Fertilizers and herbicides are routinely used in gardens and in landscaping. Fertilizers constitute food for plants, providing them with nutrients and helping them grow. Herbicides kill plants. Herbicides are designed to kill unwanted grasses, weeds or plants in your garden or landscape.
Fertilizers contain the three basic macronutrients required for plant growth: nitrogen, phosphorus and potassium. Micronutrients, such as iron, copper, zinc and sodium, may also be found in fertilizers. The concentration of these nutrients may be in an inorganic form to allow for immediate access by plant roots.
Herbicides are chemical compounds designed to control and eliminate weeds or unwanted plants. Active ingredients vary according to each manufacturer's formula and what type of plant the herbicide is designed to kill. The formulas may be biosynthesis inhibitors, seedling growth inhibitors or photosynthesis inhibitors. They may also be cell membrane disruptors or amino acid disruptors.
Fertilizers may be organic or inorganic. Organic fertilizers are made up of decomposed plant and mineral materials. The fertilizer remains in this organic state when applied to the soil. Within the soil, the fertilizer undergoes a process in which the nutrients convert to an inorganic state. Plant roots can only access inorganic material. Applications of organic fertilizer, then, must undergo this process before the nutrients are available to the plants.
Inorganic fertilizers may be made up of decomposed mineral materials to which chemical processes have been applied, rendering the nutrients inorganic. These fertilizers are available to the plants at the time of application. Synthesized nutrients may also be used to make inorganic fertilizers.
The use of inorganic fertilizers may be cause for concern. Chemicals may leach into groundwater and overuse of synthetic fertilizers may cause soil sterility.
The use of herbicides may also be cause for concern. While herbicides are designed to target specific plant organisms, they may also be detrimental to other life forms. Herbicides may poison beneficial insects such as ladybugs, butterflies and bees. Use may also result in loss of natural habitat for insects and other life forms, disrupting localized ecosystems.
The advantage of herbicide use lies in weed control. Pulling weeds by hand may prove ineffective, as the root may remain intact or the seed may remain viable. Herbicide use results in the death of the entire plant, preventing it from propagating by root or seed.
The advantage of inorganic fertilizers lies in their formulation. They are often designed as time-released products, in which the plants have access to the applied fertilizer throughout a given period of time and only when the plant needs it. There is less control with organic fertilizers.
The Scottish company Resomation Ltd. has developed a way to dispose of human remains that converts the body into an Earth-friendly byproduct. That product could be used as fertilizer. The process, which employs alkaline hydrolysis, is a different approach to cremation, the result of which is a nutrient-rich fluid that is, essentially, organic fertilizer.