Effects of elevated soil carbon dioxide (CO₂) concentrations on spring wheat (<i>Triticum aestivum</i> L.) and soil chemical properties in Sutton Bonington Campus of the University of Nottingham, UK

Abstract

This study examines the effects of elevated soil carbon dioxide (CO₂) concentrations on spring wheat and soil chemical properties in the Sutton Bonington Campus, of the University of Nottingham, United Kingdom using Artificial Soil Gassing and Response Detection (ASGARD) facility which controls CO₂ injection into the soil. Eight plots (each 2.5 x 2.5m) were laid out within the experimental area and used for the study and were treated with high CO₂ concentrations (area within 75cm from the point of injection), low CO₂ concentration (area farther than 75 cm from the point of CO₂ injection) and no CO₂ concentration (control) at CO₂ injection rate of 1.0l/min from a source point 60cm below the soil for eight (8) weeks. The variability of CO₂ concentrations were determined by 3D and barholing method. The wheat plant showed visible symptoms of wilting, chlorosis and poor development within 15- 21 days of gassing. Gassing at the rate of 1.0l/min resulted in reduced plant height and a 60% decrease in chlorophyll content of wheat plant exposed to high CO₂ concentrations when compared with control plots. The soil pH for the control plots at the depth of 15-30 cm was 6.31 and 6.7 after injection, showing a difference of 0.39. At the depth of 45-60 cm, the pH before injection was 5.89 while post injection was 6.39, showing a difference of 0.5. The study showed that organic carbon at 45-60cm depth of soil ranged from 2.54% to 2.58% with a mean value of 3.26%, while carbonate content ranged from 0.73 to 0.77%. Furthermore, at 45-60cm depth of soil after injection, the mean value of K across all experimental plots was 64.16 mg/lK, available P content ranged from 15.4 to 16.9 mg/lP, N content ranged from 11.2 to 16.9 mg/lN, Ca ranged from 1000 to 1300 mg/lCa, Mg ranged from 158 to168 mg/lMg while at 15-30cm depth of soil, Na range from low to moderate (10.16–10.2 mg/l Na). There was no significant difference (P<0.05) or changes in mineralogical content of the soil properties studied.

Keywords: controlled injection; CO₂; soil chemical properties, soil depth