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Table 12.-Results of Types of Phosphate Experiment, Fiwi Bean, Namanga Red Loam, 1947-48, Fresh Weights lbs. per acre No added phosphate, 1,956 lbs. per acre
Material
Superphosphate
Superphosphate
Superphosphate
Triple super + S/A
Ammonium phosphate
Soda phosphate
Gafsa/super mixture
Cwt./acre P2Os
Responses
0.2
2,284
0.4
1,492
0.8
2,676
0.5
1,964
0.5
1,744
0.5
804
0.5
4
...
...
0.5
464
0.5
780
0.5
1,188
0.5
1,376
·0.5
684
Nitrophosphate
Saphos rock phosphate
Gafsa rock phosphate
...
Christmas Island rock phosphate
Uganda rock phosphate
These results support those of the general exploratory experiment at Namanga in indicating the phosphate deficiency of the Namanga red loam.
Experiments on rate of application of standard fertilisers
A series of experiments was laid out to examine the response to a standard fertiliser mixture (sulphate of ammonia plus triple superphosphate, 6 per cent. N, 30 per cent. P2O1) at varied rates of application. The rates selected were:-
Cwt. N/acre Cwt. P2O5/acre Lbs. Mixture/acre
Nil
0.025
0:05
0.1
Nil 0.125
0.25 - 0.5
Nil
46
93
186
Sites were limed where
All fertiliser was placed with standard equipment.
analysis indicated the need. The design was a 4×4 Latin square with plots 0.016 acre (2 drill widths × 57 links).
The results at Kongwa are shown in Table 13.
Table 13.-Experiments on Rate, of Application of Standard Fertilisers,
Groundnuts, Kongwa, 1947-48
(Lbs. kernels per acre)
Experiment number
7
15
21
1
17
18
32
Mean
Variety
Val.
Val.
Val.
Sp.
Sp.
Sp.
N.C.
Plant number, 000/acre
24-7
29.6
6.1
9.1
21.7
16.4
16.6
Yield, no fertiliser
627
868
258
797
949
730
515
678
I. Responses.
46 lbs. fertiliser...
5
17
35
50
-233
99
103
-24
93 lbs. fertiliser...
91
155
90
41
- 56
77
81
46
186 lbs. fertiliser...
263*
164
32
171*
101
144
98
139
S.E. of responses ±
88.6
115.3
44.5
64.5
200-7 117.8 90.4
II. Soil data.
Upland
Upland Upland Grey
Soil type
Red
Red
pallid Red
pallid pallid valley
pH
5.8
6.0
6.0· 6.5
6.4
6.8
6.8
Extracted P mgm./
100gm.
0.09
0.08
0.16
0.25
0.25
0.20 0.66
Extracted Ca
mgm./100gm.
37
37.
50
25
25
37
120
Effects of this size are not likely to arise by chance in more than 1 in 20 cases.
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