FIELD CROPS 445 



can be removed or until it has developed a large tonnage of green 

 manure. The crop is worth more for feed than for green manure, 

 if there is at hand profitable live stock to make use of it, since the 

 manure can largely be returned to the land. Grass makes a good 

 preparation for wheat; while the atmospheric nitrogen added by 

 the clover to those soils which have been depleted of this fertilizing 

 substance often increases the following crop of grain several bushels 

 per acre. 



Stubble land after small grain crops is of necessity, or of choice, 

 very much used for crops of wheat. This land cannot be gotten 

 into good mechanical condition for wheat. The stubble and weeds 

 are coarse, do not quickly decay into humus, and tend to make the 

 furrow slice too loose for capillary water to rise into it, and too open, 

 allowing too free circulation of air. Wherever practicable, in a cli- 

 mate which ii subject to periods of drought, and in which grain 

 crops are planted continuously, it pays to burn the stubble and 

 weeds. The fire destroys many weed seeds, and destroys the coarse 

 materials which would do more harm than good. The extra cost 

 of making less than a ton of barnyard manure to take the place of 

 the humus-making stubble and of the nitrogen lost in burning is 

 far less than the loss arising from coarse stubble in the furrow slice 

 and weed seeds in the soil. Burning the stubble and not making 

 manure by keeping live stock is, however, undoubtedly harmful to 

 the soil. 



But, taking into consideration all things, early autumn plow- 

 ing is the most important point in the preparation of stubble land 

 for wheat. By early plowing many weeds will be covered before 

 the seeds have ripened, the stubble will have some time in which 

 to become softened and rotted, and the soil will be compacted 

 through the influence of the fall rains, and will have its capillary 

 connections made more intimate with the subsoil. 



In the spring care should be taken in preparing the seed bed 

 to thoroughly pulverize the upper two or three inches of soil. Where 

 the winds are not likely to cause the soil to drift, it is wise to make 

 the surface fine and smooth. Where drifting occurs it is necessary 

 to leave the seed bed coarser, and especially to avoid using the 

 roller, or the plank or "floater." 



Manuring. The fertility of wheat land may be maintained and 

 improved by the use of barnyard manure, commercial fertilizers, 

 and green manures, and by proper crop rotations and fallowing. 

 No general applicable rule for fertilizing wheat lands can be laid 

 down, but certain underlying principles are operative everywhere. 

 Wheat straw contains approximately 0.6 per cent of nitrogen, 0.2 

 per cent of phosphoric acid, and 0.6 per cent of potash, and the 

 grain about 2 per cent of nitrogen, 0.85 per cent of phosphoric acid, 

 and 0.55 per cent of potash. This means that a ton of straw re- 

 moves from the soil 12 pounds of nitrogen, 4 Bounds of phosphoric 

 acid, and 12 pounds of potash, and a ton of grain, or 33 1-3 bushels, 

 40 pounds of nitrogen, 17 pounds of phosphoric acid, and 11 pounds 

 of potash. As nitrogen is valued approximately at 16 cents per 



