For a
long time, soil has been seen as a simple support. The philosophy of conventional agriculture is to give each
problem its solution: if there isn't enough nutrient, you add
fertilizer, if there isn't enough water, you add irrigation and if
there's a pest attack, you spray pesticides. In conventional farming,
the soil is adapted to the crop by using a variety of inputs.
Agroceology
takes a different approach. The soil is the most important part of the
field because many ecological processes occur in it. Changing your
agricultural practices will affect those natural processes which will
change your soil and create a positive or negative dynamics.
Conventional agriculture focuses on the present and neglects those
long-term evolutions, this is why soil degradation occurs in many
place: because of a poor management of the ecological processes, the
soil was kept in a vicious circle for years. The yield was not
affected because the loss in soil quality was compensated by extra
inputs added. Farming on a degraded soil is possible but it requires
an intensive management because everything has to be brought.
Irrigated and heavily pruned tea trees |
A
good soil can store nutrients and water, the main things plants need
to grow. One of our teacher says "soil is to water what the
fridge in your house is to you, and you prefer it big and full of
good stuff". Some soils are better than others naturally,
because of their texture. Soil has particles of different size, from
big chunks of sand to tiny pieces of clay. The smaller the particles,
the better the soil can keep things in it, therefore, a clay soil is
generally preferred to a sandy soil. The soil texture cannot be
changed by agriculture, it would mean bringing tons of new material
and it is very unpractical.
However,
the structure of the soil is very dependent on what people do on the
soil. The structure means how the particles are organised. You want
the soil to be bulky enough so that it won't fly away with wind and
but not too compacted in order to offer a maximum surface contact between
the soil particles and the air. That way, you can store much more
nutrients and water : the fridge gets bigger.
The soil is so loose in some parts of Jingmai mountain that heavy rains give that hilly shape to the surface. |
In
agriculture, the main problem is compaction : it occurs when you
use tractors or when you and your cows walk on the field. It is possible to loosen the soil by digging it, but this is hard manual labor. Small dudes can do the job for free : worms. As worms crawl
through the soil, they dig galleries that will loosen the soil and
therefore improve its structure. This is one of the main reasons why
soil life is important.
Ants contribute to the soil structure |
With
a good structure, plants will grow roots easily and a special kind of
fungi called mycorrhiza will fix on the roots and grow a network of
filaments that will help the plants catch nutrients. In exchange, the
fungi can take carbon from the plant to feed itself. This is one of
the great mutualistic relationships known in Nature. It is believed that without
mycorrhizae, the nutrient catching capacity of many plants would be
severely reduced.
We
should think about the soil first, and the crop second. A fertile
soil is the guarantee of good yields on the long run. By improving
soil life, we can improve the soil structure and therefore increase
its fertility.
Manual weeding as part of an experiment in Jingmai natural tea gardens |
Hi William,
ReplyDeleteThank you for posting these details of tea soil details. It is indeed a much healthier living style than in the middle of a big city.
When you have a moment please have a look at the photos of the following link. This must have been one more reason why you liked Yunnan: http://www.lovethesepics.com/2015/03/stunning-colors-of-remote-red-land-slice-of-photography-heaven-in-china-36-pics/
Looking forward to your next post.
Rui
Hi Rui,
ReplyDeleteThanks for the link, the pictures are really beautiful, I have never been to the areas mentioned, but i can see another time that Yunnan has many jewels hidden in the countryside. In every trip I make, I am rewarded with mindblowing landscapes. You can stay for years in Yunnan and still be amazed at each mountain top .
Best
William