The Mann–Whitney test of the variance between erosion and
the pairs of intervals of litter layer showed that the most significant
differences in erosion were between 60 and 65% (Analysis 1—Pair 1,
P = 0.038; Analysis 2—Pair 1, P = 0.004) (Table 8). Therefore, it is
established that a litter layer of 60–65% represents the threshold
above which erosion is significantly reduced, and that this
threshold corresponds to effective erosion control. Coffee cultiva-
tion with Inga spp and Musa spp shade trees with 68% of litter layer
was affected by Class 1 (slight) erosion (Fig. 7). This level was found
to be effective for proper erosion control, according to the purposedesigned
verification method applied (Table 4). When the litter
layer decreased to 58% and 35%, the intensity of erosion rose to
Class 2 (moderate) and Class 3 (severe), respectively, and the
higher frequency of erosive processes revealed that these levels of
litter layer did not correspond to an effective control of erosion
(Fig. 7). On the contrary, when the litter layer was 87%, the
intensity of erosion fell to Class 0, and there were very few signs of
erosion (Fig. 7).