Farm Progress

Forage producers need rainSubsoil moisture helped by fall rainfallRotational grazing recommended

March 7, 2011

4 Min Read

The rainfall we received in January was very welcomed, but now we’re wondering when will the next beneficial rain come?  February, 2011, in the Coastal Bend was one of the driest on record, and in recent years that phrase “driest on record,” has become too common.

Farmers have been busy planting corn, and grain sorghum, while topsoil moisture is leaving fast.  Fortunately, we have good deep soil moisture thanks to last year’s good July and September rains.

If you are in the cattle business, you know it’s been a long winter, and you are tired of feeding hay and protein.  We need rain to jump start warm-season grasses. Unfortunately, long-range forecasts show below normal rainfall for the next couple of months.

Forages are the foundations of a successful cow-calf program. In general, the better the ranch’s forage system, the greater the resulting animal production, and we need rain to drive this system.

Improved pastures should be fertilized according to a recent (within two to three years) soil test recommendation, especially now with the high fertilizer costs. Proper fertilization will enhance vigorous plant growth.  A ton of forage with 10 percent crude protein contains 50 pounds of nitrogen, 10 pounds of phosphorus, 40 pounds of potassium and varying amounts of the other chemical elements needed for growth—sulfur, calcium, magnesium, iron, zinc, copper, boron, manganese, molybdenum, and chlorine.  A ton of forage will not be produced if any of these nutrients are lacking. Most soils have enough nutrients and nitrogen to produce one to two tons of forage per acre.

Improved grasses were selected for higher yield potential and need additional nutrients (especially nitrogen, phosphorus, and potassium) to produce at an economical level.  In grazing systems only a small amount of the nitrogen, phosphorus and potassium contained in the forage a cow eats is retained in the animal’s body.  Most is recycled by urine and/or feces back to the soil. This occurs in grazing systems; once phosphorus and potassium levels are brought up to a high level, they should remain there without extra fertilization. Nitrogen will still be required.

In hay systems, every ton removed from the field will remove 50 pounds of nitrogen, 10 pounds of phosphorus, and 40 pounds of potassium. This will eventually have to be replaced by fertilization. Rotational grazing

Therefore, the best system is rotational grazing and harvesting hay from the excess growth in the spring and fall.  If one neglects to put out the needed phosphorus and potassium, over time the improved grasses will slowly lose vigor and be replaced by invader grass species.

Weed control in pastures affects forage quantity and quality significantly. Broadleaf and grassy weeds infest many pastures.  Adequate rainfall, large weed seed populations, and a long growing season are conducive for weed growth, but at the expense of forage growth.

Many weed species germinate earlier than spring grass green-up, using soil moisture and fertility for rapid growth.  Only small amounts of forage are produced in weedy pastures, even with proper fertilization.  Weeds can be controlled or prevented by maintaining a thick, vigorous grass stand, or by using mechanical (shredding or plowing) or chemical methods. In native pastures one pound of grass is produced for each pound of weed controlled. In result demonstrations in improved pastures, 2 to 7 pounds of grass was produced for each pound of weed controlled.

Grazing systems can improve forage production and animal performance.  While each grazing system has its place, use of the same grazing system on all forage systems will not always be profitable.  Rotational grazing systems on native rangeland are designed to maintain or increase the presence and vigor of desired plant species. The theory is that as these higher quality desirable plants become more vigorous and predominate in the pasture, livestock performance will improve. 

Bermudagrass does not require periods of rest for stand maintenance and vigor, thus the rotation schedules are used to control utilization and quality.  Rotating bermudagrass pastures hardly ever increases average daily gain. The goal of rotating such pastures is better utilization of forage to increase gain/acre, or to allow for other management practices.

One factor that will enhance all forages is adequate rainfall, so let’s hope that this spring will bring some good rains to South Texas. 

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