Bahan kuliah PR (4): Rangeland

Rangeland refers to expansive, mostly unimproved lands on which a significant proportion of the natural vegetation is native grasses, grass-like plants, forbs, and shrubs. Rangeland also consists of areas seeded to native or adapted introduced species that are managed like native vegetation. Rangelands include natural grasslands, savannas, shrublands, many deserts, tundra, alpine communities, coastal marshes, and wet meadows. Rangeland is generally arid, semi-arid, sub-humid or otherwise unsuitable for cultivation.

arid

In general terms, the climate of a locale or region is said to be arid when it is characterized by a severe lack of available water, to the extent of hindering or even preventing the growth and development of plant and animal life. As a result, environments subject to arid climates tend to lack vegetation and are called xeric or desertic.

Semi arid

Semi-arid climate or steppe climate generally describes climatic regions that receive low annual rainfall (250-500 mm or 10-20 in). A more precise definition is given by the Köppen climate classification that treats steppe climates (BS) as intermediates between the desert climates (BW) and humid climates in ecological characteristics and agricultural potential. The Köppen climate classification allows adjustments for temperature and for seasonality of precipitation, effectively excluding forested regions (such as those in most of Canada and Siberia)

Tillage

Tillage, or cultivation is the agricultural preparation of the soil by digging it up. Tillage can also mean the land that is tilled the process of fostering the growth of something; "the cultivation of bees for honey" : the act of raising or growing plants (especially on a large scale) The process of promoting the growth of a biological culture.

Tillage systems

intensive tillage

Intensive tillage systems leave less than 15% crop residue cover or less than 500 pounds per acre (560 kg/ha) of small grain residue. These types of tillage systems are often referred to as conventional tillage systems but as reduced and conservation tillage systems have been more widely adopted, it is often not appropriate to refer to this type of system as conventional. These systems involve often multiple operations with implements such as a mold board plow, disk, and/or chisel plow. After Moldboard plowing, a disk is often used to break clods. Then a a finisher .....with a harrow, rolling basket, and cutter head can be used ..... can be used to prepare the seed bed. There are many variations.

Reduced tillage

Reduced tillage systems leave between 15 and 30% residue cover on the soil or 500 to 1000 pounds per acre (560 to 1100 kg/ha) of small grain residue during the critical erosion period. This may involve the use of a chisel plow, field cultivators, or other implements. See the general comments below to see how they can effect the amount of residue.

Conservation tillage

Conservation tillage systems are methods of soil tillage which leave a minimum of 30% of crop residue on the soil surface or at least 1,000 lb/ac (1,100 kg/ha) of small grain residue on the surface during the critical soil erosion period. This slows water movement, which reduces the amount of soil erosion; it also warms the soil, enabling the next year’s crop to be planted earlier in the spring. Conservation tillage systems also benefit farmers by reducing fuel consumption and soil compaction. By reducing the number of times the farmer travels over the field, farmers realize significant savings in fuel and labor. Conservation tillage was used on about 38%, 109,000,000 acres (440,000 km²), of all US cropland, 293,000,000 acres (1,190,000 km²) planted as of 2004 according to the USDA.

• No-till
• Strip-Till
• Mulch-Till
• Ridge-Till

Definitions

Primary tillage loosens the soil and mixes in fertilizer and/or plant material, resulting in soil with a rough texture.

Secondary tillage produces finer soil and sometimes shapes the rows. It can be done by a using various combinations of equipment: plough, disk plough, harrow, dibble, hoe, shovel, rotary tillers, subsoiler, ridge or bed forming tillers, roller.

Weed plants (seeds, tubers, etc.) may be exhausted by repeated tilling. The weeds expend energy to reach the surface, and then get turned into the soil by tilling. The cycle is repeated until the weeds are dead.

History of tilling

Tilling was first performed via human labor, sometimes involving slaves. Hoofed animals could also be used to till soil via trampling. The wooden plough was then invented. It could be pulled by mule, ox, elephant, water buffalo, or similar sturdy animal. Horses are generally unsuitable, though breeds such as the Clydesdale could work. The steel plough allowed farming in the American Midwest, where tough prairie grasses and rocks caused trouble. Soon after 1900, the farm tractor was introduced, which eventually made modern large-scale agriculture possible.

alternatives to tilling

Modern agricultural science has greatly reduced the use of tillage. Crops can be grown for several years without any tillage through the use of herbicides to control weeds, genetically modified crops that tolerate packed soil, and equipment that can plant seeds or fumigate the soil without really digging it up. This practice, called no-till farming, reduces costs and environmental change by reducing soil erosion and diesel fuel usage (although it does require the use of pesticides). Most organic farming tends to require extensive tilling, as did most farming throughout history, although researchers are investigating farming in polyculture that would eliminate the need for both tillage and pesticides, such as no-dig gardening.

In the United States, around 399 million acres (1,610,000 km²) of rangeland are privately owned. The Bureau of Land Management manages about 167 million acres (676,000 km²) of publicly owned rangeland, with the United States Forest Service managing approximately 95 million acres (380,000 km²) more. Ranchers may lease portions of this public rangeland and pay a fee based on the number and type of livestock and the period for which they are on the land. Many western states have open range laws. In these states, all land, both public and private, is designated as open range unless it is within city limits. In open range, it becomes the responsibility of the land owner to keep unwanted livestock off their land and the livestock owner is not liable for any damage caused by the livestock.

In Kenya, Rangelands make up for 75% of the land surface area,and are largely inhabited by nomadic pastrolists who are largely dependent on livestock. This movement often brings along an incursion of different diseases with the common one being the rinderpest virus in the Kenyan wildlife population from the Somalian ecosystem.

Rangeland is a prominent feature of rural Canada. A provincial jurisdiction, administration and policy regarding range use varies across the country. Like many Commonwealth countries, public tenures on crown land for the purpose of range activities is common in geographically compatible areas. Reconciling the economic needs of ranchers and the need for environmental conservation is one of the primary themes in modern range discourse.

In Australia, pastoral leases may be held over crown land and beef cattle or sheep grazed on large holdings called Sheep stations or Cattle stations.

The Society for Range Management (rangelands.org) is an international organization of natural resource scientists, researchers, educators, land management agency officials, and public and private land managers devoted to the conservation and sustainable stewardship of the world's diverse rangelands. The Society is open to anyone engaged in or interested in any aspect of the study, management, or use of rangelands, and publishes both a scientific journal, Rangeland Ecology and Management, and Rangelands, a journal of practical applied ecology, perspective and contemporary rangelands issues.