There has been a lot of research on this related to nitrogen and phosphorus, but I am not aware of anything published on potassium. Let’s first agree that loss is only going to occur if the rainfall event creates surface runoff (the CEC in question… Read More
Ideas, information and insights from real farmers on effective crop nutrient management strategies.
Like most production issues, nutrient deficiencies rarely affect an entire field. When there are areas that are exhibiting suspected nutrient issues, here is the best way to go about determining what the likely issue is. Ideally, plant tissue and soil samples should be collected for… Read More
The two biggest factors that affect potassium availability are soil moisture level and soil pH (assuming there is an adequate supply on the soil exchange sites, which are measured through soil testing). Soil Moisture Level As the soil dries, potassium availability can be decreased for two reasons:… Read More
What is the best resolution to collect soil test information (every 0.5 acres, every 2 acres, every 5 acres)?
This is a difficult answer to provide for every field and every situation. In fact, research to find this answer reveals that there is no single “right” resolution. For some fields, sampling at a resolution of 0.5 acres is economically justified, for other fields a… Read More
The soil pH is a measure of the active acidity or the hydrogen ion concentration in solution. Depending on the laboratory used, the soil pH solution can be distilled water or a low salt concentration solution like 0.01 M CaCl2 or 1 M KCl. In… Read More
Compared to corn, legume crop production thrives under slightly higher pH (6.2 to 6.8). Legumes, like soybean and alfalfa, form symbiotic relationships with rhizobia to form nodules in roots that biologically fix nitrogen. If the soil pH is too low, this can negatively affect the rhizobia… Read More
In general, phosphorus is immobile in soil due to the chemical bonds a phosphate ion can form. Phosphorus from commercial fertilizer and soluble phosphorus in the soil — phosphate — is either present as H2PO4¯ or HPO4¯2 when the soil pH is near neutral. These are… Read More
To put it simply, potassium regulates the opening and closing of plant stomata. Stomates are the pores on plant leaves that allow for gas and water vapor exchange. When plants have adequate potassium, the guard cells swell and allow for complete closure of the stoma… Read More
In short, yes, there are differences in methods. The phosphorus soil test is an index of phosphorus availability, which ultimately tells a farmer the likelihood of a response to fertilizer application. Universities have conducted many site years of research correlating plant available phosphorus in soil… Read More