[NSTITUTE, PUSA, FOR 1918-19 61 



be found to pay. Such a matter however cannot be settled 

 by experiments on small plots on account of the well known 

 difficulty in Bihar of obtaining even land to the depth made 

 use of by this crop, and of manufacturing small lots of 

 green plant. It is a matter which will have to be decided 

 by general experience of work under estate conditions. 

 Possibly the easiest and most economical method of testing 

 the point would be to manure for the previous crop and to 

 raise the indigo on land in fair condition. 



IV. Drainage and crop production. 



In the report of 1917-18, the bearing of the soil aeration 

 factor on flood irrigation, as practised by the cultivators 

 in North- West India, was discussed. It was shown that 

 successful irrigation involves more than the mere applica- 

 tion of water and that the aim of the irrigator should be 

 the provision of water in such a manner as to interfere as 

 little as possible with the aeration of the soil. At the 

 meeting of the Indian Science Congress at Bombay early 

 this year, another aspect of soil aeration was dealt with, 

 namely, inadequate drainage — a matter of particular 

 importance in many parts of India. Over large areas 

 nourished by the monsoon this factor bars progress. Its 

 removal, however, is a matter which often lies outside the 

 scope of the Agricultural Department and its mere con- 

 sideration involves a multitude of other interests — those 

 of the cultivator, the landowner, the revenue authorities, 

 the engineer and the sanitarian. 



In the plains of India, defective drainage arises during 

 the monsoon from two distinct causes. In the first place, 

 when the soils are on the stiff side, local accumulations of 

 rain water rapidly lower the fertility. In the second 

 place, the subsoil water often rises to such an extent at a 

 time when the flow of the rivers is impeded that little or 

 no general drainage is possible over large tracts of the 

 alluvium. 



Surface waterlogging has been found to affect growth 

 in two ways — by the destruction of available nitrates and 



e2 



