To enhance the growth and development of plant soil needs to be prepared and well nourished. This includes adding organic matter, fertilizing soil maintaining pH etc.
Soil need to be fertilized because soil do not provide all the nutrients to plant that are necessary for its growth. Fertilizer is applied in adequate amount and in balance when abiotic conditions are favorable.
When soil fertility is not good, natural or synthetic nutrients are applied to fulfill the needs of plant for their growth are called fertilizer.
Essential Plant Nutrients
Plant requires light, water and about 20 nutrients to complete their biological process. The nutrients are divided into two categories:
Carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur
Iron, manganese, boron, molybdenum, copper, zinc, chlorine, nickel, cobalt, sodium, silicon
Plant can not complete its life cycle without these nutrients. The elements directly involve in plant nutrition. Inadequate supply of there nutrients effect the growth of the plant leading to chlorosis, stunted growth or plant death.
Role of Macro-nutrients
Carbon, Hydrogen and Oxygen:
These macronutrients elements are not minerals in the true sense, but still included in the list as they are most essential for plant life. Plants absorb these nutrients from air and soil in the form of carbon dioxide and water.
Nitrogen: Involves in plant metabolism. It is a part of amino acids, protein and enzymes. It effects the germination ad vegetative growth directly. t is absorbed from the soil in two major ionic forms:
Nitrate (NO3–) and ammonium (NH4+)
The deficiency of nitrogen causes:
- Stunted crop growth
- Chlorosis on leaves (light green to yellow foliage)
- Weakness during the flowering and fruiting which results in lower yields.
Too much nitrogen causes:
- lush growth
- Dark green color of leaves
- Crop lodging
- Reduction of fruit quality.
Phosphorus: It is also an important crop nutrient because it affects:
- Root development
- Quality of flowering, fruiting and seed production
- Phosphorus deficiency symptoms include:
- Energy storage and transport
- Disease resistance.
- Thin shoots
- Dark green, purple, or red leaves.
- Stunted growth
- Weak roots
- Excessive amounts of phosphorus are not harmful to crops. but too much phosphorus causes lower availability and deficiency of other elements to plant (Fe, Zn, Cu, Mn, B).
Potassium: The third essential crop nutrient is potassium. It effects the uptake of water and improves resistance to drought, cold hardiness, resistance to fungal diseases and insect pests, Synthesis of protein, fat, and sugar. Potassium is required for stomatal opening in higher plants.
Deficiency of potassium causes:
- Reduced growth
- Yellowing or burning of the leaf margins
- Dead spots on older leaves
- Excessive amounts of potassium may affect the uptake of other nutrients, such as calcium, magnesium, and nitrogen.
Calcium: It acts as a co-factor for many enzymes. It is required in a small amount in mitosis process because it forms microtubules for spindle apparatus.
Deficiency of calcium causes:
- Stem collapse
- Growth termination of apical regions
- Chlorosis from the margin of leaves
- Roots become short and brown
- Rigid cell wall
Magnesium: Present in soil in exchangeable, fixed and water-soluble form. It is present in soil as magnesium silicate, an unavailable form and become available after weathering. Magnesium is absorbed as divalent Mg2+.
Deficiency of Magnesium causes:
- Chlorosis of old in first and then moves to young leaves, that’s why magnesium is called mobile element.
- Magnesium deficiency causes extensive chlorenchyma development and scanty pith formation
Sulphur: Sulphur is taken up by the plants from the soil as divalent sulphate anions (SO42-), which is enzymatically converted into an activated form before it can be incorporated into organic compounds. The activated sulphate is converted into reduced sulfur compounds, a wide variety of sulphate esters, and sulpholipids in plants.
Deficiency Symptoms of Sulphur:
- Sulphur deficiency is usually uncommon. It includes
- Chlorosis in the entire leaf, including in veins appear in younger leaves.
- Rapid leaf fall.
- Leaves roll from tips.
Determining nutrient need:
Determining yield’s supplement needs is a fundamental part of fertilizer technology. The presence of a developing yield may show need of manure; in certain plants, be that as it may, the requirement for more or various supplements may not be effectively noticeable. At times plants show side effects of poor nourishment.
Chlorosis (general yellow or pale-green color), demonstrates absence of sulfur and nitrogen. Iron deficiency produces white or pale-yellow tissue. Side effects can be misjudged, in any case. Plant ailment can deliver appearances taking after mineral inadequacy, as can different organisms.
Dry season or inappropriate development or manure application each may make inadequacy manifestations. the most exact framework comprises of laboratory examination of the supplement substance of plant parts, for example, the leaf. The outcomes, when correlated with yield reaction to compost application in field tests, can give the best estimate of lack.
Fertilizers can help in rolling out gainful improvements in cultivating. Operators can lessen costs per unit of production and increment the edge of return over all out expense by expanding rates of use of fertilizer on cash and feed crops.
They are then in a situation to put resources into fertilizing soil protection and different enhancements that are required when moving grounds from surplus yields to other uses.
Manure includes both excreta and straw or other sheet material, while the term fertilizers refers to chemicals. A lot of manure are delivered by domesticated animals; such compost has an incentive in keeping up and improving soil on account of the plant supplements,it contain humus and organic substances.
The advantages of manure are backhanded. It supplies humus, which improves the soil’s physical character by expanding its ability to absorb and store water, by upgrade of air circulation, and by favoring the exercises of lower organisms.
Compost incorporated into the topsoil will help keep disintegration from overwhelming precipitation and hinder evaporation of water from the surface. Basically, the estimation of excrement as a mulching material might be more prominent than is its incentive as a wellspring of basic plant supplements.
Future of Fertilizers:
“Complete environment” seeding in which seed, manure, and water are consolidated in a biodegradable (decompose in the soil) tape may come into utilization; with the tape planted, no further compost or water will be required until development is settled.
Such fertilizing soil utilizing biodegradable tapes have just been created on a little scale for use by home plant specialists. At long last, bigger and increasingly exact treating machines will be created and embraced.