5. The throwing out of winter grain is often prevented, because this is due to the freezing of the surface-soil.
6. Mulching prevents the growth of some weeds, because it removes from them the fostering heat of the sun.
Many of the best nursery-men keep the soil about the roots of young trees mulched continually. One of the chief arguments for this treatment is, that it prevents the removal of the moisture from the soil and the consequent loss of heat. Also that it keeps up a full supply of water for the uses of the roots, because it keeps the soil cool, and causes a deposit of dew.
7. It also prevents the "baking" of the soil, or the formation of a crust.
It is to be recommended in nearly all cases to sow oats very thinly over land intended for winter fallow after the removal of crops, as they will grow a little before being killed by the frost, when they will fall down, thus affording a very beneficial mulch to the soil.
When farmers spread manure on their fields in the fall to be plowed under in the spring, they benefit the land by the mulching more than by the addition of fertilizing matter, because they give it the protecting influence of the straw, etc., while they lose much of the ammonia of their manure by evaporation. The same mulching might be more cheaply done with leaves, or other refuse matter, and the ammonia of the manure made available by composting with absorbents.
Why is snow particularly beneficial?
It is an old and true saying that "snow is the poor man's manure." The reason why it is so beneficial is, chiefly, that it acts as a most excellent mulch. It contains no more ammonia than rain-water does; and, were it not for the fact that it protects the soil against loss of heat, and produces other benefits of mulching, it would have no more advantageous effect. The severity of winters at the North is partially compensated by the long duration of snow.
It is a well known fact that when there is but little snow in cold countries, wheat is very liable to be winter killed. The same protection is afforded by artificial mulching.
This treatment is peculiarly applicable to the cultivation of flowers, both in pots and in beds out of doors. It is almost indispensable to the profitable production of strawberries, and many other garden crops, such as asparagus, rhubarb, etc. Many say that the best treatment for trees is to put stones about their roots. This is simply mulching them, and might be done more cheaply by the use of leaves, copying the action of nature in forests;[AM] for, unless these stones be removed in spring, they will sink and compact the soil in part during open weather.