A Spatial and Economic Framework for Variable-Rate Corn Seeding Based on Liebig’s Law of the Minimum

Corn (Zea mays L.) seeding density is a key management factor for achieving high yields, yet variable-rate seeding (VRS) prescriptions often rely on empirical proxies such as soil texture. This study aimed to identify soil attributes affecting corn grain yield and to evaluate whether Liebig’s Law of the Minimum can guide VRS decisions, integrating spatial analysis with economic feasibility. The experiment was conducted in Chapadão do Céu, Goiás, Brazil, in a 97-ha field with high soil variability. Four target seeding rates (50, 55, 60, and 65 thousand seeds ha−1) were assigned to 136 georeferenced plots. Soil attributes evaluated included texture, cation exchange capacity (CEC), pH, organic matter, electrical conductivity, and macronutrients (Ca, Mg, K, P, S). Geostatistical analysis (semivariograms and kriging) and bivariate Moran’s I with Local Indicators of Spatial Association (LISA) were used to assess spatial patterns. All attributes showed strong spatial dependence, except sulfur (moderate). Grain yield was inversely correlated with clay content, CEC, Ca, and Mg, but positively correlated with sand content. LISA revealed “Low-High” clusters where high CEC and clay content coexisted with low yield, driven by limiting factors: low pH (5.03–5.30) and low potassium availability (18.5–34.2 mg dm−3). These factors overrode apparent fertility, confirming that higher plant densities in clayey soils are counterproductive when the minimum factor is not addressed. Economic analysis using Monte Carlo simulation (10,000 iterations) indicated a median Net Present Value (NPV) of USD 63,552 (14% p.a. discount rate), with simple and discounted payback periods of 3.2 and 4.2 years, respectively. The investment remained viable even under conservative scenarios (1.5 bags ha−1 gain). We conclude that integrating geostatistics with economic evaluation provides a robust framework for identifying “inefficiency zones” (where density should be reduced) and “opportunity zones” (where higher populations can be adopted), optimizing seed use and enhancing the sustainability of corn production in the Brazilian Cerrado.