Pressões De Contato E O Impacto De Conjuntos Motomecanizados Em Latossolo Com Presença E Ausência De Palhada De Cana-de-açúcar

High contact pressures applied to soil result in a greater degree of compaction, in addition to promoting other negative effects. The objective of this study was to quantify contact areas by using different methodologies, and pressures of farm equipment employed in production activity and evaluate structural changes caused in a Red Latosol with the presence and absence of straw cover. The design was completely randomized in a factorial scheme of type 4 (tire on front axle, tire on rear axle, tire on a sugarcane wagon and metallic track of sugar cane Harvester) x 2 (presence and absence of straw). The contact area (CA) of the run was obtained by three procedures: analytical measure of the area of an ellipse (CA1); digital measurement of area of an ellipse (CA2); and measurement of real contact area (RCA), with digital resources. The contact pressure was calculated from the ratio of mass of each machine’s axle and the contact area of the run. The contact area obtained according to the procedure of the ellipse (CA1 and CA2) is overrated when compared to actual area obtained digitally (RCA). The straw reduces the contact pressure in the soil, due to the deep tire treads and consequently, increased contact area. Areas where the traffic of the machines occurred with soil covered with the presence of straw showed reduced soil resistance to penetration, cone index and pre-consolidation pressure, confirming that the increased contact area produced by straw reduced the pressure applied and the compression power dissipated in the soil. © 2016, Federal University of Lavras. All rights reserved.40326527

Soil Co 2 Emission Of Sugarcane Fields As Affected By Topography

The spatial and temporal variation of soil CO 2 emission is influenced by several soil attributes related to CO 2 production and its diffusion in the soil. However, few studies aiming to understand the effect of topography on the variability of CO 2 emissions exist, especially for cropping areas of tropical regions. The objective of this study was to evaluate the spatial and temporal changes of soil CO 2 emission and its relation to soil attributes in an area currently cropped with sugarcane under different relief forms and slope positions. Mean CO 2 emissions in the studied period (seven months) varied between 0.23 and 0.71, 0.27 and 0.90, and 0.31 and 0.80 g m -2 h -1 of CO 2 for concave (Cone), backslope (BackS) and footslope (FootS) positions, respectively. The temporal variability of CO 2 emissions in each area was explained by an exponential relation between the CO 2 emission and soil temperature and a linear relation between CO 2 emission and soil water content. The Q 10 values were 1.98 (± 0.34), 1.81 (± 0.49) and 1.71 (± 0.31) for Conc, BackS and FootS, respectively. Bulk density, macroporosity, penetration resistance, aggregation and oxidizable organic carbon content explain the changes in soil CO 2 emission observed, especially when the Cone position was compared to BackS. The effect of relief form and topographic position on soil CO 2 emission variation was dependent on the time of measurement.6617783ALVENÄS, G., JANSSON, P.E., Model for evaporation, moisture and temperature of bare soil: Calibration and sensitivity analysis (1997) Agricultural and Forest Meteorology, 88, pp. 47-56BERNOUX, M., CARVALHO, M.C.S., VOLKOFF, B., CERRI, C.C., CO 2 emission from mineral soils following land-cover change in Brazil (2001) Global Change Biology, 7, pp. 779-787BERNOUX, M., CARVALHO, M.C.S., VOLKOFF, B., CERRI, C.C., Brazil's soil carbon stocks (2002) Soil Science Society of America Journal, 66, pp. 888-896CAMPOS, D.C., (2003) Potencialidade do sistema de colheita sem queima da cana-de-açúcar para o seqüestro de carbono, , Piracicaba: USP/ESALQ, 103p, Doutorado(2007) Acompanhamento da safra brasileira de cana-de-açúcar, , http://www.conab.gov.br/conabweb/download/safra/3-levantamento0708-nov2007.pdf, COMPANHIA NACIONAL DE ABASTECIMENTO, CONAB, safra, terceiro levantamento, novembro/. Available at:, Accessed 21 Jan. 2008. 2008DANIELS, R.B., HAMMER, R.D., Soil geomorphology (1992) New York: Jonh Wiley, , 236pDAVIDSON, E.A., JANSSENS, I.A., Temperature sensitivity of soil carbon decomposition and feedbacks to climate change (2006) Nature, 440, pp. 165-173DeJONG, E., Soil aeration as affected by slope position and vegetative cover (1981) Soil Science, 131, pp. 34-43Manual de métodos de análise de solo (1997) Rio de Janeiro: Embrapa/CNPS, , EMPRESA BRASILEIRA DE PESQUISA AGROPECUÁRIA, 2 ed, 212pManual de métodos de análise do solo (1979) Rio de Janeiro: Embrapa-SNLCS, , EMPRESA BRASILEIRA DE PESQUISA AGROPECUÁRIA, 247pEPRON, D., BOSC, A., BONAL, D., FREYCON, V., Spatial variation of soil respiration across a topographic gradient in a tropical rain forest in French Guiana (2006) Journal of Tropical Ecology, 22, pp. 565-574FANG, C., MONCRIEFF, J.B., GHOLZ, H.X., CLARK, K.L., Soil CO 2 efflux and its spatial variation in a Florida slash pine plantation (1998) Plant Soil, 205, pp. 135-146FANG, C., MONCRIEFF, J.B., The dependence of soil CO 2 efflux on temperature (2001) Soil Biology and Biochemistry, 33, pp. 155-165FANG, C., MONCRIEFF, J.B., A model for soil CO 2 production and transport. 1. Model development (1999) Agricultural and Forest Meteorology, 95, pp. 225-236GARDNER, W.H., Water content (1986) Agronomy Monograph, 9, pp. 493-541. , KLUTE, A, Ed, Methods of soil analysis. 2 ed. Madison: ASAHANSON, P.J., WULLSCHLEGER, S.D., BOHMAN, S.A., TODD, D.E., Seasonal and topographic patterns of forest floor CO 2 efflux from an upland oak forest (1993) Tree Physiology, 13, pp. 1-15HEALY, R.W., STRIEGL, R.G., RUSSELL, T.F., HUTCHINSON, G.L., LIVINGSTON, G.P., Numerical evaluation of static-chamber measurements of soil-atmosphere gas exchange: Identification of physical processes (1996) Soil Science Society of America Journal, 60, pp. 740-747JIA, S.AKIYAMA, T.MO, WINATOMI, M.KOIZUMI, H. Temporal and spatial variability of soil respiration in a cool temperate broad-leaved forest. 1. Measurement of spatial variance and factor analysis. Japanese Journal of Ecology, v.53, p.13-22, 2003KANG, S., LEE, D., LEE, J., RUNNING, S.W., Topographic and climatic controls on soil environments and net primary in a rugged temperate hardwood forest in Korea (2006) Ecological Research, 21, pp. 64-74KANG, S., DOH, S., LEE, D., LEE, D., JIN, V.L., KIMBALL, J., Topographic and climatic controls on soil respiration in six temperate mixed-hardwood forest slopes, Korea (2003) Global Change Biology, 9, pp. 1427-1437KANG, S., KIM, S., DOH, S., LEE, D., Predicting spatial and temporal patterns of soil temperature based on topography, surface cover and air temperature (2000) Forest Ecology and Management, 136, pp. 173-184KEMPER, W.D.ROSENAU, R.C. Aggregate stability and size distribution. In: KLUTE, A. (Ed.) Methods of soil analysis. 2 ed. Madison: ASA, 1986. p.425-441. (Agronomy Monography, 9)KOSUGI, Y., MITANI, T., ITOH, M., NOGUCHI, S., TANI, M., MATSUO, N., TAKANASHI, S., NIK, A.R., Spatial and temporal variation in soil respiration in a Southeast Asian tropical rainforest (2007) Agricultural and Forest Meteorology, 147, pp. 35-47LA SCALA JÚNIOR, N.MARQUES JÚNIOR, J.PEREIRA, G.T.CORÁ, J.E. Carbon dioxide emission related to chemical properties of a tropical bare soil. Soil Biology and Biochemistry, v.32, p.1469-1473, 2000LI, H., YAN, J., YUE, X., WANG, M., Significance of soil temperature and moisture for soil respiration in a Chinese mountain area (2008) Agriculture and Forest Meteorology, 148, pp. 490-503LLOYD, J., TAYLOR, J.A., On the temperature-dependence of soil respiration (1994) Functional Ecology, 8, pp. 315-323OADES, J.M., Soil organic matter and structural stability: Mechanisms and implications for management (1984) Plant and Soil, 76, pp. 319-337PARKIN, T.B., KASPAR, T.C., SENWO, Z., PRUEGER, J.H., HATFIELD, J.L., Relationship of soil respiration to crop and landscape in the walnut creek watershed (2005) Journal of Hydrometeorology, 6, pp. 812-824PENG, Y., THOMAS, S.C., Soil CO 2 efflux in uneven-aged managed forests: Temporal patterns following harvest and effects of edaphic Heterogeneity (2006) Plant and Soil, 289, pp. 253-264RAIJ, B., van, QUAGGIO, J.A., CANTARELLA, H., FERREIRA, M.E., LOPES, A.S., BATAGLIA, C.O., (1987) Análise química do solo para fins de fertilidade, , Campinas: Fundação Cargill, 170pRAICH, J.W., SCHLESINGER, W.H., The global carbon dioxide flux in soil respiration and its relationship to climate (1992) Tellus, 44 B, pp. 81-99RETH, S., MARKUS, R., FALGE, E., The effect of soil water content, soil temperature, soil pH-value and the root mass on soil CO 2 efflux: A modified model (2005) Plant and Soil, 268, pp. 21-33RISCH, A.C., FRANK, D.A., Carbon dioxide fluxes in a spatially and temporally heterogeneous temperate grassland (2006) Oecologia, 147, pp. 291-302(1998) SAS/STAT: User's guide, , SAS INSTITUTE, Cary: SAS InstituteSCHWERTMANN, U., TAYLOR, R.M., Iron oxides (1989) Minerals in soil environments, pp. 379-438. , DIXON, J. B, WEED, S. B, Ed, Madison: SSSASILVA, A.C.TORRADO, P.V.MARTIN-NETO, L.VASQUEZ, F.M.PÉREZ, M.G. Soil organic matter and geomorphic surface stability relationship in an oxisol toposequence (SE-Brazil). In: INTERNATIONAL MEETING OF THE INTERNATIONAL HUMIC SUBSTANCES SOCIETY, 12., São Pedro, 2004. Proceedings. São Carlos: Embrapa Instrumentação Agropecuária, 2004. v.1, p.623-626SOTTA, E.D., VELDKAMP, E., GUIMARÃES, B.R., PAIXÃO, R.K., RUIVO, M.L.P., ALMEIDA, S.S., Landscape and climatic controls on spatial and temporal variation in soil CO 2 efflux in an Eastern Amazonian Rainforest, Caxiuanã, Brazil (2006) Forest Ecology and Management, 237, pp. 57-64SOUZA, C.K., MARQUES JÚNIOR, J., MARTINS FILHO, M.V., PEREIRA, G.T., Influência do relevo e erosão na variabilidade espacial de um latossolo em Jaboticabal (SP). (2003) Revista Brasileira de Ciência do Solo, 27, pp. 1067-1074SOUZA, Z.M., MARQUES JÚNIOR, J., PEREIRA, G.T., MOREIRA, L.F., Influência da pedoforma na variabilidade espacial de alguns atributos físicos e hídricos de um Latossolo sob cultivo de cana-de-açúcar. (2004) Irriga, 9, pp. 1-11SOUZA, Z.M., MARQUES JÚNIOR, J., PEREIRA, G.T., BARBIERI, D.M., Small relief shape variations influence spatial varaibility of soil chemival attributes (2006) Scientia agricola, 63, pp. 161-168SOUZA, Z.M., MARQUES JÚNIOR, J., PEREIRA, G.T., Variabilidade espacial da estabilidade de agregados e matéria orgânica em solos de relevos diferentes. (2004) Pesquisa Agropecuária Brasileira, 39, pp. 491-499SOUZA, Z.M., MARQUES JÚNIOR, J., PEREIRA, G.T., BENTO, M.J.C., Variabilidade espacial de atributos físicos de um Latossolo Vermelho sob cultivo de cana-de-açúcar. (2004) Revista Brasileira de Engenharia Agrícola e Ambiental, 8, pp. 51-58STOLF, R., Teoria e teste experimental de fórmulas de transformação dos dados de penetrômetro de impacto em resistência do solo. (1991) Revista Brasileira de Ciência do Solo, 15, pp. 229-235XU, M., QI, Y., Soil-surface CO 2 efflux and its spatial and temporal variations in a young ponderosa pine plantation in northern California (2001) Global Change Biology, 7, pp. 667-677YOO, G., SPOMIER, L.A., WANDER, M.M., Regulation of carbon mineralization rates by soil structure and water in an agricultural field and a prairie-like soil (2006) Geoderma, 135, pp. 16-25ZAR, J.H., (1999) Biostatistical analysis, , 4 ed. Upper Saddle River: Prentice Hall, 718

Caracterização e ocorrência do distúrbio do amolecimento precoce em mamões 'Golden'

The occurrence of green skin and soft pulp in 'Golden' papaya fruit during certain seasons has been reported by farmers in the northern of the state of Espirito Santo, Brazil. The objective of this study was to characterize and determine the occurrence of this disorder, which was referred as "early softening disorder". Fruits were harvested weekly for 11 months (from September to July). The fruits were stored at 10°C, and then fruit flesh firmness and skin color were analyzed. The results of the firmness test were submitted to regression analysis assuming a linear trendline. The slope of the curve was called the 'softening index' (SI). Fruits with early softening are characterized by a loss of firmness in less than 10 days, even when stored under refrigeration. Although softened, the skin of the fruit remains partially green. Fruits with the disorder occurred more frequently from mid-summer to mid-autumn (February to May). It is not possible to distinguish early softening disorder fruits from those without the disorder by skin color and flesh firmness analysis at the time of the harvest.Tem sido relatado por produtores da região norte do Espírito Santo a ocorrência de mamões 'Golden' com casca verde e polpa mole, em determinadas épocas do ano. O objetivo deste trabalho foi caracterizar e determinar a ocorrência deste distúrbio denominado de amolecimento precoce. Foram realizadas coletas semanais durante 11 meses (período de setembro a julho). Os frutos foram armazenados a 10°C e analisados quanto à firmeza da polpa e à cor da casca. Os resultados de firmeza da polpa foram submetidos à análise de regressão, assumindo-se que a equação é do tipo linear, e o ângulo de inclinação da curva foi chamado Índice de Amolecimento (IA). Frutos com o distúrbio caracterizaram-se pela perda da firmeza em menos de 10 dias, mesmo quando armazenados sob refrigeração. Embora amolecidos, a coloração da casca manteve-se parcialmente verde. A maior frequência de frutos com o distúrbio ocorreu de meados de verão a meados de outono (fevereiro a maio). Não é possível distinguir frutos com o distúrbio do amolecimento precoce daqueles normais pela análise da cor da casca e da firmeza da polpa, no momento da colheita