4 



CKOPPING SYSTEMS FOR THE BLACK LANDS OF TEXAS. 



it necessary to plow up the field and plant to some cr(){) not affected 

 by this disease. 



The general knowledge of the beneficial efl'ect of leguminous crops 

 on the land, strengthened by the local experience of increased yields 

 resulting from turning under alfalfa, led to investigations which had 

 for their object the control or extermination of root-rot, so that it 

 might be possible to grow the legumes and estabhsh types of farming 

 which would restore the productiveness of the soil. 



The first of these investigations, which have been continued to the 

 present time, was undertaken about nine years ago by Dr. C. L. 

 Shear, of this Bureau, and his assistant, Mr. George F. Miles. Though 

 they tried every available means of eliminating root-rot without 



Fig. 1. — Expc'rinicnt-al plats of cotlun at IVaty, Tex., shuu iiig the results of deep fall plowins;. Plat A, at 

 the left, was plowed 7 to 9 inches deep on Novemlier 12, 1906. Only 26.79 per cent of thosj plants were 

 dead on November 11, 1907, and most of these had matured their crop. Plat B, at the right, received 

 ordinary spring plowing. Of these plants, 69.54 per cent were dead on November 11, 1907, and these had 

 died so early that they matured but a small part of their crop. 



success, they found that deep fall plowing (fig. 1), apphcations of 

 barnyard manure, and the rotation of grain crops with cotton in a 

 large measure controlled the disease. 



These facts, together with knowledge of certain farm practices 

 which developed of necessity under root-rot conditions, fumisli a 

 basis for the establisliment of rotations in wliich the well-known 

 crops of this region follow each other naturally. For example, being 

 compelled to plow up his alfalfa, the farmer follows it with grain, 

 usually corn or wheat. He knows from experience that cotton would 

 not succeed, for the reason that it is just as susceptible to root-rot 



[Cir. 84] 



