The Nevada County picayune., 1916-06-15
SOILS AND SOIL FERTILITY
No. 6. Rotation of Crops.

By l.. W. osborn, Assistant Asronom- ist, College of Agriculture.
 In the improvement of present sys- tems of farming there is nothing upon which success or failure depends 10 greater extent than the method of cropping the land Experiments which have been carried upon the oldest ex- pertinent stations have shown conclu- slvely that cropping practices bear s very definite relation to the way the soil fertility is maintained.
 Az & result of sixty years work at the Rothsmstead 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 off under continuous culture has been comparatively little, and has now reached a stage at which it may be maintained regularly. The eKperl- 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-fve bushels per acre Rotating corn with oats and legumes gave a yield of siXty-hve bushels of corn per acre.
 These figures are of extreme impor- tance when it 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 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 planl food In few years the amount O this plant food available becomes re duced and yields decline. Again under continuous cropping the fungus diseases which trouble the crop arc able to multiply until they become serious factor in reducing yields Cotton wilt becomes serious menaC, under such conditions. Likewise va rious experiments in the cotton bel under boil wcevil conditions hay, shown less damage done by the bol weevil where cotton was not precede, hy cotton.
 A good rotation is easily planned b, studying the characteristics, feedinl habits, and effects upon the soil different kinds of crops. review the staple ncld crops will show tha these may be diyded into genera groups for the purpose Of studylni and planning systems of rotation.
 1. Cultivated crops, such as cotton corn and sorghum, when planted tC allow for intertillage, have simiIa effects in rotation. cultivated crop is beneficial because of n. cleaning effect lt has upon mos weeds. It Is also an advantage serating and pulverizing the soil thu aiding plant food to hecoWe available This advantage becomes dlsadNau taxe when such crops are grown con tinuously on the same field
 2 Pasture snd meadow crops. ac' cd humus crops. are of consderahl importance in maintaining the suppl
 hn such crops occupy the land a turf C roots and stems is developed Whiel fills the surface soil with NePetshl matter When such a soil is broken the turf Of roots and stems is mike with tn emineral part ot the soil an, xiyes it a loamy frieblc nature nc secured with grain or cultivated crop unless farm manure IS added heavily
 3. Green manure crops are thos grown for the purpose Of produc.H orxanic matter that can be plowod ur der. Such crops are beneficial in ti same way AS the meadow crops When these crops are lcsumeS, in, nitrogen supply i. rapidly restored.
 (. Cover crops are those grown to the particular purpose or covering lR' land al those seasons of the wear whel the soil is likely 10 he eroded and so uhle plant food lost hy teaching
 3. Small grain erops, such as oats wheat. barley and rye can he used t good advantage in producing loo. stuffs for the farm Such crops seco ed in the fall esn serc the doUhl purpose of winter cover crop sr. hay. grain or green manurc crop.
 A good rotation Niu consist of 'h, judicious alterualion of the aCol groups of crops The warm winter and the humid conditions which pit vail in Arkansas require the groN .nt of winter cover crops and the turning under of green manure crops. nj :. general way, good type Of rotation will be as follows One or two year