622 Summary of Agricultural Experiments, [nov., 



■Manuring of Potatoes {Harper-Adams Coll., Field Expts., 1907). — Trials 

 were made at one centre in Staffordshire and at the College Farm to 

 compare a special potato manure and two home-mixed dressings, costing 

 the same amount per acre. The best results were obtained from the special 

 compound at the College and from one of the mixtures at the other centre. 

 A comparison of sulphate of ammonia, calcium cyanamide, and nitrate of 

 soda was also made at the College Farm. 



Manuring of Potatoes {Cambridge Univ., Dept. of Agric,, Guide to Expts., 

 1907). — This publication contains tables giving particulars of three experi- 

 ments in regard to the effect of manures on the potato crop :— (1) Experi- 

 ment at Newhouse Park Farm, St. Albans, in 1905 ; (2) another experiment 

 at the same place in 1906 ; and (3) an experiment at Barrow, Bury St. 

 Edmunds, in 1905. 



Manuring of Potatoes {Armstrong Coll., Newcastle-upo?i-Tyne, Coll. 

 Bull. No. 5). — Experiments in the manuring of potatoes were conducted at 

 four centres in Durham during 1906, for the purpose (1) of ascertaining the 

 most necessary class of manure at these centres, (2) of testing the value ot 

 potash from different sources ; and (3) of comparing the effect of dung and 

 artificials. The plan of manuring was the same as in the three previous 

 seasons. The results obtained show that while nitrogen and potash usually 

 prove the most important ingredients, the omission of any ingredient from 

 the complete dressing may cause a reduction in the crop. When potatoes 

 are manured with artificials, therefore, a complete dressing, such as i^-cwts. 

 nitrate of soda, \ cwt. sulphate of ammonia, 3 cwts. superphosphate, and 

 1 cwt. muriate of potash is to be recommended. Sulphate of potash may be 

 substituted for the muriate, and this has proved on the average of three 

 seasons to be the best potash manure, though there does not seem to be 

 much to choose between them. Dung alone, in 1906, gave a better crop 

 than any of the artificial dressings, but the profit obtained from it was 

 exactly the same as from the complete artificials containing sulphate of 

 potash. Dung and artificials did not, with the exception of one plot, give 

 profitable results compared with dung alone, or ^compared with complete 

 artificials alone. There was an increase in the crop from the combined 

 dressing, but the extra cost prevented any extra profit being obtained. The 

 best crop of all, however, was obtained from a plot receiving 12 tons of dung 

 and the dressing mentioned above without the potash. This plot also gave 

 the largest gain. 



Manuring of Potatoes {Beds. C.C.,Ag;ric. Education Com., Rept. on Demon- 

 stration Plots •,' 1907). — Manurial trials were carried out at two centres. The 

 conclusions arrived at were (1) that 12 tons of London peat moss manure, 

 with 1 cwt. sulphate of ammonia, 3 cwt. superphosphate, and 4 cwt. kainit is 

 as profitable as 24 tons of London manure, the yield being practically the same. 

 The London manure was valued at 6s. per ton, half of which was charged 

 against the crop. (2) London manure by itself is more valuable than arti- 

 ficials by themselves. (3) Sulphate of ammonia and superphosphate are 

 more valuable than nitrate of soda and basic slag. (4) Potatoes require nitro- 

 genous manures more than phosphates or potash. (5) Neither soot nor lime 

 alone is profitable. (6) Kainit proved the best potash manure this season, 

 bat in previous years the sulphate of potash was the best. This may be 

 accounted for by the cold, dull season. Several of these results were 

 confirmed by the trials at the other centre. 



