28 AGRICULTURE IN THE TROPICS [PT. I 



into the ground. In this way they increase the contents of the 

 soil in organic matter and nitrogen at a very small cost. 



Another very common method of manuring in the East is 

 folding cattle, goats, or sheep upon the land, during the drier 

 weather. A flock of 100 sheep will sufficiently manure an acre 

 in about 20 nights. 



Rotation of Crops, with which so much is done to get 

 better returns in agriculture in colder climates, is systematically 

 practised in Java, Ceylon, India, the West Indies, etc. The 

 great difficulty in the way of its general practice is the fact that 

 so many of the tropical crops, e.g. tea, coffee, rubber, cacao, 

 coconuts, are perennials, and consequently rotation is impossible 

 with them, or that they are crops like rice, with which rotation 

 is difficult. In Java the rice crop is regularly rotated with 

 various vegetable and other crops grown on the fields when dry. 



Mixture of Crops, which seems to bring in its train 

 some of the advantages of rotation, is very common, especially 

 in the more equatorial parts of the tropics, such as southern 

 Ceylon, Malaya, the West Indies, etc. In Ceylon, for example, 

 the great bulk of the country inhabited by the Sinhalese may be 

 roughly divided into "high lands" and "paddy (rice) fields," the 

 former being the higher lying lands, the ridges between the 

 valleys in fact, which are not capable of being reached by the 

 irrigation water. Upon them the villagers grow a great mixture 

 of crops, from trees such as coconuts, mangoes, jaks, silk-cottons, 

 kituls, etc., down to herbaceous plants such as yams, etc. Usually 

 they leave the ground covered with a miscellaneous turf of 

 weeds and grass, and the cattle graze upon it. The plants are 

 not arranged in any definite way, nor are two of the same kind 

 necessarily put together, but they are simply left anyhow upon 

 the land, much as they might grow in a jungle containing only 

 those species. Now the various plants of course take different 

 quantities of food stuffs from the soil some take much lime, 

 some little, some much potash, some little, and so on, so that it 

 is quite probable that the total result is to drain the soil of its 

 food materials at a rate proportionate to what it can supply, 



