PLANT INDUSTRY 393 



slaughtered for the purpose, since it is held that a live animal pro- 

 ducing manure daily from crop residues is a better fertilizing 

 agent than the same animal dead, dried, and pulverized. Where 

 stock must be killed, the cultivator will eat the flesh, and his added 

 energy will do more for the land than the sacrifice of the ox to a 

 desiccator. 



In recommending any improvements to native agriculturalists 

 it has to be remembered that every native practice has become 

 closely adapted to special local conditions. In certain areas, 

 moreover, the methods which have been employed for many 

 generations, could scarcely be improved. This is strikingly shown 

 by the practices of the Chagga of Kilimanjaro and the inhabitants 

 of Ukara Island situated in the south-east part of Lake Victoria. 

 The Ukara agriculture has been described by Thornton and 

 Rounce (1936). The natives have become so concentrated that 

 there is no opportunity for shifting cultivation, even if the country 

 was originally suitable for it, but the arable part of the island is 

 under continual cultivation, and a complicated system of crop 

 rotation has been evolved, including the growth and digging in 

 of green manures. The cattle are largely stall-fed on forage 

 specially grown for the purpose, and are housed in special com- 

 partments of the natives' own houses; their manure is transported 

 to different parts of the cultivated land in turn. When the cattle 

 are turned out to graze on the grasslands in the interior of the 

 island, they are muzzled and led through the cultivated fields. 

 Soil erosion is counteracted by earth ridges and stone walls along 

 contours, by pit cultivation on the hillsides and even by stands of 

 trees. Even such intensive methods of farming do not sufl[ice for 

 the increasing population, and young men are continually emigrat- 

 ing. When they settle in islands near by or on the mainland where 

 there is less pressure of population, they discard the practices 

 to which they were brought up in favour of the easier methods 

 of their new neighbours. Ukara Island is peculiarly interesting, 

 since the indigenous methods there differ but little from the im- 

 proved methods which agricultural and administrative officers are 

 attempting to impress upon natives in other parts of Tanganyika. 

 But it must be remembered that the system depends on the inex- 

 haustible water-supplies. From an anthropological point of view 



