The experiment was conducted at the Nsimi village within the
Zoétélé subdivision in South Cameroon (Fig. A1). The area is
located at 120 km SSE of Yaoundé, between 3070–3150N and
11450–11520E. The annual rainfall shows a bimodal distribution
pattern, leading to two rainy seasons corresponding to two
cropping periods (March–June and September–November). The
annual rainfall varies between 1500 and 1900mm and the mean
annual temperature is 24 C (