140 EXPERIMENTAL FARMS. 



Field notes regarding the growth and appearance of the clovers at certain stages of 

 growth, are to be found on pages 37 and 38 of the Annual Report of the Farms for 

 1896. 



MAMMOTH RED CLOVER. 



Considering briefly the data of the foregoing table, we notice fii'st that as regards 

 nitrogen, the greatest amount was found in the residue of the Mammoth Red clover, 

 sown at the rate of 10 pounds per acre. Above and below this rate of seeding, the 

 quantity of nitrogen decreased. Allowing for the unavoidable errors of experiment, 

 the trials with clover sown at the rate of 12, 8 and 6 pounds, respectively, per acre, 

 gave approximately the same amount of this element, averaging from 5 to 10 pounds 

 less than in the residue from 10 pounds of clover seed per acre. That sown very thickly, 

 14 pounds, and that very thinly, 4 pounds, are seen to contain, practically, the same 

 amounts. 



The greatest weights of organic matter and ash constituents were also contained in 

 the residue from 10 pounds of seed per acre. The reason that it appeared to yield a 

 smaller total weight than that of the others of this series (save that sown at 4 pounds 

 per acre) was that on analysis, it was found to contain from 10 to 13 per cent less water 

 than they. 



On all three counts, therefore, we may conclude that the maximum benefit as a 

 green manure was obtained by seeding this clover at the rate of 10 pounds per acre. 



The fertilizing value of the residues from 14 pounds and 4 pounds are, somewhat 

 strangely, almost identical. 



Of the other clovers experimented with, the Common Red clover makes the best 

 showing, and the Crimson clover the poorest, with Alsike and Alfalfa intermediate in 

 the order named. 



If we leave out of consideration all the advantages accruing from this system of 

 manuring, save the accumulation of nitrogen, and suppose that Mammoth Red clover 

 sown at the rate of 8 to 10 pounds per acre can appropriate from the atmosphere, say 50 

 pounds of this element (the rest being obtained from the soil), the economy and profit 

 of this method of supplying nitrogen by sowing clover with a grain crop for increasing 

 the fertility of soils become apparent. In this connection it may be well to remark that 

 the growth of the clover did not, on any of the plots, diminish the yield of grain. 



The question arises as to whether the clover crop, when grown solely for the pur- 

 poses of enriching the soil, should be ploughed under in the autumn or the spring. 

 Comparing the results given in last year's report with those now recorded, the conclu- 

 sion must be drawn that greater benefit is derived by ploughing under in the 

 autumn. The investigations were not on parallel lines, so that a close comparison can- 

 not be made, but nevertheless there is such a large difierence between the weights of 

 essential constituents in the crop in the autumn and the spring — the difference being in 

 favour of the former — that little room is left for doubt on this point. Moreover, the crop 

 in the autumn is green and succulent, and we have, therefore, every reason to suppose 

 that its decomposition and the subsequent setting free of its elements of plant food 

 would proceed more rapidly than the decay of the organic matter in the dead and dried 

 residue which is to be found the following spring. 



The work so far, then, makes evident the advantage of growing a nitrogen-collector 

 (one of the legumes) with the grain crop. The results of the past season show that 

 the greatest benefit was obtained from sowing 8 to 10 pounds of Mammoth Red clover 

 per acre, and favour the ploughing under of the crop at the close of the growing season 

 — ^in most localities about the middle of October. 



