Can soil health explain grain quality? A case study of a corn field in Texas

Studies show a strong relationship between soil health and crop yield, but those relating soil health and grain quality are limited. We studied the relationship between soil health and grain protein and oil content from a corn (Zea mays L.) field in Texas. Protein and oil content data were collected in the field with a CropScan monitor. Soil health values were measured at 202 locations using the Haney Soil Health Tool. We first mapped protein and oil content using apparent electrical conductivity (ECa) and 14 terrain attributes as predictors, and we then quantified the relationship with data from sample locations. Soil health was positively correlated with protein and oil content, but the relationship was rather weak. Soil health accounted for up to 13% of the variability in protein (p < .001) and between 2 and 17% in oil content (p < .1) depending on soil map unit. Their spatial distribution was mostly influenced by elevation, ECa, and wetness index. We do not recommend estimating grain protein and oil content with the Haney Soil Health Tool; however, we suggest investigating such relationship across different soil and agronomic conditions for further verification.