CONDITIONS AFFECTING PRODUCTION OF NITROGEN. 43 



tillage given or are crops more scientifically provided with food 

 than at Rothamsted. It is true that of the ten plots of land on 

 which these wheats were raised one received no manure and three 

 were not sufficiently manured. In order to make the comparison 

 more favorable to the English environment, the five plots completely 

 manured and producing the largest yields may be taken. The jdeld 

 of nitrogen per acre was 36.4 pounds for the years 1852-1861 and 

 34.6 pounds for 1862-1871. Even with the best manurmg the yields 

 of nitrogen fall very much short of those in Nebraska. 



In Nebraska no commercial fertilizers had ever been used on the 

 land on which the wheats were grown, but farm manure had been 

 applied. The soil was a heavy one, well adapted to wheat growing, 

 and had been well tilled. It had been well manured for corn in a 

 rotation of corn, oats, and wheat. The varieties, with the exception 

 of Turkish Red, had just been introduced from Europe and had not 

 fully adapted themselves to the new environment. The average 

 nitrogen production for the only acclimated variety, Turkish Red, 

 was 48 pounds per acre. It would seem, therefore, that a cKmate 

 affording high temperatures, dry air, and a moderately dry soil is 

 favorable to the accumulation of a large amount of nitrogen by the 

 wheat plant, provided there is a large supply of nitrogen in the soil. 



The heat and scant soil moisture are doubtless instrumental in 

 making available the nitrogen of the humus, and the bright sunshine 

 and dry, hot air stimulate growth and increase transpiration. 



It has just been said that hot, dry weather in the early growing 

 season contributes to a large nitrogen accumulation by the wheat 

 plant. The same conditions cut short the growing period of the 

 plant and prevent the large accumulation of starch that takes place 

 in the kernel of wheat raised in a cool or moist region. It thus 

 happens that such wheats are high in nitrogen and low in starch. 



The properties of the wheat kernel characteristic of a continental 

 chmate and rich soil are probably due to rapid nitrification and 

 liighly stimulated growth causing a large accumulation of nitrogen 

 by the crop, and to incomplete maturation, caused either by heat, 

 or frost, or lack of moisture, resulting in high nitrogen. 



It would be interesting to know what relation the production of 

 nitrogen per acre bears to the production of mineral matter, but 

 the necessary figures are not at hand. 



The wheat kernel produced in a continental climate is not usually 

 plump as compared with the kernel produced in an insular or coastal 

 one. The yield of grain per acre is also usually less. That this is 

 due to incomplete maturation is shown by the fact that winter 

 varieties of wheat that make their growth early in the season always 

 yield better than spring varieties. The latter, on the other hand, 

 have a higher, percentage of nitrogen, but usually not so large a 



