There are a number of factors that affect the health and productivity of plants. Foremost of this is nutrition or the availability of the macro and micro nutrients that are necessary for plants for grow and bear flowers or fruits. However, the availability of these nutrients is also affected by many factors and it is often necessary for farmers to provide additional inputs to ensure a proper harvest rather than rely totally on what the soil can sustain. This is where the role of fertilizers come in.
There are at least three types of fertilizer inputs that are being used by farmers nowadays and this article would briefly describe them.
What is a CHEMICAL FERTILIZER and what are its effects?
A chemical (synthetic) fertilizer is defined as any inorganic material of wholly or partially synthetic (inorganic) origin that is added to the soil to support plant growth and/or address certain nutrient deficiencies in soil. Thus, a chemical fertilizer can contain a single nutrient or multiple nutrients depending on the needs of the plants and soils. Being most required by crops, NPK fertilizers are the most commonly used, with 3 numbers (e.g., 14-14-14 or 60-30-30) indicating the proportion of nutrient content. Chemical fertilizers have helped farmers boost productivity over the past decades, however, recent studies indicate that continued use of chemical fertilizers may destroy nitrogen-fixing bacteria in soils. Moreover, several synthetic fertilizers contain acid radicals, such as hydrochloride and sulfuric radicals, and hence increase the soil acidity and adversely affect soil and plant health. Highly recalcitrant compounds can also be absorbed by some plants and continued application of these chemical inputs promotes the accumulation of toxic compounds in soils
What is an ORGANIC FERTILIZER and what are its effects?
Organic fertilizers are naturally occurring fertilizers obtained from organic plant and animal sources and may include manure, compost, vermicompost, peat, seaweed and guano, and other organic compounds, such as humic acid, fulvic acid, that are beneficial to plants. Organic fertilizers are rich in plant nutrients and are applied in the soil in either solid or liquid form (extracts). While nutrient content, solubility, and nutrient release rates of organic fertilizer are typically lower than chemical (inorganic) fertilizer; by their nature, they increase physical and biological nutrient storage mechanisms in soils thus mitigating risks of over-fertilization. In general, organic fertilizers add nutrients to soil, increase soil organic matter, improve soil structure and tilth, improve water holding capacity, reduce soil crusting problems, and improves buffering capacity against fluctuations in pH levels. It should be noted that organic fertilizers need microorganisms to decompose its organic matter and release nutrients in the suitable form for the plants.
What is a BIOFERTILIZER and what are its effects?
A Bio-fertilizer is a substance which contains living microorganisms — such as bacteria, algae and fungi — which, when applied to the seed, plant surfaces, or soil: colonizes the rhizosphere or the interior of the plant and enhances the microbial interactions thus stimulating plant hormone production and increasing the availability of primary nutrients to the host plant. Also termed as ‘microbial inoculants’, ‘soil inoculants’ or ‘bioinoculants’; biofertilizers add nutrients through the natural processes of nitrogen fixation, solubilizing phosphorus, and synthesis of growth-promoting substances. Biofertilizer microbes attach N from the air, which dissolves microbial nutrient (especially P and K) thus supply the nutrients to the plants while solubilizing precipitated phosphates and by mineralizing organic phosphorous (P) in the soil. A symbiotic relationship between phosphate solubilizing bacteria (PSB) and plants is synergistic in nature as bacteria provide soluble phosphate and plants supply root borne carbon compounds (mainly sugars), that can be metabolized for bacterial growth. Thus, when properly cultured, the biofertilizer increases soil fertility and improves plant nutrition, boosts plant health and controls harmful organisms, supports plant growth and helps increase crop productivity. It should be noted that biofertilizers can’t efficiently work without enough mineral elements in the soil.