INITIAL RESPONSES OF MAIZE AND BEANS TO DECREASED CONCENTRATIONS OF MONOMERIC INORGANIC ALUMINUM WITH APPLICATION OF MANURE OR TREE PRUNINGS TO AN OXISOL IN BURUNDI
Mtf. Wong et al., INITIAL RESPONSES OF MAIZE AND BEANS TO DECREASED CONCENTRATIONS OF MONOMERIC INORGANIC ALUMINUM WITH APPLICATION OF MANURE OR TREE PRUNINGS TO AN OXISOL IN BURUNDI, Plant and soil, 171(2), 1995, pp. 275-282
Prunings of Calliandra calothyrsus, Grevillea robusta, Leucaena divers
ifolia and farm yard manure were applied each cropping season at 3 and
6 t dry matter ha(-1) to an Oxisol in Burundi. The field plots also r
eceived basal applications of nitrogen (N), phosphorus (P) and potassi
um (K). Application of the tree prunings or farm yard manure decreased
the concentration of monomeric inorganic aluminium (Al) in soil solut
ion from 2.92 mg Al dm(-3) in the control plots to 0.75 mg Al dm(-3) i
n the plots receiving 6 t ha(-1) Calliandra prunings. The other organi
c materials also decreased the concentration of monomeric inorganic al
uminium in the soil solution. The lowered Al concentration led to a co
rresponding decrease in the percentage Al saturation of the 0-10 cm so
il layer from 80% to 68%. Grain yields of maize and beans were strongl
y inversely related to the percentage Al saturation of the soil. This
confirms that soil acidity was the main constraint to maize and beans
production. The yield improvement was mainly attributed to the amelior
ating effects of the organic matter application on Al toxicity. The nu
trient content had less effect presumably because of fertilizer use. I
n the best treatments, the yield of maize increased from 0.9 to 2.2 t
ha(-1) and the corresponding beans yield increased from 0.2 to 1.2 t h
a(-1).