60 SCIENTIFIC REPORTS OP THE AGRICULTURAL RESEARCH 



of irrigation water in wheat growing — the first edition of 

 which appeared at the end of 1915 and which has been out 

 of print for some time. At first, these investigations were 

 confined to the Quetta valley but during the last three years 

 they have been extended to the important wheat growing 

 tracts of North-West India. The results obtained are so 

 definite and the direction in which wheat production in 

 these areas can be improved is so clearly indicated, that it 

 appears desirable to take this opportunity of summing up 

 the present position of these investigations. 



The Quetta experiments fall into two stages. It was 

 first found that, on roughly levelled land, a crop of from 

 15 to 20 maunds of grain to the acre could be grown on one 

 irrigation, applied before sowing, provided care was taken 

 to obtain a good tilth and to break up rain crusts during 

 the winter and spring by means of the lever harrow. This 

 is considerably more than the yields obtained by the zamin- 

 dars on similar land with six or seven irrigations. In the 

 second stage, a further increase in the duty of water was 

 secured. This was obtained by carefully grading the land 1 

 and by the employment of a leguminous rotation. In 

 1918-19, on land carefully graded and after a summer 

 fallow preceded by a cold weather crop of clover, a yield of 

 32 mds. 27 seers (2,686 lb.) of grain and 57 mds. 13 seers 

 (4,715 lb.) of straw was obtained on an acre plo£ on the pre- 

 liminary watering only. The land was irrigated before 

 sowing on October 12th and cultivated lightly with the 

 spring tine cultivator followed by the beam on October 16th 

 as soon as ever the surface was dry enough for this pur- 

 pose. Under the thin mulch so produced, the soil dried 

 slowly and yielded a perfect tilth when it was ploughed 

 with iron ploughs on October 19th. Before ploughing, the 



1 The details relating to the method of levelling adopted and to the system of 

 irrigation for alluvial soils worked out at Quetta are described in Quetta Bulletin 

 No. 7 — The irrigation of alluvial soils — published in 1916. 



