Agroforestry för svenska förhållanden 2024 - Flipbook - Page 15
to other crops in the farm [5, 6]. Roots also break up
the soil as they grow and strengthen soil microlife
when they die and become food for the soil’s decomposers [6]. This in turn increases the production of
valuable topsoil. Leaves falling on the fields in the
autumn also help to increase the soil’s organic matter
content. Along the edges of agricultural fields and
near watercourses, trees can act as a natural buffer,
absorbing nutrients and agricultural chemicals that
would otherwise have leached from the fields [7].
While there are numerous benefits, it is not always
possible to completely plan out root interference with
the crop and the roots may need to be looked after
“It is so important that we build a fertile
soil that helps release nutrients, so that
we use the nutrients that are in the soil.
We are starting to understand this with
mycorrhiza, i.e. fungal roots that are
very important for binding carbon and
providing the plants with the nutrients
they need. A soil where there are many
different plants also becomes a more
active soil.”
- Johanna Björklund, Associate professor in environmental science at the School of Science and Technology at
Örebro University, citation from the film “Life within
Planetary Boundaries - Agroforestry”.
Kyrkbygård: I allérader med nötträd på åkermark planteras också lönn, ek, vildkörsbär, pil,
poppel och sälg som “amträd” till nötträden när
de är små. Dessa skärmträd minskar temperatursvängningar och blåst, höjer luftfuktigheten,
genomrotar jordprofilen och bidrar till högre
biologiska mångfald. Skärmträden kommer
gallras och flisa ner för att göra komposter av.
Kyrkbygård, Sweden: nut trees grown in rows
on arable land are accompanied by maple,
oak, wild cherry, willow, poplar and sallow,
which acts as “nurse trees”, protecting the nut
trees when they are small. These nurse trees
reduce temperature fluctuations and wind,
increase humidity, permeate the soil profile and
contribute to higher biodiversity. The nurse trees
will eventually be thinned and chipped to make
compost.
Converting cropland into forest land: Grasslands, which are often
the starting point for forest gardens, are dominated by bacteria.
The bacteria are active in metabolism, releasing many different
minerals. In deciduous forests, there are both bacteria and fungi,
such as mycorrhiza, which collaborate with the trees to draw water and nutrients. The use of wood piles is one way to accelerate
succession by creating a rich microflora. Below: Rydeholm forest
garden, Sweden.
“We want to find ways to keep the
nutrients within the plant system and
this is something perennial plants are
very good at. When the roots of for
example sea buckthorn, which can be
several metres long, grow down below
the normal agricultural crops and take
up excess nitrogen, nitrogen leaching
should decrease. This is one of our
hypotheses.”
- Maria Ernfors, senior lecturer at SLU (Swedish
University of Agricultural Sciences) in Alnarp, citation
from the journal Extrakt.
