FIELD CEOPS. 257 



Reports on experiments on the manuring of potatoes in 1900, R. P. Wright 

 ( West of Scotland Agr. Col. Rpl. 1900, pp. 107-143).— This work is in continuation of 

 experiments previously noted (E. S. R., 12, p. 937), and the different quantities of 

 fertilizers used are there given. The general conclusions of this year's work are that 

 large crops of potatoes can he grown with the use per acre of 20 tons of barnyard 

 manure alone, of 10 tons of manure supplemented with commercial fertilizers, and 

 also by the use of commercial fertilizers alone. The amount of increase from the 

 use of manures and the resulting profits were found to be largely dependent upon 

 the variety, a strong-growing, productive variety being usually the most profitable. 



The increase in yield with manures was entirely due to an increase in the size of 

 the tubers. Light dressings of barnyard manure produced much better results than 

 the same quantities employed as heavy dressings. The use of 10 tons per acre, either 

 alone or with commercial fertilizers, was very remunerative. Commercial fertilizers 

 were more effective when used with light dressings of manure than when given with 

 heavy applications. 



The best cooking quality and highest nutritive value were obtained in the crop 

 grown with commercial fertilizers alone, the particular application consisting of 6 

 cwt. of superphosphate, 2 cwt. of sulphate of ammonia, 1 cwt. of nitrate of soda, and 

 2 cwt. of sulphate of potash per acre. Heavy dressings of barnyard manure alone 

 produced watery tubers, but light dressings were less injurious, and commercial 

 fertilizers applied with the manure had a tendency to counteract its unfavorable 

 influence upon the quality. Considering both quantity and quality, the use of light 

 dressings of barnyard manure, together with suitable applications of commercial 

 fertilizers, is believed to be the best practice. 



Potash in commercial fertilizers given with barnyard manure increased the dry 

 matter and starch content of the tuber and the data indicated that about 84 lbs. per 

 acre furnished in 1.5 cwt. of sulphate of potash was the most profitable quantity. 

 With barnyard manure either high-grade sulphate or muriate of potash should be 

 used, and with commercial fertilizers alone the commercially pure sulphate of pot- 

 ash should be employed. In these experiments sulphate of potash gave the finest 

 quality of tubers, while those grown where kainit was used were much inferior in 

 quality. Muriate of potash produced potatoes intermediate in quality between those 

 grown with sulphate of potash and those grown with kainit. The muriate had 

 similar effects on the quantity when only commercial fertilizers were employed, but 

 with barnyard manure it was sometimes as effective, or even more so, than sulphate 

 of potash. Where commercial fertilizers were applied a top dressing of 1 cwt. of 

 nitrate of soda per acre immediately after the first weeding had no injurious effect 

 on the quality. 



Report on experiments on the manuring' of potatoes in 1901, R. P. Wright 

 ( West of Scotland Agr. Col. Rpl. 1901, pp. 15-34). — These experiments are in continu- 

 ation of those noted in the foregoing abstract, and the results obtained this season 

 confirm the conclusions previously stated. 



Report on the winter v. spring- application of manures to the potato crop, 

 J. W. Paterson ( West of Scotland Agr. Col. Bid. 24, pp. 73-82). — The Scottish 

 Triumph potato was grown on 14 plats under different fertilizer treatment and the 

 results obtained indicate that phosphoric acid, whether in the form of superphos- 

 phate or basic slag, should be applied in the drill and that special nitrogenous 

 manures should be included in the fertilizer application for potatoes. It was found 

 that kainit gave better results when applied to the plowed land in the previous 

 winter than when used in the spring, and that the time of application was not so 

 important for sulphate of potash and muriate of potash. 



Results of the German potato experiment station in 1903 (Devi. Landw. 

 Presse, 31 (1904), Nos. 14, p. 109; 15, pp. 118, 119). — The results with 34 varieties 



9071— No. 3—04 4 



