Ecological and Edaphic Drivers of Yam Production in West Africa
Table 5
Yield declines under native and nonnative soil fertility.
Soil fertility type
Year 1
Year 2
Year 3
Native fertility
D. rotundata 1
19.5
18.0
16.0
D. rotundata 2
18.3
16.7
15.0
Mineral fertilizer#
D. alata
36.0
14.0
16.0
D. cayenensis
45.0
34.0
12.0
D. rotundata, cv Efuru
40.0
25.0
11.0
D. rotundata, cv Aro
36.0
20.0
11.0
Organic fertilizer¤
Goat manure
24.5b
26.0b
27.5c
Poultry manure
26.9a
29.2a
32.5a
Oil palm bunch ash
24.6b
27.5b
29.0b
Spent grain
22.0c
23.9c
25.0c
Oil palm bunch ash + goat manure
36.0d
37.5e
40.0d
Oil palm bunch ash + poultry manure
37.5d
40.0d
42.5d
Spent grain + goat manure
31.0e
32.5f
36.0e
Spent grain + poultry manure
32.5e
34.0f
37.5e
Data sources:# [63]; [51] (significant differences by Duncan’s multiple range test, );¤ [27]. The rest have no statistical test as they were extracted from whole datasets.
