The Prescott daily news., 1916-04-27
SOILS AND SOIL FERTILITY
No. 6. Rotation of Crops. By L. w. Osborn, Assistant Agronom- ist, College of Agriculture

ist, College of Agriculture
 In the improvement of present sys- tems of farming there is nothing upon which success or failure depends to a greater extent than the method of cropping the land. Experiments which have been carried upon the oldest ex- pertinent stations have shown conclu- sively that cropping practices bear very definite relation to the way the soil fertility is maintained.
 AS 8 result of sixty years work at the Rothamstead Station, England. wheat in a good rotation gave nearly double the yield per acre as was ob- tained from the same crop when grown continuously on the same land. The yields under continuous culture have fallen off most rapidly during the first few years of the experiment. During the last fifty years the falling off under continuous culture has been comparatively little, and has now reached a stage at which it may be maintained regularly. The experi- hciltS III AuAcIlCdy tHOuBn COHuuClSu for shorter periods, tend toward the same results At the Illinois station, after ten years continuous culture, corn yielded thirty-fve bushels per acre. Rotating corn with cats and legumes gave yield of siXty-flve bushels of corn per acre.
 These figures are of extreme impor- tance when 1t is considered that cot ton is grown continuously on the same land in Arkansas, and present low yields, in large measure. can be at tributed to this factor. Experience has shown that no nation, state or community can maintain a prosper ous agriculture without maintaining soil fertility.
 There are many reasons why the yields of crop grown con tinuously upon the same land decline. In the first place, where a certain crop Is grown continuously. the roots appear to be adapted to the absorp- ton of certain limited forms of plant food In a few years the amount of
  duced and yields decline. Again, under continuous cropping the fungus diseases which trouble the crop are able to multiply until they become serious factor in reducing yields. Cotton wilt becomes serious menace under such conditions. Likewise va rious experiments in the cotton belt under boil weevil conditions have shown less damage done by the boil weevil where cotton was not preceded by cotton.
 A good rotation is easily planned by studying the characteristics, feeding habits and effects upon the soil of different kinds of crops. A review of the staple field crops will show that these may be divided into general groups for the purpose of studying and planning systems of rotation
 i. Cultivated crops, such as cotton, corn and sorghum, when planted to allow for inter-tilage. have similar effects in rotation A cultivated crop is beneficial because of the 
 weeds It is also an advantage in aerating and pulverlzing the soil, thus aiding plant food to become available. This advantage becomes a disadvan- tage when such crops are grown con tinuously on the same field.
 2. Pasture and meadow crops, acll- ed humus crops, are of considerable importance in maintaining the supply of organic matter. During the time such crops occupy the land turf of roots and stems is developed which fills the surface soil with vegetable matter. When such a soil Is broken, the turf of roots and stems is mixed with tn emineral part of the soil and gives 1t a loamy, frieble nature not secured with grain or cultivated crops unless farm manure is added heavily
 8. Green manure crops are those grown for the purpose of producing organic matter that can be plowsd un- der. Such crops are beneficial in the same way as the meadow crops When these crops are legumes, the nitrogen supply is rapidly restored
 4. Cover crops are those grown for the particular purpose of covering the land at those seasons of the year when the soil Is likely to be eroded and sol uble plant food lost by teaching
 5. Small grain crops. such as oats, wheat, barley and rye can be used to good advantage in producing food stuffs for the farm. Such crops seed ed in the fall can serve the double nurpoaa of a winter cover crop and