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Model prediction capacity of ephemeral gully evolution in conservation tillage systems
Author(s) -
Luquin Eduardo,
CampoBescós Miguel A.,
MuñozCarpena Rafael,
Bingner Ronald L.,
Cruse Richard M.,
Momm Henrique G.,
Wells Robert R.,
Casalí Javier
Publication year - 2021
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.5134
Subject(s) - tillage , watershed , ephemeral key , surface runoff , hydrology (agriculture) , environmental science , soil conservation , erosion , soil science , geology , geotechnical engineering , agriculture , computer science , geomorphology , geography , ecology , archaeology , algorithm , machine learning , biology
Ephemeral gully (EG) erosion has an important impact on agricultural soil losses and increases field surface hydrology connectivity and transport of pollutants to nearby water bodies. Watershed models including an EG component are scarce and not yet properly evaluated. The objective of this study is to evaluate the capacity of one such tool, AnnAGNPS, to simulate the evolution of two EG formed in a conservation tillage system. The dataset for model testing included runoff measurements and EG morphological characteristics during 3 years. Model evaluation focused on EG evolution of volume, width, and length model outputs, and included calibration and testing phases and a global sensitivity analysis (GSA). While the model did not fully reproduce width and length, the model efficiency to simulate EG volume was satisfactory for both calibration and testing phases, supporting the watershed management objectives of the model. GSA revealed that the most sensitive factors were EG depth, critical shear stress, headcut detachment exponent coefficient b , and headcut detachment leading coefficient a . For EG outputs the model was additive, showing low sensitivity to interactions between the inputs. Prediction of EG spatial evolution on conservation tillage systems requires improved development of gully erosion components, since many of the processes were developed originally for traditional tillage practices or larger channel systems. Our results identify the need for future research when EG form within conservation tillage systems, in particular to study gully headcut, soil erodibility, and width functions specific to these practices.