Tillage has been an essential part of
innovative development in the advancement of agribusiness, specifically in
production. The soil is tilled to achieve a fine tilth for the sowing of seed,
water, and soil preservation, and weed control. Tillage exerts different
physical, chemical and biological impacts on the soil both advantageous and
debasing, contingent upon the suitability of the systems utilized. The physical
impacts, for example, aggregate stability, penetration rate, soil and water
preservation, specifically, have a coordinate effect on soil profitability and
manageability. (FAO. 1993)
However, as the world population grows
at an alarming rate, food production has undergone a decline. This is in part
due to declining levels of soil productivity. Agriculture has to find
innovative ways of producing enough food to meet the demand, especially in
vulnerable regions like Africa and Asia, which are the most food insecure.
Swilling and Annecke state that there is
mounting evidence that the ecosystems that make agriculture possible are
steadily deteriorating as the levels of extraction and exploitation intensifies
(Swilling & Annecke. 2012). Swilling and Annecke directly links declining
yield growth to soil degradation. To achieve food security we have to find
sustainable ways of food production to meet the growing population demand.
Tillage-based crop production systems
attributes to declining yields because of its effect on the soil and the
environment. Moreover, the decline in yield growth attributes directly to
rising food prices making access to food harder. This paper aims to describe
the root causes and the effects of environmental and economic problems
associated with tillage-based crop production systems.
What is a tillage-based crop production system?
Tillage is known as the mechanical
exploitation of the soil with the intention of growing crops. This disturbance
of the soil affects the soil characteristics such as soil water conservation,
soil temperature, transpiration, and evapotranspiration processes. This means
that tillage exerts a footprint on the soil willfully to yield crops;
therefore, damages the environment.
Conventional tillage practice exerts the
most impact on the soil. It is responsible for the loss of soil organic carbon
content, nitrate leaching, greenhouse emissions. Busari, Kukal, Bhatt &
Duluzi claims that soil disturbance by conventional tillage makes the soil
serve as a source rather than a sink of atmospheric pollutants and; thus, is
unsustainable and environmentally friendly.
Busari et al. list conservation tillage
practices as ranging from No-Till (NT), Reduced Tillage (RT), Mulch Tillage
(MT), and Ridge Tillage to Contour Tillage. NT involves land cultivation with
little or no soil disturbance, the only disturbance being during planting while
minimum tillage means a reduced level of manipulation involving plowing using
primary tillage implements (Busari et al. ).
In mulch tillage, they state that the
soil is tilled in a manner that plant residues is left to cover the soil
surface to the highest degree. They explain ridge tilling as the planting of
crops in rows along both sides or on top of the ridges prepared at the
commencement of the cropping season while contour tillage is when tillage is at
right angles to the direction of the slope.
(Hub, 2018) describes soil as comprised
of organic matter, mineral deposits, water, and air. The soil’s texture,
structure, transpiration, and evapotranspiration is determined by the
combination of these elements.
The texture has two
important physical properties when it comes to indicate the soil quality those
are aggregate stability and size distribution. The particle size distribution
is the most essential physical property which defines the soil texture, and
influences the soil properties the most. These two physical properties
mentioned above reflects the resistance of soil erosion, especially in
no-tillage system, which is why they are the most important factors when it
comes to soil quality.
The soil structure
defines which different types of particles that are stored in the soil and it
exert control over the physical, biological and chemical processes. It also
explains how and where the particles are located, which is important for how
suitable the soil is for growing crops.
If the soil has a poor
structure, it can affect the nutrient availability and the nutrient uptake negatively
and increase the input energy requirement for tillage, increase the nutrient
loss and the denitrification, which is negative from an environmental point of
view. Organic matter, tillage system, biological activity matters for the
aggregate structure in a soil.
Soil’s conductivity, which is the
ability of the soil particles to attract nutrients and is influenced by the
presence of organic matter in the soil. Nutrients are spared from leaching in
soils with high organic matter content. With less organic matter content and
leaching of nutrients, overtime the soil can become more acidic.
Various research has proven that tillage
has an impact on soils physical and chemical properties. To ensure soil water
availabilty, nutrient availabilty, and proper root development, it must be
ensured there is very minimal disturbance to the soil.
Environmental effects of tillage
Intensive tillage leads to soil erosion.
Soil erosion is described as the detachment and movement of soil particles from
point of origination through the action of water and wind. Wind erosion is the
more visible, though water erosion is the most devastating. The loss of natural
nutrients and possible fertilizers directly affect crop emergence and growth.
Seeds can be disturbed or removed and pesticides can be washed off. This means
fewer nutrients for plants leading to reduced yields. Soil water erosion has
great environmental and economical implications as eroded soils can inhibit the
growth of seeds, bury seedlings, contribute to road damage, and even
contaminate water sources.
The topsoil typically has more organic
matter and more plant nutrients than the soil deeper in the soil profile.
Associated with the organic matter are billions of soil micro-organisms.
Micro-organisms are the engine that keeps a soil alive and productive. Numerous
scientific studies have shown that soil with fewer micro-organisms or a lower
diversity of micro-organisms is less productive than soils with a good balance.
Erosion can be made more severe due to man’s influences.
A soil with higher
proportion of clay and humus usually increases the stability of structure and
aggregates. Aggregate stability is characterized by the sensitivity to external
influence. The essence of aggregate stability is the organic matter, because
large parts of plants and roots acts like a barrier and prevent aggregates to
break into smaller units with help from decomposing of microorganisms that
provides with an adhesive effect. With tillage systems, organic matter is
Permeability is the
soil´s capacity to drain off water. The structure of a soil is influenced in
both the long and short term of tillage and cultivation measures, which in turn
affects the soil physical properties. Tillage
affects soil quality, structure, stability, and texture, which in turn affect
the holding capacity of the soil referred to water infiltration rate. This is
due to the decrease in soil organic matter and the subsequent aggregate
Tillage cause air to enter the soil
particles. When soil is more aerated, nitrous oxide escapes into the atmosphere
offsetting the cooling effect of carbon dioxide draw down. N2O is the most
important agent for stratospheric ozone destruction. Soil is the largest source
on N2O emissions and it is exasperated by tillage and the ever increasing use
of synthetic nitrogen (N).
2018) describes soil is one of the most important natural resources farmers
have. In the absence of soil, farmers cannot farm. As with other important
resources, it is vital to be protected or improved for the benefit and
sustainability of future generations. Once soil leaves a farmers field it is
lost forever. As soil erodes from farmer’s fields, the most valuable part of
the soil (the topsoil) is gone.
Economical effects of conventional tillage
Tillage operations are generally conducted to
prepare a seedbed, incorporate fertilizers, and cultivate for weed control. The
number of trips required to perform these operations depends on soil type and
condition, the crop, weather conditions, and the type of tillage system
utilized. Excessive tillage operations increase fuel consumption, operating
costs, machinery wear, and time and labor requirements.
reported for conventional reduced tillage systems due to poor soil quality.
This has a domino effect on farm income, exports, and food security concerns.
Arable land supplies
food and it is therefore important to develop the production and land-use plan in
a sustainable way. To grow crops for food should be both economical and
environmentally sustainable and the soil structure and quality should be taken
in consideration when cultivating our land.
We need to find new
approaches to maintain good soil structure, and minimized tillage systems have
many advantages, including reduced costs for the growing of crops, while
leaving plant material in the fields can reduce erosion and increase the
biological activity and humus content of the soil.
A non-cultivated soil
generally has a better structure due to the higher content of organic matter
and less compaction than a cultivated soil has. Soil structure is influenced by
soil and crop management inputs and has an impact on soil quality. One of the
factors that influence the quality is tillage. This input is an important
factor and relevant in the point of sustainability
recycling of organic matter contributes to a better structure and physical
environment. Soil cultivation measures do the opposite. If the structure should
be improved, the structure-building measures needs to be greater than the
structure depleting measures such a conventional tillage systems.
Adding organic matter
can preserve soil structure and increase the crop safety. Measures to improve
the structure and provide better conditions for the crops, is to return crop
residues to the soil, grow cover crops and only apply shallow tillage or no
till, which could increase the humus content in the top layer. Increased humus
content will give a lower bulk density, increased aggregate stability and
increased porosity, which in turn give the soil increased water holding
capacity and infiltration capacity.
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