Effects of omitting macronutrients on the development and nutritional status ofsorghum plants grown in nutrient solution

Abstract

The effects of macronutrients on the development and nutritional status of sorghum plants were studied in sorghum plants grown in nutrient solutions. The experiment consisted of seven treatments in which the first was the standard Hoagland & Arnon (950) nutrient solution and the next were obtained by excluding either N, or P, or K, or Ca, or Mg, or S from that solution. Three weeks after sowing, the plants were transferred to 8 L plastic containers and the mentioned treatments were then applied. Thirty days after transplanting, plant height , number of leaves, culm diameter, plant aerial part and root dry matter and the plants nutritional status were determined. The lack of N, P, Ca, and Mg was the most harmful to dry matter yield. The plants from the standard and the with omission solutions showed the following levels of nutrients in the aerial part, respectively : P = 4.8 and 0.6, K = 33.4 and 3.4, Mg = 3.8 and 0.4, S = 2.2 and .3 g kg^- and, in the roots P = 4.4 and 0.6, K = 26.2 and 6.3, Ca = 5.7 and .7 and S = 6.3 and 0.8 g kg^-. Nutrients omitted led to the decreasing of the level with which they occur in the aerial part of the plant as well as to an unbalance between the other nutrients which caused morphological modifications shown as typical deficiency symptoms. Key-words: Sorghum bicolor (L.) Moench, deficiency, nutrient, symptom