ABSTRACT. This study was performed to investigate the effects of composted tannery sludge (CTS) on the physical properties of tropical sandy soil after seven years of CTS application. CTS was applied to a Fluvisol at five rates (0.0, 2.5, 5.0, 10.0, and 20.0 Mg ha-1) in experimental plots (sized 20 m2) with four replications. Water infiltration into the soil was determined in the field with the concentric-ring infiltrometer method. Bulk density, total porosity, macroporosity, and microporosity were determined in the soil samples. The permanent CTS application altered the physical properties of the soil and led to a decrease in bulk density. The total porosity, microporosity and macroporosity values in the CTS-applied soil ranged from 44.1-51.7, 34.6-39.4, and 9.1-12.8%, respectively. Water-infiltration rates were significantly influenced by CTS. The cumulative infiltrated water in the soil varied from 21.3-34.7 cm. The basic infiltration rate was lower in the unamended soil and increased with an increase in the rate of CTS application. This study confirmed that the physical soil parameters improved after the permanent CTS application. Therefore, this application may be a suitable strategy for improving physical soil properties over time.

ABSTRACT Chromium contamination in soils affects plant growth and this metal can accumulate in plants tissues. In addition, Cr can affect soil microbial biomass and activity. On the other hand, plant growth-promoting rhizobacteria (PGPR) can protect plants against metals and, at the same time, promote plant growth and could alleviate adverse effects on microbial biomass. This study evaluated five PGPR on maize growth, Cr accumulation and soil microbial biomass in a Cr-contaminated soil. Five PGPR (LCC04, LCC41, LCC69, LCC81 and IPA403), isolated from soil under permanent application of composted tannery sludge and contaminated with Cr, were inoculated in maize plants grown in soils with (+Cr) and without (–Cr) Cr. In Cr-contaminated soil, LCC41 promoted the highest growth of maize, while LCC04 contributed with the highest N accumulation. The shoots of maize accumulated less Cr with LCC81, while LCC41 contributed to the highest Cr accumulation in roots. The translocation of Cr was highest with IPA403, while LCC81 contributed to reduce Cr translocation. In conclusion, LCC41 and LCC81 could be effective as PGPR inoculants to promote plant growth and reduce Cr accumulation in maize, respectively, in Cr contaminated soil.

RESUMO Identificar genótipos tolerantes à deficiência hídrica é essencial na manutenção da produção agrícola. Objetivou-se avaliar a variação genotípica para tolerância à seca entre genótipos de milho, por meio de análise multivariada, bem como identificar híbridos com elevada produtividade de grãos em condições de déficit hídrico e irrigação plena. Utilizou-se delineamento de blocos casualizados, com 36 híbridos de milho, sendo 34 elites experimentais e dois comerciais (testemunhas), cultivados sob déficit hídrico e irrigação plena, durante a fase reprodutiva, com quatro repetições. As lâminas de irrigação, somadas à precipitação pluvial, totalizaram 691,6 mm e 490,8 mm, respectivamente sob irrigação plena e déficit hídrico. Foram avaliados o índice de área foliar, conteúdo de clorofila na folha, intervalo entre florescimento masculino e feminino, número de fileiras por espiga, número de grãos na espiga, comprimento de espiga, massa de 100 grãos, rendimento de espiga, índice de espiga, número de grãos, número de espigas por m2, produtividade de grãos com 13 % de umidade e eficiência do uso da água. Identificou-se diversidade genética útil para tolerância à seca. Quatro híbridos elites experimentais (3G7395, 3G7415, 1G7034 e 3G7335) sobressaíram-se sob deficiência hídrica, com elevada produtividade de grãos, em relação à média dos híbridos testemunhas.

ABSTRACT The identification of genotypes that are tolerant to water deficit is crucial for the maintenance of the agricultural production. This study aimed to evaluate the genotypic variation for drought tolerance among corn genotypes by means of multivariate analysis, as well as to identify hybrids with high grain yield under conditions of water deficit and full irrigation. For this purpose, an experiment was conducted in a randomized block design, with 36 corn hybrids, being 34 experimental elite and two commercial (controls) hybrids, under water deficit and full irrigation, during the reproductive stage, with four replications. The irrigation levels, added to the rainfall, totaled 691.6 mm under full irrigation and 490.8 mm under water deficit. The evaluation encompassed the leaf area index, leaf chlorophyll content, interval between male and female flowering, number of rows per ear, number of grains per ear, ear length, 100-grain weight, ear yield, ear index, total number of grains, number of ears per m2, grain yield at 13 % of moisture and water-use efficiency. The evaluated hybrids showed useful genetic diversity for drought tolerance. Four experimental elite hybrids (3G7395, 3G7415, 1G7034 and 3G7335) stood out under water deficit, showing a high grain yield performance, if compared to the average of the control hybrids.

RESUMO. A acumulação de cromo (Cr) no solo e nas plantas tem sido relatada após sucessivas aplicações de lodo de curtume, o que é motivo de preocupação tendo em vista que este elemento pode promover a contaminação ambiental e afetar a cadeia alimentar. Neste estudo, avaliou-se o crescimento e a acumulação de Cr no milho e caupi após sete anos de aplicações consecutivas de lodo de curtume compostado (LCC) em condições de campo. O experimento consistiu na aplicação de LCC em cinco doses: 0 (controle); 2,5; 5; 10 e 20 Mg ha-1 (base seca). O crescimento e o acúmulo de Cr no milho e no caupi foram avaliados aos 75 e 65 dias após a emergência das plantas, respectivamente. A aplicação de LCC aumentou a biomassa do milho e caupi. A acumulação de Cr foi semelhante para ambas as espécies, com maior acumulação relatada nas raízes. No entanto, a acumulação de Cr nos grãos diferiu entre as espécies: o caupi acumulou Cr, enquanto o milho não acumulou esse elemento nos grãos. Em conclusão, a aplicação de LCC proporcionou maior crescimento de plantas de milho e feijão-caupi, e ambas as espécies apresentaram respostas semelhantes à acumulação de Cr nas raízes e parte aérea.

ABSTRACT. Chromium (Cr) accumulation in soil and plants has been reported after successive applications of tannery sludge, which is a matter of concern because Cr can promote environmental contamination and affect the food chain. In this study, we evaluated the growth of and Cr accumulation in maize and cowpea after seven years of consecutive applications of composted tannery sludge (CTS) under field conditions. The experiment consisted of application of CTS at five levels: 0 (control), 2.5, 5, 10, and 20 Mg ha-1 (dry basis). The growth of and Cr accumulation in maize and cowpea were evaluated at 75 and 65 days after plant emergence, respectively. CTS application increased the shoot biomass of maize and cowpea. Accumulation of Cr was similar for both plant species, with higher accumulation in roots. However, Cr accumulation in grains differed as the CTS doses increased; cowpea accumulated more Cr while maize did not accumulate more Cr in grains with higher CTS doses. In conclusion, application of CTS led to higher growth of maize and cowpea plants, and both species exhibited similar Cr accumulation in roots and shoots.

O mel de abelhas é um produto que pode ter a sua qualidade comprometida devido à sua forma de obtenção e manipulação. Coletaram-se 52 amostras de mel produzido no estado do Piauí (sendo 25 amostras de Picos, 1 de São Miguel do Tapuio, 2 de Pio IX, 9 de Itainópolis, 5 de São Raimundo Nonato, 5 de Simplício Mendes e 5 de Piripiri), que foram encaminhadas ao Laboratório de Análises Físico-químicas do Núcleo de Estudos, Pesquisa e Processamento de Alimentos - NUEPPA do Centro de Ciências Agrárias - CCA, da Universidade Federal do Piauí - UFPI, para análise da presença de sujidades e matérias estranhas segundo as metodologias I e II recomendadas por Santa Catarina (1985). Das amostras analisadas pelas metodologias I e II, 65,38 e 30,77%, respectivamente, não atendiam aos aspectos macroscópico e microscópico e aos padrões de identidade e qualidade do mel (BRASIL, 2001), por apresentarem sujidades e matérias estranhas, tais como: insetos, larvas, ácaros, pêlos humanos e de roedores, traças, dentre outras.

Honey from bees is a product that can have its quality reduced due to its form of attainment and manipulation. Fifty-two samples of honeys produced in the State of Piauí (being 25 from Picos, 1 from São Miguel do Tapuio, 2 from Pio IX, 9 from Itainópolis, 5 from São Raimundo Nonato, 5 from Simplício Mendes and 5 from Piripiri) were collected. They were sent to the Laboratory of Physical and Chemical Analyses of the Nucleus of Studies, Research and Processing of Foods - NUEPPA of the Center of Agrarian Sciences - CCA of the Federal University of Piauí - UFPI, for analysis of the presence of dirtiness and strange materials, according to methodologies I and II recommended by SANTA CATARINA (1985). Of the samples analyzed by methodologies I and II, 65.38 and 30.77%, respectively, did not attend the macroscopic and microscopic aspects and the identity and quality standards for honey1, due to the presence of dirtiness and strange materials, such as insects, larvae, mites, human and rodent hairs, moths, amongst others.