Legumes get all the nitrogen they want, and more which they leave in the ground, so that the Cotton Belt farmer now plants in the same field with his corn or cotton, helpful legumes, such as soy beans, cowpeas, velvet beans, peanuts, vetch, or clover. After the corn or cotton crop is ripe, some of these legumes continue to grow, forming a thick mat of green growth above ground and rich nitrogen lumps below.
After the corn is gathered, the pigs may come in and eat the other crop. Thus the farmer raises two crops in one field,—corn and pork,—and plows under a mass of vegeta tion the next spring. This method makes the ground richer in nitrogen and manure than it was before the corn was planted. The parts of the plants that decay in the soil make a spongy black material called humus. This gives the soil a dark color, makes it light and spongy, helps it to hold moisture better, and to break up the fine particles of rock, so the plants can get the plant food that is in them. Humus is very important for plant growth.
,44. The battle withthe ticks.— The Cotton Belt is now one of the finest places in the world for produc ing meat. For a long while the cattle were small,sickly animals.
Men have found that this condition was caused by a tick. This little animal when young is likd a tiny spider. It lives by sucking the blood of animals, especially that of cattle and dogs, and also of people. It sticks its head into the skin, and sucks blood till its body is as big as a kernel of corn. If - - - it sucks the blood from an animal that has a kind of cattle fever, it carries the fever germs to the next animal which it bites, and thus spreads the disease. Men now destroy these ticks by dipping the cattle,—ears, horns, nose, and all,—under the surface of a tank full of liquid, which kills the ticks without injuring the cattle. (Fig. 594.) In the snowy northern states, cattle have to be fed in barns for half the year. In Mississippi, Louisiana and the rest of the Cotton Belt, barns are scarcely needed. Food grows nine or ten months in the year, and many crops, such as clover, vetch, and oats, are not hurt by moderate freezing.
45. Better health.—Science does wonderful things. In many, many ways it is showing us how to raise more and better plants and animals. It is also teaching us every day how to take care of our bodies, so that we can have good health and grow to be strong men and women. Among other things, science has proved that one kind of mosquito carries malaria from one person to another, exactly as ticks carry fever from one cow to another. The Cotton Belt has so much rain and so many swamps that some places have many mosquitoes. Since we know the cause of malaria, and can prevent it more easily than formerly, the people in the Cotton Belt have better health. The old danger of having malaria is one reason why the popula tion in the Southern States did not become as dense as that in some other parts of the country (Fig. 314).
46. Lumber industry.— When white men first came, the Cotton Belt was nearly all in forests of good timber. While these splendid forests last, the Cotton Belt is also a lum ber belt. At times it has led all other parts of the country in lumber output, and Louisiana is now second only -to the state of Washington in lumber out put. Tall, straight pine
trees grow on the sandy lands of the Cotton Belt. Oaks grow on the clay hills and the rich lands along the streams. In the swamps, the curious cy press tree can live with its roots entirely under water, if only it can manage to stick out its knees. (Fig. 22.) From the cypress timber, shingles are made that last many, many years, and cypress is es pecially prized for use in side houses. The wood of the southern long-leaf pine is so hard that it is good for flooring, and for many other uses. When still harder and stronger wood is needed, we use the oak.
The Cotton Belt forests are on ground so smooth and level that wagons and trains can go almost everywhere at any season of the year. It is much easier to remove the lumber from these southern forests than from forests on the steep, stony, broken land in the mountains of the eastern or western regions. (Sec. 120.) Sawmills by the hun dreds are scattered through the Cotton Belt, and lumber is exported from every port between Galves ton, at one end of the Cotton Belt, and Norfolk, near the other end. Name and locate twelve ports on this coast. One of the greatest markets for oak lumber is Memphis, Ten nessee. A few years ago, Gulfport, Mississippi, on the Gulf of Mexico, was shipping more lumber than any other port in the world. A very small place can export lum ber. All that is needed are a few wharves piled high with lumber, and a few hundred laborers to load the ships that lie alongside. 47. Manufacturing and cities.—Besides the great number of sawmills, there are many cotton mills. Indeed, the leading manufactures are cotton yarn and cloth. The cotton-mill industry has grown very rapidly since 1890. Most of the cotton mills are in the higher part of the Cot ton Belt, around the slopes of the Appalachian Mountains. There the climate is a little cooler, and the rivers flowing down from the mountains have waterfalls to turn the wheels (Fig. 234). There are also cotton fields near by to furnish the raw materials (Fig. 30). Many Cotton Belt cities and towns have mills for crushing oil out of cottonseed, and cotton presses to press the cotton into small, tight bales convenient for shipping, and almost all ports and many inland towns have fertilizer factories making plant food for the farmers. On the whole, the Cotton Belt is not as important for manufacturing as for raw products, but manufactur ing is increasing. At pres ent, most of the people live in the country and in small towns. Massachu setts has only 15 per cent of her people living in the country, while North Car olina has 81 per cent. The 1920 census shows that city population is in creasing faster than rural population. What does this suggest about manu facturing? Each state capital has many thousand people merely because it is a state capital. Atlanta is an important railroad distributing center and cotton mar ket. The same is true of Dallas and Fort Worth, Texas, each of which is a thriving city supplying a rich country. The warm winter of the Cotton Belt brings thousands of tourists from the north each year.