Poor Emergence of <i>Brassica</i> Species in Saline–Sodic Soil Is 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 the growth and yield of ‘normal’ [corn (<i>Zea mays</i>)/soybean (<i>Glycine max</i>)] rotational crops, and more appropriate management systems are needed. <i>Brassica</i> spp. and amendment applications, such as biochar, may provide management alternatives for these areas. In two greenhouse studies, (1) 10 canola (<i>Brassica napus</i>) genotypes were evaluated for emergence in non-saline (EC_1:1 = 0.62 dS m⁻¹), moderately saline–sodic (EC = 5.17 dS m⁻¹), and highly saline–sodic (EC_1:1 = 8.47 dS m⁻¹) soils and (2) 10 canola genotypes and 3 other brassicas (<i>Brassica juncea/B. oleracea</i>) were evaluated for emergence and biomass in non-saline or moderately 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 <i>Brassica</i> spp. emergence (42%) from the moderately saline–sodic soil compared to non-amended soil (29%), although shoot biomass was similar among treatments at 60 DAP. These findings suggest that specific salt-tolerant <i>Brassica</i> spp. may be an alternative crop for NGP saline–sodic soil 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 applications may aid in plant establishment.