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Home » Journal of Soil and Water Conservation » Abstracts and Archives » Fourth Quarter 2001
Fourth Quarter 2001

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Fourth Quarter 2001 Table of Contents

Features

  • Landcare in Australia: Community Participation and Land Management
    John Cary and Trevor Webb    
  • Soil and Water Behaviors Within the Upper Mississippi River Basin
    Ted L. Napier
  • Use of Continuous No-till and Rotational Tillage Systems in the Central and Northern Corn Belt
    Peter R. Hill

Research

Departments

  • Book Review
    Visual Soil Assessment, by Doug Karlen; and Conservation Tillage and Cropping Innovation, by Doug Karlen, Frank Clearfield, and Peter Nowak

  • Upcoming

325      
Abstracts for Oral Presentations at the 2001 Soil and Water Conservation Society Annual Conference

345      Abstracts for Poster Presentations at the 2001 Soil and Water Conservation Society Annual Conference

Field attributes, water pricing, and irrigation technology adoption
(Full text appears in the Journal of Soil and Water Conservation, Vol.56, No.4) E.C. Schuck and

G.P. Green 

ABSTRACT: Water price policy can be an effective resource management tool to promote water conservation by encouraging reductions in water consumption and the adoption of less water-intensive irrigation technologies.  However, a farm’s ability to adopt alternative irrigation technologies depends upon the unique attributes of the farm site. In particular, interaction between field attributes like soil permeability and field slope can reduce and limit the influence of water price in promoting adoption of alternative irrigation technologies. This issue is examined using irrigation technology adoption data from California’s Central Valley. Results suggest that while water prices are important to water use decisions, field-specific attributes are more important to the adoption of water conserving irrigation systems. 

Keywords: irrigation, land quality, water policy

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Automated water sampling and flow measuring devices for runoff and subsurface drainage
(Full text appears in the Journal of Soil and Water Conservation, Vol.56, No.4)

S. L. Zhao, E.C. Dorsey, S.C. Gupta, J.F. Moncrief, and D.R. Huggins

ABSTRACT: Inexpensive devices that characterize water flow rates as well as take samples either during runoff or subsurface drainage are needed especially for developing countries where the commercially available equipment may be cost prohibitive. Even in the developed countries, these devices could save considerable money especially if a large number of units are needed such as in replicated plot experiments. This paper describes the design, construction and testing of such devices for characterizing flow rates and also for collecting water samples from surface tile inlets (runoff) and subsurface tile drains. For runoff, the tipping bucket device (about 4 L (1.06 gallon) per tip) sits on top of a sample holder. Flow rates, ranging from 1 to 116 L min-1 (0.26 to 30.68 gallon min-1) are measured by recording the number of tips and time between two consecutive tips. The maximum error in flow measurement is 0.4%. Water samples are collected by catching about 20 mL (0.68 oz) of flow every other tip (an equivalent to about 0.25% of the total runoff) in a polyethylene bottle in the sample holder. The sample holder houses 20 bottles, 19 are for sample collection. After a specific number of pre-programmed tips, the bottle is advanced so that the next empty bottle is under the sampling port. The device can be programmed to catch volume distributed or time distributed samples. The subsurface drainage measuring and sampling device consists of a tipping bucket (410 ml (13.85 oz) per tip) and a tygon tube connected to the sampling port at the base of the tipping bucket. A small fraction (3 ml (0.1 oz)) of the water collects in the tygon tube every other tip. The tube is emptied each day and the sample represents the daily composite drainage. A CR-10 data logger provides the electronic controls for automating the system. 

Keywords: Flow measurement, non-point source pollution, pollutant measurement, runoff, sediment, tile drainage, tile flow, tipping bucket, water quality, water pollution

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Comparing phosphorus management strategies at a watershed scale
(Full text appears in the Journal of Soil and Water Conservation, Vol.56, No.4)

R W. McDowell, A.N. Sharpley, D.B. Beegle and J.L. Weld 

ABSTRACT: The persistence of water quality problems has directed attention toward reduction of agricultural non-point sources of phosphorus (P).  We assessed the practical impact of three management scenarios of the USDA-EPA Strategy for Animal Feeding Operations to reduce P losses from a watershed.  Using an agronomic threshold of 50 mg Mehlich-3 P kg-1 soil, 55% of our watershed would receive no P as fertilizer or manure.  An environmental threshold of 190 mg Mehlich-3 P kg-1 soil, above which P loss in runoff increases, restricts future P inputs to less than crop removal to 32% of the watershed.  Finally, a site assessment P index was used which accounts for likely source and transport risks.  This showed none of the watershed was at high risk of P loss and that areas of medium risk (where remedial measures should be considered) were near the stream channel.  We suggest the P index as the best method to target remedial management to minimize P export and in the watershed studied impacted less land area than the other strategies. 

Keywords: Animal Feeding Operations, CAFO strategies, eutrophication, fertilizer management, manure management, nonpoint source pollution, nutrent management planning phosphorus index, phosphorus runoff, risk assessment, water quality, watershed runoff

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Economic analysis of cover crops in summer fallow crop systems
(Full text appears in the Journal of Soil and Water Conservation, Vol.56, No.4)

E G. Smith, L. Heigh, K.K. Klein, J.R. Moyer, and R E. Blackshaw 

ABSTRACT:  Cover crops grown on summer fallow in semiarid environments can be used to provide soil erosion protection and enhance soil nutrients.  The economic benefits and costs of fallow cover crop systems were evaluated using fall and spring rye (Secale cereale L.) cover crops with minimum and zero tillage, and using sweet clover (Melilotus officinalis (L.) Lam.) established in companion crops of field peas (Pisum sativum L.), mustard (Brassica juncea (L.) Coss.), or flax (Linum usitatissimum L.) and terminated in the fallow year by four methods.  Spring wheat (Triticum aestivum L.) followed the fallow or partial fallow year.  The fall rye?minimum tillage system had average returns similar to the no cover?zero tillage, and lower but not significantly different returns from the no cover?minimum tillage system.  The lower companion crop yields in which sweet clover was underseeded, reduced the economic benefit of the sweet clover cover crop.  Mustard was the most profitable companion crop.  Harvesting the sweet clover as hay increased net returns over soil incorporation.  For the sweet clover system to be competitive with conventional fallow, reducing the negative effect of sweet clover on companion crop yield is required.  

Keywords: Cover crop, economic, companion crop, fallow, sweet clover, rye

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Comparison of methods used to calculate tillage translocation using plot-tracers
(Full text appears in the Journal of Soil and Water Conservation, Vol.56, No.4)

D.A. Lobb, T.A. Quine, G. Govers, and G. Hecrath 

ABSTRACT: Tillage translocation is measured in the studies of soil dispersion and soil erosion.  The translocation of soil by tillage is normally measured with a tracer.  Using plots, a volume of soil is labelled and then tilled.  There are two methods of calculating translocation using plot-tracers.  For the more common method, translocation is calculated directly from the distributions of tracer before and after tillage (Distribution-Curve Method).  For the less common method, a summation curve is generated from the distribution of tracer after tillage by employing convolution, and translocation is calculated from this curve (Summation-Curve Method).  In this paper, the two methods are described and compared using hypothetical and experimental data.  Both methods provide accurate measures of gross translocation.  The Summation-Curve Method provides a measure of error associated with gross translocation and a more thorough characterization of the dispersion of translocated soil; therefore, it was considered to be the superior of the two methods. 

Keywords: tillage translocation, tillage erosion, tracer, dispersion

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Evaluation of soluble phosphorus loadingfrom manure-applied fields under various spreading strategies
(Full text appears in the Journal of Soil and Water Conservation, Vol.56, No.4)

M. Walter, E. S. Brooks, M.F. Walter, T.S. Steenhuis, C.A. Scott, and J. Boll 

ABSTRACT: A simple model was developed and applied to a dairy farm in the New York City (NYC) water supply watershed to evaluate the effectiveness of various manure spreading strategies for reducing non-point source, soluble phosphorus (SP) pollution.  Phosphorus from manure spread fields is recognized as one of the important non-point source pollutants in the region and there is acute interest in developing economically viable water quality management practices.  The NYC watershed initiative, i.e. the Watershed Agriculture Program (WAP), mandated that water quality management practices will be scientifically justifiable based on the best information available (Walter and Walter, 1999).  Thus, this project was carried-out to evaluate manure-handling strategies based on the currently available information.  The model for predicting SP loading to perennial streams via surface runoff was developed by combining a mechanistic hydrological model with an empirical relationship for SP concentration in runoff.  This study showed that, in the short term, because of soil P accumulation associated with a history of dairy farming, the maximum possible reduction in SP loading to perennial streams is about 50%.  This is attained by exporting all manure from the NYC watersheds.  Utilizing the concept of hydrologically sensitive areas (Walter et al. 2000), this study suggests possible SP loading reductions of 25% with all manure remaining on-farm.  This study supports and emphasizes the finding by Walter et al. (2000) that the timing and location of manure spreading strongly influences SP transport. 

Keywords: agricultural non-point source pollution, phosphorus, hydrologically sensitive areas (HSA), manure management, hydrological modeling, water quality, Catskill Mountains

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Modelling the effects of complex topography and patterns of tillage on soil translocation by tillage with mouldboard plough.
(Full text appears in the Journal of Soil and Water Conservation, Vol.56, No.4)

S. deAlba 

ABSTRACT: The design and results of a tillage field experiment conducted in Central Spain in 1995/96 are presented. Soil translocation models of the type d=¦(ST;SP), in which the absolute, forward and lateral translocation are calculated as functions of the slope gradients simultaneously in both directions parallel (ST) and perpendicular to the direction of tillage (SP), were developed. It was determined that: a) forward translocation dDT simultaneously is inversely correlated with the slope ST and directly correlated with the slope SP; b) lateral translocation dDP is inversely correlated with the slope SP; and c) the distance in the actual direction of soil movement dD only is inversely correlated with the slope ST. From simulation results it was concluded that the effects of complex topography and of the interactions between topography and patterns of tillage on soil translocation, are much more important than predicted using one-dimensional or diffusion type models of soil translocation. 

Keywords: tillage erosion, tillage translocation, soil degradation, modelling, mouldboard plough

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