FIELD CROPS. 



523 



ill tlie plant at diifereiit stages are represented by the following 

 numbers : 



I'ercentages of total crop of dry matter and nitrorjen at different stages. 



Of tlie total nitrogen the albuminoids constituted in the first period 

 67 per cent, in the second 70 per cent, in the third 88 per cent, in the 

 fourth 85 per cent, and in the last 83 per cent. 



"The clover liay cut at the time of full hloom contains the largest amount of 

 nitrogenous material in the most valuahle food forms, while clover cut at the end 

 of flowering contains the largest amount of dry matter, which is poorer in the 

 valuable nitrogenous compounds. . . . 



" Lime and potash are taken up by the plant the most rapidly of any of the 

 the mineral matters. Only 2 per cent of mineral matter is added to the crop after 

 full bloom. Xo potash is taken up after full bloom, and when ripe the plant con- 

 tains less potash than at the time of full bloom. . . . 



"In the first periods of clover the mineral matter is taken uji somewhat in 

 advance of the formation of organic matter, while in wheat the nitrogeu and sepa- 

 rate ash elements are assimilated much earlier in the development of the plant." 



A croi:> of 4,300 lbs. of field-cured hay growing on an acre removed 

 from the soil CO lbs. of potash, 76.4 lbs. of lime, and 28.4 lbs. of j)hoS' 

 ])horic acid. As fertilizers for clover, gypsum and wood ashes are 

 recommended by the author. 



Proximate and ash analyses give at different stages the percentages 

 of dry matter of the clover plant (exclusive of roots), of leaves, and of 

 stems. The percentages of crude piotein in the leaves for the first three 

 stages were respectively 30.68, 27.38, and 19.37 ; in the stems at cor- 

 responding stages the percentages of crude protein were respectively 

 13.44, 11.2o, and 11.26. The leaves at all stages were richer in potash 

 and poorer in lime than the stems. Since the leaves contain about 

 two-thirds of the nitrogenous matter of the plant (exclusive of roots), 

 it is important that the loss of leaves in harvesting be avoided. 



The weight of clover roots on an acre yielding 4,000 lbs. of hay was 

 at the time of full bloom approximately 1,760 lbs. This weight of 

 roots contained 39 lbs. of nitrogen, 26.7 lbs. of potash, 27.8 lbs. of 

 phosphoric acid, and 23.6 lbs. of lime. The 39 lbs. of nitrogen, a large 

 part of which was derived from the atmosphere, if purchased in com- 

 mercial fertilizers would cost $6.63. 



If the young clover had been plowed under at the first stage of 

 growth. May 9, " which would have been sufficiently early in this lati- 

 tude for planting corn," the clover on an acre would have furnished to 

 the corn crop 21 lbs. of nitrogen, worth $3.15, besides changing into 

 more available form 6.5 lbs. of phosphoric acid and 16 lbs. of potash. 



