Soil amendments of fly ash: effects on function and biochemical activity of Carthamus tinctorius L. plants

Abstract

Proper disposal and recycling of different industrial waste materials have long been recognized as a prime environmental concern. The present study evaluated the effects of soil amendment of fly ash, a major industrial waste material, on soil properties, plant growth, productivity and metabolites production of safflower (Carthamus tinctorius L.). The soil was amended with varied concentrations of fly ash (0%, 5%, 10%, 25%, 50%, 75% per pot) prior to sowing under field conditions in the herbal garden of Jamia Hamdard. Sampling was conducted at different growth stages, i.e. pre-flowering, flowering and post-flowering. Our results demonstrate that fly ash concentrations up to 25% improved the physicochemical properties of the soil as compared to non-treated control resulting in increased availability to the plant of macro and micronutrients and thereby stimulating plant growth and productivity. Contents of photosynthetic pigments, sugars, protein, and nitrate reductase (NR) activity increased under 25% fly ash amendment. The highest beneficial effect was found during the flowering stage > pre-flowering > post-flowering stages. Further increase in fly ash concentration reduced the stimulated effects on the plants, exhibiting a minimum under 75% fly ash application. Thus, it was concluded that incorporation of 25% fly ash to the cultivation soil not only improves the physicochemical properties of the soil, but also contributes to better growth, yield and metabolism of safflower.