(University College of Agriculture University of Sargodha, Sargodha)
In the present day, world agriculture and food security faces hazardous difficulties which affected human life. Humic acid have been existed extensively used for agricultural study, the quality of soil as well as yield quantity also affecting. Humic substances are responsible for the adjustment of pH, improving soil cation exchange capacity and the survival mechanism of plants grown under different stress environments such as drought, salinity and destructive effect of toxic and heavy metal components in the soil. Environmental and abiotic problems decrease the growth and productivity of plants. Humic acid are natural amendment products used in the present day , these are found in liquid or granular form and are dark brown color. Humic substances and its cousins, humus and flavic acid can be found in most soils, marsh water courses, and muddy peat moss areas.
Humic acid is a heterogeneous mixture of various compounds. Humic substances have beneficial effects directly or indirectly influence on the growth and development of plants. Humic acid also effects on cell membranes. Humic acid improve the biological, physiological and chemical properties of the soil and also increase the availability of the nutrients for the plants, their effect on the membrane of cell which lead to improve the transport of mineral nutrients, plant hormones like activity, enhanced synthesis of protein, improved the activities of enzyme, promoted photosynthesis, solubility of macronutrients and micronutrients, reduce active levels of toxic minerals and enhanced microbial population.
Humic acid is a mixture of weak aromatic and aliphatic organic acids, these are not soluble in water in acidic conditions, however soluble in water under alkaline conditions. Recently a significant increase in the consumption of vegetables in human diet and stock farming has been observed. Therefore, the increase in yield and production concern regarding excessive use of fertilizers mostly in terms of health hazards. Hence there are some methods towards using less fertilizer for better production and consumption. In agriculture uses of humic acid regulates the soil and encourage the uptake of vegetables food substances. Humic substances conserve the inorganic fertilizers which are soluble in soil and water and release which is necessary to the growing vegetables. Humic acid decrease the adverse effect of chemical fertilizer.
Humic substances play vital role directly or indirectly in the vegetables nutrition. Indirect effect of humic acid such as improving physical properties like water retention, aeration and drainage of soil. Humic acid has hormone-like activity not only improve the plant nutrient uptake and growth of several crops but also improve stress tolerance. Humic substances can be used as growth regulator to adjust the hormone levels. Plant growth enhances and also improves stress tolerance such as salinity and drought.
Humic substances useful to the soil and positively influence the soil and positively influence the soil structure and impact on the population of microbes. Recent literature shows that many areas of agriculture, such as soil fertility, chemistry plant structure as well as environmental sciences, because of different roles played by the humic substances that can greatly promote plant growth. Humic acid effects on growth and uptake of nutrients (Macro and micro nutrients) and also improving the postharvest of several horticultural crops. The investigation shows that 500mg per liter of humic acid increased number of harvested flowers per plant (52%).Humic acid levels higher that can extend the vase life of harvested flowers by 2-3.66 days can prevent and delay bent neck incidence of gerbera (Gerbera jamesonii L.) cv. Plant.
Humic acid used as natural resource to be utilized as substitute for enhancing crop production. Humic acid is a natural occurring polymeric organic compound and is formed by the decay of organic substances and is found in soil, lignites and peat. Humic acid and amino acids enhanced efficiency of chealed FeEDDHA in plants. Humic acid had stimulatory effects on seed germination, root growth, seedling growth shoot development and root growth. Humic acid influence on the cell division and enhance synthesis of protein. It can also enhance catalysis of enzyme and increase respiration and processes of photosynthesis. Furthermore, increase the water holding capacity and a good source of energy for useful soil organisms.