Page 316 this will continue to be the case when extensive clearings have been made. The rainfall, in inches, at Urambo from January to July, 1948, was as follows:-
January February March April
May
June
July
Total January to July
7-51
3.65 ·8.59
6.46
Nil
Nil
Nil
26.11
The dry gap in February and the sudden cessation of the rains are well shown.
Southern Province
2
The climate of the Southern Province is in many ways similar to that of the Western Province. It has, however, a less marked dry gap in the early part of the season, the October rains are more pronounced and the rainfall appears to be more reliable from year to year. Humidities are generally higher, and there are more cloudy days. These features are undoubtedly connected with lower altitude (1,500-2,000 feet only, as against 3,500 feet in the Western Province) and proximity to the sea. Rainfall records were kept in 1948 at Namanga, near Rupónda, from February onwards, with the following results (in inches):-
February March April
May
June
July
Total February to July
7.35
5.43
1.61
0.06
0.07
Nil
14-52
For practical purposes the rains ceased at the end of March, the subsequent rains being scattered. This is not usual, for in many seasons the rains continue into May. In most respects the Southern Province area has the most suitable climate for agricultural purposes of all the Tanganyika areas. ·
4. SOIL FERTILITY STUDIES AND FERTILISER POLICY
Fertiliser policy
2
Fertiliser policy for the 1947-48 season, in which groundnuts were to be the main crop, had to be laid down at the end of 1946 with no detailed information whatever on the soil conditions of the areas. On general tropical experience, and after a review of American investigations on groundnuts, it was concluded that deficiencies of P2O,, available N and Ca were to be expected, and that placement drilling at the same level as the seed and two inches to either side of it would give more efficient utilisation of fertiliser than broadcasting. Combine drilling of fertiliser (in contact with the seed) was ruled out by American results. The fertiliser specification recommended provided for phos- phate at the rate of 0.4 to 0.5 cwt. P2Os per acre, with 0.1 cwt. per acre of N, both in water soluble form in a granular and concentrated fertiliser. The small N dressing was intended to meet the needs of rapid growth in the crop in the early weeks before N supply from the root nodules become effective. Lime was to be applied at a low rate (8 cwt. per acre) where soil acidity and available Ca determinations indicated the need. Two materials only were commercially avail- able which met the fertiliser specification. They were:-
Percentage
N
Percentage P2O5
Rate per acre
Ammonium phosphate
11
48
1 cwt.
Mixture of sulphate of ammonia and triple
superphosphate
6
30
13 cwt.
Supplies of these materials were secured for the 1947-48 season.
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