Clover and Others 117 



ful if allowed to grow in autumn after the tillage is com- 

 pleted. The difficulty is that they cannot always be relied 

 upon to cover the land at the time when they are wanted, 

 most of them do not live through the winter, and they are 

 very likely to become a serious nuisance. It is best, there- 

 fore, to substitute some other plant for the weeds. Red 

 clover is a stand-by, but it often fails to "catch" if sown 

 late in the season, and it should stand on the land an 

 entire season in order to contribute its full value. On 

 good and well-tilled lands and in favorable seasons, con- 

 siderable herbage can be secured for turning under in the 

 spring if clover is sown the preceding August or September; 

 but in general it is unreliable as an annual crop, and is 

 not adapted to fruit-lands. Mammoth clover is considered 

 to be better than the common red. 



In approaching the question of the choice of cover- 

 crops, the grower .must understand that there are two 

 great classes hi respect to their supposed power to gather 

 nitrogen. The one class is non-leguminous, comprising 

 those plants that take only such nitrogen as has already 

 been worked over into available form by plants or animals; 

 the other class is the leguminous, comprising those plants 

 that have the power of appropriating and utilizing free 

 nitrogen through the action of root-nodules. For purposes 

 of cover and protection, the non-leguminous crops may be 

 just as good as the nitrogen-gatherers, and when the fruit- 

 plants are growing very vigorously they may be decidedly 

 better than the others because, by not adding nitrogen, 

 they do not over-stimulate the growth. 



A rotation of cover-crops will nearly always be found 

 to be important. Some of the most useful cover-crops 

 will not thrive on hard and intractable land, and in such 

 cases a rougher and coarser crop must be used. 



