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Do XRF local models have temporal stability for predicting plant-available nutrients in different years? A long-term study showing the effect of soil fertility management in a tropical field

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Autor(es):
Tavares, Tiago Rodrigues ; Minasny, Budiman ; McBratney, Alex ; Molin, Jose Paulo ; Marques, Gabriel Toledo ; Ragagnin, Marcos Mantelli ; dos Santos, Felipe Rodrigues ; de Carvalho, Hudson Wallace Pereira ; Lavres, Jose
Número total de Autores: 9
Tipo de documento: Artigo Científico
Fonte: SOIL & TILLAGE RESEARCH; v. 245, p. 15-pg., 2024-09-18.
Resumo

This study evaluates the temporal stability of X-ray fluorescence (XRF) models for predicting plant-available calcium (av-Ca) and potassium (av-K) in a tropical agricultural field under changing soil management. Understanding this stability is crucial for advancing XRF as a quick and clean tool for soil nutrient monitoring. XRF models were tested across six sampling periods (2015, 2019, 2020, and three in 2022); lime and potash rock powder were applied before 2022 samplings to assess the XRF models response to amendments, which altered the ratio of total to plant-available nutrients (T/A ratio). We evaluated a simple model (M15) calibrated using only samples acquired in 2015 (S15), and two time-specific models (M15+SS and SS models) that incorporate samples collected at each analysis period. All models showed temporal stability when the T/A ratio was consistent, with RMSE values of 3.15-6.95 mmol(c) dm(-3) (1.91 <= RPIQ <= 4.22) for av-Ca and 1.20-1.64 mmol(c) dm(-3) (1.86 <= RPIQ <= 2.55) for av-K. However, the application of lime and potash rock powder disrupted the T/A ratio for Ca and K, reducing all models accuracy, with M15's RMSE increasing to 10.78-40.64 mmol(c) dm(-3) (0.33 <= RPIQ <= 1.23) for av-Ca and to 1.86-6.37 mmol(c) dm(-3) (0.48 <= RPIQ <= 1.64) for av-K. Although time-specific models improved accuracy compared to M15, they require frequent recalibration. Overall, XRF models can reliably predict plant-available Ca and K over time if soil management maintains a consistent T/A ratio. This study underscores the need to consider soil amendments when applying XRF models for nutrient monitoring and contributes to the theoretical basis for using XRF in agricultural management. (AU)

Processo FAPESP: 20/16670-9 - Modelagem de dados espectrais para análise da fertilidade de solos tropicais: associação das técnicas vis-NIR e XRF para a modernização dos métodos tradicionais de análise
Beneficiário:Tiago Rodrigues Tavares
Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
Processo FAPESP: 22/09678-9 - Otimização da modelagem preditiva de parâmetros da fertilidade de solos tropicais brasileiros utilizando bibliotecas espectrais de sensores XRF e vis-NIR
Beneficiário:Tiago Rodrigues Tavares
Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Pós-Doutorado