Incorporação da densidade no ajuste de dois modelos à curva de retenção de água no solo

Tormena, C. A.; Silva, A. P.

doi:10.1590/S0100-06832002000200003

Resumos

A curva de retenção de água no solo é fundamental para o desenvolvimento de estudos relacionados com a dinâmica da água, com a modelagem de processos físicos do solo e crescimento das plantas. Normalmente, a curva de retenção é obtida por meio de medidas simultâneas do conteúdo de água (θ) e do potencial mátrico da água no solo (ψ) numa única amostra. Um procedimento alternativo consiste em utilizar várias amostras por ψ para descrever a curva de retenção. A utilização deste procedimento requer a incorporação dos fatores de variação existentes entre as amostras nos parâmetros das funções matemáticas utilizadas para descrever essa curva. O objetivo deste trabalho foi obter a curva de retenção, utilizando esta última sistemática, e ajustar duas diferentes funções não-lineares aos dados de θ(ψ). Amostras indeformadas (0,05 m de diâmetro e 0,05 m de altura) foram obtidas num Latossolo Vermelho distroférrico cultivado com milho sob plantio direto e preparo convencional do solo. Foram retiradas 96 amostras por sistema de preparo, na profundidade de 0-0,10 m, na linha e na entrelinha da cultura. A curva de retenção foi obtida utilizando-se 12 ψ, sendo 16 amostras por ψ: oito por sistema de preparo e quatro por posição amostrada. Os modelos de Genuchten (1980) - VG e o de Hutson & Cass (1987) - HC foram ajustados aos dados. Funções relacionando os parâmetros dos modelos com as variáveis independentes preparo, posição de amostragem e densidade do solo (Ds) os substituíram no ajuste dos dados. Não houve influência estatisticamente significativa dos sistemas de preparo e posição de amostragem (p > 0,05) no ajuste das funções aos dados . Com a função de VG obtiveram-se efeitos significativos da Ds no parâmetro n, o qual foi descrito por uma função quadrática da Ds. Resultado similar foi obtido com o parâmetro "a" da função de HC. A curva de retenção foi sensível às variações da Ds e o procedimento utilizado apresenta vantagens de natureza metodológica, bem como a redução substancial de tempo e custo para obter a curva de retenção. A precisão dos modelos utilizados foi praticamente similar, mas o modelo de HC apresentou menor número de parâmetros empíricos que o modelo de VG.

propriedades físicas do solo; funções de pedotransferência; regressão não-linear; porosidade do solo

The soil water retention curve plays a fundamental role in the development of studies on the dynamics of soil water, modeling of physical soil processes and plant growth. The retention curve is usually obtained by simultaneously measuring water content (θ) and soil water potential (ψ) in a single sample. An alternative procedure is to use several samples per ψ to describe the retention curve. The use of this procedure requires that the variation factors which exist among the samples are incorporated into the parameters of the mathematical functions used to describe the retention curve. The objective of this study was to obtain the retention curve using the latter procedure and fitting the θ(ψ) data using two different nonlinear functions. Undisturbed soil samples (0.05 m in diameter and 0.05 m in height) were collected from a Rhodic Ferralsol (Typic Hapludox) cropped with corn by no-tillage and conventional tillage. Ninety-six samples per soil tillage were taken at a depth of 0-0.10 m, from two positions: along the crop row and between crop rows. The retention curve was obtained using 12 matric potentials, with 16 samples per ψ: eight per tillage system and four per sampled position. Data were adjusted using the Genuchten (1980) model, VG, and the function proposed by Hutson & Cass (1987), HC. Mathematical functions relating the model parameters with the independent variables (soil tillage, sampling position and soil bulk density - Bd) substituted the model parameters in the fitting of the data. The tillage systems and sampling position exerted no statistically significant influence (p > 0.05) on the fitting of the data. With the VG function, Bd produced significant effects on the n parameter, which was described by a quadratic function of Bd. A similar result was obtained with the "a" parameter of the HC function. The retention curve proved to be sensitive to variations of Bd. The adopted procedure offered methodological advantages, involving substantially less time and lower costs to obtain the retention curve. The precision of the models was practically the same, but the model of HC possesses smaller number of empiric parameters than the model of VG.

soil water; physical soil properties; pedotransfer functions; non-linear regression; soil porosity

SEÇÃO I - FÍSICA DO SOLO

C. A. Tormena^I; A. P. Silva^II

^IProfessor Adjunto do Departamento de Agronomia, Universidade Estadual de Maringá - UEM. Av. Colombo 5790, CEP 87020-900 Maringá (PR). Bolsista do CNPq. E-mail:catormena@uem.br

^IIProfessor do Departamento de Solos e Nutrição de Plantas da Escola Superior de Agricultura Luiz de Queiroz - ESALQ-USP. Av. Pádua Dias 11, CEP 13418-900 Piracicaba (SP). Bolsista do CNPq. E-mail: apisilva@carpa.ciagri.usp.br

RESUMO

A curva de retenção de água no solo é fundamental para o desenvolvimento de estudos relacionados com a dinâmica da água, com a modelagem de processos físicos do solo e crescimento das plantas. Normalmente, a curva de retenção é obtida por meio de medidas simultâneas do conteúdo de água (θ) e do potencial mátrico da água no solo (ψ) numa única amostra. Um procedimento alternativo consiste em utilizar várias amostras por ψ para descrever a curva de retenção. A utilização deste procedimento requer a incorporação dos fatores de variação existentes entre as amostras nos parâmetros das funções matemáticas utilizadas para descrever essa curva. O objetivo deste trabalho foi obter a curva de retenção, utilizando esta última sistemática, e ajustar duas diferentes funções não-lineares aos dados de θ(ψ). Amostras indeformadas (0,05 m de diâmetro e 0,05 m de altura) foram obtidas num Latossolo Vermelho distroférrico cultivado com milho sob plantio direto e preparo convencional do solo. Foram retiradas 96 amostras por sistema de preparo, na profundidade de 0-0,10 m, na linha e na entrelinha da cultura. A curva de retenção foi obtida utilizando-se 12 ψ, sendo 16 amostras por ψ: oito por sistema de preparo e quatro por posição amostrada. Os modelos de Genuchten (1980) - VG e o de Hutson & Cass (1987) - HC foram ajustados aos dados. Funções relacionando os parâmetros dos modelos com as variáveis independentes preparo, posição de amostragem e densidade do solo (Ds) os substituíram no ajuste dos dados. Não houve influência estatisticamente significativa dos sistemas de preparo e posição de amostragem (p > 0,05) no ajuste das funções aos dados . Com a função de VG obtiveram-se efeitos significativos da Ds no parâmetro n, o qual foi descrito por uma função quadrática da Ds. Resultado similar foi obtido com o parâmetro "a" da função de HC. A curva de retenção foi sensível às variações da Ds e o procedimento utilizado apresenta vantagens de natureza metodológica, bem como a redução substancial de tempo e custo para obter a curva de retenção. A precisão dos modelos utilizados foi praticamente similar, mas o modelo de HC apresentou menor número de parâmetros empíricos que o modelo de VG.

Termos de indexação: propriedades físicas do solo, funções de pedotransferência, regressão não-linear, porosidade do solo.

SUMMARY

The soil water retention curve plays a fundamental role in the development of studies on the dynamics of soil water, modeling of physical soil processes and plant growth. The retention curve is usually obtained by simultaneously measuring water content (θ) and soil water potential (ψ) in a single sample. An alternative procedure is to use several samples per ψ to describe the retention curve. The use of this procedure requires that the variation factors which exist among the samples are incorporated into the parameters of the mathematical functions used to describe the retention curve. The objective of this study was to obtain the retention curve using the latter procedure and fitting the θ(ψ) data using two different nonlinear functions. Undisturbed soil samples (0.05 m in diameter and 0.05 m in height) were collected from a Rhodic Ferralsol (Typic Hapludox) cropped with corn by no-tillage and conventional tillage. Ninety-six samples per soil tillage were taken at a depth of 0-0.10 m, from two positions: along the crop row and between crop rows. The retention curve was obtained using 12 matric potentials, with 16 samples per ψ: eight per tillage system and four per sampled position. Data were adjusted using the Genuchten (1980) model, VG, and the function proposed by Hutson & Cass (1987), HC. Mathematical functions relating the model parameters with the independent variables (soil tillage, sampling position and soil bulk density - Bd) substituted the model parameters in the fitting of the data. The tillage systems and sampling position exerted no statistically significant influence (p > 0.05) on the fitting of the data. With the VG function, Bd produced significant effects on the n parameter, which was described by a quadratic function of Bd. A similar result was obtained with the "a" parameter of the HC function. The retention curve proved to be sensitive to variations of Bd. The adopted procedure offered methodological advantages, involving substantially less time and lower costs to obtain the retention curve. The precision of the models was practically the same, but the model of HC possesses smaller number of empiric parameters than the model of VG.

Index terms: soil water, physical soil properties, pedotransfer functions, non-linear regression, soil porosity.

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LITERATURA CITADA

AHUJA, L.R.; NANEY, J.W. & NIELSEN, D.R. Scaling to characterize soil water properties and infiltration modeling. Soil Sci. Soc. Am. J., 48:970-973, 1985.

ARCHER, J.R. & SMITH, P.D. The relation between bulk density, available water capacity and air capacity of soils. J. Soil Sci., 23:475-480, 1972.

ARYA, L.M. & PARIS, J.F. A physicoempirical model to predict the soil moisture characteristic from particle-size distribution and bulk density data. Soil Sci. Soc. Am. J., 45:1023-1030, 1981.

ASSOULINE, S.; TAVARES-FILHO, J. & TESSIER, D. Effect of compaction on soil physical and hydraulic properties: Experimental results and modeling. Soil Sci. Soc. Am. J., 61:390-398, 1997.

BOUMA, J. Using soil survey data for quantitative land evaluation. Adv. Soil Sci., 9:177-213, 1989.

BROOKS, R.H.& COREY, A.T. Hydraulic properties of porous media. Fort Collins, Colorado State University, 1964, 54p. (Hydrology Papers, 3)

CAMP, C.R.; SADLER, E.J.; EVANS, D.E.; USREY, L.G. & OMARY, M. Modified center pivot system for precision management of water and nutrients. Am. Soc. Agric. Eng., 14:23-31, 1998.

CAMPBELL, G.S. A simple method for determining unsatured conductivity from moisture retention data. Soil Sci., 117:311-314, 1974.

CREESWELL, H.P. & PAYDAR, Z. Functional evaluation of methods for predicting the soil water characteristics. J. Hydrol., 227:160-172, 2000.

CRESSWELL, H.P. & PAYDAR, Z. Water retention in Australian soils. I. Description and prediction using parametric functions. Aust. J. Soil Res., 34:195-212, 1996.

DEXTER, A.R. Advances in characterization of soil structure. Soil Till. Res., 11:199-238, 1988.

FELTON, G.K. & NIEBER, J.L. Four soil moisture characteristics curve functions evaluated for numerical modeling of sand. Trans. Am. Soc. Agric. Eng., 34:417-422, 1991.

GENUCHTEN, M.Th. van . A closed form equation for predicting hydraulic conductivity of unsaturated soils. Soil Sci. Soc. Am. J., 1:892-898, 1980.

GENUCHTEN, M.Th. van & NIELSEN, D.R. On describing and predicting the hydraulic properties of unsatured soils. Ann. Geoph., 3:615-628, 1985.

GLANTZ, S.A. & SLINKER, B.K. Primer of applied regression and analysis of variance. New York, McGraw-Hill, 1990. 777p.

GREGSON, K.; HECTOR, D.J. & McGOWAN, M. A one-parameter model for the soil water characteristic. J. Soil Sci., 38:483-486, 1987.

GUPTA, S.C. & LARSON, W.E. Estimating soil water characteristics from size distribution, organic carbon and bulk density. Water Res. Res., 15:1633-1635, 1979.

GUPTA, S.C.; SHARMA, P.P. & De FRANCHI, S.A. Compaction effects on soil structure. Adv. Agron., 42:331-338, 1989.

HALL, D.G.M.; REEVE, M.J.; THOMASSON, A.J. & WRIGHT, V.F. Water retention, porosity and density of field soils. Harpenden , Soil Survey, 1977. 67p. (Technician Monograph, 9)

HILL, J.N.S.L. & SUMNER, M.E. Effect of bulk density on moisture characteristics of soils. Soil Sci., 103:234-238, 1967.

HUTSON, J.L. & CASS, A. A retentivity function for use in soil-water simulation models. J. Soil Sci., 38:105-113, 1987.

KLUTE, A. Water retention: Laboratory methods. In: KLUTE, A., ed. Methods of soil analysis. 2.ed. Madison, American Society of Agronomy, 1986. p.635-660.

MAYR, T. & JARVIS, N.J. Pedotransfer functions to estimate soil water retention parameters for a modified Brooks-Corey type model. Geoderma, 91:1-9, 1999.

MINASNY, B.; McBRATNEY, A.B. & BRISTOW, K.L. Comparison of different approaches to the development of pedotransfer functions for water-retention curves. Geoderma, 93:225-253, 1999.

NETTER, J.; WASSERMAN, W. & KUTNER, M.H. Applied linear regression models. 2.ed. Homewwod:R.D.Irwin, 1989. 245p.

PAYDAR, Z. & CRESSWELL, H.P. Water retention in Australian soils. II. Prediction using particle size, bulk density and other properties. Aust. J. Soil Res., 34:679-693, 1996.

RAJKAI, K.; KABOS, S.; GENUCHTEN, M.Th. van & JANSSON, P. Estimating water-retention characteristics from the bulk density and particle size distribution of Swedish soils. Soil Sci., 161:832-845, 1996.

RASIAH, V. & AYLMORE, L.A.G. Sensitivity of selected water retention functions to compaction and inherent soil properties. Aust. J. Soil Res., 36:317-326, 1998.

RAWLS, W.J.; BRAKENSIEK, D.L. & SAXTON, K.E. Estimation of soil water properties. Trans. Am. Soc. Agric. Eng., 35:1316-1320, 1982.

RAWLS, W.J.; GISH, T.J. & BRAKENSIEK, D.L. Estimating soil water retention from soil physical properties and characteristics. Adv. Soil Sci., 16:213-234, 1991.

REEVE, M.J.; SMITH, P.D. & THOMASSON, A.J. The effect of density on water retention properties of field soils. J. Soil Sci., 24:355-367, 1973.

SCHEINOST, A.C.; SINOWSKI, W. & AUERSWALD, K. Regionalization of soil water retention curves in a highly variable soilscape. I. Developing a new pedotransfer function. Geoderma, 78:129-143, 1997.

SILVA, A.P. & KAY, B.D. Estimating the least limiting water range of soil from properties and management. Soil Sci. Soc. Am. J., 61:877-883, 1997^.

SILVA, A.P.; KAY, B.D. & PERFECT, E. Characterization of the least limiting water range. Soil Sci. Soc. Am. J., 58:1775-1781, 1994.

STATISTICAL ANALYSIS SYSTEM INSTITUTE- SAS. SAS/STAT Procedure guide for personal computers. Version 5, SAS Inst. Cary, 1998.

TOPP, G.C.; GALGANOV, Y.T.; BALL, B.C. & CARTER, M.R. Soil water curves desorption. In: CARTER, M.R., ed. Soil sampling and methods of analysis. Lewis: Boca Raton, 1993. p.569-579.

TOPP, G.C. & ZEBTCHUCK, W. The determination of soil water desorption curves for soil cores. Can. J. Soil Sci., 59:19-26, 1979.

VAN DEN BERG, M.; KLAMT, E.; VAN REUWIJK, L.P. & SOMBROEK, W.G. Pedotransfers functions for the estimation of moisture retention characteristics of Ferralsols and related soils. Geoderma, 78:161-180, 1997.

VEREECKEN, H.; MAES, H.; FEYEN, J. & DARIUS, P. Estimating the soil moisture retention characteristics from texture, bulk density, and carbon content. Soil Sci., 148:389-403, 1989.

WILLIAMS, J.; PREBBLE, R.E.; WILLIAMS, W.T. & HIGNETT, C.T. The influence of texture, structure and clay mineralogy on the soil moisture characteristic. Aust. J. Soil Res., 21:15-32, 1983.

WILLIAMS, J.; ROSS, P. & BRISTOW, K. Prediction of Campbell water retention from texture, structure and organic matter. In: GENUCHTEN, Mt. van & LUND, L.J., eds. Indirect methods for estimating the hydraulics properties of unsaturated soils. Riverside: University of California, p.427-441, 1992.

WOSTEN, J.H.M. & GENUHTEN, M.Th. van. Using texture and other soil properties to predict the unsatured soil hydraulic function. Soil Sci. Soc. Am. J., 52:1762-1770, 1988.

Recebido para publicação em fevereiro de 2001

Aprovado em novembro de 2001

AHUJA, L.R.; NANEY, J.W. & NIELSEN, D.R. Scaling to characterize soil water properties and infiltration modeling. Soil Sci. Soc. Am. J., 48:970-973, 1985.
ARCHER, J.R. & SMITH, P.D. The relation between bulk density, available water capacity and air capacity of soils. J. Soil Sci., 23:475-480, 1972.
ARYA, L.M. & PARIS, J.F. A physicoempirical model to predict the soil moisture characteristic from particle-size distribution and bulk density data. Soil Sci. Soc. Am. J., 45:1023-1030, 1981.
ASSOULINE, S.; TAVARES-FILHO, J. & TESSIER, D. Effect of compaction on soil physical and hydraulic properties: Experimental results and modeling. Soil Sci. Soc. Am. J., 61:390-398, 1997.
BOUMA, J. Using soil survey data for quantitative land evaluation. Adv. Soil Sci., 9:177-213, 1989.
BROOKS, R.H.& COREY, A.T. Hydraulic properties of porous media. Fort Collins, Colorado State University, 1964, 54p. (Hydrology Papers, 3)
CAMP, C.R.; SADLER, E.J.; EVANS, D.E.; USREY, L.G. & OMARY, M. Modified center pivot system for precision management of water and nutrients. Am. Soc. Agric. Eng., 14:23-31, 1998.
CAMPBELL, G.S. A simple method for determining unsatured conductivity from moisture retention data. Soil Sci., 117:311-314, 1974.
CREESWELL, H.P. & PAYDAR, Z. Functional evaluation of methods for predicting the soil water characteristics. J. Hydrol., 227:160-172, 2000.
CRESSWELL, H.P. & PAYDAR, Z. Water retention in Australian soils. I. Description and prediction using parametric functions. Aust. J. Soil Res., 34:195-212, 1996.
DEXTER, A.R. Advances in characterization of soil structure. Soil Till. Res., 11:199-238, 1988.
FELTON, G.K. & NIEBER, J.L. Four soil moisture characteristics curve functions evaluated for numerical modeling of sand. Trans. Am. Soc. Agric. Eng., 34:417-422, 1991.
GENUCHTEN, M.Th. van . A closed form equation for predicting hydraulic conductivity of unsaturated soils. Soil Sci. Soc. Am. J., 1:892-898, 1980.
GENUCHTEN, M.Th. van & NIELSEN, D.R. On describing and predicting the hydraulic properties of unsatured soils. Ann. Geoph., 3:615-628, 1985.
GLANTZ, S.A. & SLINKER, B.K. Primer of applied regression and analysis of variance. New York, McGraw-Hill, 1990. 777p.
GREGSON, K.; HECTOR, D.J. & McGOWAN, M. A one-parameter model for the soil water characteristic. J. Soil Sci., 38:483-486, 1987.
GUPTA, S.C. & LARSON, W.E. Estimating soil water characteristics from size distribution, organic carbon and bulk density. Water Res. Res., 15:1633-1635, 1979.
GUPTA, S.C.; SHARMA, P.P. & De FRANCHI, S.A. Compaction effects on soil structure. Adv. Agron., 42:331-338, 1989.
HALL, D.G.M.; REEVE, M.J.; THOMASSON, A.J. & WRIGHT, V.F. Water retention, porosity and density of field soils. Harpenden , Soil Survey, 1977. 67p. (Technician Monograph, 9)
HILL, J.N.S.L. & SUMNER, M.E. Effect of bulk density on moisture characteristics of soils. Soil Sci., 103:234-238, 1967.
HUTSON, J.L. & CASS, A. A retentivity function for use in soil-water simulation models. J. Soil Sci., 38:105-113, 1987.
KLUTE, A. Water retention: Laboratory methods. In: KLUTE, A., ed. Methods of soil analysis. 2.ed. Madison, American Society of Agronomy, 1986. p.635-660.
MAYR, T. & JARVIS, N.J. Pedotransfer functions to estimate soil water retention parameters for a modified Brooks-Corey type model. Geoderma, 91:1-9, 1999.
MINASNY, B.; McBRATNEY, A.B. & BRISTOW, K.L. Comparison of different approaches to the development of pedotransfer functions for water-retention curves. Geoderma, 93:225-253, 1999.
NETTER, J.; WASSERMAN, W. & KUTNER, M.H. Applied linear regression models. 2.ed. Homewwod:R.D.Irwin, 1989. 245p.
PAYDAR, Z. & CRESSWELL, H.P. Water retention in Australian soils. II. Prediction using particle size, bulk density and other properties. Aust. J. Soil Res., 34:679-693, 1996.
RAJKAI, K.; KABOS, S.; GENUCHTEN, M.Th. van & JANSSON, P. Estimating water-retention characteristics from the bulk density and particle size distribution of Swedish soils. Soil Sci., 161:832-845, 1996.
RASIAH, V. & AYLMORE, L.A.G. Sensitivity of selected water retention functions to compaction and inherent soil properties. Aust. J. Soil Res., 36:317-326, 1998.
RAWLS, W.J.; BRAKENSIEK, D.L. & SAXTON, K.E. Estimation of soil water properties. Trans. Am. Soc. Agric. Eng., 35:1316-1320, 1982.
RAWLS, W.J.; GISH, T.J. & BRAKENSIEK, D.L. Estimating soil water retention from soil physical properties and characteristics. Adv. Soil Sci., 16:213-234, 1991.
REEVE, M.J.; SMITH, P.D. & THOMASSON, A.J. The effect of density on water retention properties of field soils. J. Soil Sci., 24:355-367, 1973.
SCHEINOST, A.C.; SINOWSKI, W. & AUERSWALD, K. Regionalization of soil water retention curves in a highly variable soilscape. I. Developing a new pedotransfer function. Geoderma, 78:129-143, 1997.
SILVA, A.P. & KAY, B.D. Estimating the least limiting water range of soil from properties and management. Soil Sci. Soc. Am. J., 61:877-883, 1997^.
SILVA, A.P.; KAY, B.D. & PERFECT, E. Characterization of the least limiting water range. Soil Sci. Soc. Am. J., 58:1775-1781, 1994.
STATISTICAL ANALYSIS SYSTEM INSTITUTE- SAS. SAS/STAT Procedure guide for personal computers. Version 5, SAS Inst. Cary, 1998.
TOPP, G.C.; GALGANOV, Y.T.; BALL, B.C. & CARTER, M.R. Soil water curves desorption. In: CARTER, M.R., ed. Soil sampling and methods of analysis. Lewis: Boca Raton, 1993. p.569-579.
TOPP, G.C. & ZEBTCHUCK, W. The determination of soil water desorption curves for soil cores. Can. J. Soil Sci., 59:19-26, 1979.
VAN DEN BERG, M.; KLAMT, E.; VAN REUWIJK, L.P. & SOMBROEK, W.G. Pedotransfers functions for the estimation of moisture retention characteristics of Ferralsols and related soils. Geoderma, 78:161-180, 1997.
VEREECKEN, H.; MAES, H.; FEYEN, J. & DARIUS, P. Estimating the soil moisture retention characteristics from texture, bulk density, and carbon content. Soil Sci., 148:389-403, 1989.
WILLIAMS, J.; PREBBLE, R.E.; WILLIAMS, W.T. & HIGNETT, C.T. The influence of texture, structure and clay mineralogy on the soil moisture characteristic. Aust. J. Soil Res., 21:15-32, 1983.
WILLIAMS, J.; ROSS, P. & BRISTOW, K. Prediction of Campbell water retention from texture, structure and organic matter. In: GENUCHTEN, Mt. van & LUND, L.J., eds. Indirect methods for estimating the hydraulics properties of unsaturated soils. Riverside: University of California, p.427-441, 1992.
WOSTEN, J.H.M. & GENUHTEN, M.Th. van. Using texture and other soil properties to predict the unsatured soil hydraulic function. Soil Sci. Soc. Am. J., 52:1762-1770, 1988.