Agricultural practices can have either positive or negative impacts on soil organisms. Land management and agricultural practices alter the composition of soil biota communities at all levels, with important consequences in terms of soil fertility and plant productivity.
There are examples of both positive and negative effects of some groups of soil organisms, particularly microorganisms, phytoparasites/pathogens or rhizophagous, plant roots, and macrofauna on plant production.
The different agricultural practices used by farmers also exert an important influence on soil biota, their activities, and their diversity. Clearing forested or grassland for cultivation has a drastic effect on the soil environment and, hence, on the numbers and kinds of soil organisms.
In general, such activity reduces the quantity and quality of plant residues and the number of plant species considerably. Thus, the range of habitats and foods for soil organisms is reduced significantly.
Through changing the physical and chemical environment, agricultural practices alter the ratio of different organisms and their interactions significantly, for example, by adding lime, fertilizers, and manures, or through tillage practices and pesticide use.
Read Also: Categories and Characteristics of Soil Organism
The beneficial effects of soil organisms on agricultural productivity that may be affected include:
- Organic matter decomposition and soil aggregation;
- Breakdown of toxic compounds, both metabolic by-products of organisms and agrochemicals;
- Inorganic transformations that make available nitrates, sulphates, and phosphates as well as essential elements such as Fe and Mn;
- N fixation into forms usable by higher plants.
However, other soil organisms are detrimental or harmful to plant production. For example ants, aphids and phytophagous nematodes can be serious pests, and some microorganisms, bacteria, and actinomycetes cause also plant diseases. However, most damage is caused by fungi, which account for most soil-borne crop diseases.
Humans generally begin their influence on soil biodiversity with naturally present communities at a particular site (resulting essentially from ecological and evolutionary forces).
However, they also have the ability to introduce new organisms and, through the imposition of different management practices, put selective pressures on the naturally present or introduced soil biota.
This provides the opportunity to manage soil organisms and their activities in order to enhance soil fertility and crop growth.
In conclusion, soil biota represents a large part of the terrestrial ecosystem and carries out functions that are important to agricultural and natural systems. Some are vital to the improvement of soil health and fertility while others are less important as they are parasitic on important crops.
The bioturbating activities of the soil microorganism bring about decomposition and turnover of organic matter in the soil.
However, changes in agricultural practices can engender their existence and can cause marked changes in both the pool size and turnover rate of soil organic matter. It is therefore important to analyze the nature and impacts of these practices.
Read Also: Classification of Soil Organism
