lecture_3_study_guide-1

lecture_3_study_guide-1 - Grasslands Rangelands -...

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Grasslands –Rangelands - Grasslands cover about 26 percent of the world’s land surface - 10 percent classified as rangelands that are used to graze livestock - 25 percent of rangeland is in developing countries-cleared forests, abandoned cropland - 80 percent of annual production of beef and mutton - Extremely important in grain-poor nations Rangelands - From 1950-2001: World population:2.5-6.1 billion Cattle:720 million to1.53 billion Sheep and goats:1.04-1.75 billion Degraded rangeland: 680 million ha worldwide increasing How can rangeland be managed sustainably? o Population pressure – grow more food and more protein, can only produce so much o Climate change - many are semiarid systems, as climates change some will go from warm areas to real warm areas…some move to deserts o Invasive species - some species come in and are quite different from native species and can cause problems - 10 billion dom esticated anim als worldwide - 30 percent are ruminants - ¾ of the worlds domesticated ruminants feed n rangelands, the rest on feedlots - 200 million people graze livestock on rangeland - 85 percent in Africa and Asia U.S. Rangeland - < 5 percent of the worlds population, 9 percent of the worlds cattle - Livestock graze > 33 percent of north America - More than ½ U>S croplands planted with livestock feed
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- Focus mainly on cattle - Side note: livestock production -50 percent of the annual water consumption in the US 1 pound of feedlot-fattened beef=5 pounds of grain and 280 gallons of water 1000- pound cow = 280,000 gallons of water - Rangeland Minimal use land without irrigation Renewable resource for many materials Vegetation collectively known as  forage Forbs -brad leaved flowering plants Sedges -perennial herb with triangular stems Rushes -grass-like herbs with round stems Rangeland plant characteristics - Most grasses, sedges, rushes  perennial , forbs often  annual, biennial - Deep, fibrous root system - Highly tolerant of low moisture condition - Highly tolerant of fire - Grasses grow from the base of the plant - The lower part (-50 percent)- metabolic reserve - Needed for nourishment of extensive root system - Chronic loss of the metabolic reserve from overgrazing can destroy  rangeland sustainability Rangeland Forage - Decreasers- Highly palatable, decline in abundance with grazing - Increasers Increaser I-moderately palatable, secondary forage, slight increase or stable levels under  moderate grazing; at higher grazing levels, these species also decline
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Increaser II-increase in abundance as range declines: generally unpalatable - Invaders- non palatable Invader I- grazed as last resort Invader II-unpalatable Abundant on overgrazed and undergrazed range Rangeland Grazing - Rangeland sustainability is a function of grazing pressure , grazing and trampling, and is a function of: Type of animal
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This note was uploaded on 10/02/2011 for the course RNR 1001 taught by Professor W.kelso during the Fall '08 term at LSU.

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lecture_3_study_guide-1 - Grasslands Rangelands -...

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