Effect of reclaimed water and dehydrated sludge on the morpho-physiology and yield of sorghum.

Reclaimed water (RW) and dehydrated sludge (DS) have been used to improve plant nutrition. In this work, the effect on the morpho-physiological parameters and yield of sorghum cultivated with RW and DS was evaluated. The experiment was carried out in a greenhouse; RW and DS were obtained in a sewage treatment plant. The dewatering of the sludge occurred in drying beds. Six treatments (T), with five repetitions each, were carried out in entirely randomized blocks. Water (W) was used in T1 (W) (control), T2 (W+NPK), and T3 (W+DS); RW was used in T4 (RW), T5 (RW+P), and T6 (RW+DS). The results showed that irrigation with only RW (T4), or DS+W (T3) was very suitable for the cultivation since an adequate nutritional supply was provided. The positive effects were verified based on the morpho-physiological parameters (T3 - 148.8 cm of plant height, 1.50 cm of stem diameter, and 103 cm of stem length. T4 - 154 cm of plant height, 1.70 cm of stem diameter, and 107 cm of stem length), and grain production (T3 - the weight of 1000 seeds equal to 6.97 g and productivity of 1453 grains per plant. T4 - weight of 1000 seeds equal to 6.81 g and productivity of 1636 grains per plant). Both treatments showed for most of the parameters, no significant differences compared with those of T2 or T5 with supplementary fertilizers. T4 or T3 also showed a high production of metabolites like free amino acids (T3 - 6.45 mg g -1 ; T4 - 8.43 mg g -1 ) and proline (T3 - 1.86 mg g -1 ; T4 - 1.77 mg g -1 ), known to be a good indication of a natural defence that is used by plants against stress conditions, and soluble protein (T3 - 11.20 mg g -1 ; T4 - 13.51 mg g -1 ). Therefore, since the production of such grains in semiarid regions with RW or DS can be environmentally and economically beneficial, their use is recommended for small and medium farming operations in arid and semiarid regions.