The South needs the use of thousands of tons of lime, in connection with manures. Liming poor soils without manuring may not bring much benefit since there may be too little plant food even when the soil is sweetened.
The older regions of the world, where advanced agriculture has been practiced for centuries, use great amounts of lime. The writer has seen great chalk pits in England whence had been taken thousands of tons of chalk (a soft limestone) to enrich the adjoining farms.
In some parts of the South, however, where red clover thrives, the land has in it enough lime, and is in no need of sweetening. We will then consider the next requirement—drainage.
Alfalfa grows through the aid of little bacteria that inhabit its rootlets. These bacteria must have air. Therefore the flooding of the earth by complete saturation of water destroys the life of the bacteria and of the alfalfa itself.
If a post-hole dug three feet deep in the field where it is desired to sow alfalfa shows water standing in it for more than a few days in the year, that soil needs under-draining before being sown to alfalfa.
In general, the depth to the water level should be about forty feet. If there is a greater depth it is generally better.
Now, we will consider the matter of fertility. Alfalfa feeds deep in the soil after it gets established and it secures a part of its nitrogen through the aid of the bacteria from the air.
Nevertheless, it is a gross feeder upon phosphorus and potash and cannot secure these from the air. Nor will it at first secure all its needed nitrogen from the air.
Therefore, land destined to be sown to alfalfa should be rich when sown. If it is not rich it should be made rich before seed is consigned to it.
Next, comes the need of humus in the soil. Now “humus” is simply decayed vegetable matter, and is best supplied through turning under vegetable growths such as cowpeas, or through the use of stable manures. Humus in the soil does several very needed things.