LEGUMINOUS CHOPS. 



117 



means of those on three plots, each of which occasionally re- 

 ceived a mineral manure containing potash ; and the results 

 given in the column Series 2 are also the means of three 

 plots, each with the same mineral manure as Series 1, and 

 nitrogenous manures occasionally applied in addition. 



TABLE 37. — Red Clover. Sown frequently on the same land. 

 Total Produce per acre per annum, as Hay. 



Series 1. 



Mineral manure 



alone. 



Series. 2. 

 Mineral and 

 nitrogenous 



manures. 



Summary. Produce. 



Summary. Nitrogen (estimated). 



It should be explained that very large crops of clover were Variations 

 obtained in the first year, 1849; less than one-quarter as %^ crop> 

 much in the third year, 1851 ; and in the fourth about half 

 as much as in the first. No more clover was then obtained 

 until the seventh year, when there was very little. After 

 this, there was more or less in the eleventh, seventeenth, 

 twenty-third (on Series 2), and lastly, (on Series 1) in the 

 twenty- seventh year; but in no case, excepting in the fourth 

 year, was the amount of produce half as much as in the first. 



Comparing the results without and with the nitrogenous Ejects of 

 manure, the table shows that the average annual total pro- ^Jg^JJ* 

 duce of clover-hay, and other crops, was, reckoned over the clover. 

 29 years, 1827 lb. without, and 2093 lb. with, the nitrogenous 

 manure ; and, reckoned in the same way, the average annual 



