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The development, calibration and field testing of a soil loss and a runoff model derived from a small‐scale physical simulation of the erosion environment on arable land in Zimbabwe
Author(s) -
ELWELL H. A.
Publication year - 1990
Publication title -
journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 0022-4588
DOI - 10.1111/j.1365-2389.1990.tb00060.x
Subject(s) - surface runoff , environmental science , arable land , weed , erosion , seedbed , sowing , agronomy , hydrology (agriculture) , agriculture , geography , ecology , paleontology , geotechnical engineering , archaeology , biology , engineering
SUMMARY Soil loss and runoff prediction models were developed for a clay soil from a five‐factor small‐scale physical simulation of the field environment by following a central composite rota table experimental design. The uncalibrated models efficiently ranked observed annual soil losses and runoff over a 4–year period between nine field treatments consisting of two bare fallows, two weed fallows and five plots cropped to soyabeans. When calibrated against the field data, the soil loss model predicted the 4–year mean losses from cropped and bare fallow treatments to within 6% for two of the plots, to within 12% for five of the plots and to within 14% for all seven treatments. Over the same period, the runoff model predicted mean annual runoff for the cropped and bare fallow treatments to within 4% for four of the plots and to within 16% for all seven treatments. Percentage vegetal cover proved to be an adequate parameter for describing the role of the soyabean crop in runoff and soil loss processes for a wide range of planting densities of the crop. However, it did not prove to be an efficient index for weed fallows and it was apparent that factors other than simple above‐ground cover became important soon after germination.