1^24 On the Manuring of Grass Land, 



amanure for a crop of the same description ; and if the fine 

 nnould of our grass fields were really due to decayed grass, it 

 would be a mine of wealth to the fortunate possessor. Any one 

 may convince himself that the mould of his pastures and meadows 

 cannot have this origin by taking a quantity of hay, or even thin 

 sods, and when they are rotten applying them a single inch thick 

 upon part of a field which possesses a good depth of black 

 mould beneath the sward. The crop produced by this applica- 

 tion will assure him that the layer of similar-looking material 

 which lies above the true soil of his grass fields has a different 

 origin. He may arrive at tlie same conclusion by another 

 process. Take a high estimate of the yearly quantity of roots, 

 &c., left in the soil by grass, and we shall see that it is wholly 

 inadequate to form the thick dark layer of which we are seeking 

 the origin. 



" When the yoiin^; grass throws up its leaves into the air, from which it 

 derives so much of its nourishment, it throws down its roots into the soil in 

 quest of food of another kind. The leaves may be mown or cropped by 

 animals, and carried off the field ; but the roots remain in the soil, and as 

 they die, gradually fill its upper part with vegetable matter. On an average 

 the annanl production of roots on old grass land is equal to one third, or one 

 fourth the weight of hay, though no doubt it varies much, both with the kind 

 of grass and with the kind of soil. When wheat is cut down the quantity of 

 straw left in the field, in the form of stubble and roots, is sometimes greater 

 than the cjuantity carried off in the sheaf. Upon a grass field two or three 

 tons of hay may be reaped from an acre, and therefore from half a ton to a ton 

 of dry roots is annually produced and left in the soil. If anything like this 

 weight of roots die every year in land kept in pasture, we can readily under- 

 stand how the vegetable matter should gradually accumulate."* 



AVe will take the largest quantity here mentioned, viz., a ton 

 per year per acre, and assume, that when the fibre was destroyed 

 so as to form a dark-coloured mould it still weighed a ton, and 

 then apply it to an acre of land and appreciate the thickness of 

 the layer formed by it ! Now I happen to have seen many acres 

 dressed with a ton each of material, rather denser than this cer- 

 tainly, but still sufficiently near to afford a good criterion. I 

 have taken strangers into the fields to which the dressing was 

 applied and they have sought amongst the grass to find it ; but, 

 in every case I can remember, they have sought in vain. By 

 careful scrutiny I have found particles, but sometimes have sought 

 for some time in vain. Add to this the fact, that the decayed 

 roots of one year would be largely consumed to supply the grass 

 of the next year's growth, and I think no one will contend that 

 they alone could possibly form the dark layer familiar to every one 

 who has cut through the turf of old pastures, especially of such 



* Johnston, Elements of Agricultural Chemistry, p. 151, fifth edition. 



