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Mob Grazing –

A Tool to Improve Pastureland by heaTher SMiTh ThoMaS

T

he term mob grazing is often used to describe short duration high-intensity grazing—with many cattle on a small area of pasture, moved once a day or several times a day to a new section of pasture. Doug Peterson, NRCS State Grassland Conservationist in Missouri, says the term mob-grazing is somewhat vague and there are many interpretations.

Mob Grazing Defined At Earthwise, the Jersey cows are milked by hand out in the field. Due to the incredible abundance of feed this year, we decided to purchase a square baler and plan to harvest some feed in July on at least 5 of our 10 amended pasture acres. In the past (before we had our two cows and 3 steers) my husband would mow a few acres with his horses and store the hay (loose, stacked) in our neighbor’s barn. In order to store a greater amount of feed that is easier to handle and with minimal financial investment, purchasing a used square baler ($1,200) made the most sense for our farm. We do not have a tractor, so we also needed a piece of equipment that our draft horses could pull. The cost for the 2011 amendments were: • 18 tons lime @ $52/ton delivered . . . . . . . . . . . . . $940 • 2 ton SulPo Mag/Gypsum @ $550/ton. . . . . . . . . $1100 • Micronutrients: Zinc Sulfate, Manganese Sulfate, Boron, Humates – applied at $75/acre . . $750 • Total amount invested on amendments for 2011 . $2,790 So have we recouped our investment from last year? Not yet, but if we manage to harvest even 150 square bales this year, that will be $600 that we will not be spending on purchased feed and about 20% of our purchased feed needs. If we can hold steady with soil nutrients then we will pay off the investment in 5 years. Moreover, this investment will also be moving us closer towards our goal of not having to purchase any winter forages. We plan to take another soil test in 2013 to see how things have changed and will decide then whether it would be prudent to apply any additional nutrients. I feel that with our Management Intensive Grazing and holistic planned grazing, we are making gradual improvements year after year, and anticipate that our fields will not need any additional inputs. The soil test that we take next year will be very interesting indeed and will help us assess the value and impact that the amendments had on our pastures. We may pay off our investment sooner than we think. Lisa McCrory is a mentor and instructor for HMI’s Beginning Women Farmer Program. She can be reached at: Lmccrory@hughes.net or 802/234-5524.

“Whenever someone tells me they are mob grazing, I want to know what stock density they are using, in pounds. Are they using 100,000 pounds per acre, or 10,000, or half a million pounds of animal weight? Stock density is determined by pounds per acre, so 100 thousand-pound cows per acre would be 100,000 pounds. The calculation of stock density doesn’t take into consideration how long you leave them there (one day, half a day or two days), that’s 100,000 pounds. If you put those same 100 cows on a half acre, that’s 200,000 pounds of stock density. If the 100 cows are on 10 acres, that’s 10,000 pounds of stock density. This figure tells me almost everything I want to know. It tells me their trampling rate, how often they will be moved, and to some extent what the pasture rest period will be, and so on,” says Peterson. “My primary experience with mob grazing comes from my own operation. We have a 200 cow-calf beef operation and run another 200 contract cows on the side. I was a soil scientist with NRCS for a while and have a strong interest in soils. I’ve been a student of Jim Gerrish’s management intensive grazing (MIG) and a student of Holistic Management and Allan Savory. Savory taught me about the tool of animal impact. We had several things happen in our own operation that led us to see some of the things that animal impact and trampling could do. About 5 years ago Ian Mitchell-Innes (from South Africa) and Chad Peterson in Nebraska were both starting to get some folks following their ideas about higher density grazing, so we weren’t the first to do this, but were always willing to try new things.” ConTinueD on PaGe 14

Doug and the Peterson crew before moving fence for their cattle. Farming is a family affair.

number 145

Land & Livestock

13


#145, In Practice, Sept/Oct 2012