Importance of potassium for bermuda hay fields

Potassium is often the most overlooked element in producing hay here in East Texas.  For years producers have just thought about nitrogen.  For the last 5 years, fertilizer recommendations have been calling for more and more potassium as producers have been neglecting this much needed nutrient.  Soil potassium levels/fertility does not affect crude protein and digestibility (TDN, ADF) of forages. Deficient or low potassium fertility levels will most assuredly reduce forage growth.  In other words, it can become first limiting nutrient and decrease overall yields.

Potassium (K) is an essential element in plants and is considered one of the three macronutrients, along with nitrogen and phosphorus.  Nearly all routine soil tests show how much potassium is available along with nitrogen and phosphorus.  It is the last number in a fertilizer blend recommendation.  Unfortunately, with recent price increases, it has gone from being the least expensive to the most expensive of the three macronutrients.

In soil chemistry, you have positive (+) and negative (-) charged particles.  Potassium is taken up by plants is in the ionic form (K+).  Soils have negative electrical charges due to clay and organic matter, therefore the potassium is held magnetically to the clay and organic matter particles in the soil.  The more clay or organic matter, the more strongly the potassium is held.  Unfortunately, in our deep sands, there is little to hold the potassium and it can leach down past the root zone.  This lack of organic matter in sandy soils can be a cause of potassium deficiency.

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