ROTATION 381 



aiid likewise of the other great money crops, such as cotton, tobacco, 

 potatoes and others. 



As a general rule a rotation of three to live years is more desira- 

 ble than a longer one. The short cycle requires less trouble and time 

 to get it started and is easier to maintain when once under way. 

 If a crop fails in a three- or four-year cycle it is not difficult to 

 maintain the rotation, while if a failure occurs in a longer cycle it 

 may disarrange the system to a greater or less extent. 



Because of the rearrangement of fields and the adjustment of 

 crops, it is rather difficult to get a rotation under way, usually re- 

 quiring several years, and it is almost equally difficult to change it 

 after once it is started. The rotation should be maintained even 

 if a crop does fail. A substitute crop should be planned to take the 

 place of those crops that are liable to fail. This will not be needed 

 very often. 



The farm should be divided into as many fields as there are 

 years in the rotation and the crops grown in regular succession on 

 these fields. On large farms the rotation may be duplicated. There 

 should be at least one legume crop, preferably a biennial or peren- 

 nial, and not more than two tilled crops, during the cycle, the 

 number depending upon the soil, as these cause considerable loss of 

 organic matter. 



Places in Rotations for Crops. Corn succeeds well after 

 clovers, alfalfa and pasture and docs fairly well after wheat and 

 oats, especially for fall plowing. Jn sod ground two or three crops 

 of corn may be grown successfully, but more than two in succession 

 on ordinary soil are not deemed best. 



Wheat does not follow corn well even if the latter matures sev- 

 eral weeks before seeding time. Wheat does well after potatoes, 

 clover, alfalfa, pasture or soybeans, the only danger being its liability 

 to lodge caused by the excess of available plant food, especially 

 nitrogen. Oats is a good crop to precede wheat if the plowing is 

 done early. Wheat follows wheat very well, but there is too much 

 danger from Hessian fly in some latitudes. 



Oats is a crop that is adapted to the cooler part of the temperate 

 zone. South of this the ordinary spring-sown oats encounter the 

 hot weather at filling time, so that a partial failure may result. In 

 the South winter oats are grown to soine extent with fair success. 

 There is a belt, between these where neither fall nor spring oats 

 do well. The summers are too hot for the spring seeding and the 

 winters too cold for the fall oats. 



