Efeito de calagem e adubação com NPK na qualidade de sementes de amendoim

Peanut (Arachis hypogaea L.) seeds of the cultivar Tatu were produced in plots which received the following treatments: (a) no liming or fertilizer, (b) liming, (c) NPK, and (d) liming and NPK. Soon after harvest, the seeds were tested for weight of 100 seeds, germination and vigor, stored, and tested for germination and vigor at every three month interval for a total period of 15 months. The seeds produced in the presence of lime (with or without NPK), even though being of smaller size, were those which presented the highest values of germination and vigor at the beginning and during the whole storage period. Practically there was no effect of NPK or additive effect of NPK and lime in the physiological quality of the seeds. The seeds produced in the presence of lime, and lime + NPK maintained high germination through the whole storage period, presenting at the end of 15 months the germination percentages of 92.5 and 90.5, respectively, while those in the check and NPK plots, exhibited, at the same period, the germination indexes of 57.5% and 71.5%, respectively.Sementes de amendoim (Arachis hypogaea L.) da cultivar Tatu foram produzidas em parcelas que receberam os seguintes tratamentos: (a) sem adubo ou calcário, (b) com calcário, (c) com NPK e (d) com NPK e calcário. Logo após a colheita, as sementes foram avaliadas quanto ao peso de 100 sementes, germinação e vigor, sendo, a seguir, armazenadas e testada quanto à germinação e vigor a cada três meses, por um período total de quinze meses. As sementes produzidas em presença de calcário (com ou sem NPK), embora sendo de menor tamanho, foram as que apresentaram os valores mais altos de germinação e vigor no inicio e por todo o período de armazenamento. Praticamente, não houve efeito de NPK nem efeito aditivo de NPK e calcário na qualidade fisiológica das sementes. As sementes produzidas em presença de calcário e NPK + calcário mantiveram germinação bastante alta por todo o período de armazenamento, tendo apresentado, ao final dos quinze meses, as percentagens de germinação de 92,5 e 90,5, respectivamente, enquanto as provenientes dos tratamentos testemunha e NPK exibiram, no mesmo período, os índices de germinação de 57,5% e 71,5%, respectivamente

Armazenamento de sementes de cultivares de milho e sorgo com resistências ambientais diferentes

Seeds of the maize (Zea mays L.) cultivars IAC Maya, IAC Maya Latente, and Hmd 7974, and sorghum (Sorghum vulgare L., cv. Sart) were stored under controlled conditions of 30ºC/75% RH, 30°C/55% RH, 30ºC/33% RH, 20ºC/75% RH, 20ºC/55% RH, and 20ºC/33% RH, and under noncontrolled storage conditions at Campinas, Ribeirão Preto, and Pariquera-Açú, in the State of São Paulo, Brazil. The gradual deterioration of the seeds was evaluated by standard germination tests conducted at the beginning of storage and at every four months for a total period of 48 months. The speed of deterioration of the seeds was directly related to the temperature and the moisture content in equilibrium with the relative humidity of the several storage environments. The best suited controlled conditions for maintaining the longevity of the seeds were 20ºC/33% RH and 20ºC/55% RH. The Campinas region was more favorable than Ribeirão Preto for storing the seeds; Pariquera-Açú showed to be inadequate for this objective. The longevity of the maize hybrid 'Hmd 7974' seeds was superior to those of the other cultivars, including that of sorghum. The "latent" factor seems to have conferred more tolerance to storage environment to the 'IAC Maya Latente' seeds, when compared to those of the 'IAC Maya'.Sementes das cultivares de milho (Zea mays L.) IAC Maya, IAC Maya Latente e Hmd 7974 e de sorgo (Sorghum vulgare L., cv. Sart) foram armazenadas em condições controladas de 30ºC/75% UR, 30ºC/55% UR, 30ºC/33% UR, 20ºC/75% UR, 20ºC/55% UR e 20ºC/33% UR e em condições não controladas de armazém das regiões de Campinas, Ribeirão Preto e Pariquera-Açú, no Estado de São Paulo. A gradativa deterioração das sementes foi avaliada pelo teste padrão de germinação realizado no inicio do armazenamento e a cada quatro meses por um período total de 48 meses. A velocidade de deterioração das sementes esteve diretamente relacionada com a temperatura e o conteúdo de umidade em equilíbrio com a umidade relativa dos diversos ambientes. As condições controladas mais adequadas à manutenção da longevidade das sementes foram 20°C/33% UR e 20ºC/55% UR. A região de Campinas foi mais favorável que a de Ribeirão Preto para o armazenamento das sementes; Pariquera-Açú se comportou como uma área inadequada para essa finalidade. A longevidade das sementes do milho híbrido 'Hmd 7974' foi superior à das sementes das outras cultivares, inclusive à de sorgo. O fator ''latente" parece ter conferido maior tolerância ao armazenamento às sementes da 'IAC Maya Latente', quando comparada com as da 'IAC Maya'.

Seed maturation and yield of sesame cultivar IAC-China

Este trabalho teve por objetivo avaliar o desenvolvimento e a qualidade fisiológica e física de sementes de gergelim (Sesamum indicum L.) cultivar IAC-China, durante a fase de maturação. O estudo foi realizado por dois anos agrícolas consecutivos, em plantios tardios "das águas", em área homogênea do Instituto Agronômico, em Campinas, SP. As colheitas foram feitas a intervalos de três a sete dias até os 150 dias após emergência no campo em 1993/1994, e aos 144 dias em 1994/1995. Em cada colheita foram efetuadas as seguintes determinações: conteúdo de umidade das sementes e frutos, massa seca de mil sementes, produção por planta, e germinação até 18 meses de armazenamento em condições não controladas. Os mais altos valores de massa seca de mil sementes, as maiores produções e as menores perdas de sementes por degrana ocorreram aos 132 dias após emergência no ano agrícola 1993/1994, e aos 116 dias em 1994/1995. Nesses pontos ótimos de colheita, as sementes apresentaram graus de umidade inadequados à sua preservação; após apropriada secagem, exibiram altos índices de germinação aos zero, seis, doze e dezoito meses de armazenamento. Considerando-se os anos agrícolas, pode-se afirmar que o melhor período de colheita de gergelim da cultivar IAC-China está situado entre 116 e 132 dias após a emergência no campo.This work aimed to evaluate the development and the physiological and physical quality of seeds of the sesame (Sesamum indicum L.) cultivar IAC-China during the maturation phase. The research was conducted for two successive crop years, in late wet season plantings on a uniform area of the Instituto Agronômico, at Campinas, State of São Paulo, Brazil. The harvests were made at intervals of three to seven days until 150 days after field emergence in the 1993/1994 crop year, and 144 days in 1994/1995; in each harvest, the following determinations were made: moisture content of fruits and seeds, dry matter of 1,000 seeds, yield per plant, and germination during 18 months under uncontrolled storage conditions. The highest dry matter values, largest yields and lowest seed shattering losses occurred at 132 days after emergence in 1993/1994 crop year and at 116 days in 1994/1995. At these optimum harvest stages the seeds presented moisture contents unsuitable to their preservation; after appropriate drying, they exhibited high germination indices at zero, six, twelve and eighteen months of storage. Data from both crop years indicate that the best harvest period for the sesame cultivar IAC-China is situated between 116 and 132 days after field emergence

Efeito de sulfentrazone no sistema integrado palha de cana-de-açúcar, herbicida e vinhaça no desenvolvimento inicial da tiririca (Cyperus rotundus)

The objective of this work was to evaluate the interactions among sugarcane mulch residue, the herbicide sulfentrazone and different application methods of vinasse, a sugarcane industry residue, on the initial development of purple nutsedge (Cyperus rotundus L.). A greenhouse experiment was set up using pots with soil, in randomized complete blocks, with four replications and the following treatments were studied: control (C), straw alone (P), vinasse alone (V), herbicide alone (H), straw + vinasse (PV), straw + herbicide (PH), herbicide + vinasse applied before the herbicide (HVa), herbicide + vinasse applied after the herbicide (HVd), herbicide + vinasse applied together (HVj), straw + herbicide + vinasse applied before the herbicide (PHVa), straw + herbicide + vinasse applied after the herbicide (PHVd) and straw + herbicide + vinasse applied together (PHVj). Sulfentrazone was applied at the rate of 700 g ha-1, and in the treatments HVj, sulfentrazone was diluted in water until ¼ of the necessary volume, the remaining ¾ being completed with vinasse. In the statistical analysis the F test was used while the Scheffé test was employed to study the following contrasts: C x H, C x P, Cx V, C x treatments with H, C x treatments with S; C x treatments with V; without herbicide x with herbicide; without straw x with straw, without vinasse x with vinasse, HVa x HVd; HVa x HVj, HVa x HVj; HVa x SHVa, HVd x SHVd, HVj x SHVj, SHVa x SHVd, SHVd x SHVj and SHVd x SHVj. It was uses the Duncan’s test for the umidity straw avaliation. It was concluded that sulfentrazone applied alone or on the sugar cane mulch residue or with vinasse applied before, after or in mixture with herbicide controlled the initial development of purple nutsedge. Sugar cane mulch residue reduced the initial development of purple nutsedge but the height of plants was increased due to etiolation. Vinasse applied on the soil without sugar cane mulch residue and without sulfentrazone stimulated the development of this weed. There wasn’t difference among appling vinasse before, after or in mixture with sulfentrazone in the treatments with or without straw.      O objetivo do trabalho foi avaliar o efeito da interação palha de cana-de-açúcar, do herbicida sulfentrazone e de diferentes meios de aplicação de vinhaça no desenvolvimento inicial da tiririca (C. rotundus). O experimento foi instalado em vasos com terra, em casa de vegetação, e disposto em blocos ao acaso, com quatro repetições, sendo avaliados, vinte oito dias após a instalação do experimento, os tratamentos: controle (C); apenas palha (P); apenas vinhaça (V); apenas o herbicida (H), palha + vinhaça (PV); palha + herbicida (PH); herbicida + vinhaça aplicada antes do herbicida (HVa); herbicida + vinhaça aplicada depois do herbicida (HVd); herbicida + vinhaça aplicada junto com o herbicida (HVj); palha + herbicida + vinhaça aplicada antes do herbicida (PHVa); palha + herbicida + vinhaça aplicada depois do herbicida (PHVd); e palha + herbicida + vinhaça aplicada junto com o herbicida (PHVj). Sulfentrazone foi aplicado na dose de 700 g ha-1 e nos tratamentos HVj foi diluído com água até ¼ do volume necessário e completado com vinhaça. Na análise estatística empregou-se o teste F e quando houve significância das variáveis, o teste de Scheffé foi usado para avaliar os contrastes: C x H; C x P; C x V; C x H; C x tratamentos com palha; C x tratamentos com vinhaça; sem H x com H; sem P x com P; sem V x com V; HVa x HVd; HVa x HVj; HVd x HVj; HVa x PHVa; HVd x PHVd; HVj x PHVj; PHVa x PHVd; PHVa x PHVj e PHVd x PHVj. Para avaliar o nível de umidade da palha foi empregado o teste de Duncan a 5% de probabilidade. Concluiu-se que sulfentrazone, tanto em aplicação isolada como sobre palha ou associado à vinhaça aplicada antes, depois ou em mistura com o produto, controlou o desenvolvimento inicial da tiririca. A deposição da palha sobre o solo reduziu o desenvolvimento inicial da tiririca, mas aumentou a altura das plantas devido ao estiolamento. A vinhaça aplicada sobre o solo descoberto e sem herbicida estimulou o desenvolvimento da tiririca; entretanto, associada à palha e ao sulfentrazone, reduziu o crescimento. Não houve diferença entre aplicação de vinhaça antes, depois e mesmo em mistura com sulfentrazone nos tratamentos sem ou com palha

Transpiration and leaf growth of potato clones in response to soil water deficit

Potato (Solanum tuberosum ssp. Tuberosum) crop is particularly susceptible to water deficit because of its small and shallow root system. The fraction of transpirable soil water (FTSW) approach has been widely used in the evaluation of plant responses to water deficit in different crops. The FTSW 34 threshold (when stomatal closure starts) is a trait of particular interest because it is an indicator of tolerance to water deficit. The FTSW threshold for decline in transpiration and leaf growth was evaluated in a drying soil to identify potato clones tolerant to water deficit. Two greenhouse experiments were carried out in pots, with three advanced clones and the cultivar Asterix. The FTSW, transpiration and leaf growth were measured on a daily basis, during the period of soil drying. FTSW was an efficient method to separate potato clones with regard to their response to water deficit. The advancedclones SMINIA 02106-11 and SMINIA 00017-6 are more tolerant to soil water deficit than the cultivar Asterix, and the clone SMINIA 793101-3 is more tolerant only under high solar radiation

Studies of the mass composition of cosmic rays and proton-proton interaction cross-sections at ultra-high energies with the Pierre Auger Observatory

In this work, we present an estimate of the cosmic-ray mass composition from the distributions of the depth of the shower maximum (Xmax) measured by the fluorescence detector of the Pierre Auger Observatory. We discuss the sensitivity of the mass composition measurements to the uncertainties in the properties of the hadronic interactions, particularly in the predictions of the particle interaction cross-sections. For this purpose, we adjust the fractions of cosmic-ray mass groups to fit the data with Xmax distributions from air shower simulations. We modify the proton-proton cross-sections at ultra-high energies, and the corresponding air shower simulations with rescaled nucleus-air cross-sections are obtained via Glauber theory. We compare the energy-dependent composition of ultra-high-energy cosmic rays obtained for the different extrapolations of the proton-proton cross-sections from low-energy accelerator data

Study of downward Terrestrial Gamma-ray Flashes with the surface detector of the Pierre Auger Observatory

The surface detector (SD) of the Pierre Auger Observatory, consisting of 1660 water-Cherenkov detectors (WCDs), covers 3000 km2 in the Argentinian pampa. Thanks to the high efficiency of WCDs in detecting gamma rays, it represents a unique instrument for studying downward Terrestrial Gamma-ray Flashes (TGFs) over a large area. Peculiar events, likely related to downward TGFs, were detected at the Auger Observatory. Their experimental signature and time evolution are very different from those of a shower produced by an ultrahigh-energy cosmic ray. They happen in coincidence with low thunderclouds and lightning, and their large deposited energy at the ground is compatible with that of a standard downward TGF with the source a few kilometers above the ground. A new trigger algorithm to increase the TGF-like event statistics was installed in the whole array. The study of the performance of the new trigger system during the lightning season is ongoing and will provide a handle to develop improved algorithms to implement in the Auger upgraded electronic boards. The available data sample, even if small, can give important clues about the TGF production models, in particular, the shape of WCD signals. Moreover, the SD allows us to observe more than one point in the TGF beam, providing information on the emission angle

Combined fit to the spectrum and composition data measured by the Pierre Auger Observatory including magnetic horizon effects

The measurements by the Pierre Auger Observatory of the energy spectrum and mass composition of cosmic rays can be interpreted assuming the presence of two extragalactic source populations, one dominating the flux at energies above a few EeV and the other below. To fit the data ignoring magnetic field effects, the high-energy population needs to accelerate a mixture of nuclei with very hard spectra, at odds with the approximate E$^{-2}$ shape expected from diffusive shock acceleration. The presence of turbulent extragalactic magnetic fields in the region between the closest sources and the Earth can significantly modify the observed CR spectrum with respect to that emitted by the sources, reducing the flux of low-rigidity particles that reach the Earth. We here take into account this magnetic horizon effect in the combined fit of the spectrum and shower depth distributions, exploring the possibility that a spectrum for the high-energy population sources with a shape closer to E$^{-2}$ be able to explain the observations