USLE/RUSLE K-factors allocated through a linear mixed model for Uruguayan soils

Abstract

A. Beretta-Blanco, L. Carrasco-Letelier. 2017. USLE/RUSLE K-factors allocated through a linear mixed model for uruguayan soils. Cien. Inv. Agr. 44(1): 100-112. Soil erosion by rainfall is a process that demands management, both for the prevention of excessive soil erosion and for the protection of the quality of freshwater bodies. Erosion coefficients (K-factors) of the universal soil loss equation (USLE)/revised USLE (RUSLE) model were assigned to 99 mapped Uruguayan soil types at 1:1,000,000 scale. This work developed a linear mixed model (LMM) with 79 soils with assigned K-factors, in which the following variables were considered: soil taxonomy, chemical composition, and parent material. The developed LMM had an R 2 =0.86, in which the soil taxonomy (p<0.0001), parent material (p=0.0174), clay (p=0.0005) and sand (p=0.017) contents had significant statistical effects. The prediction capacity of this model was assessed with 10 soils not previously used in development of the LMM with assigned K-factors. The prediction assessment had an R 2 =0.84 and a mean error of 9.08% of the mean K-factor value. The LMM developed was used for the allocation of K-factors to soils mapped at a 1:20,000-resolution. Thus, the use of LMM increased the soil area with assigned K-factors from 111,822 km 2 (at a scale of 1:1,000,000) to 174,132 km 2 (1:20,000).

Availability and Environmental Performance of Wood for a Second-Generation Biorefinery

“…The situation partially explained the loss of nutrients due to bad fertilization management of rainfed crops, which reduced soil productivity [20]. The second type of water erosion of the soil corresponds to a natural risk, that is, soils with high slope and structural fragility that are present in defined soils of forest priority [18]. This situation was previously reported by Carrasco-Letelier and Beretta-Blanco [19] This last type of erosion was the one detected in the studied plots.…”

“…Moreover, the agriculture/forest residues left on soil can only be harvested in the amount that is not required to maintain the soil organic matter and soil fertility. If these variables are not considered, the harvest of agriculture/forest residues will reduce the soil erosion resistance [18][19], cation exchange capacity and soil fertility [20]. Therefore, before the development of a biorefinery, it is necessary to survey hidden natural subsidies that can be allowed by circumstantial socioeconomic conditions.…”

CMIP5 climate projections and RUSLE-based soil erosion assessment in the central part of Iran

“…For example, in China, Wang et al 101 confirmed that based on the nonlinear best fitting techniques, K factor prediction by combining Geometric Mean Diameter based and soil organic matter (SOM). Another recent study conducted in Uruguay by Beretta-Blanco and Carrasco-Lettelier 102 demonstrated that the implementation of soil taxonomy, chemical composition, and parent materials could increase the accuracy in linear estimations of this factor. These ideas agree with recent reviews published about soil mapping techniques which remark the importance of not obviating key properties since the soils are results of multiple and complex interactions 103 – 105 .…”

CMIP5 Climate Projections and RUSLE-Based Soil Erosion Assessment in The Central Part of Iran

“…However, there is still a further way to improve this model if we consider recent investigations. For example, in China, Wang et al 101 confirmed that based on the nonlinear best fitting techniques, K factor prediction by combining Geometric Mean 102 demonstrated that the implementation of soil taxonomy, chemical composition, and parent materials could increase the accuracy in linear estimations of this factor. These ideas agree with recent reviews published about soil mapping techniques which remark the importance of not obviating key properties since the soils are results of multiple and complex interactions [103][104][105] .…”