Agrochemicals

Agrochemicals and Their Effects

"Agrochemical" is a vague term, but we can break it into two main categories: pesticides and fertilizers.

Pesticides

In a perfect world, we would be able to grow plants to eat without any interference from other organisms. The reality is that a plethora of creatures threatens almost every crop that we produce, and agrochemicals called pesticides are used to deter these pests.

Herbicides

If you’ve ever gardened, or know someone who does, they’ve probably complained about weeds attempting to take over their plants. The same thing happens in farming, with other plants taking up the resources meant for the crop, in some cases even resulting in widespread crop failure. This is where herbicides come in. Herbicides, sometimes called weedkillers, attack the undesired plant while leaving the actual crop unharmed, thus preventing the weed from growing.

The application of herbicides has some drawbacks. Over the years, some herbicides have been banned or regulated because of their impacts on human health and the environment, sometimes entering water supplies or spreading to natural habitats which can be devastating.

Insecticides

As the name implies, insecticides are agrochemicals meant to deter or kill insects, preventing them from harming crops. Insects can be destructive to crops by eating them, creating habitats out of them, or by spreading pathogens. Throughout history, insects have plagued agriculture around the world. The most notorious insect is the locust, which since ancient times has eaten crops and caused famines.

Fertilizers

All plants need a mixture of nutrients to grow healthy, and fertilizers help boost those nutrients. By artificially boosting plant nutrition, farmers can produce an abundance of crops more reliably and quickly, meaning the overall food availability increases.

Fertilizers are critical to feeding the world today and played a huge role in the Green Revolution (see below).

Fertilizers come from organic sources like manure and decomposed plants as well as from artificial sources. They typically contain one of the three basic plant nutrients: nitrogen, phosphorus, or potassium.

Fig. 1 - Agrochemicals can be applied to soil and crops with modern farming equipment

Sometimes fertilizers end up in parts of the environment they shouldn't be. High amounts of rainfall lead to something called runoff, washing fertilizers into streams or groundwater sources. When fertilizers reach large bodies of water, they can cause eutrophication, an overabundance of nutrients. Eutrophication can lead to marine life dying and to water becoming infested with dangerous bacteria.

Uses of Agrochemicals

What are the uses of agrochemicals? Let's take a look at a few of them:

Increasing Yields

Of all the uses of agrochemicals, the overarching purpose is to increase yields. The Earth’s human population is exponentially increasing and the ability to grow food for everyone is essential. Perhaps ironically, the introduction and widespread use of agrochemicals meant to feed the growing population enabled the population to grow even more rapidly than before.

Resistance to Adverse Conditions

The use of pesticides and fertilizers helps crops resist adverse environmental conditions. Poor soil quality, unusually high pest counts, and poor weather can make producing crops more challenging, so agrochemicals help us produce what is necessary. By increasing the stability and reliability of agriculture, agrochemicals increase the resiliency of populations so they can withstand devastating natural events.

Agrochemicals in the Green Revolution

During the 1960s, a sweeping set of changes happened in the agriculture sector across the world, in what is known as the Green Revolution. These changes included producing more high-yielding varieties of seeds, increasing the use of mechanized farming, and new irrigation techniques, but the Green Revolution would have been impossible without agrochemicals. The Green Revolution was especially impactful in the developing world, which hadn’t seen the widespread adoption of agrochemicals.

Fig. 2 - Nitrogen fertilizers have greatly increased the ability of our population to grow

Nitrogen is a critical contributor to plant growth, and while plants get it naturally, it’s also produced artificially and added to crops so they can grow much faster, or grow in soils they otherwise would not have been able to grow in. During the Green Revolution, synthetic nitrogen fertilizer usage became more and more common, allowing for greater agricultural productivity. Fertilizer use also changed the geography of agriculture, since previously untenable lands became productive with the aid of fertilization. See the Agrochemicals Examples sections to explore more about how agrochemicals impacted certain regions of the globe.

Pesticides also played a role in the Green Revolution, with their use attributing to an overall increase in yields. Pesticides were incredibly effective at the onset of the Green Revolution since many areas had not been exposed to them previously, meaning few organisms had a natural resistance to them.

Agrochemicals Examples

The Green Revolution saw agrochemical usage in many nations. Let’s look at some major examples.

Mexico

Many of the early experiments and research preceding the Green Revolution took place in Mexico. The scientist Norman Borlaug, a leading proponent of the Green Revolution, began experimenting with ways to increase yields of wheat to help make Mexico no longer reliant on wheat imports. While much of the innovations involved cross-breeding wheat and adapting land uses, the introduction of agrochemicals was essential to tripling wheat yields by the end of the 1960s.

India

As one of the largest countries in the world both today and at the start of the Green Revolution, India was a focal point of agricultural change. Lessons learned from the Mexican experiments were also applied to wheat cultivation in India, with more pesticides and fertilizers being used.

In the years since the Green Revolution in India, attention was focused on sustainability and environmental issues surrounding agrochemicals. If pesticides and fertilizers are used excessively, they can enter water supplies and wreak havoc on the environment. Herbicides spreading to natural habitats can lead to the loss of biodiversity.

Fig. 3 - Stubble burning of an agricultural field in Punjab, India

Because plants were able to grow more quickly and during more seasons than before, a need became apparent to clear the land to plant the next crop. This resulted in more and more farms using stubble burning, which uses fire to clear land and is generally considered an environmentally damaging and polluting way to clear farmland.

Classification of Agrochemicals