Corn and Sorghum Yield Response to Chloride and Changes in Tissue Concentration in Different Plant Parts.

Total chloride (Cl) plant uptake is typically higher than other micronutrients, and grain yield response to Cl fertilizer application can be common in some regions of the US. The objective of this study was to evaluate grain yield response and Cl tissue concentration in corn (Zea mays) and sorghum (Sorghum bicolor) plant parts. Tissue analysis were evaluated as diagnostic tool, including different plant parts and different growth stage. The study was conducted at 14 locations across Kansas for both corn and sorghum between 2012-2015. Four Cl fertilizer rates (0, 11, 22, and 34 kg Cl/ha) were applied at planting using liquid magnesium chloride fertilizer. Results showed that Cl tissue concentrations varied significantly by growth stage and plant part. Chloride removal with the grain was very low (typically undetectable), suggesting very low Cl removal rates with the corn and sorghum grain. Therefore, crop residue after harvest may provide available Cl to the next crop in significant amounts. Results also showed small but consistent grain yield response across locations, particularly with low profile (0-60 cm) soil test (between 3-6 mg/kg) ppm. Pre-plant or early side-dress Cl fertilizer applications showed corn and sorghum response to a maximum fertilizer rate of 22 kg Cl/ha.