Assessing the subsequent effect of nitrogen released from tobacco-waste on maize crop using a ¹⁵N isotope technique

Abstract

The investigation of the residual effect of nitrogen (N) released from tobacco-waste (TW) using isotope techniques will provide valuable data for sustainable organic farming. For this aim, a pot experiment was conducted using the ¹⁵N isotope technique. The experiment was based on a completely randomised design with four replications and was conducted on a calcareous ustochrepts soil. TW at levels of 0, 10, 20, 30 and 40 t ha⁻¹ and N fertiliser as (NH₄)₂SO₄ at levels of 0, 20, 40, 60 and 80 kg N ha⁻¹ were used for the Bezostaja-1 wheat variety. Concerning mineral N fertilisation with 20 and 80 kg N ha⁻¹, additional treatments with ¹⁵N-labelled (NH₄)₂SO₂ (10 at.% exc.) have been applied. Following harvesting wheat plants, the Pioneer 3377 maize variety was used to see the residual effect of TW. After harvesting, dry matter yields were recorded and total N concentrations were determined. ¹⁵N determinations and calculations were also made for ¹⁵N treatments separately. TW had a significant residual effect on the growth of corn plant under the pot condition. Increasing rates of TW significantly increased the dry matter yield of corn plant following wheat from 3.31 t ha⁻¹ (at control) to 7.89 t ha⁻¹ (at the TW treatment of 40 t ha⁻¹). The ¹⁵N values derived from the ¹⁵N fertiliser decreased with increasing TW application. The average values of N derived from N fertiliser (Ndff) varied from 2.14 to 3.09% at the rates of 20 and 80 kg N ha⁻¹, respectively. However, N derived from TW (Ndftw) significantly increased from 16.93 to 24.59% (at 20 kg N ha⁻¹), and it also increased from 23.06 to 28.15% (at 80 kg N ha⁻¹) with increasing TW applications from 20 to 40 t ha⁻¹, respectively.

Keywords:

• fertiliser effects
• isotope ecology
• maize
• nitrogen fertiliser
• nitrogen-15
• plants
• tobacco-waste
• tracer techniques

Acknowledgements

This research work is the residual part of the main project sponsored by the State Planning Commission of Turkey (Project No: DPT-K120510). The authors also thank Cumhuriyet and Gaziosmanpasa Universities.