Effects of Liming on the Response of Maize to Potassium in Jiquipilas

The objective of this study was to determine the influence of liming on the response of maize to K added as two fertilizer sources and at four application rates. The study was conducted in a farmers field in Jiquipilas, Chiapas. The field had a sandy loam soil with pH 5.2, 2.3% organic matter, 48 ppm Bray-1 P, 72 ppm available K, 411 ppm Ca, 31 ppm Mg, 17 ppm Na, 0.3 ppm Zn, 22 ppm Mn, 0.3 ppm Cu, and 0,2 ppm B. The effective cation exchange capacity (CEC) of the experimental soil was 3 cmol/kg, and exchangeable Al saturation was 4%. Treatments included liming (0 or 1 t/ha of dolomitic limestone), K fertilizer sources (KCl or K₂SO₄) and K application rates (0, 60, 120, and 180 kg K₂O/ha). The resulting 16 treatments with two replications were arranged in an experimental design with split-split-plots, where main plots received limestone application, sub-plots had different K sources and sub-sub-plots had different K rates.

Grain yield (14% moisture) averaged 6.4 t/ha, and no significant effects (p > 0.05) could be detected for any treatment, possibly because of the very large variation (CV 22%) observed in the study. Average yield when lime was applied at 6.9 t/ha was 18% higher than when no lime was applied (5.8 t/ha). Also, yields decreased as foliar Mn concentrations increased.