3i6 Summary of Agricultural Experiments, [july, 



potash, nitrogen, or phosphates from the lighter of these dressings in 

 each case resulted in a greater loss than would be recouped by the 

 saving in the cost of manure. Artificials alone — 202 lb. sulphate of 

 ammonia, 524 lb. superphosphate, and 164 lb. sulphate of potash, 

 costing £2 12s. 6d. per acre — increased the yield by 3 tons 12 cwt. of 

 marketable potatoes, thus showing that where farmyard manure is not 

 available, it is possible to grow a good crop of potatoes by the use of 

 suitable artificials alone. 



Manuring of Potatoes (Lanes. C.C., Education Committee, Farmers' 

 Bull. No. 13). — Pot experiments were conducted with potatoes in 1908, 

 in order to show in a practical manner the effect upon plants of 

 complete and incomplete dressings of artificial manures. The potatoes 

 were planted in a soil made up of five parts of pure sand and one part 

 of earth, and nitrogen, potash, and phosphates were supplied, singly 

 and in combination. The results upon the growth of the plants are 

 described in this report and shown by photographs. 



Experiments in the field have been conducted for five seasons at a 

 large number of centres throughout Lancashire. The results are 

 collected together in this report, and the following recommendations to 

 growers of potatoes in the county are made :— 



Farmyard Manure alone.- — A dressing of 20 tons per acre can be 

 recommended for potatoes on land in moderately good condition. 

 Where, however, the land is in good condition, it may be more profit- 

 able to apply a lighter dressing. 



Artificial Manures alone. — Satisfactory crops of potatoes can be grown 

 with artificial manures alone, but this course cannot be generally 

 recommended. Artificial manures, however, might be used as an occa- 

 sional dressing for a particular breadth of land where, for example, 

 farmyard manure could not be procured. They might also be occa- 

 sionally used on land well stored with humus (e.g., black soils), and on 

 those soils which have been liberally treated with farmyard manure in 

 previous )^ears. The following mixture can be recommended per 

 acre : — Sulphate of ammonia, 2h cwt. ; superphosphate, 6 cwt. ; muriate 

 of potash, 2 cwt. ; costing about 665. 



Farmyard Manure in conjunction with Artificial Manures.— For the 

 production of the largest and most profitable crops, a moderate dressing 

 of farmyard manure in conjunction with a suitable dressing of artificial 

 manures can be recommended, and for general application the following 

 may be employed per acre : — Farmyard manure, 10 tons ; sulphate of 

 ammonia, 1 cwt.; superphosphate, 4 cwt.; muriate of potash, 1 cwt.; 

 artificials only costing about 335. Where no advantage arises from the 

 inclusion of a potassic manure, as might be the case on strong soils, the 

 muriate of potash should be omitted. On rich black land the quantities 

 of sulphate of ammonia recommended under each section may be reduced 

 by 25 per cent, and in some cases by 50 per cent. 



Manuring of Potatoes (Edinburgh and E. of Scotland Coll. of Agric, 

 Bull. 17). — Lime nitrogen (calcium cyanamide) was compared with 

 sulphate of ammonia at two centres in 1907. The land was liberally 

 dressed with farmyard manure in the autumn, and the artificial manures 

 broadcasted on the drills at planting. The latter were 4 cwt. super- 

 phosphate, 1 cwt. sulphate of potash, and on one plot 1 cwt. sulphate 

 of ammonia, on the other 129 lb. lime nitrogen, containing the 



