Effect of Sewage Sludge Application on Growth Parameters and Uptake of Macronutrients by Poplar Nursery

An experiment was conducted to study the effect of sewage sludge application and its combination with chemical fertilizers on growth and uptake of macronutrients by poplar nursery. Sixteen treatments namely control, 50% RDF (recommended dose of fertilizers), 75% RDF, 100% RDF, 5 t/ha SS (sewage sludge), 10 t/ha SS, 15 t/ha SS, 50% RDF + 5 t/ha SS, 50% RDF + 10 t/ha SS, 50% RDF + 15 t/ha SS, 75% RDF + 5 t/ha SS, 75% RDF + 10 t/ha SS, 75% RDF + 15 t/ha SS, 100% RDF + 5 t/ha SS, 100% RDF + 10 t/ha SS and 100% RDF + 15 t/ha SS were applied in three replications. The RDF for poplar nursery was 125, 150 and 75 kg/ha N, P2O5 and K2O, respectively. Plant height and collar diameter were the highest at 100% RDF + 10 t/ha SS (409.1 cm and 27.88 mm, respectively) which were statistically similar with 50% RDF + 15 t/ha SS, 75% RDF + 10 t/ha SS and 75% RDF + 15 t/ha SS. Dry weight of shoot, root and litterfall, and concentration and uptake of macronutrients (N, P, K, Ca, Mg and S) were significantly higher at 50% RDF + 15 t/ha SS and 75% RDF + 10 t/ha SS than other treatments. Build-up of macronutrients in the soil was highest at 100% RDF + 15 t/ha SS. It is suggested to apply 50% RDF + 15 t/ha SS or 75% RDF + 10 t/ha SS for getting good growth of poplar nursery and for saving of fertilizers to the tune of Rs. 7041/ha or Rs. 3520/ha, respectively from Rs. 14082/ha at 100% RDF.