FIELD CROPS. 937 



led him to conc-Iudo that 0.5 per cent of cail)oiiiite of lime or magnesia 

 is veiT deleterious to the orowth of lupines, are discussed, l)ut the 

 author believes this to be true in the case of sandy soils only. The 

 experiments here reported showed that on heavy clay soils double that 

 (piantity of carbonate of lime or magnesia was not injurious. 



Potato experiments {A(//\ Gaz. [Lotidon], 52 (1900), No. 1390^ p. 

 II')). — The summarized results secured in 18!)*.) b}' Wright at the West 

 ot Scotland Agricultural College in manuring potatoes are reported. 

 The data given are the averages secured from 10 farms. On umna- 

 nured land the yield of potatoes was ,5.02 tons per acre. When 20 

 tons of barnyard manuiv was applied, the3'ield increased to 7.N.5 tons. 

 Where only half of this amount of barnyard iuanure was used, the 

 vi(>ld was deci'eased l.-l tons, and when to the full ration of 20 tons of 

 barnyard manure was added 448 lbs. of superphosphate and 112 lbs. 

 each of sulphate of anunonia and of potash, the yield was increased to 

 8.22 tons. The same amount of these conmiercial fertilizers used in 

 coiuiection with lO tons of ])arnyai'd maruire resulted in a yield of only 

 l,2o2 lbs. less than when the full application of 20 tons of barnvard 

 maiuire was used. In a test of three potash manures f(jr })otatoes, the 

 yields remained practically identical. The greatest amount of starch, 

 however, was found in the potatoes fertilized with the sulphate. The 

 best fertilizer, as regards economy and preparation for the succeeding 

 crop, was that made up of 10 tons of barnyard manure, 448 lbs. of 

 superphosphate, 112 lbs. of sulphate of ammonia, and 168 lbs. of sul- 

 phate of potash. Increased quantities of commercial fertilizers gave 

 nearlv as good yields at slightly less expense, but the value of barn- 

 yard iuanure for succeeding crops it is thought more than covered any 

 slight advantage in the cheapness of the commercial fertilizers. 



Experiments on potatoes in Yorkshire {Agr. Gas. [London]., S2 

 {J900), No. 138}^^ p. 19). — A sununarized account is given of a report 

 issued by the Yorkshire College and certain county councils on exper- 

 iments with potatoes in 1899. One of the chief experiments was the 

 test of the substitution of commercial fertilizers for a part of the ])arn- 

 yard manure employed in a full dressing of 20 tons. The average 

 results secured in experiments at 5 farms show a yield of 6.38 tons per 

 acre Avhere no manure was applied; with 20 tons of barnyard manure, 

 tlie yield was 10.54 tons per acre. Where only half this amount of 

 barnyard manure was applied, the yield averaged 8.95 tons per acre. 

 AMierc to the 10 tons of barnyard mamire there was added 156 lbs. of 

 sul})hate of ammonia, ?>'M} lbs. superplios])hiite, and 224 lbs. of potash 

 salts, the yield was i-aised to !».1»2 tons per acre. When the sulphate 

 of anunonia was oiuittinl in the above formula, the yield was decreased 

 572 lbs. When superphosphate was omitted the decrease was 1,062 

 lbs. per acre. The use of commercial fertilizers alone at the rate of 

 336 lbs. of sulphate of ammonia, 560 lbs. of superphosphate, and 224 



