The profile distribution of total and extractable boron in cacao-growing soils in southwestern Nigeria

Abstract

The profile distribution of total and extractable B was determined in 16 Nigerian cacao-growing soil profiles formed from different parent materials. Total B for all soils ranged from 8 to 54/~gg-t with a mean of 24 #gg-l. The soils formed from sandstones in the rainforest zone contained higher amounts of total B than soils derived from basement complex. Boron extractable in hot water, in 0.1% CaCI2, and in IN NH4OAc varied from 0.13 to 1.38, 0.44 to 1.20 0.03 to 0.56/~gg-~ respectively. The corresponding means were 0.66, 0.75 and 0.27#gg -1 B. Soils on metamorphic rocks gave the highest values. All extractable B values were related to organic matter while only CaC12-extractable B correlated with total B. Generally total and extractable B values were higher in the top soils than in the subsoils.

Comparative effects of a tree crop (cocoa) and shifting cultivation on a forest soil in Nigeria

“…The studies on the effects of tree crops on soil (Tinker, 1963;Areola, 1984;Aweto, 1987;Chude, 1988) have been carried out independently of those on the effects of the cultivation of food crops (Obigbesan and Amalu, 1985;Njoku and Odurukwe, 1987;Aweto, 1988;Ikeorgu et al, 1989). Mainly on account of this, it is difficult to compare the effects of tree crops and the annual/biennial crops.…”