298 SOILS 



soil, especially nitrogen. The soil of the fallow 

 field is stirred frequently and is warm and moist, 

 conditions that are favourable to making inert 

 plant food soluble. This plant food is stored for 

 the crop of another year unless the soil is leachy, 

 in whicn case much of the quickly soluble nitrogen 

 may be lost. This is the chief disadvantage of 

 fallowing on certain soils. It is doubtful if it is 

 ever wise to fallow land chiefly for the purpose of 

 increasing its supply of available plant food. 

 Usually the same result can be secured, without 

 losing the use of the land, by a rotation of crops and 

 better tillage. 



Fallowing may be used to advantage in some 

 cases for cleaning land of weeds, especially the 

 weeds that gain a foothold in grain farming. Bare 

 summer fallowing is an excellent means of getting 

 rid of both perennial and annual weeds, especially 

 the Canadian thistle. But if summer-fallowed 

 land is not kept harrowed, fallowing may increase 

 weediness. 



The Methods of Fallowing. Land that is to be 

 fallowed should be plowed early and at once fitted 

 thoroughly. Most of the weeds will immediately 

 start to grow ; these may then be killed by plowing 

 again or by harrowing. In some sections fallow 

 land is plowed three times during the season. 

 Such a mixing and interchanging of particles 

 cannot help but make a soil more fertile, as well as 

 increase its moisture content and improve its tex- 

 ture. In some cases one plowing and one to three 

 harrowings, at intervals during the summer, may 

 be about as effective as three plowings. The im- 

 portant point is to keep noxious weeds from start- 

 ing; some fallows are allowed to become foul with 

 weeds. If the fallow is to be followed by rye or 



