How Pesticides Affect Runoff Soil

How Pesticides Affect Runoff Soil

A pesticide is generally any chemical or biological agent that is used to either incapacitate, kill or discourage pests. The most common pests include various insects, weeds, birds, mammals and microbes, which feed on, lay waste to or destroy property. These pests may also cause disturbance, spread diseases and are disease vectors most of the time. In general, pesticides have benefits, the main one being the killing or prevention of pest infestation in plants. However, some also have various drawbacks, such as potential toxicity to crops, soil, animals and even human beings.

Runoff soil, the movement of water and other contaminants across soil surface, occurs when water from irrigation or rain, adds water to the soil surface at a rate that is faster than the rate at which the water can enter the soil. One of the demerits of using pesticides is that most of them have negative effects on soils. Most pesticides used on crops and livestock get into contact with the top soil, and may have adverse effects on its fertility and structure (Willis 270). These pesticides end up getting carried by runoff, and end up in streams, rivers, canals and other water bodies. As pesticides are generally poisonous materials, they result in destruction of aquatic life, which includes both marine animals, fish and aquatic plants.

Solubility of pesticides affects runoff. Pesticides that are highly soluble are more likely to be carried away by running water, thereby getting washed off the treated site. The persistence of a pesticide also affects runoff. The quicker a pesticide degrades, the less it is available to be washed off in run-off. The method of application of pesticides affects run-off. For instance, pesticides sprayed onto the soil surface or close to the soil surface using a high pressure pump tend to loosen soil particles on the surface, increasing chances for run-off (Khan 75).

There are however ways of reducing the effects of pesticides on run-off. First off, users are advised to only apply pesticides directly to the treatment or affected area. This reduces the amount of pesticide that will be available for ‘washing off’. Users should also consider the location of storm drains, drainage ditches and gutters during application. Application should be in such a way that the pesticides do not end up in these drainage systems (Silburn 45). Application of pesticides during calm weather also ensures that they are not carried off by wind or rain. Some methods of application such as banded spraying and early application help in minimising pesticides carried in run-off.

In conclusion, pesticides have adverse negative effects on soil run-off, and their usage mostly results in an increase in the amount of run-off and water bodies’ contamination. The use of pesticides should therefore be controlled and restricted only to areas that require their use, to minimise their inclusion in run-off soil. Nevertheless, new methods of pesticides usage and application are constantly being devised, to enable use of various pesticides while minimising run-off and environmental pollution.

Work cited

Khan, Shahamat U. Pesticides in the soil environment. Elsevier, 2016.

Silburn, D. M., and J. L. Foley. “Managing runoff of herbicides under rainfall and furrow irrigation with wheel traffic and banded spraying.” Agriculture, ecosystems & environment 180 (2013): 40-53.

Wauchope, R. D. “The pesticide content of surface water draining from agricultural fields—a review.” Journal of environmental quality 7.4 (1978): 459-472.

Willis, Guye H., and Leslie L. McDowell. “Pesticides in agricultural runoff and their effects on downstream water quality.” Environmental Toxicology and Chemistry 1.4 (1982): 267-279.