Efeito do controle de invasoras em propriedades físicas e micropedológicas de um podzólico vermelho-amarelo

Faria, J. C.; Schaefer, C. E. R.; Ruiz, H. A.; Costa, L. M.

doi:10.1590/S0100-06831998000400019

Resumos

Nos trópicos, o impacto das gotas de chuva é capaz de destruir agregados e a porosidade natural do solo, influenciando o montante de água infiltrada e sua redistribuição. Em tais condições, a cobertura vegetal produzida pelas plantas invasoras não pode ser vista, simplesmente, como competidora com a cultura de interesse. Este projeto de pesquisa foi concebido para examinar, em condições de campo, a influência de diferentes tipos de manejo de invasoras sobre a umidade, estrutura e selamento do solo, visando contribuir para o desenvolvimento de técnicas compatíveis com uma agricultura sustentada. Quatro tipos de manejo de invasoras (coberturas): capina, sem vegetação (aplicação combinada do herbicida de pré-emergência Arsenal-250® (Imazapir) 2,0 L ha-1 e do herbicida sistêmico Gliz® (Glifosato) 5,0 L ha-1), roçado e roçado + herbicida (herbicida sistêmico Gliz®(Glifosato) 5,0 L ha-1), foram estudadas em um Podzólico Vermelho-Amarelo fase terraço em Minas Gerais. Nos períodos de elevada precipitação, as coberturas roçado e roçado + herbicida apresentaram maiores valores de umidade de solo quando comparados com capina e sem vegetação. Por outro lado, nos períodos secos, capina e sem vegetação apresentaram maiores valores de umidade de solo em relação as demais. Um selamento de aproximadamente 15 mm a partir da superfície do solo foi observado nas coberturas capina e sem vegetação, sendo particularmente bem estratificado na última. Postulou-se que processos microerosionais e microdeposicionais foram envolvidos no selamento observado na cobertura capina. Estes processos resultaram da quebra, e posterior rearranjo dos microagregados. Na cobertura sem vegetação, o selamento foi associado com alterações físicas na superfície do solo, devido ao impacto das gotas de chuva. As coberturas roçado e roçado + herbicida apresentaram grande desenvolvimento de algas, briófitas e atividade de minhocas na superfície. Baseado nos resultados obtidos, o uso de roçadeira motorizada com herbicida sistêmico, parece ser uma alternativa apropriada para o controle das invasoras, por reduzir a degradação física e as perdas de água e solo neste ambiente particular.

Uso do solo; selamento; micropedologia; Podzólico Vermelho-Amarelo; umidade do solo; controle de invasoras

In the tropical soil environment, raindrop impact is capable of disrupting natural soil aggregation and porosity, thus influencing the amount of infiltrated water and its redistribution. Under such conditions, a vegetation cover of weeds cannot be viewed simply as a crop competitor. This research project was designed to examine, under field conditions, the changes of soil properties, namely soil water content, structure and sealing, resulting from different types of weed management, with the aim of contributing to the establishment of more sustainable agricultural practices. Four weed management types - hoe-weeded, bare soil (combined application of pre-emergence herbicide Arsenal-250® (Imazapir) 2.0 L ha-1 and the systemic herbicide Gliz® (Glifosate) 5.0 L ha-1), cut and cut + herbicide (systemic herbicide Gliz®(Glifosate) 5.0 L ha-1) - were studied on an intensively cropped Kanhapludult in Minas Gerais State, Brazil. In high rainfall periods, the insulating effect of cut and cut + herbicide resulted in higher soil water, as compared to bare soil and hoe-weeded. On the other hand, in dry periods, the bare soil and hoe-weeded covers presented higher soil water content than the cut and cut + herbicide. Based on macro and micropedological observations, a sealing effect up to 15 mm below the surface was observed in bare soil and hoe-weeded covers and was particularly well-sorted and stratified in the latter. It is postulated that microerosional and microdepositional processes are involved in hoe-weeded sealing. These processes result from the breakdown of microaggregates, repacking the soil matrix. In the bare soil, the sealing was associated with physical alterations in the top layer, related to raindrop impact. Cut and cut + herbicide covers showed greater development of algae, bryophytes and worm activity in the soil surface. Based on the results obtained, the use of motorized cutters associated with herbicides appears to be a suitable alternative to hoeing and hand-weeding, reducing soil physical degradation and losses of water and soil in this particular environment.

Land use; sealing; micropedology; ultisol; soil water content; weed control

SEÇÃO VI - MANEJO E CONSERVAÇÃO DO SOLO E DA ÁGUA

J. C. Faria^I; C. E. R. Schaefer^II; H. A. Ruiz^II; L. M. Costa^II

^IDoutorando em Fitotecnia, Departamento de Fitotecnia, Universidade Federal de Viçosa - UFV. CEP 36571-000 Viçosa (MG)

^IIProfessor do Departamento de Solos, UFV

SUMMARY

In the tropical soil environment, raindrop impact is capable of disrupting natural soil aggregation and porosity, thus influencing the amount of infiltrated water and its redistribution. Under such conditions, a vegetation cover of weeds cannot be viewed simply as a crop competitor. This research project was designed to examine, under field conditions, the changes of soil properties, namely soil water content, structure and sealing, resulting from different types of weed management, with the aim of contributing to the establishment of more sustainable agricultural practices. Four weed management types - hoe-weeded, bare soil (combined application of pre-emergence herbicide Arsenal-250® (Imazapir) 2.0 L ha^-1 and the systemic herbicide Gliz® (Glifosate) 5.0 L ha^-1), cut and cut + herbicide (systemic herbicide Gliz®(Glifosate) 5.0 L ha^-1) - were studied on an intensively cropped Kanhapludult in Minas Gerais State, Brazil. In high rainfall periods, the insulating effect of cut and cut + herbicide resulted in higher soil water, as compared to bare soil and hoe-weeded. On the other hand, in dry periods, the bare soil and hoe-weeded covers presented higher soil water content than the cut and cut + herbicide. Based on macro and micropedological observations, a sealing effect up to 15 mm below the surface was observed in bare soil and hoe-weeded covers and was particularly well-sorted and stratified in the latter. It is postulated that microerosional and microdepositional processes are involved in hoe-weeded sealing. These processes result from the breakdown of microaggregates, repacking the soil matrix. In the bare soil, the sealing was associated with physical alterations in the top layer, related to raindrop impact. Cut and cut + herbicide covers showed greater development of algae, bryophytes and worm activity in the soil surface. Based on the results obtained, the use of motorized cutters associated with herbicides appears to be a suitable alternative to hoeing and hand-weeding, reducing soil physical degradation and losses of water and soil in this particular environment.

Index terms: Land use, sealing, micropedology, ultisol, soil water content, weed control.

RESUMO

Nos trópicos, o impacto das gotas de chuva é capaz de destruir agregados e a porosidade natural do solo, influenciando o montante de água infiltrada e sua redistribuição. Em tais condições, a cobertura vegetal produzida pelas plantas invasoras não pode ser vista, simplesmente, como competidora com a cultura de interesse. Este projeto de pesquisa foi concebido para examinar, em condições de campo, a influência de diferentes tipos de manejo de invasoras sobre a umidade, estrutura e selamento do solo, visando contribuir para o desenvolvimento de técnicas compatíveis com uma agricultura sustentada. Quatro tipos de manejo de invasoras (coberturas): capina, sem vegetação (aplicação combinada do herbicida de pré-emergência Arsenal-250® (Imazapir) 2,0 L ha^-1 e do herbicida sistêmico Gliz® (Glifosato) 5,0 L ha^-1), roçado e roçado + herbicida (herbicida sistêmico Gliz®(Glifosato) 5,0 L ha^-1), foram estudadas em um Podzólico Vermelho-Amarelo fase terraço em Minas Gerais. Nos períodos de elevada precipitação, as coberturas roçado e roçado + herbicida apresentaram maiores valores de umidade de solo quando comparados com capina e sem vegetação. Por outro lado, nos períodos secos, capina e sem vegetação apresentaram maiores valores de umidade de solo em relação as demais. Um selamento de aproximadamente 15 mm a partir da superfície do solo foi observado nas coberturas capina e sem vegetação, sendo particularmente bem estratificado na última. Postulou-se que processos microerosionais e microdeposicionais foram envolvidos no selamento observado na cobertura capina. Estes processos resultaram da quebra, e posterior rearranjo dos microagregados. Na cobertura sem vegetação, o selamento foi associado com alterações físicas na superfície do solo, devido ao impacto das gotas de chuva. As coberturas roçado e roçado + herbicida apresentaram grande desenvolvimento de algas, briófitas e atividade de minhocas na superfície. Baseado nos resultados obtidos, o uso de roçadeira motorizada com herbicida sistêmico, parece ser uma alternativa apropriada para o controle das invasoras, por reduzir a degradação física e as perdas de água e solo neste ambiente particular.

Termos de indexação: Uso do solo, selamento, micropedologia, Podzólico Vermelho-Amarelo, umidade do solo, controle de invasoras.

Texto completo disponível apenas em PDF.

Full text available only in PDF format.

ACKNOWLEDGEMENTS

The authors expresses your gratitude to Mrs. Marisia Cyreti Forte Pontes for the algae and briophytes identification, Mrs. Karen Gutteridge (Reading, UK) for thin-section preparation, Mr.Wilson da Silva for weed identification, and Dr. John Dalrymple, Dr. Matosinho de Souza Figueiredo and Dr. Caetano Marciano de Souza for many useful suggestions to the study. The authors are indebted to Mr. José Tarcísio Lima Thiébaut and Mr. Fernando Pinheiro Reis for support in statistical analysis. The authors are also grateful to the anonymous contributions from the scientific board of the Revista Brasileira de Ciência do Solo.

LITERATURE CITED

Received for publication in February of 1998

Aproved in July of 1998

AASAE, J.K. & SIDDOWAY, F.H. Stubble height effects on season microclimate water balance, and plant development of no till winter wheat. Agric. Meteorol., 21:1-20, 1980.
ALTEMULLER, H.J. & van VLIET-LANOE, B. Soil thin section fluorescence microscopy. In: DOUGLAS, L.A., ed. Soil micromorphology: a basic and applied science. Amsterdam, 1990. p.565-580. (Developments in Soil Science, 19)
ALVARENGA, R.C.; FERNANDES, B.; SILVA, T.C.A. & RESENDE, M. Estabilidade de agregados de um latossolo roxo sob diferentes métodos de preparo do solo e de manejo da palhada de milho. R. Bras. Ci. Solo, 10:273-277, 1986.
BISHAY, B.G.& STOOPS, G. Micromorphology of irrigation crusts formed on a calcareous soil of the mechanized farm, north-west Egypt. Pedologie, 25:143, 1975.
BRESSON, L.M. & BOIFFIN, J. Morphological characterisation of soil crust development stages on an experimental field. Geoderma, 47:301-325, 1990.
BRESSON, L.M. & VALENTIN, C. Soil surface crust formation: contribution of micromorphology. 1994. In: RINGROSE-VOASE, A.J. & HUMPHREYS, G.S., eds. Soil micromorphology: studies in management and genesis. Amsterdam: 1994. p.737-762.
BULLOCK, P.; FEDEROFF, N.; JONGERIUS, A.; STOOPS, G.; TURSINA, T. & BABEL, U. Handbook for the soil thin section description. Wolverhampton, Waine Research Publications, 1985. 153p.
CARPENEDO, V. & MIELNICZUK, J. Estado de agregação e qualidade de agregados de Latossolos Roxos, submetidos a diferentes sistemas de manejo. R. Bras. Ci. Solo, 14:99-105, 1990.
CASSEL, D.K. & LAL, R. Soil physical preperties of the tropics: common beliefs and management restraints. In: LAL, R. & SANCHEZ, P.A. Myths and science of soils of the tropics. Madison, SSSA, 1992. p.61-89 (SSSA Speciel Publication 29).
CHURCHILL, R.V. Fourier series and boundary value problems. New York, McGraw-Hill, 1963. 248p.
DE VLEESCHAUWER, D.; LAL, R. & MALAFA, R. Effects or amounts of surface mulch on physical and chemical properties of an alfisol from Nigeria. J. Sci. Food Agric., 31:730-738, 1980.
DICK, W.A., ROSEBERG, R.J. & McCOY, E.L., et al. Surface hydrologic response of soils to no-tillage. Soil Sci. Soc. Am. J., 53:1520-1526, 1989.
ELDRIDGE, D.J. & GREENE, R.S.B. Microbiotic soil crust: a review of their roles in soil and ecological processes in the rangelands of Australia. Austr. J. Soil Res., 32:389-415, 1994.
EVANS, D.D. & BUOL, S.W. Micromorfological study of soil crusts. Soil Sci. Soc. Am. Proc., 32:19-22, 1968.
FALAYI, O. & BOUMA, J. Relationships between the hydraulic conductance of surface crusts and soil management in a Typic Hapludalf. Soil Sci. Soc. Am. Proc.,39:957-963, 1975.
FARIA, J.C. Dinâmica da água, comportamento térmico e selamento de um Podzólico Vermelho-Amarelo em relação ao controle de plantas invasoras. Viçosa, UFV, 1996. 75p. (Tese de Mestrado)
FERNANDES, B. & SYKES, D.J. Capacidade de campo e a retenção de água em três solos de Minas Gerais. R. Ceres, 15, 1-39, 1968.
FITZPATRICK, E.A. Microscopy and micromorphology of soils. Chichester: John Wiley, 1993. 304p.
GREENLAND, D.J. Soil science and sustainable land management. In: SYERS, J.K. & RIMMER, D.L., eds. Soil science and sustainable management in the Tropics. Wallingford, CAB International, 1994. p1-16.
GREENLAND, D.J. The magnitude and importance of the problem. In: GREENLAND, D.J. & LAL, R., eds. Soil conservation & management in the humid tropics. Chichester, John Wiley & Sons, 1979a. p.3-7.
GREENLAND, D.J. Soil structure and erosion hazard. In: GREENLAND, D.J. & LAL, R., eds. Soil conservation & management in the humid tropics. Chichester, John Wiley & Sons, 1979b. p.17-24.
HALL, N.W. Micromorphology and complementary assessments of soil structure description and their relationships to the lenght of time under tillage and calcium carbonate contents. In: DOUGLAS, L.A., ed. Soil micromorphology: a basic and applied science. Amsterdam, Elsevier, 1990. p.41-52. (Developments in Soil Science, 19)
HILLEL, D. Soil and water, physical principles and process. New York, Academic Press, 1971. 288p.
HULUGALLE, N.R. Long-term effects of land clearing methods, tillage system and cropping system on surface properties of a tropical alfisol in S. W. Nigeria. Soil Use Manag., 10:25-30, 1994.
JENSEN, M.E; BURMAN, R.D. & ALLEN, R.G. Evapotranspiration and irrigation water requirements. New York, 1990. 332p. (ASCE Manual and Reports on Engineering Practice 70).
KER, J.C. & SCHAEFER, C.E.R. Roteiro da excursão pedológica Viçosa-Sete Lagoas. Viçosa, SBCS/UFV/CNPS-EMBRAPA, 1995. 47p.
KLUTE, A. Methods of soil analysis. Part I. Madison, Soil Science Society of America, 1986. 1188p.
KOOISTRA, M.J.; JUO, A.S.R. & SCHOODERBEEK, D. Soil degradation in cultivated Alfisols under different farming systems in western Nigeria. In: DOUGLAS, L.A., ed. Soil micromorphology: a basic and applied science. Amsterdam, Elsevier, 1990. p.61-70. (Developments in Soil Science, 19)
LAL, R., VLEESCHAUWER, D. & NGANJE, M.R. Changes in properties of a newly cleared tropical alfisol as affected by mulching. Soil Sci. Soc. Am. J., 44:827-833, 1980.
MAHBOUBI, A.A.; LAL, R. & FAUSSEY, N.R. Twenty-eight years of tillage effects on two soils in Ohio. Soil Sci. Soc. Am. J., 57:506-512, 1993.
MONTEIRO, J.A. & RESENDE, L.M.A. A pequena propriedade agrícola em Minas Gerais. Inf. Agropec. 14:10-18, 1988.
MÜCHER, H.J. & DE PLOEY, J. Experimental and micromorphological investigation of erosion and redeposition of loess by water. Earth Surf. Proc., 2:117-124, 1977.
MÜCHER, H.J.; DE PLOEY, J. & SAVAT, J. Response of loess material to simulated translocation by water: micromorphological observation. Earth Surf. Proc., 6:331-336, 1981.
OLDEMAN, L.R., HAKKELING, R.T. & SOMBROEK, W. World Map on the Status of Human-induced soil degradation. FAO, 1990.
PAGLIAI, M. & DE NOBILI, M. Relationships between soil porosity, root development and soil enzyme activity in cultivated soils. Geoderma, 56:243-256, 1993.
PARKER, I.J.; HAMILTON, G.J. & KOEN, T.B. Runoff, soil loss and physical property changes of light textured surface soil from long-term tillage treatments. Austr. J. Soil Res., 30:789-806, 1992.
SETA, A.K.; BLEVINS, R.L. ; FRYE, W.W. & BARFIELD, B.J. Reducing soil erosion and agricultural chemical losses with conservation tillage. J. Environ. Qual., 22:661-665, 1993.
SLATTERY, M.C. & BRYAN, R.B. Laboratory experiments on surface seal development and its effects on interrill erosion processes. J. Soil Sci., 43:517-529, 1992.
SPARKS D.L. Methods of soil analysis. Part 3. Madison, Soil Science Society of America, 1996. 1390p.
TOLLNER, E.W.; HARGROVE, W.L. & LANGDALE, G.W. Influence of conventional and no-till practices on soil physical properties in the southern Piedmont. J. Soil Water Conserv., 39:73-76, 1984.

Effects of weed control on physical and micropedological properties of a brazilian ultisol

Efeito do controle de invasoras em propriedades físicas e micropedológicas de um podzólico vermelho-amarelo

Datas de Publicação

Publicação nesta coleção
07 Out 2014
Data do Fascículo
Dez 1998

Histórico

Aceito
Jul 1998
Recebido
Fev 1998

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

[1] AASAE, J.K. & SIDDOWAY, F.H. Stubble height effects on season microclimate water balance, and plant development of no till winter wheat. Agric. Meteorol., 21:1-20, 1980.

[2] ALTEMULLER, H.J. & van VLIET-LANOE, B. Soil thin section fluorescence microscopy. In: DOUGLAS, L.A., ed. Soil micromorphology: a basic and applied science. Amsterdam, 1990. p.565-580. (Developments in Soil Science, 19)

[3] ALVARENGA, R.C.; FERNANDES, B.; SILVA, T.C.A. & RESENDE, M. Estabilidade de agregados de um latossolo roxo sob diferentes métodos de preparo do solo e de manejo da palhada de milho. R. Bras. Ci. Solo, 10:273-277, 1986.

[4] BISHAY, B.G.& STOOPS, G. Micromorphology of irrigation crusts formed on a calcareous soil of the mechanized farm, north-west Egypt. Pedologie, 25:143, 1975.

[5] BRESSON, L.M. & BOIFFIN, J. Morphological characterisation of soil crust development stages on an experimental field. Geoderma, 47:301-325, 1990.

[6] BRESSON, L.M. & VALENTIN, C. Soil surface crust formation: contribution of micromorphology. 1994. In: RINGROSE-VOASE, A.J. & HUMPHREYS, G.S., eds. Soil micromorphology: studies in management and genesis. Amsterdam: 1994. p.737-762.

[7] BULLOCK, P.; FEDEROFF, N.; JONGERIUS, A.; STOOPS, G.; TURSINA, T. & BABEL, U. Handbook for the soil thin section description. Wolverhampton, Waine Research Publications, 1985. 153p.

[8] CARPENEDO, V. & MIELNICZUK, J. Estado de agregação e qualidade de agregados de Latossolos Roxos, submetidos a diferentes sistemas de manejo. R. Bras. Ci. Solo, 14:99-105, 1990.

[9] CASSEL, D.K. & LAL, R. Soil physical preperties of the tropics: common beliefs and management restraints. In: LAL, R. & SANCHEZ, P.A. Myths and science of soils of the tropics. Madison, SSSA, 1992. p.61-89 (SSSA Speciel Publication 29).

[10] CHURCHILL, R.V. Fourier series and boundary value problems. New York, McGraw-Hill, 1963. 248p.

[11] DE VLEESCHAUWER, D.; LAL, R. & MALAFA, R. Effects or amounts of surface mulch on physical and chemical properties of an alfisol from Nigeria. J. Sci. Food Agric., 31:730-738, 1980.

[12] DICK, W.A., ROSEBERG, R.J. & McCOY, E.L., et al. Surface hydrologic response of soils to no-tillage. Soil Sci. Soc. Am. J., 53:1520-1526, 1989.

[13] ELDRIDGE, D.J. & GREENE, R.S.B. Microbiotic soil crust: a review of their roles in soil and ecological processes in the rangelands of Australia. Austr. J. Soil Res., 32:389-415, 1994.

[14] EVANS, D.D. & BUOL, S.W. Micromorfological study of soil crusts. Soil Sci. Soc. Am. Proc., 32:19-22, 1968.

[15] FALAYI, O. & BOUMA, J. Relationships between the hydraulic conductance of surface crusts and soil management in a Typic Hapludalf. Soil Sci. Soc. Am. Proc.,39:957-963, 1975.

[16] FARIA, J.C. Dinâmica da água, comportamento térmico e selamento de um Podzólico Vermelho-Amarelo em relação ao controle de plantas invasoras. Viçosa, UFV, 1996. 75p. (Tese de Mestrado)

[17] FERNANDES, B. & SYKES, D.J. Capacidade de campo e a retenção de água em três solos de Minas Gerais. R. Ceres, 15, 1-39, 1968.

[18] FITZPATRICK, E.A. Microscopy and micromorphology of soils. Chichester: John Wiley, 1993. 304p.

[19] GREENLAND, D.J. Soil science and sustainable land management. In: SYERS, J.K. & RIMMER, D.L., eds. Soil science and sustainable management in the Tropics. Wallingford, CAB International, 1994. p1-16.

[20] GREENLAND, D.J. The magnitude and importance of the problem. In: GREENLAND, D.J. & LAL, R., eds. Soil conservation & management in the humid tropics. Chichester, John Wiley & Sons, 1979a. p.3-7.

[21] GREENLAND, D.J. Soil structure and erosion hazard. In: GREENLAND, D.J. & LAL, R., eds. Soil conservation & management in the humid tropics. Chichester, John Wiley & Sons, 1979b. p.17-24.

[22] HALL, N.W. Micromorphology and complementary assessments of soil structure description and their relationships to the lenght of time under tillage and calcium carbonate contents. In: DOUGLAS, L.A., ed. Soil micromorphology: a basic and applied science. Amsterdam, Elsevier, 1990. p.41-52. (Developments in Soil Science, 19)

[23] HILLEL, D. Soil and water, physical principles and process. New York, Academic Press, 1971. 288p.

[24] HULUGALLE, N.R. Long-term effects of land clearing methods, tillage system and cropping system on surface properties of a tropical alfisol in S. W. Nigeria. Soil Use Manag., 10:25-30, 1994.

[25] JENSEN, M.E; BURMAN, R.D. & ALLEN, R.G. Evapotranspiration and irrigation water requirements. New York, 1990. 332p. (ASCE Manual and Reports on Engineering Practice 70).

[26] KER, J.C. & SCHAEFER, C.E.R. Roteiro da excursão pedológica Viçosa-Sete Lagoas. Viçosa, SBCS/UFV/CNPS-EMBRAPA, 1995. 47p.

[27] KLUTE, A. Methods of soil analysis. Part I. Madison, Soil Science Society of America, 1986. 1188p.

[28] KOOISTRA, M.J.; JUO, A.S.R. & SCHOODERBEEK, D. Soil degradation in cultivated Alfisols under different farming systems in western Nigeria. In: DOUGLAS, L.A., ed. Soil micromorphology: a basic and applied science. Amsterdam, Elsevier, 1990. p.61-70. (Developments in Soil Science, 19)

[29] LAL, R., VLEESCHAUWER, D. & NGANJE, M.R. Changes in properties of a newly cleared tropical alfisol as affected by mulching. Soil Sci. Soc. Am. J., 44:827-833, 1980.

[30] MAHBOUBI, A.A.; LAL, R. & FAUSSEY, N.R. Twenty-eight years of tillage effects on two soils in Ohio. Soil Sci. Soc. Am. J., 57:506-512, 1993.

[31] MONTEIRO, J.A. & RESENDE, L.M.A. A pequena propriedade agrícola em Minas Gerais. Inf. Agropec. 14:10-18, 1988.

[32] MÜCHER, H.J. & DE PLOEY, J. Experimental and micromorphological investigation of erosion and redeposition of loess by water. Earth Surf. Proc., 2:117-124, 1977.

[33] MÜCHER, H.J.; DE PLOEY, J. & SAVAT, J. Response of loess material to simulated translocation by water: micromorphological observation. Earth Surf. Proc., 6:331-336, 1981.

[34] OLDEMAN, L.R., HAKKELING, R.T. & SOMBROEK, W. World Map on the Status of Human-induced soil degradation. FAO, 1990.

[35] PAGLIAI, M. & DE NOBILI, M. Relationships between soil porosity, root development and soil enzyme activity in cultivated soils. Geoderma, 56:243-256, 1993.

[36] PARKER, I.J.; HAMILTON, G.J. & KOEN, T.B. Runoff, soil loss and physical property changes of light textured surface soil from long-term tillage treatments. Austr. J. Soil Res., 30:789-806, 1992.

[37] SETA, A.K.; BLEVINS, R.L. ; FRYE, W.W. & BARFIELD, B.J. Reducing soil erosion and agricultural chemical losses with conservation tillage. J. Environ. Qual., 22:661-665, 1993.

[38] SLATTERY, M.C. & BRYAN, R.B. Laboratory experiments on surface seal development and its effects on interrill erosion processes. J. Soil Sci., 43:517-529, 1992.

[39] SPARKS D.L. Methods of soil analysis. Part 3. Madison, Soil Science Society of America, 1996. 1390p.

[40] TOLLNER, E.W.; HARGROVE, W.L. & LANGDALE, G.W. Influence of conventional and no-till practices on soil physical properties in the southern Piedmont. J. Soil Water Conserv., 39:73-76, 1984.