Piracicaba Region Research Articles

Potential of soil minerals to sequester soil organic carbon

The capacity of soil to sequester carbon (C) is a key process that promotes the reduction of CO2 in the atmosphere. Soils can absorb as much as 20% of anthropogenic carbon emissions, which can contribute to mitigate climate change. This capacity relies on the organo-mineral association, which includes different minerals, Fe and Al oxides, which have a critical soil organic carbon (SOC) sorption surface. Based on an equation of the potential C saturation deficit of fine soil particles (<20 μm/silt and clay fractions) for tropical regions, this study investigated the SOC sequestration potential of the clay fraction for soils in Piracicaba region, São Paulo State, Brazil as influenced by the clay minerals. This potential was fitted to a spatial regression model for soil depths 0–20 cm and 80 to 100 cm. In the surface layer, the sequestration potential was mostly explained by the relative abundance of soil minerals (Kaolinite, Hematite, Goethite and Gibbsite) determined using vis-NIR-SWIR spectroscopy. A direct relationship was observed with Goethite and Gibbsite, indicating that low concentrations would reduce the sequestration potential. At 80 to 100 cm depth, Kaolinite and Hematite explained most variation in SOC sequestration potential. Additionally, the C associated with the mineral fraction and the C saturation potential as a function of minerals were modeled and a strong importance of hematite in the C sequestration and stabilization cycle was identified at both depths. The individual mineral contribution to SOC sequestration potential was also mapped, which identified high contributions of goethite and gibbsite for deep soil layers. The influence of land use on the carbon sequestration potential of minerals was observed, with the greatest potential being found in areas with pasture and cropping mosaics and grassland and forest mosaics, with a high presence of kaolinite and hematite. These minerals have a greater potential for carbon sequestration at greater depths and, therefore, could be critical in climate change mitigation strategies.

Aquifer recharge capacity assessment of an anthropogenically impacted wetland by the DC resistivity geophysical method

Population growth and social and economic development demand increasing volumes of water for public supply, especially in scenarios where surface sources such as rivers may not meet the basic demands for the population. In southeastern Brazil, with emphasis on the Piracicaba region, there is a conflict over water use regarding agricultural and industrial activities, where the sugar-alcohol sector is widely highlighted. The region has thousands of hectares of sugarcane cultivated, which requires intensive use of fertilizers and pesticides, in addition to the need for large volumes of water in the production of sugar and ethanol, where the main effluent produced is represented by vinasse, used as fertilizer complement and soil hydration in sugarcane fields. This work presents the results of a geophysical diagnosis in a closed wetland, located in a sugarcane field region, to evaluate the hydrogeological function of this environment in aquifer recharge and the risks that land use can cause in the quality and availability of surface and underground water resources. The geophysical survey consisted of nine lines of electrical resistivity tomography in Schlumberger arrangement, submitted to 2D processing and inversion followed by interpolation and generation of 3D visualization models. The results indicate a direct connection between water accumulated in the wetland and the aquifer underneath, separated by an aquitard interface about 44 m thickness. The study points out to the high vulnerability to the input of pesticides and vinasse effluent from the surrounding sugarcane fields to the interior of the wetland, given the absence of riparian forest or buffer zone, in addition to the risk of contamination of surface and groundwater. Understanding the local hydrological dynamics should subsidize the sustainable use of the soil providing preservation of water resources, with emphasis on aquifers, a source of increasing importance in the face of the imminent scarcity of surface resources.

Land use/land cover changes and bare soil surface temperature monitoring in southeast Brazil

The land surface temperature (LST) provides important information about energy exchange processes, which are influenced by land use/land cover (LULC). Thus, our objective was to evaluate LST patterns driven by LULC changes, detected over a time series of Landsat images. The study area of 2990 km2 is located in the Piracicaba region, state of São Paulo, Brazil. We acquired Landsat images from 1985 to 2019, in dry and moist seasons. Six LULC classes (agriculture, bare soil, straw, forest, water, and pasture) were identified by maximum-likelihood supervised classification every five years and then LST was estimated using the inversion of Planck’s function in the thermal band. Spectral indices representing vegetation, water, bare soil, and straw were calculated and correlated to LST in specific years. Bare soil images and their respective LST in both seasons were used annually to approach the influence of bare soil areas on the LST, considering soil class, time and rainfall. LULC alterations over 1985–2015 were an important factor on the LST change, which varied on average from 21.46 °C to 41.31 °C in the moist season and 17.05 °C to 31.67 °C in the dry one. Water bodies and vegetation had the lowest LST values, whereas bare soil and straw had the highest ones. The correlation between LST and spectral indices somewhat agreed with such patterns. Arenosols presented the highest LST mean values in both seasons and differed from Acrisols in the dry season, which is probably related to their texture and mineralogical composition. In the moist season, LST was negatively correlated to rainfall, suggesting the influence of soil moisture content on its surface temperature. In the dry season, the LST of bare soil areas increased by an average of 0.13 °C per year, indicating a warming trend. In general, LST increased in the studied period, probably due to the increase of anthropic activity, such as the expansion of agricultural areas. These findings can assist future studies on the influence of soils and land use on climate alterations.

Conversion of ammonium to nitrate and abundance of ammonium-oxidizing-microorganism in Tropical soils with nitrification inhibitor

The use of nitrification inhibitors (NIs; dicyandiamide - DCD) is an alternative to reduce oxidation of ammonium (NH4 +-N) to nitrate (NO3 – -N) in the soil, reducing NO3 – -N losses from fertilization practices. Based on the hypothesis that DCD reduces conversion of NH4 +-N to NO3 – -N in tropical soils and inhibits ammonia oxidizing microorganisms (AOM) abundance, soils from the Piracicaba region, Sao Paulo, with different textures (sand, loam and clay) were incubated with ammonium sulphate (AS) and DCD. Contents of NH4 +-N, NO3 – -N, soil pH, and AOM abundance were quantified periodically. Ammonium sulphate increased AOM abundance in all soils, but AS+DCD presented AOM abundances similar to the control. During 90 days of incubation, the effectiveness of DCD in reducing NO3 – -N production was 1.8, 86.4, and 145.6 mg kg–1, while the effectiveness of DCD in reducing AOM abundance was 1.2, 3.0 and 2.3 × 10–3 g soil–1 for sandy, loamy, and clayey soils, respectively. DCD effectiveness was greater in loamy and clayey soils due to the naturally low nitrification in sandy soils. Application of AS treated with DCD showed potential not only to reduce NO3 – -N production in loamy and clayey soils, but also to decrease the soil nitrification rate. Overall, DCD was effective in reducing AOM abundance and conversion of NH4 +-N to NO3 – -N in loamy and clay soils evaluated here. The increase in clay content directly influences DCD effectiveness in reducing conversion of NH4 +-N to NO3 – -N.

&lt;b&gt;Micromorphometric analysis of porosity changes in the surface crusts of three soils in the Piracicaba region, São Paulo State, Brazil

O objetivo deste trabalho e analisar micromorfologicamente as modificacoes na porosidade do solo devido a ocorrencia de eventos chuvosos considerados erosivos. Foram avaliadas a porosidade total, distribuicao e numero de poros de um Latossolo Vermelho - Amarelo distrofico tipico (LVAd) de textura media, Argissolo Vermelho - Amarelo distrofico tipico (PVAd) de textura arenosa/media e Nitossolo Vermelho Eutroferrico tipico (NVef) de textura argilosa. Os solos foram preparados com auxilio de grade pesada e niveladora para garantir condicoes iniciais homogeneas e para simular as condicoes de plantio adotada em sistemas convencionais de cultivo. O solo foi mantido descoberto e foram contabilizados eventos chuvosos erosivos com intensidade superior a 25 mm h-1. Por meio das analises micromorfologicas conclui-se que os tres solos apresentam a formacao de crostas superficiais, sendo estas influenciadas pela textura do solo. O NVef apresentou alteracoes significativas na porosidade total, numero e morfologia dos poros, enquanto LVAd e PVAd nao sofreram modificacoes significativas na porosidade total, numero e morfologia dos poros.

Pedological mapping through integration of digital terrain models spectral sensing and photopedology

New tools for soil mapping are needed to increase speed and accuracy of pedological mapping processes. This study integrated various technologies to map soils of the Piracicaba region in São Paulo State, Brazil. Each technology was expected to provide different information to design a detailed map. We carried out field survey and soil sampling for laboratory analysis. Initially, we conducted field visits to obtain soil patterns of a reference site. We applied the acquired patterns to an validation site, based solely on information obtained from remote sensing and cartographic databases, namely LANDSAT 7/ETM, digital elevation models (DEM) and aerial photographs. We integrated the information from each product to generate the map of the validation site, which was validated by field inspection. Textural classification using satellite imaging ranged from 21-51% of accuracy. Band 5 in the sensor showed the best performance to discriminate between clayey and sandy soils. Aerial photographs provided the best information because, besides their own inherent characteristics, they operate on a larger scale and result in a map with up to 50 polygons, while DEM reached a maximum of 30 polygons. The digital mapping technology generated 45 mapping units. Finally, the mapping efficiently separated the Latosols from the other classes; however, in some cases there was confusion in the identification of Cambisols and litholic Neosols.

Emissões de gases de efeito estufa pela deposição de palha de cana-de-açúcar sobre o solo

Biocombustíveis contribuem para reduzir as emissões de gases de efeito estufa (GEE). No Brasil, o principal biocombustível é o etanol de cana-de-açúcar. Além dos colmos, as folhas de cana-de-açúcar também podem ser usadas para produzir etanol. O objetivo deste trabalho foi avaliar as emissões de GEE (CO2, CH4 e N2O) induzidas pela presença de palha sobre o solo. Três experimentos foram conduzidos em Latossolos, em Piracicaba: imediatamente após a colheita, aos seis e aos 12 meses após a colheita. Foram avaliados os efeitos de três doses de palha (0%, 50% e 100% da quantidade disponível na superfície) sobre as emissões. Imediatamente após a colheita, as emissões de CO2 e CH4 aumentaram com o aumento da quantidade de palha. Aos seis meses após a colheita houve consumo de CH4 à medida que a quantidade de palha aumentou. Doze meses após a colheita, as emissões dos três gases foram similares, independentemente da quantidade de palha. Remover a palha de cana-de-açúcar não aumenta as emissões de GEE do solo em comparação ao manejo sem retirada da palha da superfície. Contudo, estudos adicionais são necessários para investigar os efeitos sobre a produtividade de cana-de-açúcar, sobre a erosão e sobre outros atributos do solo.

Using numerical classification of profiles based on Vis-NIR spectra to distinguish soils from the Piracicaba Region, Brazil

Considering that information from soil reflectance spectra is underutilized in soil classification, this paper aimed to evaluate the relationship of soil physical, chemical properties and their spectra, to identify spectral patterns for soil classes, evaluate the use of numerical classification of profiles combined with spectral data for soil classification. We studied 20 soil profiles from the municipality of Piracicaba, State of São Paulo, Brazil, which were morphologically described and classified up to the 3rd category level of the Brazilian Soil Classification System (SiBCS). Subsequently, soil samples were collected from pedogenetic horizons and subjected to soil particle size and chemical analyses. Their Vis-NIR spectra were measured, followed by principal component analysis. Pearson's linear correlation coefficients were determined among the four principal components and the following soil properties: pH, organic matter, P, K, Ca, Mg, Al, CEC, base saturation, and Al saturation. We also carried out interpretation of the first three principal components and their relationships with soil classes defined by SiBCS. In addition, numerical classification of the profiles based on the OSACA algorithm was performed using spectral data as a basis. We determined the Normalized Mutual Information (NMI) and Uncertainty Coefficient (U). These coefficients represent the similarity between the numerical classification and the soil classes from SiBCS. Pearson's correlation coefficients were significant for the principal components when compared to sand, clay, Al content and soil color. Visual analysis of the principal component scores showed differences in the spectral behavior of the soil classes, mainly among Argissolos and the others soils. The NMI and U similarity coefficients showed values of 0.74 and 0.64, respectively, suggesting good similarity between the numerical and SiBCS classes. For example, numerical classification correctly distinguished Argissolos from Latossolos and Nitossolos. However, this mathematical technique was not able to distinguish Latossolos from Nitossolos Vermelho férricos, but the Cambissolos were well differentiated from other soil classes. The numerical technique proved to be effective and applicable to the soil classification process.

Aspectos sobre a decisão de canais no pequeno varejo: a escolha entre o atacado e o atacarejo

This article talks about purchase decision from small and medium retailers from Piracicaba Region, São Paulo State. The bibliographic and field research showed the main influence factors and decision criteria of small retailers for purchase, related to the choice between the traditional wholesale and the wholesale and retail outlet, which is a type of store that allows the wholesaler sales to sell to small or medium-sized retailers and for end consumers who are looking for the best price. The topics treated are the distribution channels, types of agents, the role of each one and the retailers' decision of purchasing. The exploratory research was applied to small and medium-sized retailers from Piracicaba Region, Sao Paulo State Countryside. From the eight case studies it was possible to identify the aspects considered relevant for retailers in the purchase decision and partner choice. Retailers were expressed by five attributes considered the most relevant, they are: convenience, variety, price, reliability and quantity.

Importância das cooperativas de crédito para fornecedores de cana-de-açúcar: um estudo de caso

No presente trabalho analisa-se a importância das cooperativas no mercado de crédito rural do Brasil, com foco na visão de quem demanda empréstimos. Para tanto, realizou-se um estudo de caso referente à Cooperativa de Crédito Rural dos Fornecedores de Cana e Agropecuaristas da Região de Piracicaba (Cocrefocapi). O objetivo principal é mostrar a importância da Cocrefocapi no financiamento dos fornecedores de cana de Piracicaba, a partir da análise da influência de vários fatores presentes na decisão dos cooperados em escolher esta instituição como principal financiadora. Assim, foram elaborados e testados dois modelos econométricos de resposta qualitativa, além de várias análises descritivas. Os resultados mostram que o tamanho da terra é um fator que deve ser considerado ao se analisar a demanda por crédito agrícola. Além disso, não existe evidência econométrica que mostre que os associados com maior participação no capital institucional da Cocrefocapi tenham maiores incentivos para tomar empréstimos junto à cooperativa. Por outro lado, embora os fornecedores que tomaram empréstimos na Cocrefocapi a tenham escolhido principalmente por menores custos de transação, os resultados indicam que muitas destas pessoas tomaram empréstimos em outras instituições, pois, além de produzirem cana, conduzem outras atividades econômicas que não são financiadas pela Cocrefocapi.

Temas ambientais relevantes

NESTE trabalho, são indicados os principais temas ambientais para o Brasil, num futuro próximo (2022). Impactos do aumento da temperatura são estudados através de cenários, que podem modificar o balanço hídrico em algumas regiões, tendo sido observado um aumento da ordem de 0,78ºC no período de 1917 a 2003, na região de Piracicaba. Para a região amazônica, foi observado um aumento de 0,56ºC durante o século XX. Tanto o desmatamento quanto as Mudanças Climáticas Globais atuam na direção de um aumento da temperatura, enquanto o desmatamento influi na direção de uma diminuição das precipitações. O desmatamento provoca, ainda, uma grande perda de biodiversidade, sendo estimadas em uma perda entre 8.000 até 34.000 espécies, considerando-se que o desmatamento aumenta em 1% ao ano.

Epidemiological analysis of maxillofacial fractures in Brazil: A 5-year prospective study

The aim of this study was to assess the characteristics of maxillofacial fractures in the Piracicaba region of Brazil during a 5-year period and to delineate comparisons with worldwide facial fracture patterns. A descriptive statistical analysis was developed based on data collected using a specifically designed clinical survey of all patients who attended the Division of Oral and Maxillofacial Surgery at the Piracicaba Dental School from 1999 to 2004. Information regarding age, gender, etiology, and type of maxillofacial injury and its associated lesions were evaluated. In addition, treatment modalities and complication rates during patient follow-up were assessed. A total of 1024 patients presenting 1399 maxillofacial fractures were analyzed. Patients' ages ranged from 0 to 88 years (mean age, 28 +/- 16.4 years). The ratio of men to women was 4:1. Most fractures were caused by traffic accidents (45%), followed by assaults (22.6%), falls (17.9%), sports accidents (7.8%), and work accidents (4.5%). The prevalent anatomic regions of facial fractures (in percentages) were the mandible (44.2%), the zygomatic complex (32.5%), and the nasal bones (16.2%). Associated systemic lesions were found in 41.9% of patients, with prevalence for injuries to the upper (24.1%) and lower limbs (15.4%). Patient management was considered to be conservative in 490 patients (47.9%), and surgical therapy was performed in 493 patients (48.1%), of whom 399 (80.9%) were treated with open reduction and rigid internal fixation. Complications occurred in 76 patients (7.4%), mainly due to infection and malocclusion. The findings of this study indicated that epidemiological research of maxillofacial fractures allows the presentation patterns of the most affected individuals and the nature of their lesions to be outlined according to the region evaluated. Furthermore, treatment evaluation and complication rate analysis permits a more realistic interpretation of how patients should be managed.

Stable carbon and nitrogen isotopic composition of bulk aerosol particles in a C4 plant landscape of southeast Brazil

The carbon and nitrogen isotopic compositions of aerosol particles collected in the Piracicaba region, where C4 plants like sugarcane and pasture dominate the land cover, were measured. For comparison, aerosol particles were also analyzed from the Santarém region, Amazon basin, where the main land cover is primary forest. The average δ 13C value of samples collected in Piracicaba was equal to −20.9±0.8‰. The average δ 13C of samples collected in Santarém was almost 5‰ smaller than in Piracicaba (−25.8±0.5‰). This difference between the two sites was attributed to the presence of C4 material in Piracicaba aerosol particles. On the other hand, there was no statistical difference between the average δ 15N values observed in Piracicaba (10.6±2.8‰) and Santarém (11.5±2.1‰). The δ 13C and δ 15N values of aerosol particles collected in Santarém were higher than vegetation tissues and soil organic matter, which are the potential sources of organic matter to aerosol particles.

Concentrations of Fe, Cu and Zn in rum by EDXRF using APDC preconcentration

Ten rum (“aguardente”) samples commercialized in Piracicaba region, Sao Paulo State, Brazil Southeast, were analysed by energy-dispersive X-ray fluorescence (EDXRF) using ammonium pyrrolidinedithiocarbamate (APDC) preconcentration in order to determine Fe, Cu and Zn concentrations. The effect of sucrose (2%) was also studied in this methodology, using a multielemental standard solution (40% ethanol). Copper concentrations in two samples were higher than the value allowed by Brazilian law. Limits of detection for these elements were in the ng.ml-1 range.

Estrutura e dinâmica de populações arbóreas de um fragmento de floresta estacional semidecidual na região de Piracicaba, SP

Para verificar a hipótese de que a fragmentação das florestas tropicais associada às perturbações antrópicas podem resultar numa maior perda de espécies arbóreas e na mudança na composição florística ao longo do tempo foi analisado um fragmento de floresta estacional semidecidual de 9,5 ha localizado na região de Piracicaba, Estado de São Paulo, onde houve dois incêndios em passado recente. Neste fragmento, denominado de Mata do Pomar, o recrutamento, a mortalidade e a mudança do tamanho populacional de espécies arbóreas foram obtidos num intervalo de quatro anos (1991 e 1995). Padrões de recrutamento, mortalidade e conseqüente mudança populacional variaram entre as espécies e os grupos ecológicos. As dez espécies mais abundantes no ano de 1991, que representam a classe 1 de densidade ( &gt; ou = 15 indivíduos/ha), foram responsáveis por 79,9% do recrutamento, contra apenas 7,5% da classe 2 (5,2 a 13,8 indivíduos/ha) e 9,0% da classe 3 (1,7 e 3,4 indivíduos/ha). Particularmente, as três espécies mais abundantes em 1991, Bauhinia forficata, Aloysia virgata e Urera baccifera, todas pioneiras, e uma espécie oportunista, Croton floribundus, foram responsáveis pelo alto recrutamento apresentado pela classe 1 de densidade. Apenas essas espécies perfizeram 75% do recrutamento e, conjuntamente com uma baixa mortalidade, experimentaram um aumento pronunciado em suas populações. Além do baixo recrutamento obtido pelas classes 2 e 3, as espécies pioneiras e oportunistas foram responsáveis por 74,2% do recrutamento nessas duas classes e apresentaram maior ganho em densidade que as espécies tolerantes e reprodutoras à sombra. Além desses resultados, foi também realizada uma análise comparativa deste fragmento com outros dois: um fragmento de mesmo tamanho (fragmento Santa Rita - 9,5 ha) e um fragmento com tamanho superior (fragmento Capuava - 86 ha), ambos também localizados no mesmo município. O fragmento Mata do Pomar apresenta menos da metade do número de espécies encontrado nos fragmentos Santa Rita e Capuava, embora tenha o mesmo tamanho do fragmento Santa Rita. Além disso, ocorre uma alta dominância local de poucas espécies no fragmento Mata do Pomar: as quatro espécies mais abundantes, B. forficata, A. virgata, U. baccifera e Trema micrantha, todas pioneiras, são responsáveis por 62,0% do total de indivíduos, ao passo que as quatro espécies mais abundantes nos fragmentos Santa Rita e Capuava perfazem apenas 30,6% e 23,2% dos indivíduos, respectivamente. Este estudo demonstra que as estratégias de conservação da biodiversidade em fragmentos de floresta estacional semidecidual no interior do Estado de São Paulo devem considerar o histórico de perturbações na identificação de prioridades.

Elaboração de cartas de zoneamento geotécnico: exemplo da folha de Piracicaba, São Paulo - escala: 1.100.000

This work presents the general engineering geological zoning map of the Piracicaba region at the 1:100.000 scale and the rules adopted for the elaboration of this graphic document in regional engineering geological mapping. Other aspects are discussed, such as the importance of the general engineering geological zoning map in the elaboration of other most specific maps and the fundamental attributes.

Melhoramento genético da cana-de-açúcar: VI. Ensaios de clones provenientes de hibridações realizadas em 1974, 1977, 1978 e 1979, avaliados na Região de Piracicaba (SP)

Testou-se uma série de clones obtidos de cruzamentos realizados em 1974, 1977, 1978 e 1979 no Instituto Agronômico, em dois locais na região de Piracicaba (SP). Os clones foram comparados com as testemunhas 'SP70-1143', 'IAC64-257', 'NA56-79' e 'CB41-76', em ensaios em blocos ao acaso, avaliando-se os caracteres agroindustriais na média de três cortes. Foram escolhidos para cultivo, na região, o IAC78-23, por sua elevada produção de cana e açúcar, indicado para meio e fim de safra, e o IAC79-1011, como material precoce, de produção média e alto teor de açúcar. Para colheita em meio de safra em solos férteis, foram escolhidos os seguintes clones de produção média e alto teor de açúcar. IAC77-186, IAC78-54, IAC78-90 e IAC79-1159.

Fatores ambientes e iniciação floral de cana-de-açúcar, no ano agrícola 1984/85, na região de Piracicaba, SP

Com o objetivo de determinar as épocas de iniciação e emergência da inflorescência da cana-de-açúcar (Saccharum spp.), correlacionando-as aos fatores climáticos, coletaram-se amostras dos cultivares NA 56-79, SP 70-1143 e IAC 52-150, em experimentos na região de Piracicaba, SP. De cada cultivar, colheram-se, semanalmente, dez palmitos dos colmos mais vigorosos, de 20 de fevereiro a 3 de julho de 1984. Analisaram-se a diferenciação e o desenvolvimento floral através de cortes histológicos da região apical e de medidas do comprimento da inflorescência. Coletaram-se os dados climáticos, durante o período de indução (25 de fevereiro-20 de março) no posto meteorológico da Estação Experimental do Instituto Agronômico, em Piracicaba. A ocorrência de temperaturas elevadas (Tmáx&gt; 31° C), a baixa precipitação (47,3mm) e a alta freqüência de dias (76%) com diferença entre temperaturas máximas e mínimas acima de 13°C no período indutivo, afetaram a diferenciação floral. Os cultivares NA 56-79 e SP 70-1143 não floresceram e o 'IAC 52-150' apresentou uma redução de cerca de 50% no florescimento. O primeiro estádio reconhecível da iniciação floral foi detectado em 6 de abril, quando o domo apical media 0,011 cm, só ocorrendo a emergência da panícula na primeira semana de julho.

Comportamento de variedades de cana-de-açúcar no plantio de setembro-outubro na região de Piracicaba (SP)

São apresentados os resultados obtidos em experimento conduzido na Estação Experimental do Instituto Agronômico, em Piracicaba, durante o período de 1976 a 1979, em Latossolo Roxo, a fim de estudar o comportamento de algumas variedades de cana-de-açúcar, cultivadas no Estado de São Paulo, no plantio de setembro-outubro. Das diversas variedades de cana estudadas, observou-se que, pelo comportamento em relação à produção de cana (t/ha) e teor de açúcar, prestam-se ao plantio de setembro-outubro, na região de Piracicaba, as seguintes: NA56-79, CB47-89, IAC52-150 e Co740.

An evaluation of natural infestation by leaf pests on soybean (Glycine max (L.) Merrill) cultivars

Damage caused by leaf pests of soybean on five cultivars was evaluated. Afield experiment was carried out at the Piracicaba region, cultivars Davis, IAC 73-228, PI 227.687,PI 171.451, and PI 229.358 having been compared. Leaf damage was produced by natural infestation of Anticarsia gemmatalis and Plusia sp. Cultivar PI 171.451 showed lower comsumption of leaves in relation to control ('Davis') and other cultivars. Damage was more serious on IAC 73-228 than on PI 227.687 and PI 229.358.