Simulation of soil organic carbon changes in crop systems with castor bean using the RothC model

El objetivo del presente trabajo fue la simulación de los cambios del carbono orgánico del suelo (COS), por el modelo RothC, en razón del cambio de uso de suelo del sistema tradicional – asociación maíz‑calabaza (TMC) – a sistemas con higuerilla (Ricinus communis): multiestratos (MUL), callejones (CALL) y monocultivo de higuerilla (HIG). Las simulaciones del COS se hicieron para las profundidades de suelo 0–20 y 0–40 cm, para el periodo de 1980–2040, considerándose como línea base al sistema TMC. Las tasas de cambio de COS estimadas con el RothC, en ambas profundidades de suelo, estuvieron en 0,5–1,2, 0,4–0,8, 0,3–0,5 y 0,04–0,1 Mg ha-1 de C por año en los sistemas HIG, MUL, CALL y TMC, respectivamente, y fueron consistentes con las reportadas en la literatura. El desempeño del RothC tuvo 89% de eficiencia (EF), con R2=0,9, lo que muestra que este modelo puede usarse con información temporal del COS escasa, información de la historia de uso de suelo y mediciones de la entrada de residuos vegetales aéreos y subterráneos en el suelo.The objective of this work was to simulate, by the RothC model, the changes in soil organic carbon (SOC) caused by changes of land use – from the traditional maize‑squash (TMC) association to systems with castor bean (Ricinus communis): multilayer (MUL), alleys (CALL) and monoculture (HIG). SOC simulations were performed for 0–20 and 0–40 cm soil depths, for the period 1980–2040, considering the TMC system as the base line. SOC change rates estimated with RothC, for both soil depths, were 0.5–1.2, 0.4–0.8, 0.3–0.5 and 0.04–0.1 Mg ha-1 C per year in the HIG, MUL, CALL and TMC systems, respectively, and were consistent with those reported in the literature. RothC perfomance had 89% efficiency (EF) and R2 = 0.9, which shows that this model can be used with scarce SOC temporal information, information on the history of land use, and with input measurements of aerial and underground plant residues in the soil

Simulation of soil organic carbon changes in Vertisols under conservation tillage using the RothC model

The purpose of this study was to determine the measured and simulated rates of soil organic carbon (SOC) change in Vertisols in short-term experiments when the tillage system is changed from traditional tillage (TT) to conservation tillage (CT). The study was conducted in plots in four locations in the state of Michoacán and two locations in the state of Guanajuato. In the SOC change simulation, the RothC-26.3 carbon model was evaluated with different C inputs to the soil (ET1-ET5). ET was the measured shoot biomass (SB) plus estimated rhizodeposition (RI). RI was tested at values of 10, 15, 18, 36 and 50 % total biomass (TB). The SOC changes were simulated with the best trial where ET3 = SB + (0.18*TB). Values for model efficiency and the coefficient of correlation were in the ranges of 0.56 to 0.75 and 0.79 to 0.92, respectively. The average rate of SOC change, measured and simulated, in the study period was 3.0 and 1.9 Mg ha−1 yr−1, respectively; later, in a simulation period of 45 years, SOC change was 1.2 ± 0.8. In particular, without making adjustments in the RothC parameters and with information on measured plant residue C inputs to the soil, it was possible to simulate changes in SOC with RothC and estimate trends over a period of more than 45 years

Simulación de los cambios de carbono orgánico del suelo en sistema de cultivo con higuerilla por el modelo RothC Simulation of soil organic carbon changes in crop systems with castor bean using the RothC model

El objetivo del presente trabajo fue la simulación de los cambios del carbono orgánico del suelo (COS), por el modelo RothC, en razón del cambio de uso de suelo del sistema tradicional - asociación maíz-calabaza (TMC) - a sistemas con higuerilla (Ricinus communis): multiestratos (MUL), callejones (CALL) y monocultivo de higuerilla (HIG). Las simulaciones del COS se hicieron para las profundidades de suelo 0-20 y 0-40 cm, para el periodo de 1980-2040, considerándose como línea base al sistema TMC. Las tasas de cambio de COS estimadas con el RothC, en ambas profundidades de suelo, estuvieron en 0,5-1,2, 0,4-0,8, 0,3-0,5 y 0,04-0,1 Mg ha-1 de C por año en los sistemas HIG, MUL, CALL y TMC, respectivamente, y fueron consistentes con las reportadas en la literatura. El desempeño del RothC tuvo 89% de eficiencia (EF), con R²=0,9, lo que muestra que este modelo puede usarse con información temporal del COS escasa, información de la historia de uso de suelo y mediciones de la entrada de residuos vegetales aéreos y subterráneos en el suelo.The objective of this work was to simulate, by the RothC model, the changes in soil organic carbon (SOC) caused by changes of land use - from the traditional maize-squash (TMC) association to systems with castor bean (Ricinus communis): multilayer (MUL), alleys (CALL) and monoculture (HIG). SOC simulations were performed for 0-20 and 0-40 cm soil depths, for the period 1980-2040, considering the TMC system as the base line. SOC change rates estimated with RothC, for both soil depths, were 0.5-1.2, 0.4-0.8, 0.3-0.5 and 0.04-0.1 Mg ha-1 C per year in the HIG, MUL, CALL and TMC systems, respectively, and were consistent with those reported in the literature. RothC perfomance had 89% efficiency (EF) and R² = 0.9, which shows that this model can be used with scarce SOC temporal information, information on the history of land use, and with input measurements of aerial and underground plant residues in the soil