Soil tillage is the agricultural preparation of soil by mechanical agitation of various types, such as digging, stirring, and overturning the soil – Wikipedia.
We do not know tillage to increase yields, but rather has negative impacts on food production particularly on our soils in the long-term. For the following reasons and elaborations on soil tillage negative effects, we must take a different and positive approach to agriculture and adopt conservation agriculture.
Types of Soil Tillage
Before we go to the problems of tillage, let us look at the 3 basic types of tillage. There are various derivatives of tillage based on the 3 basic types of tillage depending on the degree of soil disturbance and residue.
1. Conventional Tillage
Conventional tillage practice is where farmers loosen the soil by turning it over. They achieve this either manually with hoes or mechanically with a plough or disc. This exposes the soil to erosion by wind or rain. In areas where they use only simple tools like hoes, land preparation is done by the “slash and burn” method before ploughing.
2. Conservation Tillage
Generally, this method tries to reduce the disruption of the topsoil to prevent erosion and to enrich the soil. You can achieve this by allowing on the field previous season’s crops residues, before and after planting the next crop.
No-Till is the kind of conservation tillage, where there is no (or very little) disruption of the topsoil. In this case, even mechanical planters are designed and operated to minimally or not to disrupt the soil. The farmer maintains soil cover to prevent erosion, loss of soil moisture etc.
Negative Effects of Soil Tillage
1. Soil Erosion
Tillage causes the soil to break down into smaller particles. The Wind easily blows away these particles. Again, heavy rains wash the particles as topsoil to lower elevation. In these instances, nutrients are either blown away or washed away and easily leached away from the reach of roots. Then, you would need more fertilizer to get consistent yields.
2. Reduction of amount of soil organisms
Soil organisms are very vital to organic matter decomposition and their activities are vital to soil improvements. In very simple terms, tillage displaces and exposes soil organism to air and direct sunlight. Soils with low of soil organisms experience low rates of decomposition and therefore reduced amounts of soil nutrients.
3. Loss of nitrogen
Microorganisms, during the breakdown of organic matter, release nitrogen, an essential plant nutrient for plant growth. Tillage releases the accumulated nitrogen in the soil whiles exposing the microorganisms. The farmer would then need more fertilizer to make up for the loss, increasing the cost of production.
Read also: 10 Benefits of Cover Crops
4. Soil compaction
After continuous tillage and exposure to several impacts, the soil forms a hardpan just below the depth of tillage. This hardpan prevents soil water drainage and root development. Moreover, soil compaction impedes root development and decreases the plant’s ability to take up nutrients and water. Without adequate and timely rains and correct fertilizer application, it reduces yield. In wet seasons, it reduces soil aeration resulting in loss of nitrate-nitrogen to the atmosphere. Besides, soil compaction can induce nitrogen and potassium deficiency.
5. Additional cost of production
Soil tillage is an additional cost to farmers and is expensive. Consider the cost of fuel and maintenance of machinery and if manual, the cost of labour. All these instances would need extra fertilizer in addition to other costs.
6. Environmental Damage
As stated before, heavy tillage exposes soils to both water and wind erosion. When soil with accumulated toxic substances from chemicals used on the farm, wash or blow into streams, rivers and ponds they cause pollution. Then, fish and wildlife are also endangered when soil particles are washed into waters clouding them.
7. Not sustainable in the current climate change
Soil tillage is not a sustainable agricultural practice. Tillage makes the soil non-productive for food production after a period. In addition, we do not know of any proof that it increases yields of crops.
To ensure long-term production of food, we must adopt conservation agriculture. This reduces the cost of production, increases yield, improves soil and environment and is the only solution to the climate change.