A moléstia da cana-de-açúcar na década de 1860: a lavoura / The sugar cane blight of the 1860s: science applied to agriculture

O Imperial Instituto Fluminense de Agricultura incentivou debates com vistas a solucionar a moléstia que assolava as plantações de cana-de-açúcar na Bahia. Participaram das discussões os proprietários rurais, membros do governo e homens das ciências. O artigo apresenta o contexto das ciências aplicadas na lavoura, sobretudo a química agrícola e a repercussão das 'descobertas' de Justus Liebig, no Brasil. Analisa o debate no Imperial Instituto acerca da moléstia da cana-de-açúcar, as ideias ali defendidas, identifica os personagens envolvidos na questão, os procedimentos e soluções apresentadas, bem como a formação de redes de conhecimentos em torno das ciências agrícolas, então em processo de institucionalização.

The Imperial Instituto Fluminense de Cultura (Fluminense Imperial Institute of Agriculture) encouraged debate with a view to eradicating the blight that devastated sugar cane plantations in the State of Bahia. Rural landowners, government officials and men of science participated in the discussions. The article presents the context of the sciences applied to agriculture, especially agricultural chemistry and the repercussions of the 'discoveries' of Justus Liebig in Brazil. The debate at the Imperial Instituto about the sugar cane blight was analyzed, together with the ideas espoused there and the characters involved in the issue. The procedures and solutions presented are studied, as well as the formation of knowledge networks around the agricultural sciences, which was in the process of institutionalization at the time.

Fate of atrazine in the agricultural soil of corn fields in Fars Province of Iran

Atrazine, a herbicide widely used in corn production, is frequently detected as pesticide in water resources. In this research, four agricultural fields with a long history of atrazine application in Shiraz and its vicinity in Fars province of Iran, have been studied to determine the fate of atrazine through the passage of time. These four farms were cultivated under a crop rotation [corn-wheat] during the past 10 years. Samples were collected from four soil profiles of 0-10, 10-20, 20-40, and 40-60 cm soil depth at different times. The time intervals for soil sampling started before atrazine application and continued until no atrazine was detected. According to the general linear model, there was no significant difference between atrazine residual concentrations and the soil moisture and depth [p?0.05]. But, significant difference between atrazine residual concentrations and the sampling regions was observed [p<0.001]. Based on the data, atrazine leaching and dissipation rate in different soil profiles in the four sampling regions were high and significant. Therefore, there is a high risk of atrazine pollution in groundwater resources of the region

Marcadores AFLP en la evaluación de la diversidad genética de variedades y líneas élites de arroz en Venezuela / AFLP markers in the evaluation of genetic diversity of rice varieties and elite lines in Venezuela

Los marcadores moleculares representan una herramienta de gran precisión para la evaluación de la diversidad genética y la determinación de la identidad de variedades, especialmente en cultivos de estrecha base genética tales como el arroz. El objetivo de este estudio fue evaluar la diversidad genética de variedades de arroz venezolanas y de líneas élites provenientes del Plan Nacional de Mejoramiento Genético de Arroz (INIA y otras instituciones), de la Fundación Danac de Productores Asociados Chispa, usando cinco combinaciones de iniciadores AFLP. Además se incluyeron dos arroces rojos. Se registraron 220 bandas desde 25 a >300pb, de las que 60 (27,27 por ciento) resultaron polimórficas, con promedio de 12 bandas por combinación. El índice de diversidad de Shannon para cada combinación varió de 0,17 a 0,41 con promedio de 0,29 ±0,10. Dicho índice mostró un moderado nivel de polimorfismo genético entre las variedades, líneas élites y arroz rojo. El análisis de agrupamiento permitió identificar cinco grupos, a una distancia de ~0,50 unidades ultramétricas. El primer grupo quedó conformado solo por arroces rojos; los grupos restantes estuvieron constituidos tanto por variedades como por líneas experimentales avanzadas. Las combinaciones AFLP permitieron la diferenciación de todos los materiales, observándose asociación entre los agrupamientos generados y la combinación genética de los genotipos. Este trabajo corrobora la utilidad de los AFLP como herramienta para discriminar entre individuos altamente emparentados.

The 15N isotope to evaluate fertilizer nitrogen absorption efficiency by the coffee plant

The use of the 15N label for agronomic research involving nitrogen (N) cycling and the fate of fertilizer-N is well established, however, in the case of long term experimentation with perennial crops like citrus, coffee and rubber tree, there are still shortcomings mainly due to large plant size, sampling procedures, detection levels and interferences on the system. This report tries to contribute methodologically to the design and development of 15N labeled fertilizer experiments, using as an example a coffee crop fertilized with 15N labeled ammonium sulfate, which was followed for two years. The N of the plant derived from the fertilizer was studied in the different parts of the coffee plant in order to evaluate its distribution within the plant and the agronomic efficiency of the fertilizer application practice. An enrichment of the fertilizer-N of the order of 2 percent 15N abundance was sufficient to study N absorption rates and to establish fertilizer-N balances after one and two years of coffee cropping. The main source of errors in the estimated values lies in the inherent variability among field replicates and not in the measurements of N contents and 15N enrichments of plant material by mass-spectrometry.

O uso do traçador 15N em pesquisas agronômicas que envolvem o ciclo do nitrogênio (N) e o destino do N do fertilizante está bem estabelecido, entretanto, para o caso de experimentação com plantas perenes como citrus, café e seringueira, ainda existem limitações devidas ao porte das plantas, à amostragem, aos níveis de detecção e à interferência no sistema. Este estudo procura contribuir metodologicamente no delineamento experimental e no desenvolvimento desse tipo de experimentação, em condições de campo, fazendo uso, por dois anos, do experimento de uma cultura de café adubada com fertilizante marcado com 15N. O N da planta derivado do fertilizante foi estudado nas diferentes partes da planta de café para determinar sua distribuição dentro dela e a eficiência agronômica da prática de adubação. Um enriquecimento do N do fertilizante da ordem de 2 por cento em abundância de 15N foi suficiente para estudar taxas de absorção de N e estabelecer balanços do N do fertilizante depois de um e dois anos de cultivo. A principal fonte de erros dos valores estimados está na variabilidade agronômica das repetições e não na precisão das medidas de conteúdo de N e de enriquecimento em 15N por espectrometria de massa.

Mineralización y cinética del fósforo en el tejido óseo de pollos alimentados con fosfatos no defluorinados / Bone mineralization and phosphorus kinetic in chicks fed wit non defluorinated phosphates

Para determinar la mineralización y la cinética del fósforo en el tejido óseo de aves alimentadas con fosfatos sedimentarios no defluorinados, 280 pollos de un día fueron distribuidos en 7 grupos, con 4 repeticiones de 10 animales, en diseño aleatorio. Se evaluaron los fosfatos de Riecito (RIO), Lizardo (LIZ), Chiguará (CHI), Jají (JAJ), Monte Fresco (MON) y Navay (NAV), y un fosfato dicálcico de alta pureza (DIC) como testigo. Las aves fueron alimentadas con dietas experimentales la última semana del período de prueba de tres semanas, con raciones isocalóricas (3100kcal EM/kg), isoproteicas (24 por ciento PC), con igual Ca (1 por ciento). Los fosfatos aportaron 0,20 por ciento a la ración basal con 0,41 por ciento P. Se registró peso y consumo de alimento. Luego se administró vía oral 10µCi 32P (Na2HPO4) para estudios cinéticos. Se determinó el tiempo medio (t1/2) de entrada y salida del 32P del hueso, relacionando actividad específica en hueso con el tiempo postdosificación. Las aves mantuvieron peso constante y la mineralización ósea varió. El contenido de cenizas y de P fue superior (P<0,05) para DIC, seguido por LIZ y RIO, menor (P<0,05) para CHI, MON, NAV y JAJ. La máxima incorporación de 32P fue a las 5h postdosificación, con actividad específica de 0,041; 0,047; 0,043; 0,061; 0,069; 0,064 y 0,067, para DIC, RIO, LIZ, CHI, JAJ, MON y NAV, sin diferencias entre DIC, LIZ y RIO, pero si (P<0,05) con CHI, MON, NAV y JAJ. La salida del 32P del hueso fue más rápida para DIC (16,34) y mas lenta para los fosfatos de roca, con t1/2 de 22,50; 20,75; 21,26; 23,34; 21,00 y 24,67h, para RIO, LIZ, CHI, JAJ, MON y NAV, respectivamente, y el promedio de disponibilidad biológica del P (por ciento) en relación al DIC (100 por ciento) fue de 74,0; 79,4; 73,3; 53,5; 67,2 y 63,7 por ciento

Comparison between aerobic and anaerobic co-composting of agricultural residues

Three co-composting were carried out at the experimental station of the Faculty of Agriculture in Abis. Two aerobic co-composting of winter and summer crop residues and one anaerobic co-composting inter crop residue were produced. The development of the co-composting processes controlled by the temperature, moisture content and chemical composition was studied. The aerobic co-composting of winter crop residues was found to be the best experiment. This co-compost is expected to be free from pathogenic microorganisms as the dominant temperature was almost about 50C from the 42nd day till the 101st day of the experiment

Ammonium adsorption properties on clinoptilolite as soil amendment

The physical, chemical and mineralogical properties of the zeolite were examined by different physicochemical methods of analyses. Chemical analysis of major elements and determination of Si/Al atomic ratio were performed aiming to compare its content with the standard sample. The clinoptilolite samples was subjected to a physico- chemical study for evaluation of its cation exchange capacity [CEC]. The quantitative determination of CEC through molecular sieving properties indicated that it was controlled by particle size, so that the increase in the particle size slightly decreased the CEC values. Two particle sizes [20-50 and 50-75 mum] of K-clinoptilolite were used to study the exchange of K+ by NH4+ on zeolite. It has been shown that the amount of NH4+ uptake on clinoptilolite is higher for the smaller particle size fraction, increasing with increase of NH4+ concentration

checklist of the gymno sperms of chitral district, N. W. F. P., Pakistan and their ethnobotany

Altogether, 7 genera and 15 species belonging to 4 families of the Gymnosperms of Chitral District, N.W.F.P., Pakistan have been listed, namely Abies pindrow, A. spectablitis, Cedrus deodara, Picea smithiana, Pinus gerardiana, P. wallichiana, Juniperus communis, J. excelsa, J. squamata, J. trukestanica, Taxus wallichiana, Ephedra gerardiana, E. intermedia, E. procera and E. regeliana. The information obtained while studying the flora of the area is presented here. 2 species are identified as tea/coffee substitutes, 1 as edible, 5 as timber yielding and 9 species are reported as medicinal. For each species, the botanical name with family, vernacular names, description, plant part used, flowering and fruiting period and action and uses, etc. are given

Physicochemical studies of aloe barbadensis Mill, of Karachi region

The physicochemical studies of Aloe barbadensis Mill. family Liliaceae have been carried out. The three forms of Aloe i.e. Aloe gel, Barbados aloe and Aloe powder have been investigated and comparison between imported forms of Aloe and values given in literature have been compiled

Chemistry of the medicinal plants of the genus cestrum [family solanaceae]

The botanical and chemical background of plants of the genus Cestrum N.O. Solanaceae has been described. Many inestigators have isolated and characterized a variety of compounds such as saponins, glycosides, hydrocarbons alkaloids, fatty acids and essential oils. The medicinal and curative effects generally associated with chemical constituents have been briefly outlined. The biological activity of 1 alpha, 25-dihydroxycholecalciferol in calcium absorption and in the synthesis of the intestinal Vitamin D dependent calcium binding protein has been discussed