VALUE OF FAKMYAHJ^ .MANUIIK Toi: (;1:AS> k;:, 



the pliotograpli, Fig. '27, of turf taken {'nnw this phM in \\h)V,. 

 Anotlier feature in these two IMots, 10 and 4--J, wliieh i-i-eeive 

 nitrogen but no potasli, is the weakness of tlie stems; sln.rt as 

 the grass is, it is often laid l)efore it is ready to cut. The grass 

 is also found to l)e more susceptil)U' to fungoid attacks on tlies(^ 

 plots than elsewhere. 



The diagram Fig. 28 shows a comparison of the yields of 

 the unmanured plot, the plot receiving mineral mamu'es only, 

 and the plots receiving mineral manures and varying amounts of 

 nitrogen as nitrate of soda or annnonium-salts. 



V. T//e Artio)t of Organic Matter. 

 In the early years of the experiments farmyard manure 

 was applied every year to two of the plots, but owing to 

 the accumulation of unrotted material on the surface it was 

 found necessary to discontinue the experiment in this form. 

 On another of the plots, however, an attempt was made to 

 ascertain the effect of the organic matter present in dung 

 by adding to a complete artificial manure, such as is sup- 

 plied to Plot 9, 2000 lb. of chaffed wheat straw every year. 

 The wheat straAv will contain so little manm^ial matter, compared 

 with the quantities artificially supplied, that it may be neglected ; 

 thus the straw should ])e regarded as simply providing organic 

 matter. If we com23are the crop on this Plot i:3 with that of 

 Plot 9, we see that the straw has had its effect, and that on the 

 average a larger crop l)y about 7 cwt. per acre per annum has 

 been produced. The effect of the wheat straw has been due 

 partly to the shelter it provides in tlie early spring (for it is 

 noticed that the gi-ass starts more quickly on this plot than on 

 the others), and partly also to the water-retaining power of the 

 hunuis produced by its decay. Of late years the organic 

 matter added accumulated to such an extent as to form ;i 

 peaty layer that was beginning to injure the growth ol the 

 plant; in consequence the application of straw has been 

 discontinued. The value of occasional applications of farmyard 

 manure to trrass land is thus seen to be a mechanical factor 



