lant fertilizers are substances that supply one or more plant nutrients essential to the growth of plants. Soils may be fertilized directly or indirectly.

Soil:

Soil is a complex mixture of organic matter, air, water, minerals, and microorganisms. It provides the environment for the growth of roots in the process called “root functioning”. It plays a key role in supporting infrastructure including human facilities like buildings and roads; natural resources like water filtration and aquifers; toxic waste containment; habitat for invertebrates including earthworms; and food sources such as fruits, nuts, vegetables, and animal feed. Soil is also a major component of the carbon cycle and thus plays a role in combating climate change. Soil pollution is an increasingly serious problem, with many toxic chemicals utilized in industrial and urban development. This leads to soil degradation, contamination, and loss of functionality.

The best-known types of fertilizers are mineral—derived from mines or quarries; organic—originating from biological sources (usually crops grown expressly for the purpose), and synthetic—manufactured chemically from chemical elements. Organic fertilizers include manure, green waste (such as rice hulls), guano (the accumulated excrement of seabirds and bats), sewage sludge (wastewater), compost (Food scraps and yard waste), and coffee grounds (nitrogen, calcium, potassium, iron, phosphorus, magnesium and chromium). Soil quality aspects such as porosity, water retention capacity, etc., are affected by these substances. Which provide nutrients required by plants including carbon.

Organic Fertilizers:

Organic matter can be introduced to the soil by the application of both “living” and “non-living” organic material. Principles of plant nutrition established over a century ago still guide modern agricultural nutrient management, which is vital to maintaining crop health and fertility.

Soil is a natural repository for nutrients until they are released by decomposition (and thus become available for plant roots) or leached away (usually through rainfall). Soil organisms consume and transform dead plant materials back into soil resources. However, not all of the input is retained in the system because some must be withdrawn from the soil via harvest. Soil retention time has been estimated at between 200 years to 400 years.

Agricultural fertilizers:

Agricultural fertilizers help produce food, fiber, and forest products without depleting land resources. Soil productivity depends on the nutrients available in the soil. Plant health and soil are maintained by natural processes of erosion, mineralization of organic matter, and soil formation. Soil quality is a reflection of the balance between its principal elements: minerals (elements occurring naturally), air (the physical atmosphere necessary for life), water (consider all forms including liquid and vapor), and living organisms (ecosystem services). Soils contain thousands of different substances, most of them still undiscovered or too small in quantity to detect individually.

In general, vegetable crops need more nitrogen and phosphorus. Whole grains such as wheat or rice are better suited to potassium fertilization. Excess fertilizer that runs off into nearby water bodies can cause an over-enrichment of nutrient levels. Which may result in algal blooms followed by large fish kills if the area is also used as a recreational waterway.

History of Plant Fertilizers:

For many years the foundation of fertilization was the application of superphosphate (Ca(H2PO4)2·12H2O). One of a family of chemicals called soluble phosphates that are highly effective at providing phosphorus to plants. In its original form, it is mixed with water so that over time the ions will dissipate from the solution, leaving behind solid deposits on soil surfaces where they become available to plants. Soils contain varying amounts of organic matter which may be required by certain plants and not by others. Therefore, NPK fertilizers including nitrogen are usually “urea-form” (UAN) urea is also a byproduct of the same process used to manufacture hydrochloric acid, which is often used in fertilizer production.

Soils may be oversaturated with nitrogen from previous applications and “flush” the excess before additional nitrogen can be incorporated into plant cells. Soil texture refers to the mixture of sand, silt, and clay particles that make up soils. Soil moisture affects whether nutrients will become available to plants at what rate they are absorbed. In the 20th century, some products began to be manufactured specifically for application to plant foliage. Superphosphate was produced for foliar feeding by mixing it with water followed by spraying it onto leaves. Both calcium nitrate (Ca(NO3)2) and ammonium nitrate (NH4NO3) were developed as dry forms so that the nitrogen source could be absorbed through plant stomata.

Rising Concerns

In the 21st century, concern over protecting the environment has led to increased use of organic fertilizers such as animal manure, green waste, and others which avoid releasing carbon dioxide during decomposition. Poor application rates have caused nitrate contamination of groundwater in many locations around the world. Soil erosion often leads to increased mineral concentrations in the remaining soil which can increase the presence of essential plant nutrients. It also dumps those elements into waterways where they may contaminate waterways with excessive amounts of nitrate or other dissolved solids.

 

Use of  Plants Fertilizers:

The use of fertilizers is controversial because it can also cause harm to the environment and human health. The use of synthetic fertilizers with high concentrations of nitrogen can damage natural flora and fauna by depleting the oxygen in water bodies. Also contributes to algal blooms that leave behind decay organisms that consume large amounts of dissolved oxygen. Nitrates bind with hemoglobin in the bloodstream where they interfere with the ability of red blood cells to transport oxygen.

The use of excess fertilizer may contribute to the loss of species diversity. The use of contaminated water can lead to mercury poisoning or other health problems. Use on land which drains into nearby waterways also contributes to eutrophication as discussed above. Additionally has been shown to speed up the decomposition of organic matter in waterways. Which can lead to a decrease in dissolved oxygen. The use of ammonium chloride has been shown to contribute significantly to soil salinity, and toxicity. Damages are also caused by chloropicrin, an organophosphorus compound used as a fumigant for soils with low nutrient content.

Efficient use of fertilizers can reduce costs while protecting the environment. Most fertilizers undergo an application process that targets specific plants with specific needs. Therefore, understanding how to apply fertilizer remains important even in developed countries. Soil quality affects plant growth and health. Influencing the yield quantity and quality, and ultimately food transportation safety for human consumption.