Finance

Soil particles of various sizes derived from the breakdown of rock r found in soil. Soil particle size affects the availability of water, oxygen, and minerals in the soil. A soil’s composition refers to its organic and inorganic components. Topsoil is a complex ecosystem teeming with bacteria, fungi, protists, animals and roots of plants. Some agricultural practices can deplete the mineral content of soil, tax water reserves, and promote erosion. The goal of soil conservation is to minimize this damage.
Plant requires essential elements to complete their life cycle. Macronutrients: elements required in relatively large amounts, include carbon, oxygen, hydrogen, nitrogen and other major ingredients of organic compounds. Micronutrients elements required in very small amounts, typically have catalytic functions as cofactors of enzymes. Deficiency of a mobile nutrients usually affect older organs more than younger ones; the reverse is true for nutrients that are less mobile within a plant. Macronutrient deficicies are most common, particularly deficiencies of nitrogen, phosphorus and potassium.
Plant nutrition often involves relationships with other organisms. Rhizobacteria derive their energy from the rhizosphere, a microbe-enriched ecosystem intimately associated with roots. Plant secreions support the energy needs of the rhizosphere. Some rhizobacteria produce antibiotics, whereas others make nutrients more available for plants. Plants satisfy most of their huge need for nitrogen from the bacterial decomposition of humus and the fixation of gaseous nitrogen. Nitrogen fixing bacteria onvert atmospheric nitrogen to nitrogenous minerals that plants can absorb as a nitrogen source for organic synthesis.
Mycorrhizae are mutualistic associations of fungi and roots. The fungal hyphae of mycorrhizae absorb water and minerals which they supply to their plant hosts. Epiphytes grow on the surfaces of the other plants but acquire water and minerals from rain. Parasitic...