Performance Characteristics of Various Electrical Resistance Units and Gypsum Materials

Perrier, Eugene R.; Marsh, A

doi:10.1097/00010694-195809000-00006

Cited by 11 publications

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“…Methods The experimental area was fenced and plots 10 x 11 feet were centrally equipped with Bouyoucos resin impregnated gypsum blocks (Bouyoucos, 1954) so that the moisture depletion at the 6-, 12-, 20-, and 36-inch depths could be measured. These blocks were previously field calibrated in clay loam to develop the relation according to the method described by Perrier and Marsh (1958) (Table 1). On April 15, 1957, 20-inch deep columns, 6 x 12 inches, were excavated from nitrogen-phosphorus and check plots, and roots were removed by washing.…”

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confidence: 99%

Annual-Range Fertilization in Relation to Soil Moisture Depletion

McKell¹,

Major²,

Perrier³

1959

Journal of Range Management

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confidence: 99%

Annual-Range Fertilization in Relation to Soil Moisture Depletion

McKell¹,

Major²,

Perrier³

1959

Journal of Range Management

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“…Typically plaster of Paris drains at matric potentials below -100 kPa and a plot of log matric potential against log resistance is generally linear. The use of different mixtures of plaster of Paris allows these sensors to be adapted to different ranges of matric potential (Perrier and Marsh, 1958).…”

Section: Porous Matrix Sensorsmentioning

confidence: 99%

Measurement of the matric potential of soil water in the rhizosphere

Whalley

Ober

Jenkins

2013

Journal of Experimental Botany

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The availability of soil water, and the ability of plants to extract it, are important variables in plant research. The matric potential has been a useful way to describe water status in a soil-plant system. In soil it is the potential that is derived from the surface tension of water menisci between soil particles. The magnitude of matric potential depends on the soil water content, the size of the soil pores, the surface properties of the soil particles, and the surface tension of the soil water. Of all the measures of soil water, matric potential is perhaps the most useful for plant scientists. In this review, the relationship between matric potential and soil water content is explored. It is shown that for any given soil type, this relationship is not unique and therefore both soil water content and matric potential need to be measured for the soil water status to be fully described. However, in comparison with water content, approaches for measuring matric potential have received less attention until recently. In this review, a critique of current methods to measure matric potential is presented, together with their limitations as well as underexploited opportunities. The relative merits of both direct and indirect methods to measure matric potential are discussed. The different approaches needed in wet and dry soil are outlined. In the final part of the paper, the emerging technologies are discussed in so far as our current imagination allows. The review draws upon current developments in the field of civil engineering where the measurement of matric potential is also important. The approaches made by civil engineers have been more imaginative than those of plant and soil scientists.

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“…Since the pioneering works of GARDNER and KIRKHAM (1952) and VAN BAVEL (1958, 1963, a wide range of research has been carried out for the evaluation and improvement of the neutron scattering method (see for example IAEA, 1967;1974;1983;VACHAUD et al, 1977;GREACEN and HIGNETT, 1979;SINCLAIR and WILLIAMS, 1979;KASI, 1982;NAKAYAMA and REGINATO, 1982;HODGSON and CHAN, 1987;AMOOZEGAR et al, 1989). Similar attention has been given to the development of tensiometers (e.g., MILLER, 1951;MARSHALL, 1959;RICHARDS, 1960;KLUTE and GARDNER, 1962;VILLA NOVA et al, 1989) and of resistance blocks (e.g., BOUYOUCOS and MICK, 1940;BOUYOUCOS, 1949;TANNER et al, 1949;KIRKHAN and TAYLOR, 1950;PERRIER and MARSH, 1958). Tensiometers work only in the wet range of soil water content, up to soil water matrix pressures of about -80 kPa (MARSHALL, 1959).…”

Section: Introductionmentioning

confidence: 97%

Comparison of neutron moisture gauges with nonnuclear methods to measure field soil water status

Ki̇rda

Reichardt

1992

Sci. agric. (Piracicaba, Braz.)

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SUMMARY:The neutron moisture gauge is compared with the gravimetric-core soil sampling technique, tensiometers and resistance blocks in relation to stability, Held variability, spatial dependence and number of samples needed at a given level of significance. The variance of field water content measurements with neutron moisture gauges is lower than that of the gravimetric sampling, which therefore requires 2 to 6 times as many samples as the number of measuring sites of the gauges to attain the same level of significance. The space dependence of the measurements made with the subsurface gauge varied depending on the average field soil water content. No space dependence was evident when the water content was lower than 0.2 cm 3 .cnr -3 (50% saturation). Measurements with the tensiometers and resistance blocks manifested no spatial dependence and therefore randomly selected measuring sites can be adapted to Held research work where these methods are to be utilized. Soil water content measurements estimated with neutron moisture gauges showed well defined temporal stability (i.e., the lowest, average and the highest soil water content measurements occur at the same field site) which implies that soil water status of an entire field can be assessed with measurements limited to few locations. Measurements with both tensiometers and the resistance blocks are time variant (i.e., the site giving field average water content changes spatially in time) owing to their relatively smaller measuring domains (i.e., scale of the area which can be represented by a single measurement) as compared to neutron gauges. Therefore it is not possible to define the measuring sites of the tensiometers and resistance blocks as to assess soil water status of the entire field, as it could be done with the neutron gauge. Key Words: neutron gauges, tensiometers, resistance blocks, spatial variability, soil water. COMPARAÇÃO DE SONDAS DE NEUTRONS COM MÉTODOS NÃO NUCLEARESNA ESTIMATIVA DA ÁGUA NO SOLO EM CONDIÇÕES DE CAMPO RESUMO: A sonda de neutrons é comparada com a amostragem gravimétrica, com a tensiometria e com o uso de blocos de resistência, em relação à estabilidade, variabilidade do campo, dependência espacial e múmero de amostras necessárias levando em conta determinado nível de significância. A variância das medidas de umidade do solo obtidas por sonda de neutrons é menor do que para a amostragem gravimétrica, que requer um número de amostras 2 a 6 vezes maior em relação à sonda de neutrons dentro de um mesmo nível de significância. A dependência espacial das medidas feitas com sondas de profundidade variou de acordo com os níveis de umidade do solo. Nenhuma dependência espacial ficou evidente para umidades menores que 0,2 cm 3 .cm 3 (50% da saturação). Medidas com tensiômetros e blocos de resistência não manifestaram dependência espacial e, por isso, a escolha das parcelas para medida facilmente se adaptam a esquemas experimentais nos quais estes métodos podem ser utilizados. Medidas de umidade de solo obtidas por sondas de neutrons m...

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Performance Characteristics of Various Electrical Resistance Units and Gypsum Materials

Cited by 11 publications

References 0 publications

Annual-Range Fertilization in Relation to Soil Moisture Depletion

Annual-Range Fertilization in Relation to Soil Moisture Depletion

Measurement of the matric potential of soil water in the rhizosphere

Comparison of neutron moisture gauges with nonnuclear methods to measure field soil water status

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