Coalchar-Mediated Soil Moisture Conservation under Dryland Agroecosystem

Aims: To evaluate the effect of coalchar application on soil moisture retention and maize performance under semi-arid agroecosystem conditions, and to assess whether functional groups present in coalchar contribute to improved soil water-holding properties. Study Design: Randomized Block Design. Place and Duration of Study: The experiment was conducted in a Kallakudi, Tiruchirappalli district during the rabi (October to January) cropping season. Methodology: Soil moisture dynamics were monitored using the gravimetric method and tensiometer readings at regular intervals in both coalchar-amended and control plots. Coalchar amended samples were analyzed using Fourier Transform Infrared (FTIR) spectroscopy to identify functional groups, particularly hydroxyl groups. Soil samples from coalchar-amended plots were also examined to detect the transfer of these functional groups. Maize growth and vigour parameters were recorded to evaluate crop performance. Results: Coalchar application consistently enhanced soil moisture content compared to unamended control plots. FTIR analysis confirmed the presence of hydroxyl functional groups in coalchar, which were also detected in coalchar-amended soils, indicating functional group transfer. This was associated with improved water-holding capacity and better maize growth and vigour under moisture-limiting conditions. The improvement in crop performance was directly linked to enhanced soil moisture retention in treated plots. Conclusion: Coalchar application is an effective non-conventional amendment for conserving soil moisture and improving maize productivity in semi-arid regions, with its hydroxyl functional groups potentially contributing to better soil water-holding capacity.