appearance makes the work with machines easier. However, these machines are also operated with fossil fuels, which could be saved with mixed crops that require more human labour.
Monocultural forests are also more affected by pests. Wood is often short-living and stores only little CO2. In addition, forest fires, which are likely and frequent in monocultural forests, release a lot of CO2. Mixed forests store more water, promote undergrowth, which also stores CO2, and promote the humus growth, which also binds CO2. In addition, a higher proportion of hardwood (since coniferous trees only occur naturally in marginal locations in our latitudes anyway) should be aimed for. Mixed deciduous forests are more resilient, better adapted to the prevailing climate and also create a microclimate within the forest that is several degrees cooler. Furthermore, attention should be paid to an increased proportion of old trees (these store particularly large amounts of CO2) and a mix of both tree species and age of the trees.
Agroforestry systems, as perennial crops, can even store CO2 in the long term. Because the trees in agroforestry systems remain standing for several years and do not die completely like annual vegetable plants, the CO2 that they remove from the air by photosynthesis can be removed from the atmosphere in the long term. In addition, there are positive effects for the soils and especially protection against erosion and an improvement of the ocular water balance.
How long does it take the measure to become effective?
In mixed forests, it takes the time until the trees have reached the appropriate size and have incorporated CO2. With regard to trees, Co2 is bound from the time of planting, but the positive effects (as well as the amount of CO2 bound per year) increase with the growing period of the new crops. In the case of mixed crops, which do not need pesticides or fertilizers, from the first time they are renounced.
Other positive effects
It can be planted closer if no/less/other machines are used. The yield per hectare increases, which means that less area is needed overall. This would require the support of farmers through more labour. Biodiversity increases in the areas under cultivation, both through more different crops and through more animals that can live on them (e.g. insects and amphibians). Renunciating from pesticides also prevents the collateral damage it causes, such as species extinction and health risks. Since the uniform appearance of the plants is no longer important, no genetic clones need to be used, which in turn reduces susceptibility to pests. Less soil compaction by heavy machinery. Very effective protection against soil erosion and soil degradation.
Continuative literature and sources
(e.g. effectiveness studies, articles on pilot projects, etc.) "wer die Saat hat, hat das Sagen" - Anja Banzhaf (book) IPCC (the second)
Floh 11-19-2019 17:41 note Agroforestry systems as perennial crops can even store CO2 in the long term. Because the trees in agroforestry systems remain standing for several years and do not die completely like annual vegetable plants, the CO2 that they remove from the air by photosynthesis can be removed from the atmosphere in the long term.
Conceptual acknowledgement: In my understanding, an agroforestry is not a perennial crop, but a system in which perennial crops are part of.
Laki.7 25.11.2019 08:35 Important measure! Perhaps, within the framework of this measure, we can also include more explicit aspects such as natural tree species mixing, a higher proportion of hardwood, more old trees and forest in all developmental phases...
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