RESUMO O solo é um dos compartimentos de água de maior importância em uma bacia hidrográfica. A vegetação depende majoritariamente da água retida pelo solo para atender às suas demandas; e o início do escoamento superficial depende fortemente da umidade inicial do solo. Este estudo teve como objetivo avaliar a permanência da efetividade da água no solo sob condições de vegetação preservada no bioma Caatinga, Semiárido do Nordeste brasileiro. Para isso, foram analisados dados horários de umidade do solo através de sensores TDR obtidos entre os anos de 2003 e 2010 para três associações solo-vegetação presentes na Bacia Experimental de Aiuaba. Os resultados indicam que, durante nove meses ao ano, a água no solo encontra-se abaixo do ponto de murcha permanente para duas associações, cujos solos são Argissolo Vermelho -Amarelo e Luvissolo Hipocrômico. Na terceira associação, cujo solo é raso (Neossolo litólico), a água encontra -se não efetiva durante quatro meses ao ano. Avalia-se que a maior permanência de água neste solo dê-se pela limitação de percolação profunda, induzindo o escoamento sub-superficial; o que não se verifica nos solos mais profundos. Verificou-se in situ que o longo período de umidade abaixo do ponto de murcha permanente não comprometeu a vida das espécies da Caatinga. Após o início de cada período chuvoso, observa -se o crescimento de uma densa massa de vegetação, apesar do longo período sob estresse hídrico. | ABSTRACT Soil is an important water compartment into a watershed scale, mainly due to its role in providing water to plants and to the influence of antecedent moisture on the runoff initiation. The aim of this research is to assess the permanence of water effectiveness in the soil under preserved-vegetation constraints in the Caatinga biome, in the semiarid northeastern Brazil. For this purpose, hourly soil moisture measurements were collected with TDR and analyzed between 2003 and 2010 for three soil-vegetation associations in the Aiuaba Experimental Basin. The results showed that in nine months per year soil moisture was below wilting point for two associations, whose soils are Chromic Luvisol and Haplic Lixisol (Abruptic). In the third association, where the shallow soil Lithic Leptosol prevails, water was found non-effective four months per year. A possible reason for the high water permanence in the shallowest soil is the percolation process, generating sub-surface flow, which barely occurs in the deeper soils. In situ observations indicates that the long period of soil moisture below the wilting point was not enough to avoid the blooming season of the Caatinga vegetation during the rainy periods. Indeed, after the beginning of each rainy season, there is a growth of dense green vegetation, regardless of the long period under water shortage.

Soil is an important water compartment into a watershed scale, mainly due to its role in providing water to plants and to the influence of antecedent moisture on the runoff initiation. The aim of this research is to assess the permanence of water effectiveness in the soil under preserved-vegetation constraints in the Caatinga biome, in the semiarid northeastern Brazil. For this purpose, hourly soil moisture measurements were collected with TDR and analyzed between 2003 and 2010 for three soil-vegetation associations in the Aiuaba Experimental Basin. The results showed that in nine months per year soil moisture was below wilting point for two associations, whose soils are Chromic Luvisol and Haplic Lixisol (Abruptic). In the third association, where the shallow soil Lithic Leptosol prevails, water was found non-effective four months per year. A possible reason for the high water permanence in the shallowest soil is the percolation process, generating sub-surface flow, which barely occurs in the deeper soils. In situ observations indicates that the long period of soil moisture below the wilting point was not enough to avoid the blooming season of the Caatinga vegetation during the rainy periods. Indeed, after the beginning of each rainy season, there is a growth of dense green vegetation, regardless of the long period under water shortage.

RESUMO Os estudos sobre alimentação e nutrição de camarões ainda são muito escassos, pouco se sabe sobre o aproveitamento pelos camarões de subprodutos da agroindústria, portanto o objetivo deste trabalho foi à avaliação nutricional e energética de ingredientes proteicos para camarões (Litopenaeus vannamei). O delineamento foi inteiramente casualizado, com seis tratamentos e quatro repetições: uma Reference diete cinco dietas teste compostas de 70% da Reference diete 30% do ingrediente teste (farinha vísceras de aves-FVA, feno folha de mandioca- FFM, farinha cabeça de camarão-FCC, levedura de cana-de-açúcar-LC e farelo de mamona -FM). Utilizou-se 720 camarões com peso médio de 8g. Os parâmetros de qualidade não apresentaram diferença significativa pelo teste de Tukey (P > 0,05). Os coeficientes de digestibilidade aparente dos ingredientes FVA, FFM, FCC, LC e FM foram respectivamente, 27,44; 76,26; 77,78 e 90,10% para matéria seca; 76,61; 70,44; 97,67 e 78,29% para proteína e (33,10; 51,19; 90,70 e 78,05%) para energia bruta. A energia digestível dos ingredientes foi 1.749, 2.457, 3.914, 3.030 e 2.130 kcal/kg e proteína digestível foi de 42,4; 16,09; 54,62, 23,71 e 14,31%. A FCC apresentou os maiores coeficientes de digestibilidade aparente da proteina bruta e energia bruta e para energia digestível. A LC apresentou o maior valor do coeficiente de digestibilidade aparente da matéria seca. A FCC e a LC são os ingredientes que apresentaram os melhores aproveitamentos dos nutrientes e da energia para L. vannamei. | ABSTRACT Studies on feeding and nutrition of shrimp are still quite scarce; little is known about the use of agribusiness byproducts in shrimp diets. Therefore, this study aimed to perform nutritional and energy assessments of protein-based ingredients for feed of shrimp of the Litopenaeus vannamei species. The design was completely randomized, with six treatments and four replications: a standard diet and five test diets composed of 70% standard diet and 30% test ingredients (poultry viscera flour - PVF, cassava leaf hay - CLH, shrimp head flour - SHF, sugarcane yeast - SCY and castor bean meal - CBM). We used a total of 720 shrimps with mean weight of 8 g each. The parameters of quality showed no significant change by the Tukey's test (p >0.05). The apparent digestibility coefficients of PVF, CLH, SHF, SCY and CBM were respectively 27.44, 76.26, 77.78 and 90.10% for dry matter; 76.61, 70.44, 97.67 and 78.29% for protein; and 33.10, 51.19, 90.70 and 78.05% for gross energy. The digestible energy of the ingredients was 1749, 2457, 3914, 3030 and 2130 kcal/kg; and digestible protein was 42.4, 16.09, 54.62, 23.71 and 14.31%. The SHF reached the highest coefficients of apparent digestibility, crude protein, gross energy and digestible energy. The SCY had the largest apparent digestibility of dry matter. Both SHF and SCY presented improved availability of nutrients and energy for L. vannamei.

Studies on feeding and nutrition of shrimp are still quite scarce; little is known about the use of agribusiness byproducts in shrimp diets. Therefore, this study aimed to perform nutritional and energy assessments of protein-based ingredients for feed of shrimp of the Litopenaeus vannamei species. The design was completely randomized, with six treatments and four replications: a standard diet and five test diets composed of 70% standard diet and 30% test ingredients (poultry viscera flour - PVF, cassava leaf hay - CLH, shrimp head flour - SHF, sugarcane yeast - SCY and castor bean meal - CBM). We used a total of 720 shrimps with mean weight of 8 g each. The parameters of quality showed no significant change by the Tukey’s test (p > 0.05). The apparent digestibility coefficients of PVF, CLH, SHF, SCY and CBM were respectively 27.44, 76.26, 77.78 and 90.10% for dry matter; 76.61, 70.44, 97.67 and 78.29% for protein; and 33.10, 51.19, 90.70 and 78.05% for gross energy. The digestible energy of the ingredients was 1749, 2457, 3914, 3030 and 2130 kcal/ kg; and digestible protein was 42.4, 16.09, 54.62, 23.71 and 14.31%. The SHF reached the highest coefficients of apparent digestibility, crude protein, gross energy and digestible energy. The SCY had the largest apparent digestibility of dry matter. Both SHF and SCY presented improved availability of nutrients and energy for L. vannamei.

RESUMO Objetivou-se levantar e avaliar os perfis tecnológicos, zootécnicos e socioeconômicos, identificar e quantificar indicadores referência, para sistemas de produção de bovinos de leite, de caráter não experimental, de forma a contribuir para a sustentabilidade e competitividade da pecuária de leite na mesorregião do Agreste pernambucano. Para identificar e quantificar os indicadores referência foram avaliados durante doze meses, trinta e seis sistemas de produção de leite da agricultura familiar e empresarial. Os sistemas foram caracterizados em relação ao perfil tecnológico e aos indicadores de tamanho, zootécnicos e econômicos. Foram determinados os coeficientes de correlação com a taxa de remuneração do capital investido e geradas equações de regressão, para cada indicador, em função de quatro cenários da taxa de remuneração do capital (4, 6, 8 e 10% ao ano). Os indicadores correlacionados foram: produção de leite/vacas em lactação; produção de leite/área; preço médio do leite; custo operacional efetivo, custo operacional total e custo total / preço do leite e lucratividade. A pecuária leiteira no Agreste pernambucano, paga os custos mensais, mas a tendência é a não remuneração adequada da mão-de-obra familiar e a injeção de capital externo para a reposição dos bens. A produtividade dos fatores de produção terra e animal apresentaram maior correlação com rentabilidade, indicando a necessidade do aumento da produção, por meio do aumento da produtividade da terra e da produção de leite/vacas em lactação. A identificação e quantificação de indicadores referência podem contribuir para a identificação dos pontos frágeis da pecuária leiteira no Agreste tornando-a sustentável e competitiva. | ABSTRACT The objective of this work was to identify and assess the technological, zootechnical and socioeconomic profiles and identify and quantify benchmarks for dairy cattle production systems, in a non - experimental approach, aiming to contribute to the sustainability and competitiveness of dairy farming in the Pernambuco Agreste region, northeastern Brazil. Thirty-six milk production systems of family and corporate farming were evaluated during twelve months, in order to identify and quantify the benchmarks. The systems were characterized regarding their size and technological, zootechnical and economic profiles. The correlation coefficients of the return rate on invested capital were assessed and regression equations were developed for each indicator, according to four scenarios of annual return rates (4, 6, 8 and 10%). The indicators evaluated were milk production per dairy cows, milk production per area, average price of milk, effective operational cost, total operating cost, total cost per price of milk and profitability. The dairy farming in the Pernambuco Agreste region pays the production costs, but tends to a not adequate remuneration of family labor and a need of external capital input for replacement of the assets. The productivity of production factors area and animals showed higher correlation with cost-effectiveness, denoting the need for increase the production through increases in land area and milk productivity per dairy cow. The identification and quantification of benchmarks may help to identify the weak points of dairy farming in the Agreste region, making it sustainable and competitive.

The objective of this work was to identify and assess the technological, zootechnical and socioeconomic profiles and identify and quantify benchmarks for dairy cattle production systems, in a non-experimental approach, aiming to contribute to the sustainability and competitiveness of dairy farming in the Pernambuco Agreste region, northeastern Brazil. Thirty-six milk production systems of family and corporate farming were evaluated during twelve months, in order to identify and quantify the benchmarks. The systems were characterized regarding their size and technological, zootechnical and economic profiles. The correlation coefficients of the return rate on invested capital were assessed and regression equations were developed for each indicator, according to four scenarios of annual return rates (4, 6, 8 and 10%). The indicators evaluated were milk production per dairy cows, milk production per area, average price of milk, effective operational cost, total operating cost, total cost per price of milk and profitability. The dairy farming in the Pernambuco Agreste region pays the production costs, but tends to a not adequate remuneration of family labor and a need of external capital input for replacement of the assets. The productivity of production factors area and animals showed higher correlation with cost-effectiveness, denoting the need for increase the production through increases in land area and milk productivity per dairy cow. The identification and quantification of benchmarks may help to identify the weak points of dairy farming in the Agreste region, making it sustainable and competitive.

RESUMO As cucurbitáceas possuem grande importância econômica, nutricional e social no Semiárido brasileiro. Nesta região, diversos fatores podem acarretar em redução na produtividade dessas culturas, destacando-se as doenças fúngicas e viróticas, tornando-se necessário o conhecimento das mesmas para um adequado manejo. Assim, o objetivo desse trabalho foi identificar as principais doenças de cucurbitáceas produzidas em alguns municípios localizados no Sertão Pernambucano. Para tanto, foram coletadas amostras de plantas com sintomas em cultivos nos municípios de Salgueiro, Serra Talhada, Floresta, Petrolândia, Ibimirim, Custódia e Inajá. Também foi aplicado um questionário visando obter informações do perfil produtivo dos produtores. Identificou-se sete patógenos fúngicos infectando cucurbitáceas, Pseudoperonospora cubensis, Colletotrichum sp., Podosphaera xanthii, Rhizoctonia solani, Didymella bryoniae, Fusarium sp. e Alternaria sp., e três vírus, Papaya ringspot virus type watermelon (PRSV-W), Watermelon mosaic virus (WMV), Zucchini yellow mosaic virus (ZYMV). Verificou-se que nos pequenos cultivos, a busca por informações para cultura implantada ainda é limitada, sendo esses cultivos, em sua maioria, provenientes de sementes crioulas em contraste com médios e grandes produtores que utilizam cultivares melhoradas. A cultura do melão e da melancia são as mais exploradas comercialmente e as abóboras utilizadas na agricultura de subsistência. Quanto a problemas fitossanitários, a maior parte dos entrevistados relatou conhecer as principais doenças que ocorrem na cultura e realizam controle com base na experiência pessoal e/ou através do auxílio da assistência técnica fornecida por lojas agropecuárias. Em poucos casos, em propriedades de grande porte, havia um engenheiro agrônomo para auxiliar nesse tipo de controle. | ABSTRACT Cucurbits have great economic, nutritional and social importance in the Brazilian semiarid region. In this region, many factors can result in reduced productivity of these crops, especially fungal and viral diseases. Therefore, knowledge of cucurbits is crucial for proper disease management. The objective of this work was to identify the major diseases of cucurbits grown in some municipalities in the Hinterland of the state of Pernambuco. Thus, plant samples were collected with symptoms in crops in the municipalities of Salgueiro, Serra Talhada, Floresta, Petrolândia, Ibimirim, Custódia and Inajá. A questionnaire was also applied to gather information about the production profile of producers. Seven fungal pathogens infecting cucurbits were identified: Pseudoperonospora cubensis, Colletotrichum sp., Podosphaera xanthii, Rhizoctonia solani, Didymella bryoniae, Fusarium sp. e Alternaria sp., and three viruses as well: Papaya ringspot virus - watermelon strain (PRSV-W), Watermelon mosaic virus (WMV), Zucchini yellow mosaic virus (ZYMV). It was found that in small crops, there is limited search for technical information om cropping, and these crops originate mostly from native seeds, in contrast to medium and large producers, who use improved cultivars. The melon and watermelon crops are the most commercially exploited, while pumpkins are used in subsistence agriculture. As for plant health problems, most respondents reported knowing the main diseases that occur in crops and perform disease control based on personal experience and / or through the help of the technical assistance provided by agricultural stores. In a few cases, in large farms, there was an agronomist to assist in this type of control.

Cucurbits have great economic, nutritional and social importance in the Brazilian semiarid region. In this region, many factors can result in reduced productivity of these crops, especially fungal and viral diseases. Therefore, knowledge of cucurbits is crucial for proper disease management. The objective of this work was to identify the major diseases of cucurbits grown in some municipalities in the Hinterland of the state of Pernambuco. Thus, plant samples were collected with symptoms in crops in the municipalities of Salgueiro, Serra Talhada, Floresta, Petrolândia, Ibimirim, Custódia and Inajá. A questionnaire was also applied to gather information about the production profile of producers. Seven fungal pathogens infecting cucurbits were identified: Pseudoperonospora cubensis, Colletotrichum sp., Podosphaera xanthii, Rhizoctonia solani, Didymella bryoniae, Fusarium sp. e Alternaria sp., and three viruses as well: Papaya ringspot virus - watermelon strain (PRSV-W), Watermelon mosaic virus (WMV), Zucchini yellow mosaic virus (ZYMV). It was found that in small crops, there is limited search for technical information om cropping, and these crops originate mostly from native seeds, in contrast to medium and large producers, who use improved cultivars. The melon and watermelon crops are the most commercially exploited, while pumpkins are used in subsistence agriculture. As for plant health problems, most respondents reported knowing the main diseases that occur in crops and perform disease control based on personal experience and / or through the help of the technical assistance provided by agricultural stores. In a few cases, in large farms, there was an agronomist to assist in this type of control.

RESUMO Objetivou-se com este trabalho avaliar a eficiência de recuperação de nitrogênio (N), fósforo (P) e potássio (K) pela cultura da cenoura. Foram implantados dois experimentos em área de cultivo localizada em Rio Paranaíba - MG. A cultivar "Juliana" foi semeada no período de verão e a cultivar "Nayarit" no período do inverno. Os tratamentos consistiram de seis combinações de fertilizações N-P2O5-K2O (kg ha-1): sem N (0-500-450), sem P (100-0-450), sem K (100-500-0), padrão (100-500-450), maior que o padrão (100-700-600) e menor que a padrão (100-300-300). A colheita foi realizada quando a maior parte das raízes apresentavam-se dentro do padrão comercial mais aceito pelos consumidores. Quantificaram-se as matérias fresca e seca das raízes e das folhas e com base na matéria fresca de raízes calculou-se a produtividade. Determinaram-se os teores de N, P e K em folhas e raízes por ocasião da colheita e com bases nesses teores e na matéria seca de raízes e de folhas determinaram-se a absorção e a exportação de nutrientes. As fertilizações testadas influenciaram a produtividade comercial de ambas as cultivares. A omissão da fertilização com N, com P ou com K reduziu a produtividade da cultivar "Juliana". Para a cultivar "Nayarit" apenas a omissão de P reduziu a produtividade. Para essa cultivar o incremento de P e K aumentou a produtividade. A cultivar "Nayarit", mais produtiva que "Juliana", absorveu maiores quantidades de N, P e K. As eficiências de recuperação desses nutrientes por ambas cultivares de cenoura foram baixas. | ABSTRACT The objective of this work was to evaluate the carrot crop recovery efficiency of nitrogen, phosphorus and potassium from fertilizers. Two experiments were conducted in an experimental area in Rio Paranaiba - MG. The cultivar ("Juliana‟) was sown during the summer period and the cultivar "Nayarit‟ during the winter period. In both experiments, the treatments consisted of six fertilization combinations of N, P2O, K2O (kg ha-1): fertilization without N (0-500-450), without P (100-0-450), without K (100-500-0), standard (100-500-450), higher than standard (100-700-600) and lower than standard (100-300-300). The harvest was carried out when most of the roots presented commercial standard well accepted by the consumers. The fresh and dry matter of roots and leaves were quantified, and the yield was calculated based on the fresh matter. The analysis of N, P and K contents in leaves and roots were carried out by harvest time, and the nutrients absorption and exportation were determined based on these contents and on the dry matter of roots and leaves. N, P and K omissions reduced the yield of the cultivar "Juliana‟. For the cultivar "Nayarit‟, only P omission reduced and P and K fertilizations increased the yield. The cultivar "Nayarity‟, which is more productive than "Juliana", absorbed more quantities of N, P and K. Carrot recovery efficiency of nitrogen, phosphorus and potassium is low.

The objective of this work was to evaluate the carrot crop recovery efficiency of nitrogen, phosphorus and potassium from fertilizers. Two experiments were conducted in an experimental area in Rio Paranaiba - MG. The cultivar („Juliana‟) was sown during the summer period and the cultivar „Nayarit‟ during the winter period. In both experiments, the treatments consisted of six fertilization combinations of N, P 2 O, K 2 O (kg ha - 1 ): fertilization without N (0 - 500 - 450), without P (100 - 0 - 450), without K (100 - 500 - 0), standard (100 - 500 - 450), higher than standard (100 - 700 - 600) and lower than standard (100 - 300 - 300). The harvest was carried out when most of the roots presented commercial standard well accepted by the consumers. The fresh and dry matter of roots and leaves were quantified, and the yield was calculated based on the fresh matter. The analysis of N, P and K contents in leaves and roots were carried out by harvest time, and the nutrients absorption and exportation were determined based on these contents and on the dry matter of roots and leaves. N, P and K omissions reduced the yield of the cultivar „Juliana‟. For the cultivar „Nayarit‟, only P omission reduced and P and K fertilizations increased the yield. The cultivar „Nayarity‟, which is more productive than „Juliana”, absorbed more quantities of N, P and K. Carrot recovery efficiency of nitrogen, phosphorus and potassium is low.

ABSTRACT A significant increase in the use of integrated farming systems have been observed in the Brazilian Cerrado, such as crop-livestock integration (CLI), which combined with the no-tillage system (NTS) have shown significant influence on soil properties. Therefore, the objective of this work was to evaluate the influence of a CLI system on the chemical, physical and microbiological soil characteristics, in an area in the Cerrado biome, Montividiu, State of Goias, Brazil. The soil fertility, remaining phosphorus (Prem), total organic carbon (TOC), total nitrogen (Nt), aggregate stability (geometric mean diameter - GMD), microbial respiration (C-CO2) and easily-extractable glomalin-related soil protein (EE-GRSP) were evaluated. Soil samples were collected at depth of 0-5 and 5-10 cm in three areas with: CLI (13 years of annual rotation with Urochloa ruziziensis); Urochloa decumbens pasture (15 years of implementation); and native Cerrado vegetation. The CLI area had higher pH, Mg, P available (0-10 cm) and Prem (5-10 cm) values compared to the other areas, and equal values of TOC, Nt, EE-GRSP (0-10 cm) and aggregate stability (5-10 cm) compared to the pasture area. The CLI had no differences in C-CO2 emissions compared to the Cerrado, but had lower rates compared to the pasture. The P available and Prem were sensitive indicators to show the differences between the CLI and pasture systems, with higher contents in the CLI area. The TOC and Nt indicators had no differences between these two systems. The GMD results indicated a better aggregation in the pasture (0-5 cm) compared to the CLI area, while the EE-GRSP were similar in these areas. The total values of C-CO2 emission from the soil aggregates showed the stability of respirometry rates in the CLI and Cerrado areas. | RESUMO No Cerrado brasileiro têm-se observado um aumento na adoção de sistemas integrados de cultivo, como a integração lavoura-pecuária (ILP), aliada ao sistema de plantio direto (SPD), os quais vêm exercendo considerável influência nos atributos do solo. O objetivo deste estudo foi avaliar a influência do sistema de integração lavoura-pecuária (ILP) sob alguns atributos químicos, físicos e microbiológicos do solo sob Cerrado, Montividiu, Goiás. Foram avaliados a fertilidade do solo, fósforo remanescente (Prem), carbono orgânico total (COT), nitrogênio total (Nt), estabilidade de agregados (diâmetro médio geométrico - DMG), respiração microbiana (C-CO2) e a proteína do solo relacionada à glomalina - facilmente extraível (PSRG-FE). Coletaram-se amostras de solo nas profundidades de 0-5 e 5-10 cm, em três áreas: ILP (13 anos de rotação anual com Urochloa ruziziensis); pastagem de U. decumbens (15 anos de implantação); e Cerrado nativo. A área de ILP apresentou maiores valores de pH, Mg, P disponível (0-10 cm) e Prem (5-10 cm) que as demais áreas, e valores similares de COT, Nt, PSRG-FE (0-10 cm) e estabilidade de agregados (5-10 cm) à área de pastagem. A ILP não alterou as emissões de C-CO2 em relação ao Cerrado, mas reduziu essas taxas em relação à pastagem. O Pava e Prem foram indicadores sensíveis para evidenciar diferenças entre os sistemas de ILP e pastagem, com níveis mais elevados no ILP. Enquanto os indicadores COT e NT não mostraram diferenças entre estes dois sistemas. O DMG indicou maior agregação na pastagem (0-5 cm) em comparação com a ILP, enquanto a PSRG-FE não mostrou diferenças entre essas áreas. A emissão de C-CO2 indicou estabilidade nas taxas de respirometria no ILP e no Cerrado.

A significant increase in the use of integrated farming systems have been observed in the Brazilian Cerrado, such as crop - livestock integration (CLI), which combined with the no - tillage system (NTS) have shown significant influence on soil properties. Therefore, the objective of this work was to evaluate the influence of a CLI system on the chemical, physical and microbiological soil characteristics, in an area in the Cerrado biome, Montividiu, State of Goias, Brazil. The soil fertility, remaining phosphorus (Prem), total organic carbon (TOC), total nitrogen (Nt), aggregate stability (geometric mean diameter – GMD), microbial respiration (C - CO 2 ) and easily - extractable glomalin - related soil protein (EE - GRSP) were evaluated. Soil samples were collected at depth of 0 - 5 and 5 - 10 cm in three areas with: CLI (13 years of annual rotation with Urochloa ruziziensis ); Urochloa decumbens pasture (15 years of implementation); and native Cerrado vegetation. The CLI area had higher pH, Mg, P available (0 - 10 cm) and Prem (5 - 10 cm) values compared to the other areas, and equal values of TOC, Nt, EE - GRSP (0 - 10 cm) and aggregate stability (5 - 10 cm) compared to the pasture area. The CLI had no differences in C - CO 2 emissions compared to the Cerrado, but had lower rates compared to the pasture. The P available and Prem were sensitive indicators to show the differences between the CLI and pasture systems, with higher contents in the CLI area. The TOC and Nt indicators had no differences between these two systems. The GMD results indicated a better aggregation in the pasture (0 - 5 cm) compared to the CLI area, while the EE - GRSP were similar in these areas. The total values of C - CO 2 emission from the soil aggregates showed the stability of respirometry rates in the CLI and Cerrado areas.

ABSTRACT Mixed infections in cucurbits are frequently observed in natural conditions between viruses from the Potyvirus genus and Cucumber mosaic virus (CMV), which significantly decreases productivity. The objectives of the present study was to compare the host range of PRSV-W, WMV, and ZYMV isolates and evaluate the effects of mixed infections with CMV in zucchini plants (Cucurbita pepo L.). Host range studies comprising 23 plant species confirmed some similarities and biological differences among the isolates of PRSV-W, ZYMV, and WMV. RT-PCR confirmed the amplification of DNA fragments of the PRSV-W, WMV, and ZYMV coat protein gene (cp) and cytoplasm inclusion gene (ci). The virus interaction studies in zucchini Caserta plants indicated synergistic interactions, particularly among species from the Potyvirus genus, and some CMV interference with some virus combinations. | RESUMO Infecções mistas em cucurbitáceas são observadas com grande frequência em condições naturais entre os vírus do gênero Potyvirus e o Cucumber mosaic virus (CMV), reduzindo significativamente a produtividade das culturas. Os objetivos deste trabalho foram comparar a gama de hospedeiras de isolados de PRSV-W, WMV e ZYMV e avaliar os efeitos de infecções mistas entre esses isolados e um isolado de CMV em abobrinha (Cucurbita pepo) cv. Caserta. Estudos de gama de plantas hospedeiras, envolvendo 23 espécies vegetais confirmaram similaridades e diferenças biológicas entre PRSV-W, ZYMV e WMV. Estudos moleculares com RT-PCR possibilitaram a amplificação de fragmentos de DNA para as regiões do gene da CP (cp) e do gene da CI (ci) de PRSV-W, WMV e ZYMV. Estudos sobre interação sinérgica entre os vírus do gênero Potyvirus e CMV em abobrinha cv. Caserta evidenciaram efeitos sinérgicos, sobretudo entre as espécies do gênero Potyvirus e interferência do CMV em algumas combinações.

Mixed infections in cucurbits are frequently observed in natural conditions between viruses from the Potyvirus genus and Cucumber mosaic virus (CMV), which significantly decreases productivity. The objectives of the present study was to compare the host range of PRSV - W, WMV, and ZYMV isolates and evaluate the effects of mixed infections with CMV in zucchini plants ( Cucurbita pepo L.). Host range studies comprising 23 plant species confirmed some similarities and biological differences among the isolates of PRSV - W, ZYMV, and WMV. RT - PCR confirmed the amplification of DNA fragments of the PRSV - W, WMV, and ZYMV coat protein gene ( cp ) and cytoplasm inclusion gene ( ci ). The virus interaction studies in zucchini Caserta plants indicated synergistic interactions, particularly among species from the Potyvirus genus, and some CMV interference with some virus combinations.

A major problem affecting some upland rice cultivars is the increase in plant size when subjected to high doses of nitrogen fertilizer, leading to high levels of lodging. A method to reduce the height of upland rice, and therefore lodging, would be to use plant growth regulators. However, little information exists on the effect of these regulators on plant physiological processes. Therefore, the objective of this study was to evaluate the influence of trinexapac-ethyl application in upland rice via analysis of growth and gas exchange. The experiment was carried out under greenhouse conditions using the BRS Primavera cultivar. A completely randomized design with eight replications was used. Treatments were carried out with and without the application of the plant growth regulator, and plants were subject to two-stage assessments in which physiological and gas-exchange indices were measured. The use of trinexapac-ethyl improved the growth of rice plants from the flowering to the physiological maturity stage, resulting in higher values of leaf area ratio, specific leaf area, and leaf matter ratio in treated plants. At the same time, it provided smaller reduction in net CO2 assimilation at the physiological maturity stage. Thus, net/apparent assimilation rate did not change after the application of growth regulator, but relative growth rate decreased in these treated plants. These results indicate the occurrence of self-shading in rice plants induced by what might be a supra-optimum trinexapac-ethyl concentration.

RESUMO: Um dos grandes problemas de alguns cultivares de arroz de terras altas é o aumento do porte da planta quando submetido a altas doses de fertilizante nitrogenado, atingindo altos índices de acamamento. Uma opção para diminuir a altura das plantas de arroz, e com isso também o acamamento, seria a utilização de reguladores vegetais, entretanto, existem poucas informações sobre o efeito desses reguladores nos processos fisiológicos da planta. Assim, objetivou-se, por meio da análise de crescimento e de trocas gasosas, avaliar a influência da aplicação de etil-trinexapac na cultura do arroz de terras altas. O experimento foi conduzido em casa-de-vegetação usando-se a cultivar BRS Primavera. Foi utilizado o delineamento experimental inteiramente casualizado, com oito repetições. Os tratamentos foram constituídos sem e com aplicação de regulador de crescimento vegetal e dois estádios de desenvolvimento avaliados. Foram estimados os índices fisiológicos e trocas gasosas. O uso de regulador de crescimento etil-trinexapac proporcionou melhor desenvolvimento das plantas de arroz do estádio de florescimento a maturação fisiológica, resultando em valores de RAF, AFE e PMF mais elevados nas plantas tratadas. Paralelamente, proporcionou menor redução na assimilação líquida de CO2 na fase de maturação fisiológica. Assim, a TAL não sofreu alteração em função do regulador de crescimento e a TCR apresentou redução nas plantas tratadas. Estes resultados indicam a ocorrência de autosombreamento na cultura induzida pela concentração do etil-trinexapac, que pode ter sido supra ótima. | ABSTRACT: A major problem affecting some upland rice cultivars is the increase in plant size when subjected to high doses of nitrogen fertilizer, leading to high levels of lodging. A method to reduce the height of upland rice, and therefore lodging, would be to use plant growth regulators. However, little information exists on the effect of these regulators on plant physiological processes. Therefore, the objective of this study was to evaluate the influence of trinexapac-ethyl application in upland rice via analysis of growth and gas exchange. The experiment was carried out under greenhouse conditions using the BRS Primavera cultivar. A completely randomized design with eight replications was used. Treatments were carried out with and without the application of the plant growth regulator, and plants were subject to two-stage assessments in which physiological and gas-exchange indices were measured. The use of trinexapac-ethyl improved the growth of rice plants from the flowering to the physiological maturity stage, resulting in higher values of leaf area ratio, specific leaf area, and leaf matter ratio in treated plants. At the same time, it provided smaller reduction in net CO2 assimilation at the physiological maturity stage. Thus, net/apparent assimilation rate did not change after the application of growth regulator, but relative growth rate decreased in these treated plants. These results indicate the occurrence of self-shading in rice plants induced by what might be a supra-optimum trinexapac-ethyl concentration.