274 



CROP EOTATION 



Ohio Station (Bulletin 282). The experiments are being conducted 

 on silt loam soils which were depleted when the tests were begun. 



A S-year Rotation Better than a S-yeai Rotation m Soil Improvement 



(As mdicated by the yield of corn) 



System of cropping 



Corn continuously 

 Corn continuously 



Corn in 5-year rotation * 

 Com m 3-year rotation j 

 Corn in 5-year rotation 



Corn in 3-year rotation 



Soil treatment 



No treatment 



Manure, 5 tons per acre per 

 year 



No treatment 



No treatment 



Manure, 8 tons twice in rota- 

 tion — to corn and wheat 



Manure, 8 tons every third 

 year — 'On corn 



Average 

 yield for 

 20 years 



Bus'^ els 



15 5 



37 

 29 



518 



Average 

 yield for 

 17 years 



Bvshels 



35 2 



6D2 



* Rotation of corn, oats, wheat, clover, timothy (Crops grown m order named ) 

 t Rotation of corn, wheat, closer (Crops grown m order named ) 



It is to be noted that the average yield of the 3-year rota- 

 tion without any soil treatment is 21.3 per cent greater than that 

 of the 5-year rotation without manure. With manure, the 3-year 

 rotation produced an average yield 16.2 per cent greater than 

 that of the 5-year rotation. This is significant, since both are 

 considered good rotations. 



It is interesting to note that the average yield for the 3-year 

 rotation without manure is almost as good as that of continuous 

 cropping wherein five tons of manure are used annually. 



SOME PRACTICAL EOTATIONS 



Because of the great variety of crops, soil condition, climate, 

 and of the varied combinations of crops in different systems of 

 farming, many different kinds of rotations are practiced, some of 

 which are recognized as standard. A few of these rotations are 

 given here to show how important crops of the different sections 

 of the country may be grown with best success. Most of these 

 rotations include the use of manure and commercial fertilizers. 



Rotations to Increase Organic Matter. — In beginning the 

 improvement of most depleted soils it is best to practice a rotation 

 that will increase the soil organic matter. In the Northern states 

 a 3-year rotation of corn, grain and clover is common. Farther 



