In order to get maximum benefit from fertilizers and biostimulants many aspects should be given careful consideration, like the crop species, the soil type and the climatic conditions. First of all, they should not only be applied in the right amount but also in proper time and in right manner.
Fertilizers are substances containing chemical elements that improve the growth of plants. They give nutrition to the crops. Fertilizers do not only assist in increasing yields but also promote healthy growth and development of plants. They contain nitrogen which acts as a growth booster which can be characterized by the green color of plants. Phosphorus substance in fertilizers aids in the faster formation of seeds and root development. Potassium helps photosynthesis, regulates the water status in the plant and plays an essential part in enhancing fruit quality. Many other nutrients are required for plant growth like calcium, iron, zinc and magnesium. Nutrient requirements of different crops are different and even for a single crop the nutrient requirements are not the same at different stages of growth. Besides, organic fertilizers contain organic matter which is a fundamental component of healthy and fertile soils.
Biostimulants are defined as products the function of which is to stimulate plant nutrition processes independently of the product’s nutrient content with the sole aim of improving one or more of the following characteristics of the plant or the plant rhizosphere: nutrient use efficiency (NUE); tolerance to abiotic stress, crop quality traits, or availability of confined nutrients in soil or rhizosphere. Examples of physiological functions that biostimulants can affect include such things as increases in root growth and biomass, increased uptake and translocation of nutrients, activation of hormone signaling pathways and gene expression, protection of photosynthetic activity during stress, and even improving a plants rhizosphere which can provide a better environment for symbiotic relationships with beneficial microbials in the soil. Stimulation of these physiological functions then result in actual physical changes in plants, such as a better nutritional composition of plants, improvements in nutrient use competence, improved water use capability, enhanced resistance to and recovery from abiotic stress - such as drought and salinity, and higher chlorophyll concentrations.
Fertilizers and biostimulants can be applied in four main ways: leaf, soil, root or seed application. Each method of application has advantages and can be suitable depending on the cultivation system and the purpose of the treatment. Furthermore, some application methods involve the use of specific equipment or agricultural machinery.