INSTITUTE, PUSA, FOR 1918-19 63 



importance as a fall in the level of the ground- water means 

 a strong downward pull and the temporary resumption of 

 drainage and of soil-aeration. In interpreting field experi- 

 ments therefore in the monsoon, the amount of drainage 

 which is possible may easily prove to be an important 

 factor. 



The effect of improved surface drainage on crop pro- 

 duction has been found to be very considerable in the 

 Botanical Area at Pusa. Not only is the loss of nitrates 

 by denitrification greatly reduced but good drainage, com- 

 bined with the checking of erosion, has had the effect of 

 maintaining the fertility with a comparatively small 

 expenditure of organic manure. The behaviour of two 

 typical plots in the Botanical Area brings out this point 

 clearly. In the case of plot 10, one and three-quarter 

 acres in area, a typical wheat soil of rather heavy texture, 

 the records show that during the last 15 years this field has 

 produced 13 heavy cereal and 2 good pulse crops while the 

 manurial treatment has consisted only of three green 

 manurings with sanai (Crotalaria juncea) and a single 

 dressing of castor cake at the rate of 15 mds. per acre. 

 The present condition of the land shows that it has 

 improved under the treatment. In 1919, yields of over 30 

 mds. of wheat to the acre were produced in a season which 

 did not favour heavy crops. Another plot, No. 1, of some- 

 what lighter land and about one acre in area, has given, 

 since 1905, 10 good crops of cereals, three of pulses and 

 two of indigo seed. The manuring for these 15 heavy 

 crops consisted of three green manurings, a total of 15 

 tons of farmyard manure per acre and a single dressing 

 of 10 maunds of oilcake to the acre. The wheat crop of 

 the last year was over 29 mds. per acre, the highest so far 

 given by the area. Here again the land has increased 

 rather than decreased in fertility. Similar experience 

 has been obtained at Quetta where an area of land 

 about 3 acres in area has been continuously cropped 

 with wheat without manure since 1912. The wheat is 

 raised on a single irrigation applied before sowing and 



