Growth of Short Rotation Cajanus Cajan Fallow and Its Impact on a Degraded Tropical Alfisol

Abstract

Cajanus cajan (L) Millsp. has been reported to improve soil fertility in many areas of the humid tropics. Although this woody species is widely cultivated in the South-western Nigeria usually in association with other agricultural crops, reports of its successful use as a fallow species are scanty. To determine the extent of the beneficial effects of C.cajan fallow on soil, experimental plots were established on an extensively cultivated soil using C. cajan fallow and natural bush fallow. Soil chemical properties to a depth of 30 cm were measured prior to the establishment of the fallow species and 12 and 25 months after. The type of fallow
species affected soil nutrient content. Organic carbon (OC) and phosphorus (P) were observed to be significantly lower under C.cajan fallow compared to the natural fallow at 12 weeks after fallowing. However, by the 25th month after fallowing there had been significant improvement in soils under cajanus fallow with organic carbon, total nitrogen (TN) and P being 19.9%, 37.5% and 38.3% respectively higher than in the natural fallow.