PKACTICAL USTFEKEtfCES. 119 



thus, in the case of wheat, the average produce per acre 

 over thirty years, was about thirteen bushels on the 

 unmanured plots, as against thirty-six on highly manured 

 plots (mineral and ammonia salts, and mineral and 

 nitrate respectively), some plots also producing the largest 

 quantities of straw, the nitrate producing rather more 

 than the ammonia. The quality of the produce of wheat 

 as measured in pounds per bushel is not so different, 

 that on the unmanured plots being usually nearly equal 

 to that of the highly manured plots. From this point of 

 view, farm-yard manure proved more beneficial than the 

 artificial nitrogenous and mineral manure yielding the 

 largest quantity of grain. The corresponding figures in 

 the case of barley, are seventeen and forty-nine ; the 

 highest produce was with nitrate and. minerals, but the 

 largest amount of straw was yielded with a manure con- 

 taming a large proportion of nitrate of soda with 

 minerals. Of hay, the average produce under like cir- 

 cumstances over twenty years, was two thousand three 

 hundred and fifty two pounds on the unmanured, and 

 six thousand nine hundred and forty-four pounds on 

 highly manured plots (mineral and ammonia.) 



In like manner, turnips varied from one or two tons per 

 acre without manure to eight tons with superphosphate, 

 and nine to twelve tons with superphosphate combined 

 with nitrogenous manure, such as ammonia or rape-cake. 

 Sugar beet produced, when unmanured, from seven to 

 eight tons per acre in the earlier, to five tons in the later 

 years, but eighteen tons with farm-yard manure ; nitro- 

 genous manures increased the yield largely, but super- 

 phosphate was of no use to the beet and mangel. With 

 mangel, the produce on the unmanured plot was from 

 one to six tons per acre (average 4.6 tons), as compared 

 with nineteen tons with farm-yard manure (or on the 

 average fourteen tons). Potatoes varied from about half 

 a ton on the unmanured, or about two tons on the 



