Soil Nitrogen (N-NO₃) as Related to Corn Nutrition When Applying Sulfuric Acid and Sub-Soiling to a Calcaric rhodic Luvisol of Yucatan Mexico

Nitrogen (N) is one of the essential elements that most limit corn production in the state of Yucatan. The high pH leads to high contents of hydroxyls (OH-) which, when reacting with available inorganic ionic forms such as NH₄ , favor their volatilization as ammonia gas (NH₃). The red arable rhodic Luvisols of Yucatan Mexico, in addition to facing alkalinity problems, have been exposed to more than 30 years of intensive corn cultivation with consequent soil compaction and negative collateral effects. In this work, the effect of the application of acid and sub-soiling on the concentration of N-NO₃ in the soil and on the nutrition of maize Chichen Itza (Nukuch Nah) variety in a rhodic Luvisol was evaluated through the following treatments: T1 = Without Acid Sub-soiling, T2 = Without Acid No Sub-soiling, T3 = With Acid Sub-soiling, T4 = With Acid No Sub-soiling. The N-NO₃ in the soil were higher than the Critical Limit of 20 ppm when applying acid whilst where no acid was applied, the N-NO₃ were below the Critical Limit. On the other hand, regardless of the acid, when subsoiling, the amount of N-NO₃ in the soil decreased. The N (%) in leaves of all treatments were below the Critical Limit of 2.7%. It is noteworthy that the N content in leaves was higher (2.6%) With Acid No sub-soiling while the lowest (2.45%) was Without Acid Sub-soiling. The ANOVA of the treatments did not show statistical differences. However, a very good correlation was found between the soil N-NO₃ (ppm) vs. the N contents (%) in the plant (r² = 0.98).