Ta. Quine et al., Tillage erosion, water erosion and soil quality on cultivated terraces near Xifeng in the Loess Plateau, China, LAND DEGR D, 10(3), 1999, pp. 251-274
This study sought to contribute to the understanding of soil redistribution
by tillage on terraces and the extent and causes of within-field variation
in soil properties by examining the spatial distributions of soil redistri
bution rates, derived using caesium-137, and of total nitrogen and total ph
osphorus concentrations, within a ribbon and a shoulder terrace in a yuan a
rea of the Loess Plateau of China. Additional water erosion rate data were
obtained for nine other terraces.
Water erosion rates on the ribbon terraces were low (<1 kg m(-2) yr(-1)), u
nless slope tangents exceeded 0.1. However, despite the use of animal tract
ion, high rates of tillage erosion were observed (mean 5.5 kg m(-2) yr(-1))
. Soil nitrogen concentrations were related to rates of soil redistribution
by tillage on the ribbon terrace examined in detail. In general, higher ra
tes of water erosion (0.5-2.9 kg m(-2) yr(-1)) and lower rates of tillage e
rosion (mean 1.4 kg m(-2) yr(-1)) were evident on the longer shoulder terra
ces. On the shoulder terrace examined in detail, soil phosphorus concentrat
ions were related to net rates of soil redistribution.
A statistically significant regression relationship between water erosion r
ates and the USLE length and slope factor was used in conjunction with the
simulation of tillage erosion rates to evaluate a range of terrace designs.
It is suggested that off-site impacts of erosion could be further reduced
by ensuring that the slope tangents are kept below 0.06 and lengths below 3
0 m, especially on the shoulder terraces. Tillage erosion and the systemati
c redistribution of soil nutrients could be reduced by modification of the
contour-cultivation technique to turn soil in opposing directions in altern
ate years. Copyright (C) 1999 John Wiley & Sons, Ltd.