round Harlingen in the Lower Rio Grande Valley of Texas, indowners shape their land for irriation for several quite logical rea ons. Mostly, it is for the better control { water. This means lower cost of labor or irrigating. It also means holding sses of water to a minimum. Leveling of fields makes possible e even distribution of irrigation ater and rainfall, resulting in unirm crop growth. Land leveling on a large scale began in the Rio Grande Valley about 1950. In the 20 years since, nearly half of the Harlingen area's 780,000 acres of irrigated land has been graded to meet today's standards. The earth moved would build a dam 50 feet high and 100 miles long. Most land-leveling jobs in the area require moving about 400 cubic yards of earth for each acre. Roughyards of earth for each acre. Rougher land may raise this figure to 1,000 or even 1,500 cubic yards to the acre in some instances. The average land-leveling job costs $75 an acre. Heavier jobs cost $150 or more an acre. The investment, most landowners say, is recovered in 3 years. The most commonly used equipment for land leveling in the Lower Rio Grande Valley is a large farm tractor with two 4- or 6-cubic-yard carryall scrapers pulled in tandem. At all points in the field, the land surface is graded within 0.1 foot or less of the planned elevation. The final work is done by floats or landplanes 45 to 80 feet long. These assure a smooth surface by filling in After the scraper, a landplane eliminates minor irregularities in the surface. or cutting off minor irregularities level irrigation method, which re left by the scrapers. If deep cuts are necessary, they are made to a few inches below the planned elevation, and the areas are backfilled with topsoil. This eliminates or shortens the time required to bring such an area up to normal crop production. No other special soil treatment ordinarily is necessary. Land leveling must be designed in accordance with variations in soils, the crops to be grown, the water supply, and the method of irrigation in each case. As in other parts of the United States, standards for land leveling in the Lower Rio Grande Valley are set forth in the local Soil Conservation Service Irrigation Guide. The guide is based on proved irrigation principles and knowledge of the special conditions of the local area. Much of the land leveling in the Lower Rio Grande Valley is for the quires a surface that is essentially level with a very slight grade to facilitate water spreading and re moval. For the graded border o graded furrow method, the land ha somewhat more slope on which water is applied under a differen principle of irrigation. No matter how good a land-level ing job may be, shaping the lan in itself will not accomplish the ful benefits of a conservation-irrigation system. The real payoff comes from good water management that applie the correct amount of water at th right time and the right place-i.e in the root zone-and with uniform distribution over the field. Irrigators in the Harlingen are have found that land leveling, plu good water management, has pai big dividends in conservation of irri gation water, retention of neede rainfall, lower costs, and more uni form and better crops. Tew Orleans is a city hemmed in New sion for Jefferson, Orleans, and St. by water, marshes, and the Bernard parishes arranged with Where to build? Mississippi River. The land is boggy, below sea level, and good building sites are at a premium. "Where are we going to put all the people in the next 20 years?" the planners ask. The city, with its suburbs, has well over a million residents now. Like most such centers, it is growing rapidly. Another million residents are expected in the next two decades. The fact is New Orleans has run out of land for its needed development—almost. There is an abundance of land, however, for other ases. SCS for the survey and asked Mike Aulick, a planner with the commis sion, to head the project. The SCS, The commission selected 50,000 The findings in the survey were not surprising. The soil scientists found the answer to why many homes and streets cracked, and why lawns sank away from the foundations. Organic soils occupy much of the area surveyed. They are different from mineral soil which is made up of sand, silt, and clay. Organic soil (peat and muck) is mostly grass that has partly rotted. When organic soil is drained, the The Regional Planning Commis- surface subsides and oxygen gets to A soil survey recently completed by the Soil Conservation Service, with the city paying half the cost, olds some of the answers needed by the puzzled New Orleans offiials. New Orleans gets the answers No rustic decoration, the boards at right, but a needed addition after the driveway sank below the carport. A 3-year-old levee (left) built of Kenner muck was ruined by shrinkage of the organic material. SCS Soil Scientist B. Spicer (above) tells a reporter and planning commission member about limitations of the organic soil beneath marsh grasses. the old grass, which begins to decompose rapidly. Some organic soils are 10 feet or more thick. They will subside several feet the first year after drainage and about an inch a year thereafter, depending on the level of the water table. Aulick said the survey information will help planners make recommendations for general land uses. For example, it will show which land should be used for residential, commercial, light and heavy industrial purposes, where parks and playgrounds should be, and how sewage and drainage can best be done. New Orleans is one of the first major metropolitan areas to program soil facts into computers to aid in making land use decisions. Soil properties including texture, wetness, and thickness of organic layers, along with other resource data such as population densities, will be programed. "This way we can rapidly determine the areas best suited to each urban land use and avoid costly mistakes," Aulick explained. The soil survey also will help evaluate the soil problems and costs when it is necessary to modify the soil, remove it, or design special foundations or structures to overcome soil problems that cannot be removed or corrected. The Planning Commission will make the survey available to the public as well as use the information in its own programs. SCS will continue to give technical help in choosing land uses and designing conservation treatments based on soils and other information. Job well done- Calvin Leftwich's accident led to the construction of a swimming area on his North Dakota farm. It would require swimming to restore the damaged nerve muscles in his leg. With the help of the Soil Conservation Service through the Towner County Soil Conservation District, a small dam was built and the excavation area in the pool made deep enough to maintain fish in this northern community where ice often freezes to a depth of 3 feet or more But very little snow fell during the winter and expected runoff from the watershed was almost nil. Leftwich decided to pump water from a larger coulee just below the dam to provide water for boating and swimming. His family handplanted some 50 individual trees to give shade and beauty to a selected picnic area The picnic area and dam were grassed with native sod to provide quick erosion cover to these areas The Agricultural Stabilization and Conservation Service cost shared the dam and pool develop ment and windbreaks to surround the pool area. The Bureau of Spor Fisheries and Wildlife furnished bas and bluegill to stock the pond. Leftwich has not said how much swimming he has done in his new swimming area, but he and his fam ily have a beautiful recreation are Almost everybody agrees that only 1/4 mile from their farmstead most of the soils around New Orleans are not the best for building. But, as Aulick points out, "They are what we have to work with and I think the soil survey will help us put the land to its best use." -DAYTON MATTHEWS AND S. A. THIBODEAUX, soil scientist and district conservationist, SCS, New Orleans, La. that provides fun for all-swimming fishing, boating, and picnicking, quiet place to rest and enjoy th beauty of nature; and a job wel done-FRANK A. HOBBS, distric conservationist, SCS, Cando, M Dak. When the Norwood Hills Coun try Club in St. Louis, Mo., t out to install an irrigation system -with improvement of greens a speal objective-the path to tee-off d straight to the office of the St. ouis Soil and Water Conservation istict. The outcome was the customary greement between landowner and istrict board. The difference was the setting, one in an urban area ith recreation the prevailing land se. The Norwood Hills Club agreed › install all works of improvement s listed in its conservation plan, ith the Soil Conservation Service iving technical assistance. Available water would not be nough to keep the course in top ondition. It was evident that a eservoir would be needed. SCS onservationists selected the site for he impoundment. Soil, geological, nd topographic investigations showd the site feasible. SCS engineers esigned the dam. Fill material came from a nearby mall watershed, which resulted in nother smaller lake. In time the system was in operaon, with water going to points in Putting conservation on the 300-acre layout through 13 miles of pipe. Two pumps deliver 1,300 gallons a minute when operating. Water comes on by program, with time clocks set to start the system and to shut it off at the proper time. The first summer Norwood Hills used 55 million gallons of water for irrigation. Thirty million gallons of it came from the County Water Company for $8,000. The rest came from the club's own supply. The lakes cost $25,000. The club figured the water from the lakes was worth $5,000, indicating that the lakes would return their cost in 5 years. The cost of the entire irrigation project came to a quarter of a million dollars, with the delivery system representing the biggest part. The club placed one of the tees on the earthfill dam and planted ornamental shrubs around the lake borders. Ducks made themselves at home on the water. And members often observed how much beauty had been added to the course. The supervisors of the St. Louis District look upon the achievement at Norwood Hills as a logical-although a slight departure from the normal-service. In other words, in the district's business, applying conservation to a golf links is about par for the course.-MELVIN M. THOMPSON, area conservationist, SCS, Fulton, Mo., and N. Howard Funk, district conservationist, Kirkwood, Mo. |