72 EXPERIMENTS UPON GRASS. [AppeiUltX, 



A mixture of silicate of potash with gypsum produced no sensible effect, 

 neither did Turnbull's artificial guano. 



1°. In this repetition of his experiment, therefore, the nitrate of soda on si- 

 milar land again increased greatly the produce of hay — giving, at the first cut- 

 ting, an excess of upwards of 1 ton, at a cost of 30s. 



2°. But on comparing this action of the nitrate upon grass with its action in 

 the same field the previous year upon wheat — we find that though it considera- 

 bly increased the crop of wheat, yet every additional bushel raised cost 12s. 6d. 

 as the price of the nitrate added to the land (Appendix, p. 19). It appears, 

 therefore, that upon soils where the nilrate will not pay when applied to wheat, it 

 may ye/ pay well when appUcd la grass. 



'S^. Again, we find above tnat 3 cwt. of common salt lessened in a slight de- 

 gree the crop of hay, while, in 1811, IJ cwt. increased considerably the produce 

 of wheatiu the same field — the additional grain reaped from the salted portion cost- 

 ing only Gd. a bushel (p. 19). It would appear, therefore, that on soils where 

 aniimoa salt can be proJiLably used upon wheal it may do injury upon hay. The 

 only circumstance that renders this deduction less safe is that 3 cwt. of salt per 

 acre were applied to the grass, which may have been too much considering the 

 dryness of the season. 



4°. The latter remark applies also to the sulphate of soda which was laid on 

 at the rate of 3 cwt. per acre. A less addition might possibly have aided the 

 crop. Yet the negative influence of this salt seems great, since 1^ cwt. of nitrate' 

 — itself tending to increase the crop — was unable entirely to overcome the dimin- 

 ishing influence of 1 cwt, of sulphate. 



But the reason of this apparent inefficiency of the nitrate, when mixed with the 

 sulphate, is in some measure explained by the remarkable fact, that on both of the 

 patches to which the sulpJude of soda loas applied, the grass that came up consisted 

 almost entirely of red fescue (Festuca Rubra), though rye grass, timothy, and red 

 cloacr were the only grasses soion. The sulphate, therefore, must first have checked 

 or entirely destroyed the grasses which had already sprung up, and then have 

 incited the dormant seeds of fescue to germinate, before the fertilizing agency of 

 the nitrate could come into play. 



This effect of the sulphate, should it be confirmed by later experiments, will 

 establish the important theoretical principle, that those substances which, when 

 present in the soil, will destroy some of our cultivated grasses, will encourage the 

 growth of others; and the no less important practical truth, that saline substan- 

 ces exercise sucli a special action on the several crops we grow that we may 

 hope to discover the means of aiding the growth of the one or the other at plea- 

 sure, and it may be at little cost. 



Suggestion IX. — It is to be recollected that in the case of Mr. Fleming's 

 field it may have accidentally happened that the seeds of the fescue particularly 

 abounded in those plots to which the sulphate was applied. With every dis- 

 position, therefore, to advance as rapidly as we possibly can, I think it better 

 to suspend our judgment upon this point — until the following two series of ex- 

 periments shall have been made in two or three different localities : — 



a. By top-dressing any of the ordinary grasses sown — excluding the fescues 

 — on four or more plots, with i cwt., 1 cwt., 2 cwt., and 3 cwt. of sulphate 

 of soda respectively, and marking the kind of grasses that most abundantly 

 spring. 



b. By sowing half an acre of one or more of the fescues, and especially the 

 Rubra, and noting the effect of the sulphate applied in similar proportions upon 

 as many patches as before. 



These experiments, it is obvious, would be rendered more interesting were 

 nitrate of soda, alone and mixed with the sulphate, tried on other plots, and on 

 both varieties of grass. I trust Mr. Fleming, whose educated eye enabled him 

 to detect the interesting fact in question, may be induced himself to prosecute 

 thft-subject by further experiments. 



5*^. Suggestion X. — We have already seen i\ Jhe above joint action of the 



