MANAGEMExNT OF SPECIAL SOILS 267 



levelling of the coarse surface particles by the packer 

 will tend to encourage soil blowing. For this reason pack- 

 ing is not a desirable practice in the control of soil drift- 

 ing on all types of *soil. 



222. Increasing the Organic Matter Content. — This is 

 the chief and probably the most permanent means of 

 lessening the danger of soil drifting. The organic mat- 

 ter content may be increased, (1) by growing perennial 

 or biennial hay crops, (2) by applying farmyard man- 

 ure, or (3) by plowing under green crops. The choice 

 rests between (a) growing grass crops, which in some 

 parts are not considered profitable, or (b) going into 

 stock or mixed farming and hauling manure to the land, 

 or (c) plowing under green crops, which has never been 

 shown to be profitable under semi-arid conditions, or (d) 

 doing all of these things. 



The use of hay crops for the purpose of adding humus 

 or root fibre to the soil results in, ( 1 ) improving the soil 

 as a result of their dense root systems, and (2) provid- 

 ing forage for stock from which manure for further im- 

 proving the soil may be obtained. The low yields of hay 

 from perennial grasses under semi-arid conditions is well 

 known, nevertheless the use of such hay and pasture 

 crops furnishes what is probably, the best means of main- 

 taining the organic matter of much of our lighter soils. 

 Brome grass, owing to its very dense root system, is prob- 

 ably the best for this purpose. Sweet clover promises 

 much, not only as a forage crop but also as a soil improv- 

 er. It has one advantage over brome grass in that it is a 

 legume. It therefore leaves the soil richer in nitrogen 

 than does brome grass, but the latter probably leaves 

 more root fibre. 



The chief value of manure is not in its content of plant 



