Changes in Soil Chemical Characteristics at the Two Soil Series
Compared to the initial soil analysis (Table I), soil organic carbon, total nitrogen and cation exchange capacity
(CEC) had increased markedly on pigeon pea fallow plots. Differences in soil pH, Bray 1 phosphorus and
exchangeable potassium were apparent.After two years fallow period,soil organic carbon,total nitrogen and CEC
were significantly higher on pigeon pea fallow plots (T1, T2 and T3) than the natural fallow plots at both soil
series. However, differences observed as a result of pigeon pea pruned biomass management options (T1, T2 and
T3) were not significant (Tables IV and V). After the two-year fallow period, percent increase of soil organic
carbon on the pigeon pea fallow land over natural fallow land was 305percent, total nitrogen 485percent and
CEC 178percent. With the first maize cultivation after the two-year fallow, between 37 and 41percent of the
variability in maize grain yield was explained by soil total nitrogen alone (Figure 1).