 |
||||
|
||||
|
|
||||
Better Weaning Weights Reported; More Crop For Grazing Possible Fertilizing forage crops with sulphur may improve ruminant performance and provide more crop for grazing, according to soil scientists and agronomists that have worked with the nutrient. "Preliminary research in sulphur-deficient areas indicates it may be possible to achieve an economically profitable response in animals by adding sulphur to crops," said Dr. Vivien Allen of Texas Tech University. She first witnessed the trend while conducting research in Virginia. "Calves grazing on sulphur-fertilized fescue had higher weaning weights than calves grazing fescue that wasn't sulphur-fertilized." "The study of calf weaning weights probably translated into a $5 to $10 per acre increase in value as a result of added sulphur," Dr. Allen said, although the results from added sulphur will vary with the area and the crop. Animal responses have occurred even when soil testing indicated no sulphur deficiency, said Dr. Allen, one of seven soil scientists and agronomists that gathered for a round-table on managing sulphur in hay and forage production. The session was held in conjunction with the annual meeting of the American Society of Agronomists. More study is needed, but cows grazing sulphur-fertilized pastures produced calves with higher weaning weights. Dr. Allen thinks the added sulphur -- a building block of protein -- resulted in higher milk production or that it altered milk in a positive way. Increased Crop Availability Besides an economic return on increased weaning weights, adding sulphur might also benefit producers by increasing the crop available to grazing animals. "With hay, we have typically seen a 10% to 30% yield increase with added sulphur in responsive soils," said Dr. Mike Phillips of the University of Arkansas. "That easily will pencil out to a $20 to $30 per acre per year increase in net return. In a cow-calf operation or with stockers, that would increase the carrying capacity of the land at about that same level." Dr. Jack Rechcigl of the University of Florida said that, in his state, the average stocking rate is about two cows per acre. "You might be able to increase the stocking rate because you have more forage grass available to animals. "If we could increase cattle production by a conservative estimate of 10%, this could potentially lead to an increase of $36 million a year to the Florida beef industry. That's the bottom line," he said. Other Benefits Besides increased weaning weights, studies show that added sulphur may have other benefits for animals and crops. In the animal, sulphur improves nitrogen utilization. It also improves dry matter digestibility, which has been demonstrated both in vitro (in the lab) and in vivo in animal studies, Dr. Allen said. "This is contrary to what you'll find in most textbooks; they tell you that if it's not in the feed, don't worry about it, because you can put it in the mineral supplement and go directly to the ruminant animal. That's true for many minerals, but it has not been true for sulphur," she said. "More of the crude protein or nitrogen consumed by the animal is retained in the body. Sulphur-fertilized forage resulted in less nitrogen excretion. That tells us there's better utilization of crude protein." In fact, "In the case of nitrogen utilization in the animal, we've gotten about twice the response by going to the animal through the plant," Dr. Allen said. Similar responses have been found in the Southeast. Dr. Rechcigl said, "Sulphur fertilization resulted in a 1% to 2% improvement in protein content in annual rye grass, a winter crop. It improved in vitro digestibility with Bahia grass forage." Positive results attributed to sulphur fertilization of forage crops tend to show up soon after application. "We see dramatic increases in protein and digestibility 30 days after sulphur application. The benefits tend to disappear after the first harvest, even though we still see increases in crop yield," Dr. Rechcigl said. Dr. Ray Lamond of Kansas State University reported, "In brome grass, we didn't see much difference in crude protein or digestibility when analyzed around harvest time. But when we sampled in mid-April -- prime grazing time for forage and closer to the time of sulphur application -- we saw major, positive differences." Determining Sulphur Needs To determine when and how much sulphur should be added, Dr. Allen said, "I'd look at a plant tissue analysis. If sulphur content is less than 0.2%, then I'd start looking for other indicators that there might be a need for sulphur fertilization." Dr. Phillips said that if a soil test indicates less than 25 pounds per acre of sulphur, "We recommend sulphur be added with the first nitrogen application on warm-season perennials at a rate of 24 or 25 pounds of sulphur per acre. That's our recommendation whether it's for hay or grazing purposes." Dr. Donald Messick of The Sulphur Institute in Washington, D.C., noted that the type of sulphur added is important. For a first-time application, a sulphate form of sulphur is generally preferable, particularly if conditions are wet and cool. If using an elemental form of sulphur, make sure to select a source whereby conversion to sulphate occurs within the growing season if an immediate response is required. Kansas State University's Dr. Lamond, who has studied various forms of sulphur sources for forage crops, agreed and added, "It's only an issue the first time you fertilize with sulphur in cool-season forages. Elemental sulphur can be used for subsequent annual applications." In cooperation with university agronomists, The Sulphur Institute has prepared a series of non-commercial, educational bro- chures about sulphur need and use in major field crops, including forages, for various regions of the country. For free copies, send your name, address and list of crops grown to The Sulphur Institute, 1140 Connecticut Avenue NW, Suite 612, Washington, DC, 20036. Phone: 202/331-9660. Fax: 202/293-2940. E-mail: agmarkt@ sulphurinstitute.org. URL: http:// www.sulphurinstitute.org. |
||||
|
|
||||
|
|
||||
|
All information is copywrited by Feed Lot magazine and cannot be printed or re-printed
without the publishers express consent. Please contact
Feed Lot Magazine for reprint and copy authorization.
|
||||