Page 386
they are inferior. The upright types maintain their performance values until January 14, while those of the more spreading types are distinctly lower at that date.
The oil percentages show characteristic results (see below) related to variety and growth habit, the more upright types having higher oil contents. Kongwa shows an intermediate value as might be expected of a mixed stock. Oil yields within any one variety broadly follow kernel yields, though the tendency for oil percentages associated with the earliest and latest plantings to be lower than those associated with intermediate plantings seems fairly consistent. Only in the case of the earliest plantings did the oil yield of the long season varieties. equal or exceed that of the short season ones. These differences may, how- ever, be associated with differences in the proportion of immature nuts in the produce of the different varieties at harvest.
At Urambo, experiments testing mid- and late-season plantings of Spanish, Natal Common, Virginia Bunch and Valencia groundnuts were carried out on both red and grey soils. The results were as follows:-
Table 22.-Results of Time of Planting Experiments, Groundnuts, Urambo Grey and Red Soils, 1947-48.
Variety
Valencia Spanish
Natal Virginia Common Bunch
Mean
I. Plant population, 000/acre:
Red soil:
January 14
29-0
21.0
20.7
10.5
22.6
February 11
23.6
11.5
18.7
16.6
17.6
Mean
26.3
16.2
19.7
18.1
20.1
...
Grey soil: February 6
21.5
9.0
*14.2
14.5
14.8
16
17.8
6:1
16.5
11.2
12.9
95
Mean
19.6
7.5
15.4
12.9
13.8
II. Yields, lbs. kernels/acre:
Red soil:
January 14
976
616
894
794
820
February 11
373
94.
258
217
236
་་་
Mean
675
355
576
506
528
Grey soil: February 6
402
130
296
267
274
16
305
75
311
156
212
งา
Mean
....
353
103
304
212
243
III. Performance values (kernels/
1,000 plants) lb.: -
Red soil: January 14
34
29
February 11
16
8
Mean
25
19
28
...
Grey soil: February 6
19
14
21
16
17
12
220
42
41
36
14
13
13
27
25
18
18
19
14
16
""
Mean
18
13
20
16
17
:
Both grey soil planting dates were in fact late. February was a dry month in 1948 at Urambo, and the inability of Spanish to withstand the dry planting conditions is once again clearly shown. The fall in yield and in performance values with later planting is also marked.
The performance values derived from these experiments, both at Kongwa and at Urambo, are plotted against planting dates in Figure 2.
It will be noted that the curves have in the main the same slope and are quite close to each other, even though the data are drawn from different soil. types in widely separated areas of differing climate. This may indicate that the poor groundnut yields at Urambo in 1947-48 are not necessarily representa- tive of what might be achieved by earlier and better planting.
Page 386
Page 386
140
+
R I
"
..
n
I
J:
,1