58 BULLETIN 355, U. S. DEPARTMENT OF AGRICULTURE. 
of the farm on crops which require the nitrogen as well as the other 
elements, and so increase the fertility of the whole farm. Manure 
applied to meadow land should be well composted, so that its ferti- 
lizing constituents are largely soluble and will be leached down into 
the soil at once, and the straw used as bedding will be rotted and will 
not be raked up with the hay. 
As a rule it is better to plow manure under when applied on such 
crops as corn, cabbage, sugar beets, etc., because then it causes no 
difficulty in cultivating these crops, as it often does when applied 
as a top-dressing after the land is plowed. But on heavy clay soils 
the manure is more effective when applied as a top-dressing and culti- 
vated into the soil, because then it is more readily oxidized than when 
plowed under. It can be used as a top-dressing in this way if well 
rotted. 
The rate at which the manure should be applied will, of course, be 
determined in part by the supply produced on the farm. But it is 
much better to use small quantities frequently than large quantities 
seldom. Four or five tons to the acre every three years is better than 
12 or 15 tons every nine years. The even distribution of manure, 
such as can be accomplished with the manure spreader, is also a matter 
of great importance. 
GREEN MANURES. 
(Ref. No. 7, pp. 348-362; or No. 6, pp. 342-348.) 
Decaying vegetable matter in some form is indispensable for keep- 
ing a soil in the best physical condition and in the highest state of 
fertility. If the system of farming is such that not much live stock is 
fed upon the farm, the manure will not be sufficient to supply the 
needed amount of vegetable matter to the soil, and some other means 
should be adopted as a substitute. In such a case, the most practical 
method is to grow crops to turn back to the soil. Such crops are 
called green manures. 
There are two ways of furnishing green manures: (1) A crop is pro- 
duced during the regular growing season, but instead of being har- 
vested, it is returned to the soil. This method may be necessary in 
the North where the growing seasons are short; (2) a crop to return to 
the soil is grown with the regular harvested crop and left on the ground 
from the harvest; or a crop is sown after the regular crop is removed 
and gets its growth during the fall and winter months, in which case 
it is called a cover crop. This method of green manuring is now much 
used in the Southern States. 
In addition to the value to the soil of vegetable matter supplied, 
the following benefits come from the green-manure crops: (1) Where 
a cultivated crop has been grown and harvested, considerable avail- 
able plant food is left in the soil which may be taken up in the growth 
