Abstract
Soil erosion decreases soil productivity and threats global food
security. Various relationships between crop yield and soil erosion were
found for different regions, but a comprehensive global synthesis of the
relationship is lacking. To quantify crop yield and soil erosion, we
conducted a meta-analysis with a hierarchical mixed-effects model based
on global-scale studies, and incorporating erosion depth, crop yield,
grain type, soil type, measure, and other factors. The results confirmed
that crop yield was negatively affected by soil erosion, but the
decreasing trend of crop yield with erosion thickness was different.
Crop yields did not decreased significantly when erosion depth was
< 5 cm. When erosion depth was > 20 cm, crop
yield clearly decreased no matter what soil management measures were
adopted, which indicated that the degradation of soil productivity could
not be restored. In addition, the effect degree of erosion was
significantly different between 5 - 10 cm and 10 - 15 cm erosion depth
intervals. We conclude that a widely used linear relationship does not
well describe the relationships between crop yield and soil erosion, and
we suggested that the crop yield response curve was concave when erosion
depth was > 5 cm.