Physiological Role of Humic Acid and Nicotinamide on Improving Plant Growth, Yield, and Mineral Nutrient of Wheat (<i>Triticum durum</i>) Grown under Newly Reclaimed Sandy Soil

Abstract

Humic acid is not a fertilizer as it does not directly provide nutrients to plants, but is a compliment to fertilizer. Nicotinamide (Vitamin pp) is a stress-associated compound that can induce and regulate secondary metabolic accumulation and/or the manifestation of defense metabolism in plants. A field experiment was conducted at the experimental station of National Research center at El-Nubaria region, Egypt, to study the role of foliar application of humic acid (as soil conditioner 13 cm/l) and/or priming grains in nicotinamide (vitamin pp 5 mg/l) in saving irrigation water, decreasing fertilizer dose of NPK and at the same time increasing durum wheat ( Triticum durum ) cultivars’ (Beni Sweif-1 and Beni Sweif-3) productivity grown under newly reclaimed sandy soil exposed to drought for three weeks continuously. The results showed that plant treated with humic acid or nicotinamide increased significantly all morphological criteria (plant height, leaves number, fresh and dry weights of shoots), metabolism (photosynthetic pigment, total soluble sugar, total carbohydrates, total amino acids and proline), mineral contents (N, P, K, Ca and Mg) and yield (grain, straw and biology) of both cultivars amended with either recommended or half recommended doses of NPK. Foliar application of humic acid to plant priming in Vitamin pp induced significant increases in all studied parameters (morphology, chemical and yield) of plants amended with recommended or half recommended doses of NPK as compared with control plants. The maximum yields of grain, straw and biology of both cultivars were obtained in response to triple treatment (humic acid + nicotinamide + recommended dose of NPK) or (humic acid + nicotinamide + half recommended dose of NPK) respectively.