E.—GEOGRAPHY 117 
in constructing heavy fences round it to keep off graminivorous animals, 
as he has to do if he grows cereals ; nor does he risk loss from plagues of 
locusts. On the other hand, the manioc suffers much in every District 
from depredations of bush pigs and from elephants where these are 
numerous. Thirdly, this plant is less susceptible than the cereals to 
rainfall deficiency. For all these reasons the inhabitants of manioc 
Districts rarely suffer from hunger—indeed there are several which have a 
regular export of cassava meal ; ‘ meal in Mankoya is almost a currency.’ 
The Government is obviously fully justified in its efforts to induce extended 
cultivation of this valuable and reliable plant. 
The other two common staples are sorghum and maize. Both are 
more characteristic of relatively treeless land, and the former is the more 
resistant to drought. At their best they are the crops of the open alluvial 
plains, and we find them characteristically in the river bank gardens of 
the Zambezi and Luangwa and many of their tributaries, where two crops 
are often taken—especially of maize—the first from the wet silt of the 
receding river flood, and the second from the summer rains. We also 
find them on the older alluvium abounding in termite hills, which form 
the very best soil when levelled. But these cereals are by no means re- 
stricted to alluvial soils, as witness their wide distribution on the central 
plateau on both sides of the railway. Maize in outlying Districts is 
commonly eaten green, but here there is a market for surplus grain which 
may be sold for transport to the mines. Herein lies the importance of 
the freedom of this area from tsetse fly ; for the cultivator is also a cattle 
owner and he has readily taken to the plough. 
Ploughing gives great advantage in maize cultivation, and some also in 
the case of sorghum. Moreover, the acquisition of carts enables the native 
to market his produce. Yet even from this central region it is interesting 
to note that in the Broken Hill District, sorghum and eleusine are both 
commoner than maize, which is disliked because harder to grind. Again, 
in the plateau section of Kalomo, while maize predominates in the east 
where ploughing prevails, this is not true of the fly belt to the west, for 
here ground must be hoed, and the hoe is the woman’s tool. But the 
women cannot be induced to raise a surplus for export. 
This account of the distribution of staple crops must suffice to illustrate 
the kind of contribution which co-operative inquiry has made to our 
knowledge of the native agriculture. 
I have now given a fair sample of the kind of information which we 
have gained by this piece of co-operative research in human geography. 
There are many other matters that I have had to omit. For instance, 
the inquiries as to animal pests and to the amount and nature of hunting 
have led to replies which give a good general idea of the distribution 
of the principal mammalian fauna. Again, we have learned much of 
fishing in relation to the rise and fall of rivers ; we have data relating to 
the seasonal migrations in search of fish and various food relishes such 
as caterpillars. Most important of all is the whole subject of seasonal 
rhythm of occupation and its regional variations, a matter upon which 
the reports are of great service. 
