AND NITROGEN ON THE GROWTH OF TURNIPS. 91 



series of experiments, on a lari^e scale, in the Lothians iii 1878, 

 conducted by their chemist, JJr Andrew P. Aitkeu. A partial 

 report of the results of these experiments appear in the Society's 

 annual volume of "Transactions," 4th series, volume xi., 

 which, so far as it goes, points apparently in the same direction 

 as the results of the Aberdeen experiments. 



I, Kke the general bulk of farmers, had been accustomed to 

 look upon undissolved mineral phosphates as worthless for manurial 

 purposes, until treated with sulphuric acid. The results of the 

 Aberdeen experiments were therefore at first taken by me, as 

 also by the general agricultural community, with a considerable 

 grain of salt, but the confirmatory proof of the experiments of 

 subsequent years, as also the unmistakable leaning of Dr 

 Aitkeu in the same direction, determined me to try the question 

 fairly on soil in ordinary rotation for turnips. The piece of soil 

 which I selected is a light gravelly soil, from 6 to 8 inches deep^ 

 overlying the Old lied Sandstone, and not naturally of a very pro- 

 ductive character. It is about 270 feet above sea level, and 

 thoroughly drained. The mode of cropping which has been 

 followed in this field is the ordinary five-shift (2 grain, 2 grass, and 

 1 green crop), in which rotation it has been wrought for upwards 

 of thirty years. The usual rule observed on the farm is to make 

 one half of the fallow break potatoes and turnips alternately, 

 thus it is ten years since turnips were grown on tliis portion of 

 the field. Eight years ago it received about 3 tons of lime per 

 acre. Five years ago it was regent potatoes, grown with farm- 

 yard manure fresh from the yards. The next crop was wheat, 

 which received a dressing of 20 tons per acre of town and farm- 

 yard manure mixed. The succeeding two years' grass was 

 pastured by cattle and followed by a crop of potato oats. After 

 the removal of the oat crop, the stubble got a close deep furrow 

 in September 1878. During the ploughing the soil was in nice 

 dry condition, and was allowed to lie in the plough furrow until 

 the first week of May 1879, when it was harrowed, grubbed, and 

 rolled ready for drilling. The portion of the field out of which I 

 was to select an acre for the experiments, was drilled up on the 

 26tli May — drills 27 inches apart. I may add that during the 

 preparation and drilling of this part of the field, the soil, in point 

 of condition, was all that could be desired. In selecting an acre 

 for the experiments, I endeavoured, as far as the nature of the 

 field would allow, to give all parts of the plot an equal chance of 

 sit\iation, soil, &c. The acre I selected consisted of 30 drills, 

 216 yards long, extending to within 92 yards of the one end and 

 16 yards of the other end of the field. There were also turnips 

 in ordinary cultivation on either side of the plot, as well as on 

 the continuation of the drills at each end of it. 



These 30 drills I subdivided into four equal parts, making four 



