Show increased profits and yields by rotation erosion controlled by proper farm planning the growing of inter tilled crops such as corn and soybeans not only uses plant food faster but the loss los from erosion is greater too enroll on roll ing land according to careful checks made at iowa state college to overcome this condition rotation is important the first requirement of a good crop rotation is thal thai it contains plenty of legumes sod crops of legume 0 grass combination produce much in uch feed per acre and in addition they increase the yields of other crops in the rotation help maintain soil fertility particularly ticul arly the nitrogen and matter produce good soil help control erosion where corn was grown enla in a four year rotation of corn oats followed by clover and timothy for tac years the yield of corn was 32 bushels higher than when grown ir in a corn oats rotation in poor crop years the difference in yield may be than those obtained in 1 r the good crop years of 1942 to 14 1944 4 however the difference between the 98 70 66 n 2 VIAR 4 y g go C OATS CO OATS R car badow legumes in rotation increase the yield of corn marshall silt loam soil conservation experimental farm clarinda la ia years 1912 1942 44 poor and good rotations will probably become greater the longer the treatments are continued one of the most important reasons why crop yields decrease when land is kept in grain crops such as corn and oats is that these crops lower the nitrogen and organic matter content of soils |