Initial properties of both the pot and field soils did vary considerably,
especially with respect to texture and base saturation (Table 2). However,
both soils responded to the treatments in like manner. Soil pH increased
with an increase in the rate of RHA without combining with phosphorus
(Table 3). A fall in soil pH was observed (Table 4) when high rates of RHA
( . 20 t ha21) were applied combined with P over time. In both experiments,
the best combination of treatment, which gave the highest responses and
yields, was 20 t ha21 RHA together with 20 mg kg21 P (i.e., 40 kg P ha21).
Their interaction effect was not significant; hence, it can be inferred that the
effects of RHA and that of P are independent of one another.