320 EXPEKIMENTAL STATIONS — EEPORT FOR 1881. 



Plot 27, which has remained unmanured (see scheme of ex- 

 periments, p. 330), has produced the smallest crop on the station, 

 viz., 13| bushels of oats per acre. Next to it is plot 22, which has 

 been regularly manured with potash salts alone. The result is 

 that it has produced only one bushel more per acre, showing us 

 plainly that potash is not the ingredient that is most wanting in 

 that soil. Next above that is plot 12, whose annual allowance 

 is bone ash alone. It has produced only three bushels per acre 

 more than the unmanured plot, although enough of phosphate 

 was applied to supply the wants of a crop of oats of 60 bushels 

 per acre ; that is to say, only one-twentieth of the phosphate has 

 been used by the crop, and nineteen-twentieths remain un- 

 appropriated in the soil. It is evident from the crops obtained 

 on these plots that to use potash salts alone or phosphates alone 

 on Pumpherston is to bury money, much of which may never 

 be found again. Even when we apply the two together, as 

 show^n on plot 17, the crop is a failure, only 18 J bushels per 

 acre, or scarcely five bushels more than the unmanured plot. 

 How different is the result obtained by the application of nitro- 

 gen. Plot 18 has all along received only nitrate of soda, and 

 the crop this year is about 34 bushels, and a very large pro- 

 portion of straw, viz., 24 cwts., showing that there is in the 

 soil a considerable reserve of phosphates and potash salts, but 

 for the want of nitrogen the plant is unable to make use of 

 them. The amount of nitrogen applied to plot 18 (in common 

 with all the other plots which received nitrogen) is 40 lbs. per 

 acre, and that is just about the quantity of nitrogen contained 

 in 34 bushels of oats and 24 cwts. of straw. 



When to this nitrogenous manure there are added phosphates, 

 as in plot 21, there is a very slight increase in the amount of 

 grain, although there is not so much straw. When to the 

 nitrogenous manure there is added potash, as in plot 11, the 

 increase of grain is very considerable, but there is no increase 

 in the amount of straw. Lastly, when all these are combined, 

 and a well-balanced manure containing nitrogen, potash, and 

 phosphates is applied, the best results are obtained both in the 

 quantity of grain and of straw. 



An instructive plot is No. 26, which formerly had applied to 

 it a mixed manure which was a kind of imitation guano, and 

 its produce compared not unfavourably with other guano plots. 

 For two years the manure has been discontinued, and the result 

 is that this year it has yielded less than half a crop, thus show- 

 ing that the soil of this station is in poor condition and depen- 

 dent for its fertility upon the immediate application of manures. 

 If we compare these results with those obtained at Harelaw 

 station we find very similar indications, only that as the latter 

 has practically been manured for the first time, the differences 

 are not quite so marked. The two unmanured plots, 26 and 27, 



