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

Abstract

ABSTRACT The effect on the morpho-physiological parameters and yield of sorghum cultivated in a greenhouse with reclaimed water (RW) and (dehydrated sludge (DS) obtained in a sewage treatment plant, was evaluated. 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 W + DS (T3) was very suitable for the cultivation since an adequate nutritional supply was provided. The positive effects on the morpho-physiological parameters, plant height, stem diameter and stem length (in cm), were: T3 – 148.8, 1.50, and 103, respectively; T4 – 154, 1.70, and 107, respectively; and on the grain production in weight of 1000 seeds (g), and productivity in grains per plant: T3 – 6.97 and 1453, respectively; T4 – 6.81 and 1636, respectively. Both treatments showed for most of the parameters, no significant differences compared with those of T2 or T5 with supplementary fertilizers. A high production of metabolites (mg g–1) like free amino acids was also shown: T3 – 6.45; T4 – 8.43 and proline: T3 – 1.86; T4 – 1.77, known to be a good indication of a plant natural defence against stress conditions, and in soluble protein: T3 – 11.20; T4 – 13.51. Therefore, since the production of such grains with RW or DS can be environmentally and economically beneficial, their use is recommended for small and medium farmers in semiarid regions.