194
Page 370
Table 11.-Results of Experiments on Types of Phosphate, Groundnuts,
Kongwa, 1947-48
(Lbs. Kernels per Acre)
(Materials appear in descending order of citric solubility)
Experiment No.
Cwt. P2Os per acre
9
20
24
4
14
29
Mean
Variety
Mean, population,
000/acre...
Mean yield, no added
Val.
...
Sp.
Sp.
N.C.
N.C.
N.C.
27.5
7.8
9.5
36.0
15.2 22.5
19.8
P
Nil
868
171
293
893
767
311
...
550
1. Responses to—
Superphosphate
0.2
0.4
196
""
0.8
Triple super+ S/A...
0.5
--104
Ammonium phos-
phate
0:5
211
Triple
superphos-
phate
0.5
Soda phosphate
0.5
Gafsa + super mixture
0.5
Nitrophosphate
0.5
--147
Saphos rock
0.5
182
TO 2002
4
39
248+
43
97
29
110
110
I
25
148
18
67
22
89
100
215*
172**
Gafsa rock
0.5
82
48
Christmas Island rock
0.5
75
124
-100*
Uganda rock
0.5
67
43
GOJUUNNA 4 CAN
14
22
-200
175
14
15
57
121
90
57
171*
109
57
0
62
125
64
150
81
175
50
ļ
109
22
86
23
36
36
72
103
50
-136
-110
132
7
71
162
78
28
Kate a no-2=0
32 57
61 23
18 60
75
80
68
48
3
46
16
50
11
58
60
57
-
22
-138
3
NOOZA й 8No4。
19.
Standard error±
147
81
41
78
140
102
II. Soil data.
Upland
Upland
Soil type
Red
...
pallid Red Red
pallid
Red
pH
6.8
Extractable P mgm./100gm.
Ca mgm./100gm.
No 0.15 data
50
6.8 6.0 0.07 0.08
6.0
6.6
0.13
0.14
50
25
25
130
✔
It is evident that the design has proved inefficient, the measure of control provided by two large blocks being inadequate. The superphosphate scale is valueless, but it is of some interest that the average responses to the materials decrease roughly in order of decreasing citric solubility of the phosphate they contain. The order of the response to 0.5 cwt. water-soluble phosphate, broad- cast, is similar to that obtained in the general exploratory experiments at Kongwa.
At Urambo, on the grey soil, yields in the corresponding experiment were low and responses not significant, with the exception of an apparent depres- sion of yield by Christmas Island rock phosphate. This accords with the results of soil analysis. On the Urambo red soil, although there was some indication that certain of the water-soluble materials were effective, results were very variable and no responses were significant. At Namanga, the fiwi bean fresh weight figures (see page 129) show large responses to many of the materials.
* Effects Pages27&afod y to arise by chance in more thanage 27Qsef 1097
+
"
""
""
27
95
1 in 100 cases.
""
132
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