FIELD CROPS. 593 



constituents. The total i^ercentage of nitrogen does not appear to be 

 increased by the api)licatiou of nitrogenous manures, and where manures 

 rich in this constituent are used the percentage of albuminoid nitrogen 

 decreases so that even when such manures increase the weight of the 

 crop they decrease its feeding quality by lowering the amount of albu- 

 minoid nitrogen contained in it. The presence of a moderate amount 

 of soluble nitrogenous constituents, however, somewhat increases the 

 percentage of sugar. 



Residual value of manures applied to the turnip crop in 1893, 

 as shown in the effect on an oat crop in 1894, K. P. Wright {Glas- 

 gow and West (>/ iSvotland Technical Collajc^ Agl. Dept. Rpts. ISO'j^ pp. 

 28-32). — In 1893 turnips were grown on 12 twentieth-acre plats of clay 

 loam dirterently fertilized, both roots and leaves removed, Oats were 

 sown the following spring, one-half of each plat being left unmaiuired 

 and the other half receiving nitrate of soda at the rate of 112 lbs, per 

 acre. Tables are given showing statistics of fertilizers applied and 

 crops of oats and hay jiroduced on the unmanured half plats, and of 

 oats on the half plats receiving nitrate of soda. 



Each of the fertilizers showed a large residual value and every plat 

 yielded a crop of oats much greater than that from the unmanured 

 plat. Most of the fertilizer on 8 plats consisted of i)hosphates at the 

 rate of 672 lbs. of superphosphate per acre, yet the residual eft'ect of 

 these moderate quantities not only fully recouj^ed the land for the 

 exhaustion caused by the removal from the fertilized plats of from 10 

 to 20 tons of turnips more than from the unmanured plat, but gave an 

 increase of nearly GO per cent in the oat crop. The soluble superphos. 

 phate produced a better subsequent eft'ect than basic slag, as well as a 

 better immediate eftect. Bone meal did not give as large yield of 

 turnips as superphosphate, but its slow-acting nitrogen produced a 

 marked eftect on the succeeding oat crop. The addition of a nitroge- 

 nous fertilizer to plats which had received only phosphates largely 

 increased the yields, and the author concludes that "a comparison of 

 all the plats where only artificial manures were applied in 1893 with 

 plats to which barnyard manure was applied, shows that where turnips 

 are grown with (juickly available, and, perhaps, incomplete artificial 

 manures alone, and where the whole crop is removed from the field, it 

 is absolutely necessary to apply manures to the succeeding crops also if 

 a full yield is desired." 



The largest oat crops, both in graiu and straw, were obtained from 

 the barnyard manure plats, as were also the largest turnip crops in the 

 preceding year: but 10 tons of barnyard manure with 33G lbs. of super- 

 phosphate and 112 lbs. of nitrate of soda produced a greater eftect on 

 the croi)s of both years than 20 tons of barnyard manure alone. 



The addition of nitrate of soda to the half plats resulted in a profit- 

 able increase in every case. 



