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Fig. 4.46 General
outline of biological
plant protection
Fig. 4.45 General outline of a biology based integrated plant growing system (N nitrogen)
The joint application of agrotechnical and biological methods is important in chemical free
agriculture. One fundamental aim of this is to
increase biological diversity. It is experienced that
the higher is the number of plant species grown in
a farm (with careful design) the smaller the threat
of infection and the number of pests will be. A
disadvantage of higher biological diversity is that
machines cannot be used in such farms. Therefore
in mechanised plant growing the crop rotation and
soil cultivation system enabling highest biological diversity have to be found.
Numerous forms of agroecological farming
were worked out in certain poor regions. In Africa,
for example, agricultural forestry is widespread
in many countries. Various tree and shrub species
are planted or left in arable and pastoral lands.
These protect the soil, help the water cycle in the
area, control the microclimate and contribute to
the pollination of commercial plants and maintain
the biodiversity of the landscape just like natural
forests. Some trees have a role in nitrogen adsorption while falling leaves help the regeneration of
the soil and some trees and shrubs could also be
used as fodder for small- scale cattle keeping.
Traditional use of trees (building wood, firewood)
also contributes to the provisions of the farming
community—taking care of avoiding overuse.
4 Changes on Earth as a Result of Interaction Between the Society and Nature