Importance Of Potassium In Soybeans
Soybeans have a big appetite for potassium, writes agronomist Dan Davidson on ILSoyAdvisor.com. So, are you feeding them enough?
Soybeans require potash and plenty of it and remove more than corn. A 200-bushel corn crop will remove 50 lbs. of potassium per acre, while an equivalent 70-bushel bean crop will remove 84 lbs. How much attention do you pay to making sure potash levels are adequate before you plant your soybean crop?
Many growers have routinely applied fertilizer before two successive crops of corn and let their soybeans scavenge for leftovers. We all know what happens to pigs that become the runts of a litter — they always get the leftovers and remain small their entire lives.
The problem with potassium is that what you apply is not necessarily readily available to the second-in-the-rotation soybean crop, especially 18 months after you apply it. When managing your potassium program, consider the following:
- Potassium is relatively immobile in the soil, so availability depends on location and soil characteristics.
- No-till and minimum tillage methods, as well as compaction, can limit root growth and access to potassium.
- No-till can stratify potassium near the surface, above the root zone.
- Soil temperature, pH and moisture impact potassium availability.