BARNYARD MANURE 147 



the rotation, and the use of stable manure which in- 

 volves the keeping of stock. 



GREEN-MANURE 



146. Crops are sometimes grown for the purpose of 

 plowing under as green-manure. Rye, buckwheat, cow- 

 peas, crimson clover, are frequently grown for this purpose 

 This is a desirable practice when the land is very deficient 

 in humus. So far as possible, such crops should be grown 

 without extra labor. Crimson clover or cowpeas may be 

 sown in corn or cotton at the last cultivation with little 

 expense except for seed. In regions too far north for these 

 plants rye is often used. It should be plowed under in 

 the spring before it has made enough growth to exhaust 

 the water of the soil. 



It is not often wise to make a regular practice of plow- 

 ing under crops that are worth harvesting. It will be 

 better to feed them to stock and use the manure. If one 

 is trying to get worn-out land to produce, or under 

 certain conditions where stock cannot profitably be kept, 

 the practice may be followed regularly, and by many 

 means catch crops too small to harvest, but worth plow- 

 ing under, may be procured. 



One is likely to be deceived as to the amount of material 

 that is being added to the soil by the practice. Green 

 crops are about 70 to 75 per cent water, which is likely 

 to deceive one as to the amount of organic matter. 



Some of the best potato growers plow under a clover 

 crop every three years for keeping up the humus supply. The 

 potatoes are grown on the sod and are heavily fertilized. 



