Showing papers on "Soil conservation published in 1977"

Predicting soil erosion

Abstract: Erosion of soil by water poses an increasing threat as needs for food and fiber production and space for social and economic necessities of a growing population add pressures to the nation's land resources. The Universal Soil Loss Equation (USLE) developed through many years of cooperative efforts of the Agricultural Research Service, state experiment stations, and the Soil Conservation Service is a highly useful tool for predicting sheet and rill erosion under various conditions of land use and management. It is widely accepted and used by soil conservationists and others. However, there are some problems associated with its use and some additional needs to supplement its use in the field.

Soil deterioration and the growing world demand for food.

Abstract: A recent survey of five watersheds in south-central Wisconsin, where corn is now the dominant annual crop, illustrates the soil erosion damage that is occurring on sloping land under modern agricultural technology and prevailing market forces. In 70 percent of the 93 quarter-sections sampled, estimated soil losses, on the average, were more than twice the amounts considered compatible with permanent agriculture. Scattered studies by others indicate that the findings are meaningful for a large area in the United States when row cropping is prevalent on sloping soils. Pressures on cultivated land, in general, are mounting rapidly because of the rising demand for meat in industrialized nations and the soaring numbers of marginally fed people in Third World countries. The world population-food problem makes increasing stress on U.S. soils inevitable in the foreseeable future. Adequate protection against excessive loss of productive topsoil requires that the level of publicly supported soil conservation activities be promptly adjusted to this circumstance.

Development and Use of the Soil Conservation Service Dispersion Test

Abstract: This paper presents information from and experience with a test developed by the Soil Conservation Service (SCS) to identify dispersive clay soil. Background information on erosion and piping problems, which led to the development of the test, are reviewed. Comparisons of the SCS dispersion test with field performance and pinhole test data are made.

The Potential Wind Erosion Problem in the United States

Abstract: WIND erosion is a serious problem in many areas of the United States. Damage to soil, damage to crops, and atmospheric pollution caused by wind erosion are major areas of concern. The nature and extent of wind erosion have been subjects for observa-tion and study by researchers and soil conservationists for many years. Wind erosion control has received high priority in the Soil Conservation Service (SCS) activities since 1935. The catastrophic dust storms of the early 1930's focused public attention on the problems of wind erosion and resulted in public support for remedial and preventive action.

Encountering Dispersive Clays on Soil Conservation Service projects in Oklahoma

Abstract: Dispersive clays occur frequently in nature, possessing properties detrimental to agronomic tillage practices and to engineering structures such as dams, terraces, channels, etc. Surface erosion occurs readily, since the fines are easily detached and suspended in runoff water. Where water can enter cracks in dispersive clays, subsurface erosion usually develops rapidly and extensively in areas of strong relief under favorable climatic conditions. For many years, the Soil Conservation Service has relied upon the Laboratory Dispersion Test as the benchmark for identification of these problem clays. Improved sampling techniques and the supplementary use of two field identification tests have been extremely helpful in recent years, particularly in embankment zoning. Liming the surface layers of dispersed clay embankments has provided a satisfactory means for stabilization. Three lime-treatment jobs have not been damaged in seven years. Aluminum sulfate is being evaluated on a field trial basis.

Predictability of Effects of a Severe Local Storm in Pennsylvania

Abstract: On 24 May 1975, an isolated thunderstorm in east-central Pennsylvania produced over 4 inches of rain in 2 h over an Agricultural Research Service instrumented area. The return period for this storm appears to exceed 650 years. Simulation of the precipitation excess from all soils within the storm area using a modification of the Mein and Larson infiltration equation indicated surface runoff from a limited number of soil types—the same soils which exhibited severe erosion plus the alluvial soils of the stream channels. About 17% of the area affected by the storm accounted for nearly all of the measured surface runoff. Post-storm field investigation showed that the principal damage by erosion was restricted to corn fields on two soil groups, both silty clay loams over a fragipan. Soil losses due to sheet and rill erosion were estimated in the field as ranging from 15 to 110 tons acre−1. Soil losses resulting from gully erosion could have been as high as 300 tons acre−1 in some areas. Simulation of ...

Natural Versus Man-made Forest in Nilgiris with Special Reference to Run-off, Soil Loss and Productivity

Abstract: The paper present the results of investigations on run-of soil loss accumulation of leaf litter and timber yield under native vegetation cover and under plantation of Eucalypius globulus (blue-gum) employing runoff plots. It has been concluded that there was not much difference in runoff between different forest covers though a mixed plantation of blue-gum and black wattle ( Acacia mearnsii ) gave less run-off Litter production was nearly the same (2.315 tonns/ha/yr) in both native "Shola" forests and Eucalyptus plantations. Mixed plantion of blue-gum and wattle is preferable to pure plantation both from ehe point of view of timber production and soil and water conservation.

Priority Watersheds for Soil Conservation Works in Matatilla Catchment

Abstract: The concept of priority watersheds has been introduced for soil conservation treatment works to imply watersheds that contribute to maximum silt at ion of a reservoir. The methodology for delineating priority watersheds comprises mapping of erosion units defined in terms of physiography, slope, soil characteristics, land use, vegetation and erosion. Weightage values are assigned to the mapping units corresponding to the resultant of the interaction of these factors in producing silt yield. Mapping is made on a base map with delineations and codifications of sub-catchments, watersheds, sub-watersheds. The silt yield index for each watershed is computed by summation of the product of the areas by the different units and their weightage values. The delivery of the eroded material to the reservoir is estimated by adjusted delivery ratio. The relevant factors of the delivery ratios are discussed in the paper. Estimations of priority watersheds by following this method for Matatilla catchment, Madhya Pradesh revealed that out of the total area of 5.56 lakh ha, 1.73 lakh ha, constituting about 30% of the total area falls under very high and high priority categories demanding immediate attention for soil conservation works.

History and Challenges in Soil and Water Conservation and Management1

Abstract: Soil and crop management practices have been used for centuries in some parts of the world, but in the United States it was not until the 1930's that the public became concerned over the abuse of land. In response a series of emergency and long-range programs were initiated on the conservation and wise use of natural resources. Information generated by the publicly supported agricultural research system undergirded these programs. The net effect has been major improvements in how our natural resources are used. The job is far from done. Among the challenges and opportunities for additional research in the future are: (i) refine the universal soil loss equation and extend the data base to those areas where it is not available now, (ii) complete soil survey as soon as possible, (iii) strengthen our present effort to assure greater efficiency of water use for agricultural purposes, (iv) develop extensive quantitative information on the relationship between weather variables in a growing season and the yield of different crops, (v) assemble, summarize, and evaluate existing information and develop new information when needed relative to specific sets of conditions for use by all concerned in the development of realistic and practical land use plans, (vi) generate additional data essential in developing sound programs to improve the environment and at the same time maintain our capacity to meet future food requirements, (vi) improve existing tillage systems and develop new ones tailored to meet a wide range of soils, crops, and climatic conditions, and (viii) develop knowledge and plans whereby strip-mining operations can be carried out without permanent damage to the environment and soil productivity.

Tunnel-Gully erosion and urban development: A case study

Abstract: An area of tunnel gully erosion induced by the excavation of a drain through a residential subdivision in Southern New South Wales was examined. Twelve months after excavation, tunnels extend 7 m from the drain wall and threaten residential blocks only 5 m further away. A survey of a major tunnel by excavation and probing indicated tunnel formation along soil cracks around large (50 to 100 cm diameter) structural units. Soil analyses rated the soil as highly dispersible by all the routine tests used by the Soil Conservation Service (SCS) of New South Wales, namely, Emerson's Crumb Test, Ritchie's Dispersal Index, and Floyd's Sticky Point Test, and showed that this dispersibility could be attributed to a high exchangeable sodium percentage (ESP) (mean 10.5). In addition, the soil had a low volume expansion (<5 percent) and was relatively impermeable. These analyses have been compared with published criteria to show that the soil could have been identified as highly susceptible to tunnel erosion prior to excavation. This would have permitted an improved channel design, with a more gently sloping batter and stressed the need for lime stabilization, topsoiling, and immediate revegetation to minimize the possibility of tunnel development.

Application of Soil and Land Resources Inventory Data in Development Planning

Abstract: Importance of basic soil and land resources data for development planning, particularly for land and water management has been emphasised and illustrated by interpreting such data for Indore district, Madhya Pradesh. The soil and land resources inventory data were collected by using small area sample survey technique and were machine processed for determining extent under different characteristics. Interpretation of basic soil and land facts shows that nearly 63% of rainfed cropland, 48% of irrigated cropland and 87% of grassland need one or the other kind of soil conservation treatment. Total treatment costs for district work out at Rs. 240 lakhs over a period of 15 years. Average cost per hectare is about Rs. 129. Overall benefit: cost ratio for class IIe-1 lands is estimated at 7.1 and for class IIe-2 lands at 3.2 under rainfed cropping. Different land capability units under grassland development show benefit: cost ratio of 1.4 to 6.3

Land resource inventories for integrated land use planning with special reference to the catchment of Pohru river in Jammu and Kashmir state

Abstract: A Soil and land Use Map of Pohru catchment was prepared through the adoption of a systematic Air Photo-interpretation procedure including selective field studies in such a manner that the ten delineated mapping units were co-extensive with major Land Resource Areas. Defined in terms of physiography, soil profile, soil erosion and present land use each of the ten units has unique characteristics requiring differential management, which was arrived at through joint field studies by Pedologists who prepared the Map, Foresters, Soil Conservationists, Agronomists. a Horticulturist and an Agricultural Chemist. Stemming from this integrated effort a Land Use Plan for the catchment was drawn up with its major objective as the conservation of Land and Soil Resources leading to a reduction in sediment yields that are now so high as to clog the Jhelum river at the polnt where Pohru river joins it. In respect of four Land Resource areas, the plan prescribes radical readjustments of Land Use such as conversion of Forest Department owned Himalayan Southern slopes to grass lands, change of cropping pattern in Karewa side slopes and conversion of the northern and southern Himalayan footslopes now under cultivation into orchards. The areal extents of the different Land Resource Areas as also the cost of implementing the conservation recommendations have been furnished for every one of the twentyeight watersheds falling under the eight subcatchments of the Pohru catchment. The total cost of implementing the conservation recommendations approximates to about fifty five million rupees.

Land-use in semi-arid southern Africa

Abstract: Africa south of the Equator has a low population density which reflects the scarcity of reliable supplies of potable water. Productive agricultural methods have been demonstrated and are practised on advanced enterprises throughout the subcontinent, but most of the population still live by subsistence agriculture which is increasingly destructive of soil and water resources as numbers increase. Higher priority for agriculture, better rewards and status for food producers and the urgent application of known techniques of soil conservation are all necessary if the semi-arid areas of southern Africa are to feed their increasing populations.

Preliminary guidance for estimating erosion on areas disturbed by surface mining activities in the interior western United States. Interim final report

Abstract: Surface mining activity in the Interior Western U.S. is increasing. As disruption of surface lands increases, a tool is needed to evaluate alternative mitigating measures needed for reclamation of disturbed lands. This publication provides guidance on the use of the Universal Soil Loss Equation (USLE) to predict water-related erosion on areas disturbed by surface mining. The USLE is a method of estimating soil loss from sheet and rill erosion as a function of rainfall intensity, soil erodibility, length/percent slope, vegetative protection and erosion control practices (contour tillage and stripcropping). The information gained by application of the USLE can be used as a basis for comparing alternative conservation practices used in reclamation planning. (Color illustrations reproduced in black and white)