Agriculture Reference
In-Depth Information
Chapter 5
E
FFECT OF
L
IMING
,
N
AND
P
F
ERTILISATION OF
A
L
IXISOL ON THE
G
ROWTH OF
S
ELECTED
S
OYBEAN
C
ULTIVARS UNDER
S
UB
-
HUMID
T
ROPICAL
C
ONDITIONS IN
Z
IMBABWE
J. Nyamangara
*
, C. Musharo, M. Matokwe
Department of Soil Science and Agricultural Engineering, University of Zimbabwe, P.O.
Box MP 167, Mount Pleasant, Harare, Zimbabwe
A
BSTRACT
Soybean (
Glycine max
(L) Merr) production in the smallholder farming areas of
southern Africa is constrained by soil acidity and nutrient deficiency among other factors.
A study was conducted to determine the performance of four soybean cultivars
commonly grown in Southern Africa, in acid soil, their response to liming, and N and P
fertilisation. Soybean was grown over two cropping seasons at a research station and in a
sub-humid smallholder farming area in north-eastern Zimbabwe. Liming increased the
number of nodules and nodule dry matter yield (NDMY) in both cropping seasons in all
the four soybean cultivars tested but the differences were only significant in the second
cropping season (nodule number, p=0.004; NDMY, p=0.025). In both seasons liming
increased grain yield (season 1, p=0.046; season 2, p=0.023) but cultivar differences were
not different. Addition of P fertiliser increased P uptake, grain and stover yield and
liming further enhanced both P uptake and grain and stover yield. Addition of 30 kg N
ha
-1
as ammonium nitrate significantly (p<0.05) reduced nodules numbers and grain yield
compared to treatments where N had not been applied. It was concluded that soybean
productivity in acid soil prevalent in humid and sub-humid areas of SSA can be
effectively increased through liming and P fertilisation. Application of mineral N not
supported by soil testing reduces the effectiveness of biological N fixation thereby
depriving farmers of a cheaper source of N where soil N is relatively high.
Search WWH ::
Custom Search