Page 14-Corn Talk, Lancaster Farming, Saturday, July 17,1993 TILLAGE AND CROP ROTATION EFFECTS ON CORN YIELDS Greg Roth A recent study published in the Journal of Production Agri culture by M. G. Lund, P. R. Carter, and E. S. Oplinger eva luated the effects of two tillage systems no-till and mold board plowing and crop rotations (continuous cropping, com/soybean, wheat/soybean/ com, and soybean/wheat/com) on the growth and yield of com wheat and soybeans. The study showed that conti nuous cropping reduced yields of com by 10 percent and soy bean by 15 percent compared to when die crops were in rotation. Generally, yield, reductions because of continuous cropping were greatest under no-till. The effects of rotation and tillage were less consistent on wheat as the effect varied from none in one year to a 36 percent reduction in another. With wheat, the tillage influence on MILK q —: 0 g ; M&R GRAINS, INC. 4* * ■ #• g ROASTED SOYBEANS o DEALERS IN BARLEY, CORN & SOYBEANS FITNESS YOU CAN DRINK Not Just Your Ordinary Top Loader! (519) 856-4927 the rotation effect was less con sistent in some years the tilled plots were most affected and in another year when Sep toria and leaf rust diseases were severe, no-till treatments were more affected by continuous cropping. Com yields were similar in each of the three rotation sequ ences except for no-till com after wheat, where yields were reduced by 6 percent. The authors suggest that the same allelopathic factors that reduce yields of com following rye may cause the yield reductions following wheat, since the early season com was about 8 inches shorter than the no-till com fol lowing soybeans. In this study, the straw from the wheat was not baled or removed and this may have increased the poten tial for allelopathic effects. This study did not show any difference in soybean yields for a one- or two-year rotation. Some previous research has shown a benefit from increas ing the time between soybeans Unload vonr silo without t/ A Blower V Any Gearboxes f/ An Electric Ring Get Greater Volume Of Output Yes, We Can Install In Fall Or Partially Full Silos. Never climb your silo to change doors. in the rotation to more than just one year, but the authors sug gest it may need to be more than two years as they had in this study to be significant. In summary, the study did not show any consistent improvement in com and soy bean yields by going to a three year rotation, including wheat. In Pennsylvania, the advan tages of wheat in a rotation may be greater than in this study for several reasons: • In southeast Pennsylvania, wheat yields are not reduced by late planting following com and soybeans as much as they are in Wisconsin. • In some areas, soybeans can be double cropped with the wheat, adding to the profitabili ty of the wheat. • Control of perennial weeds in no-till programs can be suc cessful following wheat harvest. A common problem with surface applications of urea containing fertilizers such as urea and UAN solution is the potential for a significant loss of N from the fertilizer by volatilization. The results of a three-year study designed to evaluate the effect of application timing and method of liquid nitrogen (UAN) to com was recently published in the Journal of Pro duction Agriculture. The study In grain bodies, aluminum makes Sense. CHECK OUT THESE FEATURES/BENEFITS • Up to 40% lighter than steel, for greater payload • Designed for long life • Resale value • Corrosion resistant, never needs painting • Appearance to complement any truck • Complete list of popular options, including * tailgates, tarps and sides. Committed to the Agri Transportation Business NITROGEN MANAGEMENT OF UREA-AMMONIUM NITRATE SOLUTION (UAN) IN NO-TILL CORN Greg Roth Doug Beegle / / /