Computer Can't Evaluate Range
Management If Data Is Wrong

By David Bowser

TRUTH OR CONSEQUENCES, N.M. — Garbage in, garbage out. Dr. Jerry Holechek says computers are only tools, not silver bullets. The information that comes out of them is only as good as the information that goes into them.

Holechek, a professor at New Mexico State University, wrote the program for the Forest Service's forage management. While permittees say they are told by the Forest Service that the computer program demands they run fewer cattle on their grazing permits, Holechek says that decision has to be made by people, not computers. He also says that what the computer program indicates as far as forage management and related stocking rates depends upon the information put into the program.

Earlier this fall, Holechek and a number of academics toured a grazing permit near here in which the Forest Service had cut the allotted number of animal units. The permittee is appealing their decision.

Holechek says based on what he had been told, he expected to see a dry, arid high desert pasture with little grass. What he saw were pastures with plenty of forage.

The problem, Holechek says, appeared to be not with the computer program that indicates the stocking rate should be cut, but rather with the information that was put into the program.

Apparently, the Forest Service last monitored the pastures in the early summer following a dry spring. That was the information fed the computer.

The region, however, gets its monsoonal rains in July and August. By the fall when Holechek, the Forest Service and the permittee returned to the pastures, they were filled with thick growths of grass.

The moral of that story, Holechek says, is that rangelands need to be more closely monitored. Although the Forest Service pleads a shortage of time and personnel, viewing it once a year is not enough to provide adequate data on which to make decisions, whether a computer is used or not.

Still, Holechek says, grazing is grazing, and a few basic principals will always apply.

The cornerstone of grazing management, he says, is a combination of proper stocking rate, proper distribution of grazing animals, proper types of grazing animals and the proper grazing system.

"Generally, the most important of these is considered to be the proper stocking rate," Holechek says.

The stocking rate is based on the amount of forage available and the amount that a rancher or government agency, in the case of grazing public lands, will allow to be used.

Heavy grazing is defined by the Society of Range Management as a degree of herbage use that does not permit desirable forage species to maintain their presence. Moderate grazing is defined as maintaining the sustainability of grazing, while light grazing allows for maximized production of the forage species.

"This is well confirmed by research," Holechek says.

He is a proponent of conservative grazing, which he defines as between light and moderate grazing.

Holechek says he reached this conclusion after reviewing various studies on North American grazing. Such a grazing program, he says, would involve removal of about one-third of the forage from the pasture being grazed.

"Whether that's necessary to maximize your financial position and maintain the range, that issue is debatable," Holechek says.

The grazing picture can also change with the introduction of wildlife into the equation, he notes.

"We visit a lot of areas where the elk really do impact the range condition and forage production," Holechek says.

Trees are another serious problem on some grazing permits.

"If they get too dense, you'll lose all the feed," he warns.

He says he found research done on the Jornada Experimental Range concerning black grama, one of the most important forage plants in Southwest New Mexico, to be most interesting.

With plots of black grama being grazed conservatively at about 30 percent usage, moderately at about 50 percent usage and heavily at about 60 percent usage, the conservatively grazed plots did better than protected plots that were used for control purposes.

"The plants were actually healthier," he says.

He made a point to further study protected areas in New Mexico and Texas.

"I decided from the ecosystem health of these plants that this grazing is probably a whole lot better than no grazing at all," Holechek says.

The NMSU professor also worked with ranchers in Mexico.

"I found out that none of them ever took any classes in grazing management, but they had years of experience," he says.

They, too, were firm believers in conservative use of their forage through light stocking rates and well-distributed watering points.

During a dry period when he was working with them, Holechek says, he was amazed driving through their herds and seeing nice, fat cattle.

They told Holechek that they try to stock lightly through the worst of years, and they shuffle their cattle around to where they have rain by manipulating their water resources.

"There were elements of rotation in there," Holechek says.

Among the keys points of different grazing studies he's reviewed, Holechek says, there are certain things that the studies seem to have in common.

"Among the things that jumped out at me were how sensitive calf crops were to the stocking rates," he says.

Based on the studies, he also concludes that it is much better to err on the side of too light a stocking rate than too heavy.

Holechek says that while there may be some disagreement among range experts on range management, most agree that specialized grazing programs will not overcome the impact of excessive stock.

In Holechek's review of grazing studies, he also looked at various rotational grazing programs.

"When I averaged all these, the financial returns were slightly higher for the continuous system while higher livestock productivity is associated generally with continuous systems," Holechek says.

There was, however, one important exception, Holechek says.

"The Merrill three herd/four-pasture system down in Texas has been a solid performer and given better results," Holechek says. "It's really given superior results in livestock productivity, financial returns and vegetation performance. I think this is the strategy that we really need to look at here in New Mexico."

Where heavy stocking really catches up to ranchers is in dry years, he says, particularly in the desert environment.

"Heavy stocking has the greatest effects on forage production in drouth years, and that's when you need it the most," he says.

Another of the things that stands out in the research he has studied is how much more reduction in forage there is in desert areas during drouth years than in tallgrass prairies and shortgrass prairies.

"In 1994 and 1995 we were so dry we produced almost next to nothing," he says of New Mexico.

Other studies show that mulch and residue levels go up as the water intake rate goes up, generally resulting in increased forage.

Studies going back to 1953 conclude that conservative stocking rates result in higher financial returns.

While there are some studies out of Arizona, Holechek says, that show year-around grazing is better than rest-rotational grazing, the New Mexico professor says he does some consulting work for some Arizona ranchers who have had good results with rotational grazing.

"In rugged terrain, I think these rotation schemes can be effective in riparian recovery and can work well in uplands," Holechek says, "particularly when combined with conservative use."

Many of the rotation grazing systems seem to work well from a range condition and forage standpoint. Financially, it may take 10 years before the fencing is paid off, so such systems would have to be viewed in extended time period terms.

Holechek says that in some of the studies he's reviewed, there seems to be little difference in vegetation response between short duration grazing and continual grazing in New Mexico, but there is a significant difference in livestock production.

"The results indicated that cow-calf performance under short duration grazing was less than under moderate continuous grazing," Holechek says.

His basic conclusions are that stocking rates rather than grazing systems are the primary factor for biological and financial outcomes of livestock grazing on rangeland, whether computers are used or not.

Rotational grazing has also shown little ecological advantage and no financial advantage over continuous grazing in arid and semi-arid environments, he says. Rotational grazing systems have been most effective ecologically in rough terrain.

But perhaps most important to the permittees dealing with federal agencies concerning stocking rates is that decisions based on Holechek's computer program can be subject to human error.

Computers do not take the measurements nor do they monitor the land; they only crunch the numbers that are entered into their databanks.