72 



Problems in Potato Growing. 



[may, 



plants and a preservative of moisture. The advantage was 

 attained, moreover, without any disadvantage to the succeeding 

 crops of the rotation, the wheat crop having been practically 

 equal to that of the better of the other two plots, the seeds hay 

 crop nearly equal on all three, and the oat crop greatly superior 

 on the plot manured in its drills in the spring. 



In the same trial the 20 tons of fresh farmyard manure applied 

 in the drills were tested against the residues of two lots, each of 

 the same original quantity of 20 tons, rotted respectively in the 

 field and under cover, and applied in the drills. The yield from 

 the manure rotted in the open was 1 ton 5 cwts. per acre less than 

 from the fresh manure, and that of the manure rotted under 

 cover was 10 cwts. 2 qrs. less. With respect to this comparison, 

 it is to be observed that farmers know perfectly well that there 

 is a waste in rotting manure, and they incur it for the sake of 

 destroying the vitality of weed and hay seeds in it. If the same 

 quantity of rotted as of fresh manure had been applied in the 

 drills, the comparison might have had an entirely different result. 



If there had been any comparison of the quality of the potatoes 

 grown with fresh and rotted manure respectively, it is probable 

 that the latter would have proved superior. 



In reference to the quality of potatoes in relation to the 

 manures used for them, further investigation is needed to 

 confirm or refute the common statement that nitrate of soda, as 

 compared with sulphate of ammonia, and muriate of potash or 

 kainit, as compared with sulphate of potash, are injurious to 

 quality. 



Such an investigation, at the same time, would throw light 

 upon the relative productive qualities of these rival manures, 

 if carried out in a large number of places, although uniformity 

 of results could not be expected, because variations in both soils 

 and seasons would lead to diversity. As a rule, nitrate of soda 

 gives its best results in a dry season, and sulphate of ammonia 

 in a wet one ; but this cause of conflicting evidence would be 

 obliterated by experiments conducted for a moderately long 

 series of years. The comparison has been made in some ex- 

 periments, but only in comparatively few. It is not improbable 

 that nitrate of soda, as the more quickly acting manure, would 

 prove usually superior as to yield for first and second-earlies, 

 while the more gradually operative sulphate of ammonia might 

 be expected to show the best results in late crops. 



