grasslands

Cattle grazing may restore grasslands and reverse desertification

In a series of lectures, Dr. Allan Savory, a biologist and former Zimbabwean farmer claims that mis-managed cattle grazing, such as has occurred in Africa, has turned grassland into desert, but properly managed cattle grazing can reverse the process, reclaim the desert, and turn it once again into productive grassland.

Savory was a member of the Rhodesian Parliament and had to go into exile after opposing the policies of Ian Smith. In 1992, Savory founded the Savory Institute in Boulder, CO, and the Africa Centre for Holistic Management in Victoria Falls, Zimbabwe. You can watch videos of his 2009 lectures here and a February, 2013, lecture here (22 minutes).

Savory’s basic thesis on grazing is this:

“In the past, large wild herds of herbivores such as caribou and buffalo migrated over the land to find food and avoid predators. These herds grazed, defecated, stomped and salivated as they moved across the grasslands, building soil and deepening plant roots. Once these herds had migrated onward they would not return to an area until it had recovered.”

“Unfortunately, over time, the wild herds disappeared and were replaced by small numbers of domestic, sedentary livestock. Without the timely stomping and excrement of large numbers of animals, the cycle of biological decay in these grasslands was interrupted and the once-rich soils turned into dry, exposed desert land.”

Savory’s solution is to concentrate grazing in small areas and move the cattle frequently. I have seen this method practiced in the Cape Province of South Africa when I was doing geologic exploration there many years ago. There, the land is very flat as shown in my photo. There are miles and miles of miles, as one South African colleague put it.

The Savory setup is to establish a central water source, then encircle it with six to eight, relatively small, wedge-shaped pastures enclosed with barbed wire. Cattle are grazed in one or two of the wedges and moved frequently. This short-term, intense grazing does help restore the grasslands in this area.

Would this method be beneficially applicable to cattle grazing in Arizona? To find out, I consulted a friend who is a cattle rancher in Southern Arizona, an expert on desert grasses, and familiar with the Savory system. The answer is “no” at least in Southern Arizona, because:

The Savory Method is highly intensive, requires enormous expense in mini-pasture fencing and constant moving of livestock. Desertification is certainly a concern in Africa. But here it is of less concern because of our intensively monitored and managed systems (developed largely on the Santa Rita Research Ranch in the Green Valley area by U of A agricultural experts). We manage according to agreement with the Forest Service and State Land Department based on this locally-derived science. Desertification is simply not happening in this area.

The pattern here is larger pastures with rest-rotation systems geared to our bimodal rainfall regime with the primary growth in the summer. Entire summer rest is provided (in fact, about 20 months) every other year on most of our summer pastures. Our herds are generally in one large pasture for a season and then are moved to pastures with forage that has had a significant regrowth period. This process seems to produce the best plant community including wildlife habitat and promotes sustainable or steadily above-sustainable production of herbage with the widest variety.

Our rugged, distant, forest pastures don’t lend themselves to mini-pastures: we’d have to drill many more wells or put in more miles of expensive pipelines. We would also have the problem of maintaining many fences cut by folks moving illegally north. The Savory system may well get good results in flatter, privately owned, access-controlled land, but that is quite different from Southern Arizona ranchland.

We see, therefore, that there is not a universal solution, but great benefit when methods of better practice are designed for local conditions. And in each case examined here, cattle grazing can benefit the environment.

While this result may be surprising to some and contrary to the precepts of radical environmental groups, it is just common sense that cattle growers have an economic interest in keeping the range healthy and productive.

See also:

Buenos Aires National Game Refuge This post gives a history of ranching in the Altar Valley.

Ranching and agriculture in Arizona, The Arizona Experience

Biofuels program destroying grasslands in American Midwest

Biofuels destroying grasslandA new study by researchers at South Dakota State University, published in the Proceedings of the National Academies of Science (see full paper here), shows that more than 1.3 million acres of grasslands in the western corn belt (WCB) of North Dakota, South Dakota, Minnesota, Iowa, and Nebraska, have been converted to agricultural use since 2006 to grow corn and soybeans for biofuel production.

The researchers introduce their paper by writing:

“In the US Corn Belt, a recent doubling in commodity prices has created incentives for landowners to convert grassland to corn and soybean cropping. Here, we use land cover data from the National Agricultural Statistics Service Cropland Data Layer to assess grassland conversion from 2006 to 2011 in the Western Corn Belt (WCB)…”

They go on to write:

“Our analysis identifies areas with elevated rates of grass-to-corn/soy conversion (1.0–5.4% annually). Across the WCB, we found a net decline in grass-dominated land cover totaling nearly 530,000 ha.[hectares]. With respect to agronomic attributes of lands undergoing grassland conversion, corn/soy production is expanding onto marginal lands characterized by high erosion risk and vulnerability to drought. Grassland conversion is also concentrated in close proximity to wetlands, posing a threat to waterfowl breeding in the Prairie Pothole Region. Longer-term land cover trends from North Dakota and Iowa indicate that recent grassland conversion represents a persistent shift in land use rather than short-term variability in crop rotation patterns.”

“The concentration of grassland conversion on lands vulnerable to erosion implies negative impacts on soil quality and a subsequent cascade of negative impacts on, e.g., crop yields, primary productivity, and carbon sequestration. Tillage of adjacent uplands increases sediment inputs to wetlands by several orders of magnitude, limiting the productivity of duck food sources, including aquatic plants and invertebrates, and reducing food water storage.”

In the conclusion, the researchers note:

“Our results show that rates of grassland conversion to corn/soy (1.0–5.4% annually) across a significant portion of the US Western Corn Belt are comparable to deforestation rates in Brazil, Malaysia, and Indonesia, countries in which tropical forests were the principal sources of new agricultural land, globally, during the 1980s and 1990s. Historically, comparable grassland conversion rates have not been seen in the Corn Belt since the 1920s and 1930s, the era of rapid mechanization of US agriculture. Across the WCB, more than 99% of presettlement tallgrass prairie has been converted to other land covers, mostly agricultural, with losses in Iowa approaching 99.9% of an original 12-million ha. of tallgrass prairie. Potential expansion of corn and soybean cultivation into remaining fragments of tallgrass prairie in the WCB presents a critical ecosystem conservation issue.”

This is another example of so-called “green energy” being not so green. As the authors note, ” A number of studies have now shown that a biofuel strategy based on corn ethanol and soy biodiesel may indeed be suboptimal in terms of net energy and carbon balances.”

See also:

Ethanol fuel not as green as you think

Ethanol from Sugarcane, not so green

Death Toll from Biofuels