Agricultural chemistry is the study of chemistry, especially organic chemistry and biochemistry, as they relate to agriculture. This includes agricultural production, the use of ammonia in fertilizer, pesticides, and how plant biochemistry can be used to genetically alter crops. Agricultural chemistry is not a distinct discipline, but a common thread that ties together genetics, physiology, microbiology, entomology, and numerous other sciences that impinge on agriculture.
Agricultural chemistry studies the chemical compositions and reactions involved in the production, protection, and use of crops and livestock. Its applied science and technology aspects are directed towards increasing yields and improving quality, which comes with multiple advantages and disadvantages.
The goals of agricultural chemistry are to expand understanding of the causes and effects of biochemical reactions related to plant and animal growth, to reveal opportunities for controlling those reactions, and to develop chemical products that will provide the desired assistance or control. Agricultural chemistry is therefore used in processing of raw products into foods and beverages, as well as environmental monitoring and remediation. It is also used to make feed supplements for animals, as well as medicinal compounds for the prevention or control of disease. When agriculture is considered with ecology, the sustainablility of an operation is considered.
However, modern agrochemical industry has gained a reputation for its maximising profits while violating sustainable and ecologically viable agricultural principles. Eutrophication, the prevalence of genetically modified crops and the increasing concentration of chemicals in the food chain (e.g. persistent organic pollutants) are only a few consequences of naive industrial agriculture.
Agricultural chemistry often aims at preserving or increasing the fertility of soil, maintaining or improving the agricultural yield, and improving the quality of the crop.
The discovery of the Haber-Bosch process led to increase in production of crops in the 20th century. This process involves converting nitrogen and hydrogen gas into ammonia for use in fertilizer. Ammonia is essential for crop growth as nitrogen is vital in cellular biomass. This process dramatically increases the rate at which crops are produced, which is able to support the growing human population. The most common form of nitrogen fertilization source is urea, but ammonium sulphate, diammonium phosphate, and calcium ammonium phosphate are also used.
A drawback to the Haber-Bosch process is its high energy usage.
Chemical materials developed to assist in the production of food, feed, and fiber include herbicides, insecticides, fungicides, and other pesticides. Pesticides are chemicals that play an important role in increasing crop yield and mitigating crop losses. A variety of chemicals are used as pesticides, including 2,4-Dichlorophenoxyacetic Acid (2,4-D), Aldrin/Dieldrin, Atrazine and others. These work to keep insects and other animals away from crops to allow them to grow undisturbed, effectively regulating pests and diseases. Disadvantages of pesticides and herbicides include contamination of the ground and water. They may also be toxic to non-target species, including birds and fish.
Plant biochemistry is the study of chemical reactions that occur within plants. Scientists use plant biochemistry to understand the genetic makeup of a plant in order to discover which DNA creates which plant characteristics. Innovations in plant biochemistry seek to increase plant resilience and discover new, more effective ways, of maintaining food sources. Genetically Modified Organisms (GMO's) are one way of achieving this. GMO's are plants or living things that have been altered at a genomic level by scientists to improve the organisms characteristics. These characteristics include providing new vaccines for humans, increasing nutrients supplies, and creating unique plastics. They may also be able to grow in climates that are typically not suitable for the original organism to grow in. Examples of GMO's include virus resistant tobacco and squash, delayed ripening tomatoes, and herbicide resistant soybeans.
That being said, concerns with GMO's include potential antibiotic resistance from eating a GMO. There are also concerns about the long term effects on the human body since many GMO's were recently developed.