CHAPTER VI 

 GREEN MANURES AND COVER CROPS 



91. As a source of humus. It has been previously in- 

 dicated (76) that humus in large amounts is essential to 

 success in every line of vegetable gardening and that 

 stable manure supplies it in the best form. While this is 

 true, it is impossible for thousands of commercial grow- 

 ers to secure enough stable manure to maintain the pro- 

 ductiveness of their soils. This is particularly true of 

 truckers living remote from great centers of population. 

 It is easy enough for gardeners operating a few miles 

 from the city to secure sufficient manure to produce good 

 crops, but it is quite a different proposition for the 

 grower living hundreds of miles from available supplies. 

 It is impracticable for extensive truckers to use very 

 freely manure which costs as much as $3 a ton spread on 

 the land. In many trucking sections it is not only much 

 more economical to maintain the necessary amount of 

 vegetable matter in the soil by the use of green crops, 

 but it is also an effective means of keeping the soil in the 

 proper sanitary condition. 



92. Extent used. The growing of green crops and 

 catch crops for manurial purposes has become a general 

 practice in many trucking sections. Marked progress 

 in the use of green manures has been made in New Jer- 

 sey, where, for example, at Freehold, potatoes have been 

 grown annually upon the same land for many successive 

 years by sowing crimson clover, rye or wheat after har- 

 vesting each crop of potatoes. It often happens that the 

 continued use of crimson clover year after year results 

 in an accumulation of too much nitrogen for the best re- 

 sults with potatoes and it is necessary to substitute rye 



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