Fifty Year* Progress of British Agriculture. 
on grass land, which, with very little change on each of the 
twenty plots, has been continued to the present time. The ex- 
perience of the past thirty years shows that the natural produce 
of grass may be doubled, and even trebled, by the continuous 
use of special manures. As two-thirds of the cultivated land 
in this country, and all the permanent pastures, are in grass, 
this series of experiments is of very great interest and value. 
"'It is quite certain," says Sir John Lawes, "that arable 
soils are poorer than the pastures from which they are frequently 
derived, and that their fertility must be restored to them before 
a fresh pasture can be said to be re-established. It is the cost 
of this operation that has given rise to the saying that ' laying 
land down to pasture breaks a man.' The question is whether 
some of the cost incurred cannot be saved. There is plenty of 
foul land in the country upon which the experiment might be 
made. And I should be disposed to advise those who have the 
misfortune to own such land at all events to try whether the 
superior grasses, when aided by manure, will not be competent 
gradually to drive the weeds out of the soil." 
In the wheat experiments it is not surprising to find, after 
forty successive crops, that the soil begins to exhibit signs of 
exhaustion. This has been corrected by interposing a heavily- 
dunged green crop ; while the introduction of red clover, at long 
iutervals, between the corn crops is also found to add greatly to 
the corn-producing power of the soil. To attain a maximum- 
paying produce Sir John Lawes finds that the land should 
be dunged heavily for mangel, to be followed with wheat, or 
barley, or oats, for several years in succession ; then interpose 
clover, and follow it with corn crops, keejjing the land perfectly 
clean, and manuring all the corn crops with nitrate of soda and 
superphosphate. "When the land shows need of change, begin 
again with heavily-dunged green crops. Successive crops of 
barley he finds to pay better, and they are more certain in his 
climate, Hertfordshire, than either wheat or oats, and give more 
corn in proportion to straw. If a heavily-dunged green crop is 
introduced, it is not necessary for a further succession of years 
to give any other manure to the com crops than nitrate of soda 
and superphosphate. Potash (which may be supplied by dung) 
is very necessaiy in a grass manure, especially for clover, which, 
unlike corn, is injured by ammonia. The grass experiments 
show that by giving food to the plants, the strongest and best 
varieties appropriate what they most need, and by the law of the 
strongest put the weaker down. In the best plots the weeds 
almost disappear, while on one plot to which no manure is 
applied the weeds form 50 per cent, of the produce. 
