Biochar Application to Low Fertile Sandy Soil Enhances Sweet Corn Resilience under Water-saving Irrigation Regime

This study evaluates the hypothesis that biochar (BC) amendment in clay-sandy soil can improve sweet corn resilience under water-saving irrigation. In water-limited conditions, sweet corn in BC-amended soil produced ears with phenotypes similar to controls, while non-amended soil plants had deformed, stunted ears. Plant height reduction was notably lower in BC-amended soil (14%) compared to non-amended soil (38%). Ear diameter reduction was also less pronounced in BC-amended soil (19.4%) versus non-amended soil (32.8%). Under drought stress, non-amended soil plants accumulated 2.7 times more MDA-TBA complex than BC-amended soil plants. At the molecular level, stress-marker gene expression was analyzed. ZmNCED9 (key to ABA biosynthesis) was upregulated 18.4-fold in non-amended soil under drought stress, but showed no significant change in BC-amended soil. The nitrogen deficiency marker ZmASP (encoding Asparagine synthase) was upregulated 2.35-fold in non-amended, drought-stressed plants compared to BC-amended ones. These findings suggest biochar amendment mitigates drought stress, supporting its potential in water-saving irrigation for low-fertility sandy soils. Further research is needed to optimize biochar application rates and methods for effective sweet corn yields in water-limited agroecosystems.