Efecto de un inhibidor de la ureasa (NBPT) en la eficiencia de uso del nitrógeno, las pérdidas de amoníaco y las emisiones de óxido nitroso y metano en cultivo de arroz de secano
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Fecha
2024
Tipo
tesis de maestría
Autores
Giraldo Sanclemente, Weynner
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La producción arrocera en Costa Rica ha sido afectada por el cambio climático, el alto costo de los insumos agrícolas, así como una fuerte competencia con el mercado internacional. Una opción para incrementar la productividad del cultivo de arroz es mejorar la gestión de la fertilización nitrogenada, aplicada mayoritariamente en forma de urea. La urea (U) es el fertilizante que presenta las mayores pérdidas de nitrógeno (N) producto de la volatilización de amoníaco (NH3). Estas pérdidas pueden reducirse al utilizar inhibidores de la ureasa (UI), que retardan la hidrólisis de la urea en el suelo, aumentando la posible absorción del N por parte de las plantas y por ende la productividad. Metodología: esta investigación se realizó durante tres ciclos de producción arrocera en el cantón de Parrita, Costa Rica, evaluando tres tratamientos: urea impregnada con el inhibidor de la ureasa N-(n-butil) tiofosfórico triamida (NBPT) (UI), urea sola (U) y un tratamiento control (CK) sin aplicación de N. Se evaluaron las pérdidas de N como NH3 empleando el método de trampas ácidas y determinación del NH3 por espectrofotometría. La eficiencia en el uso del N (EUN) mediante el seguimiento isotópico con 15N. Las emisiones de metano (CH4) y óxido nitroso (N2O) se evaluaron por cromatografía de gases. El rendimiento fue evaluado. Resultados: las pérdidas de N como NH3 se redujeron en 40% aproximadamente al utilizar urea con NBPT en comparación de solo urea. El tratamiento UI incrementó la EUN en grano en 4.8% con respecto a U solo en un experimento. El rendimiento de UI con respecto a U no mostró diferencia en los tres experimentos evaluados. Las emisiones de N2O y CH4 no mostraron diferencias entre U y UI. Discusión: la ineficacia del NBPT se atribuyó principalmente al pH medio del suelo (5.90 y 6.20), las altas temperaturas ambientales (promedio 28 °C), la alta capacidad de intercambio catiónico (CICE) (31.5 y 33.2 cmol(+) L-1), la textura franco-arcillosa, el contenido de humedad en suelo, y el espacio poroso lleno de agua del suelo (EPLA) cercano o superior a 80%. Conclusión: el pH, la textura, la capacidad de intercambio catiónico, el EPLA, en conjunto con altas temperaturas y lluvias frecuentes son posibles factores claves que afectaron la estabilidad del NBPT y modularon su eficacia. Futuras investigaciones sobre el NBPT, deberían de considerar previamente las propiedades físicas y químicas del suelo, para identificar condiciones propicias o propensas a pérdidas por N.
The rice production in Costa Rica has come affected by the climate change, the high cost of inputs, and into and major competition with an open international market. To increase the productivity of rice crop, an option is improving the management of nitrogen fertilization, mostly applied in the form of urea. The urea is the fertilizer with higher losses of nitrogen (N) product of the ammonia (NH3) volatilization. These losses could be reduced using a urease inhibitor (UI), that delay urea hydrolysis in soil increasing the possible absorption of N by plants and hence the productivity. Methodology: this research was realized during three rice cycles crop in Parrita Region, Costa Rica, evaluating three treatments: urea impregnated with urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) (UI), only urea (U) and a control treatment (CK) without N application. The gaseous losses of N by NH3 were measure employing the acid traps method and NH3 determination by spectrophotometry. The N use efficiency (EUN) was evaluated by 15N isotopic tracer. The methane (CH4) and nitrous oxide (N2O) emissions were evaluated by gasses chromatography. The yield was measured. Results: the NH3 losses by N were reduced in 40% approximately when urea with NBPT was used in comparison with only urea. The UI treatment increase the EUN in grain in a 4.8% in comparison with U just in one experiment. The yield did not show differences in UI in comparison with U in the three experiments performed. The N2O and CH4 emissions did not present difference between U y UI. Discussion: the NBPT inefficacy was mainly attributed to the pH in soil (5.90 and 6.20), the high ambient temperatures (average 28 °C), the high cation exchange capability (CEC) (31.5 and 33.2 cmol(+) L-1), the clay-loam texture, the wetness content of soil, and the water filled pore space (WFPS) closest or higher than 80%. Conclusion: the pH, the texture, the CEC, the WFPS, in conjunction with high temperatures and a rainy condition, were possible key factors modulating the inefficacy and the instability of the NBPT. Future research in NBPT should consider previously the chemical and physical soil properties, to identify adequate o susceptible conditions to N losses.
The rice production in Costa Rica has come affected by the climate change, the high cost of inputs, and into and major competition with an open international market. To increase the productivity of rice crop, an option is improving the management of nitrogen fertilization, mostly applied in the form of urea. The urea is the fertilizer with higher losses of nitrogen (N) product of the ammonia (NH3) volatilization. These losses could be reduced using a urease inhibitor (UI), that delay urea hydrolysis in soil increasing the possible absorption of N by plants and hence the productivity. Methodology: this research was realized during three rice cycles crop in Parrita Region, Costa Rica, evaluating three treatments: urea impregnated with urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) (UI), only urea (U) and a control treatment (CK) without N application. The gaseous losses of N by NH3 were measure employing the acid traps method and NH3 determination by spectrophotometry. The N use efficiency (EUN) was evaluated by 15N isotopic tracer. The methane (CH4) and nitrous oxide (N2O) emissions were evaluated by gasses chromatography. The yield was measured. Results: the NH3 losses by N were reduced in 40% approximately when urea with NBPT was used in comparison with only urea. The UI treatment increase the EUN in grain in a 4.8% in comparison with U just in one experiment. The yield did not show differences in UI in comparison with U in the three experiments performed. The N2O and CH4 emissions did not present difference between U y UI. Discussion: the NBPT inefficacy was mainly attributed to the pH in soil (5.90 and 6.20), the high ambient temperatures (average 28 °C), the high cation exchange capability (CEC) (31.5 and 33.2 cmol(+) L-1), the clay-loam texture, the wetness content of soil, and the water filled pore space (WFPS) closest or higher than 80%. Conclusion: the pH, the texture, the CEC, the WFPS, in conjunction with high temperatures and a rainy condition, were possible key factors modulating the inefficacy and the instability of the NBPT. Future research in NBPT should consider previously the chemical and physical soil properties, to identify adequate o susceptible conditions to N losses.
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CULTIVO DE ARROZ, SUELOS TROPICALES, ARROZ DE SECANO, NITRÓGENO, RECURSOS NATURALES, CIENCIAS AGRÍCOLAS