history of manuring each field can easily be designated by "cross-hatching" the particular field manured and inserting the number of the year in which the manure was applied. Where only a part of the field is manured in a single year, that part of the field to which the manure was applied should be "cross-hatched." Figure 36 illustrates the method of keeping the record of manuring.

EXERCISES FOR PUPILS

1. Make an outline map, to scale, of the home farm, showing the location of farmstead and all natural divisions of the land. Show the fences and field divisions, and the crops grown last year.

2. Make a separate plan of the farmstead, showing locations of the various buildings and the distances between them.

3. Make a revised plan of the farm showing how it can be laid out so as to be worked to better advantage.

4. Calculate the number of rods of fencing that will be required under the new and the old plans.

5. Calculate the average distance from the barn to the fields under the old and the new plans.

PROBLEMS

How many each case in Traveling at

1. Under one plan the fields of a farm average 14 rods from the farmstead. Under another plan the average distance is 46 rods. miles would be traveled in going to and from the fields in raising a 30-acre field of corn requiring 396 one way trips? the rate of 3 miles an hour, how many more days, of 10 hours each, would be required in producing the crop under the second plan?

With a yield of 40 bushels an acre, how much more would it cost to produce a bushel of corn on the second field than on the first, if man and team are worth $4.50 a day?

2. How many more turns must be made in plowing a field 80 rods square with a walking plow turning a 14-in. furrow, than would be necessary in plowing a field 40 rods wide and 160 rods long?

If it requires 30 seconds to make each turn, how much longer will it take to plow the first than the second?

His manure

3. A man has a rectangular forty-acre field to manure. spreader will hold just enough to go across the field. The spreader is brought back empty. Would the distance traveled in manuring the field be increased or decreased if he were to manure to the middle of the field

and back with the first load, and from the middle of the field to the farther side and back to the middle with the second load, continuing in this way over the entire field? The spreader covers a strip 4 ft. wide in spreading. How many miles would be traveled in manuring the field under each method?

4. Man labor is worth 16¢ an hour and horse labor costs 10¢ an hour. A man and team can cover 11⁄2 acres of land with manure in a 10-hour day. How many bushels an acre must the yield of the first crop of corn be increased in order to pay for the cost of manuring, if corn sells for 42¢ a bushel?

5. What will be the cost of fencing with woven wire 80 acres of land which is 160 rods long and 80 rods wide, if four fields are made, 40 x 80 rods? Woven wire fence can be erected for $1.05 per rod.

6. The wire fence in the above problem takes up 13 feet on each side. How many acres will be lost to cultivation on fencing the four fields allowing loss only on one side of the outside fences? How many, if only two 40-acre fields are made running the fence across the farm?

7. How many more turns will it be necessary to make in cultivating once, 20 acres of corn where it is divided into two square 10 acre fields than where there is just one field 80 by 40 rods? The rows are 3 feet 6 inches apart and in the latter case the cultivating is done the long way of the field.

REFERENCES

U. S. Department of Agriculture, Bureau of Plant Industry, Bulletin No. 236.

Cyclopedia of American Agriculture, Vol. I, pages 142-161; Vol. II, pages 90-109.

Farm Development.-W. M. Hays, pages 96-126.

Farm Management.-G. F. Warren, pages 365-401.

CHAPTER VIII

CROPS AND CROP ROTATION

71. Main Crop Desirable. In most farming regions some leading crop usually becomes the main market or feed crop. This is desirable in most instances because it gives opportunity for specialization in one crop or commodity. The main crop is usually chosen because of especial adaptation to climate and soil, or because of market facilities for that crop, or because of labor conditions favorable to its growth.

In the Dakotas, Minnesota and Canada, wheat has been the leading crop on most farms. It will continue to be the leading crop so long as satisfactory yields are secured, and shipping facilities are good. The wheat crop is especially adapted to new regions where the product must be shipped long distances to market. It stands transportation well. Less capital is required to equip for wheat raising than for stock raising and is favored for that reason also. And many who settle on new lands do not care to take up the more complex systems of farming. In Illinois, Indiana, and other Central states, Indian corn is the leading crop, and the one which determines largely the system of farming. Likewise, the Southern and Southeastern states are especially adapted to cotton and fruit growing. In some sections, cotton leads, in others fruit growing is the main line of production. Kansas, Utah, and some of the other Western states are especially adapted to alfalfa growing; California to fruit growing, oranges, grapes and lemons being the specialties. The New England states are more concerned with the production of hay and dairy products.

72. Dangers of Continuous Cropping. Where single line farming is followed extensively, there are grave dangers and trouble is likely to be experienced either from (1) weeds, (2)

88

insect pests, or (3) plant diseases. In the spring-grain growing territory, wild oats and wild mustard become serious pests. Many of the fields in the spring-grain growing states are so badly infested with these weeds that yields are materially reduced, because large areas are farmed and it is sometimes impossible to plow all of the land. As a consequence, the land is disced in the spring and the grain sown in the stubble of the crop of the previous year. On land so farmed, Russian thistles, Canada thistles, wild rose bushes, and the weeds above mentioned have secured a strong foothold. The chinch-bug

FIG. 37.-On the left is corn growing on land that has grown corn continuously for 19 years. On the right is corn in a five-year rotation. Both fields were planted on the same day to the same kind of corn. The yield on the field to the left is 27.5 bushels an acre. The field on the right gives 61.3 bushels an acre. These are the average yields for ten years.

is a common enemy to the spring-wheat growers. The clover midge is likely to infest clover fields unless frequent changes are made. The corn root louse and corn root worm infest the land that is planted continuously to corn. Flax growing has been discontinued in some regions because the land has become infested with the disease known as wilt. Recently, investigators have found that fungus diseases attack the roots of the small grain plants when continuously grown, interfering with the full development of the plants and reducing the yield. Smut and rust of wheat are likely to follow continuous wheat

growing. Corn smut infests the crop grown on land that has produced corn continuously. There are many adverse conditions and diseases which are met by the one who tries to

form humus.

grow a single crop

for any number of years on the same piece of land.

73. Difficulties Avoided by Crop Rotation. Most of these difficulties may be avoided by crop rotation. It does not necessarily follow that because

crops are rotated, a

main or leading crop cannot be grown. The combination of fields and the arrangement of crops may be made in such a way that more of the main product is secured than where single line farming is followed. The yields on the rotation plots at University Farm, Minnesota,

indicate that as much wheat can be produced in three years by rotating the crops, as can be produced in four years of continuous cropping. There is also much less trouble from weeds and insect pests, and moisture conditions are more easily controlled.