Increasing yields and soil chemical properties through the application
of rock fines in tropical soils in the western part of Cameroon, Africa
Abstract
Rock fines from basalt, trachyte and volcanic pyroclastic materials in
addition to limestone and gneiss were applied as fertilizers on tropical
soils in several localities in west Cameroon. After harvesting, soil
samples from controls and different treatments were collected and
analyzed to assess the variation of textures and soil chemical
compositions. Cabbage and potatoes as the test crops treated under fines
from volcanic pyroclastic materials and basalt yielded the highest and
lowest productivities, respectively. The initial loamy sand of the
controls moves towards clay textures while initial clay textures
remained unchanged, suggesting a loss of sand proportion and an increase
in clay particles. For the pH, the slightly, moderately to strongly
acidic properties of the local soils (4.8 ≤ pH ≤ 6.5) were shifted
upwards in between the slightly acidic and the slightly alkaline soils
(6.6 ≤ pH ≤ 7.2). However, a sample treated with fines from pyroclastic
materials showed a remarkable pH increase from 5.9 to 6.9. The trends of
fluctuation of organic carbon and organic matter are parallel with a
general increase of these chemicals in soils. Na and K remains constant
with a general increase trend for Mg and Ca in most treatments. The
highest available phosphorus content of 96.0 ppm was found on the
treatment with trachyte fines; followed by 50.9 and 51.5 ppm encountered
on treatments with limestone and basalt fines, respectively. Then, this
suggests a significant increase of phosphorus in soil after treatments
with some rock fines such as trachyte, limestone, gneiss and basalt.