High Yields Demand High Soil Tests

Farmers and researchers planning to work toward higher yields must consider the nutrient uptake requirements for higher yields. Not only does the total nutrient removal increase, but also the daily nutrient requirement increases, so soil test levels must be increased to help insure that the total daily demand for nutrients can be met throughout the growing season. Since up to 98% of the nutrients move to the plant by diffusion, higher concentrations in the soil help increase rate of availability.

As examples of the daily nutrient supply needed to grow high-yielding crops, Tables 1 and 2 report the nutrient uptake rates measured by Dr. Roy Flannery at Rutgers University of his high-yield corn (308 bu/A) and soybeans (101 bu/A). This is one of the few studies where detailed nutrient uptake rates were measured for such high yield levels.


TABLE 1.



TABLE 2.





Summarized by H. F. Reetz, 11-26-2000.