CHAP. v. FORMATION OF PERMANENT GRASS LAND. 819 



It appears, therefore, that a good permanent grass-field had been 

 formed upon this arable soil in Hertfordshire, not only without loss, 

 but with some profit. Much of the success was doubtless due to the 

 town dung, and to the comparatively small cost of cartage, owing to 

 the field being but half a mile from the railway station. The results 

 of annual mowing for nearly thirty years are held to show that fair 

 quality of herbage, as well as full quantity, may be maintained, pro- 

 vided judgment be exercised in the manuring. The general conclusions 

 may be thus summarised : 



1. By the judicious employment of manures, both natural and 

 artificial, arable land was converted into permanent grass, not only 

 without loss, but with some profit to the tenant. 



2. The important constituents, nitrogen and phosphoric acid, were 

 proved to be supplied in the manures in larger quantities than they 

 were removed in the crops ; but potash in only about the same 

 quantity as it was removed. 



3. The application of dung not only compensated for much of the 

 exhaustion due to the removal of hay, but it had a beneficial influence 

 on the botanical composition of the herbage. 



4. Although the grass had been mown every year for nearly thirty 

 years, there had been a considerable accumulation of fertility within 

 the soil. 



5. Analysis showed that there had been an increase of nitrogen in 

 the surface-soil, beyond that which could be explained by excess 

 supplied in manure over that removed in crops, and by the combined 

 nitrogen coming down in rain, and in the minor deposits from the 

 atmosphere. 



6. On laying down arable land to permanent grass, especially if 

 hay is to be removed, it is essential to supply, not only nitrogenous, 

 but an abundance of mineral manures, and especially of potash, a large 

 quantity of which is removed in the crops, and must be returned. 

 When the grass is not mown, but fed, the exhaustion is much less, but 

 it is greater when consumed for the production of milk than when 

 for that of store or fattening increase. 



CHAPTER V. 



* 



ON THE CULTURE OF GRASS LAND. 



IN laying land away to grass there are two conditions, compliance 

 with which is absolutely indispensable to permanent success : 1st, 

 the land must be clean ; 2ndly, the selected seeds must be pure. 

 Compliance with only one, and not the other, of these conditions is 

 futile ; for it is equally useless to sow pure seeds upon a foul seed-bed 



3 G 2 



