The Brinkley argus., 1916-04-28
SOILS AND SOIL FERTILITY


 No. c. Rotation of Crops.
 By L. w. Osborn, Assistant Agronom-
 list, College of Agriculture.
 In the improvement of present sys- tems of farming there is nothing upon which success or failure depends to 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.
 Al . result of sixty years work at the Rothamstead Station, England, wheat in 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 of under continuous culture has been comparatively little, and has now reached a stage at which 1t may be maintained regularly. The experi- ments in America, though conducted for shorter periods. tend toward the same results. At the Illinois station, after ten years continuous culture. corn yielded thirty-five bushels per acre. Rotating corn with oats and legumes gave yield of sixty-five 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 prosper ous agriculture without maintaining soil fertility.
 There are many reasons why the yields of crop grown con tinuously upon the same land decline. Tn the first place, where certain crop Is grown continuously, the roots appear to be adapted to the absorp- tion of certain limited forms of plant food. In a few years the amount of this plant food available becomes re- duced and yields decline. Again, under continuous cropping the fungus diseases which trouble the crop are able to multiply until they become a serious factor in reducing yields Cotton wilt becomes a 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 weeyil 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 oi the staple field crops will show that these may be divided into general groups for the purpose of studying and planning systems of rotation. l. Cultivated crops. such as cotton corn and sorghum, when planted te allow for inter-tillage, have similar effects in rotation. A cultivated crop is beneficial because of the cleaning effect 1t has upon mos' weeds. It is also an advantage ir aerating and pulverizing 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 q turf o roots and stems Is developed whict falls the surface soil with vegetable matter. When such soil is broken the turf of roots and stems Is mixed with tn emineral part of the soil ant gives it a loamy, friabls nature no secured with grain or cultivated cropl unless farm manure is added heavily
 8. Green manure crops are thos' grown for the purpose of producing organic matter that can bs plowed un der. Such crops arc beneficial in thu same way as the meadow crops When these crops are legumes. th' nitrogen supply Is rapidly restored.
 4. Cover crops are those grown fo the particular purpose of covering thu land at those seasons of the year whei 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 t' good advantage in producing foot stuffs for the farm. Such crops seed ed in the fall can serve the double purpose of a winter cover crop ans hay. grain or green manure crop.
 A good rotation will consist of thu tudicious alienation of the abov' groups of crops. The warm winter and the humid conditions which pre- vail In Arkansas require the growing of winter cover crops and the turning under of green manure crops. In ; general way, a good type of rotation will be as follows One or two year of cultivated crops (cover crops plant ed in the falD, the next year a smal grain crop followed by cowpeas ans soy beans.