PLANT INDUSTRY 377 



are reasons for supposing that the elephant grass belt of the terri- 

 tory verging on the north-western corner of Lake Victoria was 

 originally a dense monsoon forest, which has been destroyed by 

 shifting cultivation. 



Shifting cultivation is admirably adapted to the needs of primi- 

 tive peoples, provided there is sufficient land available. The period 

 needed for regeneration by natural vegetation varies according to 

 conditions from four to twenty years. Before European occupation 

 the balance between the number of population and the area of 

 land was adjusted in most parts of the continent, so that there was 

 ample time for rejuvenation. This is still the case in many areas: 

 for example, in Uganda each village is a self-contained unit with 

 its necessary requirements of reserve land. With the introduction 

 of cotton as an export crop, however, the balance of nature has 

 been upset, particularly where the rainfall is badly distributed. It 

 is hoped that adjustments will be made in time by the movement 

 of excess population into areas at present unpopulated, since in 

 Uganda there is fortunately no lack of fertile land, which has not 

 hitherto been required. Even in Uganda, however, the department 

 of agriculture has found that the problem of soil deterioration 

 requires serious study. In the past ten or fifteen years there has 

 been an enormous increase of cultivation, perhaps amounting to 

 100 per cent and the problem has become, as elsewhere, one of 

 inadequate rest periods. Here the main causes are the use of the 

 plough and the introduction o^ fixed individual holdings in parts of 

 the country. The department has instituted an agricultural survey 

 as a basis for the redistribution of population and is investigating 

 methods of manuring by composts, mulching with cut grass, and 

 the planting of abandoned land with suitable grasses. 



Since a detailed survey of the whole area is impracticable, the 

 study referred to is based on a sample method, each agricultural 

 officer being made responsible for one mutala or ridge, as the hill 

 slopes in which native cultivation is carried out are called. In the 

 absence of detailed agricultural statistics these surveys have con- 

 siderable value, and they have an additional advantage in that 

 data are obtained on the conditions of native food crops, the size 

 of holdings, and systems of alternating crops in each of their 

 areas. 



