Crop Production
Applying Liebig’s law of the minimum for variable rate soybean seeding based on CEC-nutrient fertility index
A Scientific Reports study applied a CEC-based fertility index for variable soybean seeding and reported higher yields and net returns than fixed-rate seeding.
The study evaluated two fields with different limiting nutrients: magnesium constraints in one field and calcium deficiency in the other. Researchers built a fertility index (CEC multiplied by the limiting nutrient) to define five management zones per field.
Higher seeding rates were used in lower-index zones and lower rates in higher-index zones. The paper reports improved yield and economics versus fixed-rate seeding, including net income gains of 11.3% in field A and 6.9% in field B, with additional profit estimated at USD 5–57 per hectare.