Changes in soil moisture throughout the experiment are shown in
Fig. 2. As expected, the annual variability in soil moisture was high.
Soil water tension was higher in the second year of the experiment
(i.e., lower water availability) than in the first and third years. Despite
large variability, our results also showed that the treatments had a significant
influence on soil moisture (F3, 1294 = 3.427, P = 0.017). The
vermicompost treatment significantly reduced soil water tension
(i.e., increase water availability) more than the other treatments
(Fig. 2a). Higher soil water tension was measured on several dates for
the compost and control treatments and intermediate values were
noted for the manure treatments. Biochar incorporation had variable effects
on soil moisture (F1, 1296 = 31.22, P b 0.001). It significantly decreased
soil water tension for the vermicompost treatment in the
second year of the experiment but significantly increased it for the control
and vermicompost treatment in the last year of the experiment
(Fig. 2b).