If you expect more from your soybeans… maybe they are expecting more from you? If you can’t answer “yes” to all these questions, fertility management could be holding back your soybean yields.
- Do you soil test at least every 4 years?
- Is your % base saturation for potassium 3% or greater?
- Are you tissue sampling for micronutrient deficiencies and hidden hunger?
- Are you maintaining a soil pH in the mid 6’s?
- Do you apply P & K every year on your beans or just once every two years before corn?
- Do you apply any sulfur?
- Are you applying enough fertilizer to replace what record yields are removing today?
- Have you ever applied any micro-nutrients such as boron, zinc or manganese?
- Have you ever tried any foliar nutrition products?
- Do you have a specific fertility management program for soybeans in place? Or… are they supposed to get by on what your previous corn or wheat crop didn’t use?
Does it surprise you that a 75 bushel soybean crop removes 227 lbs. of nitrogen, 150 lbs. of potash, 98 lbs. of phosphate, 15 lbs. of sulfur, 2.6 lbs. of zinc and 2 lbs. of boron? This is just the amount of nutrient that is removed with the grain as it leaves the field. The plant actually needs and takes up far more than this, but the rest of it is recycled back to the soil as the leaves, stems and roots decay. Soybeans actually use far more nitrogen than they fix through their nodules. Enabling a soybean to fix more nitrogen during seed fill could increase soybean yields. Soybeans can scavenge for nutrients, but you should consider the fact they might yield more if adequate amounts of essential nutrients are readily available.
In addition to selecting the right varieties, managing diseases, planting early, utilizing seed treatments, controlling weeds before they exceed 4-6” in height, planting in narrow rows and minimizing harvest losses don’t overlook the basics of soil fertility and plant nutrition when you are striving for higher soybean yields.
Lance Tarochione is a technical agronomist with Asgrow/DEKALB in west central Illinois. His work has focused on crop production, research and product development, and through his role at Monsanto he currently supports the Asgrow and DEKALB brands in seven counties in western Illinois.