Principles of Grazing Management
Feeding the underground herd By Gilda V. Bryant
D
URING THE DEVASTATING DUST BOWL ERA OF THE 1930s, scientists developed a strategy to help farmers and ranchers take better care of their
land by minimizing wind and water erosion. Today, the USDA Natural Resource Conservation Service (NRCS) recommends a 5-point approach to maintaining healthy pastures.
Grazing management begins with the soil. Bare soil often forms a crust that limits water and
air infi ltration. It tends to have massive structure — large, hard chunks of compacted dirt lacking insects, bacteria or humus. It’s diffi cult for roots to penetrate to capture water and nutrients. Soil experts say this soil is bare, naked and hungry. One sign of healthy soil is a vegetative layer that keeps
it cool and moist. Easy-to-dig holes produce a rich, earthy aroma. Dark organic matter and soil particles that clump together in a crumb-like structure should be visible. Earthworms and various insects are present, indicat- ing a robust population of bacteria and other microbes.
90 The Cattleman February 2015
Bacteria and protozoans, such as amoebas, are the
unseen heroes of soil health. These “bugs” or “biology” are necessary for the nutrient cycle to occur. Bacteria can be called the jackrabbits of the micro-
world because predators eat them. The nutrient cycle works the same way. Protozoans have to eat 6 bacteria to meet their carbon
requirements. Needing only 1 unit of nitrogen, how- ever, they accumulate excess amounts in their bodies and release it into the soil as waste. It then becomes plant-available nitrogen. Charles Kneuper, range management specialist with
USDA NRCS, says it takes around 50 units of nitrogen to produce 2,000 pounds of a warm season grass. Several years ago, Kneuper took soil samples from a pristine prairie and sent them to be assayed. He then estimated the site’s forage production to be 6,000 pounds. “The soil sample showed that we only had 50 units
of nitrogen in the soil,” recalls Kneuper. “How did we produce 3 tons of biomass, when we only had enough nitrogen for 1 ton? It’s because we had bacteria and
thecattlemanmagazine.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124