January, the average moisture of so

January, the average moisture of soil is 12, 6, and 3.5% (wb), respectively. The Digger can
separate cassava rhizomes after digging and put them on the ground. Regarding the test in
February, the moisture of soil is less than 1% (wb). The soil is quite hard so it’s impossible
for the digger to penetration in the soil. It can only grate the soil surface. Therefore, the data
has not been kept for this month.
The hypothesis of the study has found that if digger can break soil clods into small pieces
and place the cassava on the ground after the excavation, this condition will help the bucket
to scoop cassava rhizomes from the ground. Therefore, in this study, sizes of soil clods have
been measured by 2 values: the percentage of soil clods that are bigger than 75mm. and
average size of soil clod (mm.). The results of the analysis of the sizes of soil clods after
excavation (Tables 2 - 3) has found that reducing the angle of digger when soil moisture is
between 3.5 - 12.0% (wb) will make the soil clods smaller after digging while soil clods which
are bigger than 75 mm. also show a statistically significant decrease in amount (P-value
3.03-06 - Table 2). The average size of the soil clods has also decreased statistically (P-value
2.04-12 - Table 3). The percentages of soil clods which are bigger than 75 mm show no
difference in amount for the operation while the soil has that kind of moisture.
From the observation, it has been shown that after digging the soil clods have become
smaller in size. Cassava rhizomes after excavation will float more from the ground because
the sifter that is attached at the back of the digger can separate larger amounts of soil from
the cassava rhizome before they fall on the ground behind the sifter.