Agriculture and its impact on ecosystem
A.Agricultural farmland as a unstable ecosystem:
An agricultural ecosystem is established and manipulated by human beings in various ways to suit their own purposes, e.g . for food production.
This ecosystem is unstable in many aspects:
1.Continual removal of soil mineral nutrients due to absorption by crops and weeds. Natural recycling of minerals is hindered as a result of harvesting and subsequent export of biomass from the ecosystem.
2.Removal of the original plant vegetation (and also the animal s) inhabiting the area in order to clear up the land for growing crops. This lead to the loss of plant and animal species.
3.Monoculture - growing the same or a few number of crop species on a large area for a long period of time. This lead to the exhaustion of certain types of minerals from the soil.
4. The crops are grown in high densities so create the problem of pests.
5.Excessive use of inorganic fertilizers leads to impair of soil texture.
6.After harvest, the bare ground is easily subject to soil erosion.
B.Agricultural practices that impoverish soil
Removal of trees from steep slopes exposes the topsoil which is no longer protected from leaf canopies. The soil is washed away easily by heavy rain or blown away by wind.
(i)Cattle, especially goats, trends to overgraze. I.e. eating the whole grass including the roots. It becomes very serious when the population size of cattle is large and the area for grazing is small.
(ii)The trampling of such a large population of cattle on soil makes it become a compact and hard layer that can hardly absorb rain. Eventually, the soil become dry and easily blown away.
3.Farming methods that damage soil texture