Influence of sewage sludge and saline water irrigation on soil soluble ions and nutrient uptake under Pearl millet-Wheat cropping system in semi-arid region

Abstract

Salinity is the most common problem in arid and semi-arid regions hindering nutrient accumulation in plants. A field trial (2017-18) was carried out to study the effect of sewage sludge (SS) and saline water irrigation on nutrient uptake under the pearl millet-wheat system and soluble ions in the soil. The experiment consisted of three irrigation levels (canal water, 8 and 10 dS/m ECiw saline water) and five fertilizer treatments i.e., control, sewage sludge (SS)- 5 t/ha, SS (5 t/ha) + 50% recommended dose of fertilizer (RDF), SS (5 t/ha) + 75% RDF and 100% RDF where sewage sludge was applied in rabi season only. The results indicated that the saline water irrigation significantly increased the concentrations of soluble ions (Na+, K+, Ca2++Mg2+, HCO3-, SO42- and Cl-) in the soil, and also the increase was non-significant under sewage sludge application. Na+ and Cl- ions were dominated under saline conditions among the soluble ions in the soil. The nutrient (N, P and K) uptake by grain and stover/straw of pearl millet and wheat crops were significantly reduced under saline environment. However, the maximum uptake in both crops was obtained under canal water irrigation (0.35 dS/m). Among fertilizer treatments, the maximum uptake (NPK) in both crops was attained under RDF being at par with SS (5 t/ha) + 75 RDF except K uptake in pearl millet crop, where the highest K uptake was obtained with SS (5 t/ha) + 75 RDF which was remained statistically at par with RDF treatment. The interactive effect was however non-significant. It is concluded that incorporating SS would enhance nutrient uptake in crops under saline conditions besides solving its dumping problem.