Poor Emergence of <i>Brassica Species</i> in Saline-Sodic Soil Was Improved by Biochar Addition

Salt-affected soil areas are increasing in the Northern Great Plains (NGP) with patches occurring in some of the most productive croplands. High electrical conductivity (EC) and sodium and/or sulfate concentrations of saline-sodic areas impede growth and yield of ‘normal’ [corn (Zea mays)/soybean (Glycine max)] rotational crops and more appropriate management systems are needed. Brassica sp. and amendment application, such as biochar, may provide management alternatives for these areas. In two greenhouse studies, 1) 10 canola (Brassica napus) genotypes were evaluated for emergence in non-saline (EC1:1 = 0.62 dS m-1), moderately saline-sodic (EC = 5.17 dS m-1), and highly saline-sodic (EC1:1 = 8.47 dS m-1) soils and 2) 10 canola genotypes and three other brassicas (Brassica juncea/B. oleracea) were evaluated for emergence and biomass in non-saline or highly saline-sodic soils with or without two 5% biochar (hardwood or softwood) amendments. Canola emergence at 28 days after planting (DAP) in moderately and highly saline-sodic soils was less than 12% for most genotypes, although one had 37% emergence. The hardwood biochar improved Brassica sp. emergence (42%) from the saline-sodic soil compared to nonamended soil (29%), although shoot biomass was similar among treatments 60 DAP. These findings suggest that specific salt-tolerant canola genotypes may be an alternative crop for NGP saline-sodic areas. Florida broadleaf mustard, typically used for forage, had the greatest emergence (52%) in the saline-sodic soil and may be a suitable cover crop for these areas. In addition, hardwood biochar application may aid in plant establishment.