Subsoil-potassium depletion accounts for the nutrient budget in high-potassium agricultural soils

• Autores: Correndo, Adrián Alejandro; Rubio, Gerardo; García, Fernando Oscar; Ciampitti, Ignacio Antonio
• Año de publicación: 2021
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Scientific Reports; Vol.11; art.11597; http://www.nature.com
• Materia: POTASSIUM; SUBSOIL; NUTRIENT BUDGET; POTASSIUM
• Institución: Universidad de Buenos Aires. Facultad de Agronomía

Fil: Correndo, Adrián Alejandro. Kansas State University. Department of Agronomy. USA.
Fil: Rubio, Gerardo. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales (INBA). Buenos Aires, Argentina.
Fil: García, Fernando Oscar. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias. Balcarce, Buenos Aires, Argentina.
Fil: Ciampitti, Ignacio Antonio. Kansas State University. Department of Agronomy. USA.
Continuous potassium (K) removal without replenishment is progressively mining Argentinean soils. Our goals were to evaluate the sensitivity of soil-K to K budgets, quantify soil-K changes over time along the soil profile, and identify soil variables that regulate soil-K depletion. Four on-farm trials under two crop rotations including maize, wheat and soybean were evaluated. Three treatments were compared: (1) control (no fertilizer applied); (2) application of nitrogen, phosphorus, and sulfur fertilizers -NPS-; and (3) pristine condition. After nine years, crops removed from 258 to 556 kg K ha−1. Only two sites showed a decline in the exchangeable-K levels at 0–20 cm but unrelated to K budget. Topsoil exchangeable-K levels under agriculture resulted 48% lower than their pristine conditions, although still above response levels. Both soil exchangeable-K and slowly‑exchangeable K vertical distribution patterns (0–100 cm) displayed substantial depletion relative to pristine conditions, mainly concentrated at subsoil (20–100 cm), with 55–83% for exchangeable-K, and 74–95% for slowly- exchangeable-K. Higher pristine levels of exchangeable-K and slowly-exchangeable-K and lower clay and silt contents resulted in higher soil-K depletion. Soil K management guidelines should consider both topsoil and subsoil nutrient status and variables related to soil K buffer capacity.
tbls., grafs.