THE IMFIiO VEMEN T IN THE YIELD OF INDIAN WHEA T. 197 



these matters for the I'easoii that only the surplus production of 

 wheat and other seeds is exported. Any increase therefore in 

 tlie present crops will leave a far greater margin for trade and 

 might even enable India to undersell her competitors in the seed 

 markets of the world. 



We will now deal with the methods of cultivation and soil 

 management under which these high yields can be obtained con- 

 tinuously on the same land. 



Hot weather cultivation. The exposure of the wheat lands by 

 iron ploughs in the hot weather of April and May is, we consider, 

 one of the chief causes of the increased yield and continued fer- 

 tility of the wheat land. Exposure of the land is beneficial in two 

 different -w^j^. In the first place all the early monsoon rainfall is 

 absorbed by the soil and the loose open surface soil enables water 

 to reach the subsoil and to be stored up as it were for the next rahi 

 crop. If the rahi stubbles were properl}^ broken up before the 

 monsoon in the plains, an enormous amount of the water which 

 now runs off the hard surface into the rivers, would be absorbed hj 

 the soil. In this way the irregularities of the monsoon would be of 

 less importance to India and less irrigation water would be required. 

 The year 1908 was one of very short and badly distributed rainfall 

 at Pusa, when about 22 inches fell during the whole year. In 

 spite of this over 25 maunds of wheat to the acre were grown at 

 Pusa without irrigation and without rain after sowing time. 

 The cultivators' crops failed and a famine was declared in the 

 District. 



The second way in which the exposure of the soil in the hot 

 weather is beneficial is in increasing the fertility of the land. Ex- 

 posure of the soil to the hot weather acts as if the land had been 

 manured and the explanatian of this increase in fertility is, we 

 consider, a bacteriological one. As is well known the soil is ex- 

 ceedingly rich in bacteria of many different kinds some of which 

 are essential to plants in breaking down organic matter for the 

 production of nitrogenous salts which are taken up by the roots 

 in the soil water. Besides these useful bacteria other bacteria and 

 soil organisms sour the soil and destroy the useful bacteria. 

 Exposure of the land has the effect of partially sterilising the soil 



