Repositório RCAAP

Alexandergrass (Brachiaria planraginea) infestations occur very frequently in soybean producing areas in the Southem region of Brazil, causing economic losses in productivity, of this oil seed crop, resulting also in problems to the harvesting operation. This study searched to investigate its interference in soybean, within weed density variable from moderate to high. Data obtained in several trials, conducted during three seybeah growing seasons in Eldorado do Sul, RS, Brazil, were used. In this research, 35 plot pairs were sampled, which were performed by treatments maintained weed-free throughdut the growing season by hand hoeings, 9r infested by the weed during all crop season. Alexandergrass den

With the objetive to evaluate the effect of soil tillage methods and crop systems on N uptake and com yield, an experiment was established in 1985 at the University Experimental Station in Eldorado do Sul (RS), Brazil. Thrce soil tillage methods (conventional, reduced and no tillage), three crop systems (oats(Avena strigosa)/corn, oats+clover (Trifolium subterraneum)lcom, oats+clover/corn+cowpea (Vigna unguiculata)) and two leveis of nitrogen(0 and 120 kg/ha) were tested. The results of the first five years of N absorption and com yield are reponcd in this paper. The dry matter yield of winter cover crops and its N contens above ground varied from 2.6 to 6.7 t/ha and 28 to 136 kg/ha, respectively. In 1988, the year of best clover establishment, this pasture had 80 kg/ha of N and the oats 56 kg/ha, in the oats+clover mixture. The com grown after, without N, produced 80% of the yield obtained after oats with 120 kg/ha of N. The tillage methods did not affect the yield and N absorption by com.

Effects of fertilizer placement and soil tillage systems in nutrient uptake and com yield were evaluated in the second year (1989) of a field experiment in a Rhodic Paleudult soil. The soil tillage systems, in the main plots, were conventional, strip, and no tillage; and fertilizer placements, in the plots, were broadcast, strip and row, with three repetitions. Fertilizers were applied as triple superphosphate (80 kg de P 202/ha = 35 kg P/ha) and potassium chloride (40 kg de K 20/ha=33 kg de IU ha). Phosphorus content in the plant tissuc at different com growth stages was affected by fertilizer placement and/or soil tillage systems; however, potassium uptake was not affected. Com growth and grain yield and nutrient contem were not influenced by treatments of fertilizer placement or soil tillage

A high surface roughness and appropriate Geometric Means Diameter (GMD) of soil clods are a desirable surface property to control soil erosion. However, the effect of seeding operation over these properties are not much known. In a Podzolico Vermelho-Amarelo soil, the effect of three planting furrow openers (modified double disk, double disk, chisel) on the surface roughness and the GMD of the clods was evaluated. Surface roughness and GMD were induced by chiselling operation in the presence of three amount of vegetal residues of vetch and oat. GMD of clods induced by scarifier was not affected by planting furrow openers. Surface roughness that remains from chiselling operation was affected by chisel furrow.

Size and density of sediment particles determines its transportability by erosive agents. This work was conducted with the objective of to evaluate the sediment particle size distribution of runoff samples originated from two different surface flow types, processed at the field and in laboratory, and to evaluate the effect of the laboratory samples storage time and the oscillation time during the wet sieving on the sediment particle size distribution. From two field experiments two kinds of runoff samples were collected, the first from rill concentrated flow without rainfall and the second from broad sheet flow under simulated rainfall. In the two cases, a freshly tilled Paleudult sandy loam soil was used. The sediment particles were splited into eight size classes and a median size was determined by the D index. For the samples originated by rill concentrated flow, the Ds, index from samples sieved at field was greater than the Ds, index from samples sieved in the laboratory (0.509 and 0.305 mm, respectively) and there was no effect for the laboratory samples time storage and time oscillation during the wet sieving. For the runoff samples originated by broad sheet flow under simulated rainfall, there was no difference in the median particle size among all different treatments. 

The objective of this work was to determine the effects of cow manure, rice straw, fertilizers and lime additions on iron uptake by irrigated rice. Samples were collected from two soil horizons (A and Cg) in a low humic grey soil of São João River Valley, Casemiro de Abreu, RJ, Brazil, and mixed with cow manure, rice straw, NPK, or lime in various combinations. Rice seeds of BR IRGA 409 cultivar were sowed in pots and rice was cultivated in a greenhouse of the Depto. de Solos, UFRRJ. The results show that addition of NPK and/or lime, with or without organic manure reduced iron concentration in the aerial parts of the rice planta grown in horizon Cg, while organic manure alone caused an increase in iron concentration.

A Indirect enzyme-linked immunosorbent assay (ELISA) kit was used for diagnosis of foot and mouth disease virus (FMDV) typeS 01, A24, C3 which occured in Rio Grande do Sul State, Southern Brazil during 1984-1993. The samples were randomly selected and tested by. Elisa, Complement Fixation Test (CFT) and in tissue ctilture. Out of 106 samples 78 (73:5%) were positive by Elisa and 39(36.8 %) were found positive in CFT, when original suspensions were used. Once_those samples were inoculated onto tissue culture both tests gave similar results, although Elisa picked tip more positive samples during the lst passage in tissue culture. The negative samples (16) included in this study were negative in all tests. The Elisa was more sensitive than and as speci fie as CFT. Elisa and tissue culture together were shown to be a better system for detection of Foot and Mouth Disease (FMD) antigen than CFT.

Experimento were carried out at the Seeds Research Center of Júlio de Castilhos (RS) from September of 1993 to May of 1994 to evaluate the progress in grain yield due to the soybean breeding programo in Rio Grande do Sul state, under three environmental conditions related to soil and crop management. The treatments included 21 soybean cultivars from different eras, chosen by their yield potential and their percentage of use by the soybean growers. The resulto show high progress in grain yield for the last 40 years.The genetic gain was 19 kg/ha/year or 1.1% per year, rangin g from 14.7 to 25.3 kg/ . ha annually, within every environment. When the cultivar 'Amarela Comum' was excluded the gain was 11.7 kg/ha/year, for a 30 years period. However, the grain yield gain hes been decreasing along the years probably because the soybean cultivars have reached high productivity levei and also because there has been constant use of the same germplasm bank for hybridization, creating a genetic narrow base. With emergente of new dioceses in the last decade, there were great changes on soybean varieties preferente, changing from varieties derived from Hill and Hood cultivars to genotypes originated from Davis cultivar. The changing was driven by resistancc to brown stem rot (Phialophora gregata). The great difference in grain yield among environments was due to better use of tecnology on soil and crop tillage.

 The immune response of three different formulations of foot-and-mouth disease (FMD) oil vaccines in vaccinated cattle was compared. The vaccines used were: 1) standard oil vaccine (VOR) without aluminum hydroxide; 2) VOR with aluminum hydroxide (VOAI) and 3) oil vaccine containing antigen 10x concentrated by aluminum hydroxide (V010x). Each vaccine was used in a group of 9 animais, and each animal received a 5m1 dose of vaccine by intramuscular rouco. Neutralizing antibodies were evaluated by vírus neutralization test (VN) at day 0 and at 30, 90 and 180 days post vaccination. All animais were shown previously to be free of either neutralizing or anti-VIA (vira) infection associated antigen) antibodies and were considered to be susceptible to FMD. Serology for anti-VIA antibodies was carried out and the tests were negativo during the experiment. The results obtained showed that concentrating antigen (10x) was not enough to increase significantly (P>0.05) the leveis of neutralizing antibodies, and also that the aluminum hydroxide (HAI) included in VOR did not increase significantly the levei of these antibodies. Antigen concentration (10x) plus the addition of HAI increased significantly (P<0.05) the antibody levels of vaccinated animais.

Aspects related to the aetiology, signs of infection, diagnosis and control of leptospirosis in pigs are discussed in this article, based on specialized literature on the subject. Leptospirosis is one of the most important diseases causing reproductive problems in pigs in Brazil. In the State of Rio Grande do Sul, it has high prevalence, being diagnosed mainly by serology. bratislava and prevention Leptospira are more measures, prevalent pomona also was since discussed the then, most in in prevalent our this State. paper. serovar This is until an important 1993, while ftnding Leptospira that should icterohaemorrhagiae be considered aiming and Leptospira treatment

A produção de sementes é um processo que incluem diversas etapas desde o melhoramento, produção, certificação, até a manutenção depois da colheita, cuja finalidade especifica é obter sementes de qualidade, com alta pureza genética, pureza física, qualidade fisiológica e sanitária, que afetam a sua capacidade de originar plantas de alta produtividade. Objetivou-se com esta revisão abordar os principais aspectos práticos verificados durante a produção de sementes de crambe, visando obter sementes de elevada qualidade física, fisiológica, genética  e sanitária. A metodologia estudada foi a revisão de literatura com levantando e análise de dados sobre a cultura. Verificou-se que para sementes de crambe ainda não há na literatura informações suficientes quanto às diversas etapas de um sistema de produção de sementes, especialmente no que se refere ao estabelecimento e condução de campos de produção. Diante destas considerações, o conhecimento das condições ideais durante a produção de sementes é de fundamental importância, uma  vez  que  somente  aquelas  de  elevado  nível  de  qualidade proporcionam a maximização da ação dos demais insumos e fatores de produção empregados na lavoura, com respostas na produtividade das culturas.

 The state of Rio Grande do Sul is responsable for approximately 25% of the national grain production. With the exception of rico, practically all the others agricultura' crops are grown without irrigation therefore depending on the natural rainfall regime. The simplest way of cstimating the climatic water availability for crops is through comparison of the amount of rainfall with the potential evapotranspiration. Our objetives were to estimate the probability of rainfall bcing cqual to or greatcr than the monthly average potential evapotranspiration during the growing season of the spring-summer crops in the state (September to May). Our study was bascd on 27 meteorological stations well distributcd in the state and with a homogcncous historie series. The probability of monthly rainfall bcing grcater than the potential evapotranspiration decreases as we approach the summer months. In the ctitical months accordind to the water availability (December, January and February), for the spring-summer crops, Chis probability is equal to or less than 60% in a great portion of the state, including the principal grain producing regions

Wheat grain yield is a result of the number of spikes per unit ama, number of kemeLs per spike, and kemel weight. The degree of dependance of genotypes on each grain yield component is variable and usually there is compensation among them when quantifying the grain yield. A study was conducted to determine the relative importance of each yield component of some short cycle Argentinian wheat genotypes: cv. 'Federal', 'LAJ 3239', 'LM 3254', 'LAP 2350' and 'T4I This study was conducted at Pergamino, Bs.As., Argentina (33°53'S, 60°34'W, and altitude 68 m) from July to December 1992. Diffcrences in the relative importance of each wheat yield component and yield component compensation were observed among the genotypes. In general, the yield of genotypes is quantificd as follows: 'Federal' is based on tillering efficiency; 'LAJ 3239' is based on spiké fertility; ILAI 3254' is based on the number of tillers per plant and grain weight; 'LAP 2350' is based on the number of tillers per plant, spike fertility, and grain weight; and 741' is based on the number of tillers per plant and tillering efficiency. 

Nine oat genotypes were cultivated in vitro in order to estim ate callus initiation capability. 7Wo experiments were realized, first the culture medium were tested with different hormones dosages and the genotypes for variability, atter, the cultivars were exposed to the best medium. The immature embryo were measured to test the adequate size to calogenese and the data was similar to literature. All genotypes produced cali, and variability was observed among them concerning this caracter. Almost all cali revealed organogenic and embryogenic structures. The A and B medium (with 2 and 4 mg/1 2,4 D respectivily) were adcquatcd to cali induction in oat.

Arbuscular mycorrhizae (Glomus intraradices Schenck & Smith) increased root and shoot growth, and P content in sour orange (Citrus aurantium L) seedlings. The application of indolebutyric acid (IBA) at 2.0 g/I as root dip was innefective in increasing growth to nonmycorrhizal seedlings, but applications to mycorrhizal seedlings had a positive interactive effect. The application of naphthaleneacetic acid (NAA) at 0.5 g/I was innefective to both nonmycorrhizal and mycorrhizal seedlings. 

This research was carried out at the FEPAGRO Experiment Station (Viamão-RS) in 1995, to study the selectivity of acaricides on natural enemies, in a five-year-old orange orchard of cv. 'Valencia'. The desing was randomized blocks with four replicates. The treatments and the quantities of a. i. at grams/100 liters of water, were: fenpyroximate (5); cyhexatin (25); abamectin + mineral oil (0.54 + 189); acrinathrin (0.5); amitraz (37.5); sulfur (400); fenpropathrin (15); check. The estimates were done at three days before and at five, 12, 25, and 45 days after pulverization. The sampling was based on five-minute-suction at two troes per plot, with a suction collecting machine. The counting of beneficiai artropods captured, was done in laboratory, with a stereoscopic microscope adjusted for until 40 times. The sulfur showed prominence in selectivity for the artropods whereas the fenpropathrin showed higher toxicity.

This trial was conducted in Lages, SC, Brazil, with the purpose of evaluating the effects of using higher than recommended plant densities on com yield and components. Two hybrids were used: Cargill 901 (very early) and XL 370 (early). Each hybrid was evaluated at three plant densities: 57,500, 71,500 and 82,500 pl/ha. Increasing plant population from 57,500 to 82,500 pilha did not affect grain yield of hybrid C 901 but it linearly reduced productivity of hybrid XL 370. Hybrid XL 370 presented heavier grains than hybrid C 901. Both cultivars linearly decreased number of grains per ear with the increase in plant density. The number of ears per plant was not affected by treatments. Within the levei of productivity obtained in the experiment, increasing plant density above the values suggested currently did not promote any positive effect to com grain yield. 

The Fronteira Oeste region of Rio Grande do Sul State has been highlighted by the productive diversification and the development in the fruit sector. The correct nutrition of the orchards is one of the essential factors to guarantee the success of this new producing region. The objective of this study was to evaluate the nutritional status of the orange trees 'Lanelate', 'Navelina', 'Salustiana', 'Valencia', 'Midknight Valencia' and ' Valencia Delta Seedless' grafted under Poncirus trifoliata under the edaphoclimatic conditions of this region. The orchards in which the samples were taken are adult plants. It was observed that the orchards of Cacequi and Rosário do Sul generally have deficiency in N, Ca, Mn and Zn and excess of the elements: Cu and P. This indicates the need of adequacy of soil management and fertilization, in order to increase the content of organic matter, the splitting nitrogen fertilization and the improvement of Mn and Zn fertilization.

Bees are responsible for the majority of cross-pollination dependent on animals, and their breeding has economic and environmental relevance. Therefore, beekeepers and stingless bee breeders, in addition to producing honey and other products, can be important in the process of preserving these insects. However, bees suffer from various pests and diseases, such as varroa mites, nosemosis and sac brood disease, for example. Lately, other factors, such as global warming, deforestation and use of pesticides, resulting from anthropic activity, have caused high bee mortality. But, one of the current problems has been the theft of hives. Thus, this study aimed to assess the occurrence of theft in beekeeping and meliponiculture, through a semi-structured questionnaire, available online, with anonymous and voluntary responses. Of the 259 who responded, 29.1% said they had already been stolen. The item most targeted by thieves was beehives, as 83% declared that they had already lost in wooden boxes or baits. Despite the high rate of thefts, 75.5% did not report the occurrence to the police and 56.4% do not believe that the record has any practical effect. Thus, it is concluded that the man, although promoter of the creations, can be considered a pest of beekeeping and stingless bee creations, and needs specific policies for the activity.

A utilização de sementes de elevada qualidade representa prática de manejo essencial para o estabelecimento e desempenho das culturas, sendo insumo fundamental para o desenvolvimento da agricultura. O uso de técnicas adequadas nos diversos sistemas de produção das culturas é fator fundamental para se obter maiores produtividades. Nesse sentido, cita-se que é crescente a utilização de novos produtos para incorporação de aditivos às sementes, objetivando melhorar seu potencial produtivo. No entanto, pouco se sabe sobre o real efeito desses produtos no desenvolvimento e produtividade agrícola e qualidade das sementes produzidas. Objetivou-se com o presente trabalho abordar os principais efeitos verificados no tratamento de sementes com produtos à base de fertilizantes e reguladores de crescimento. Destaca-se que os resultados verificados na literatura quanto à utilização de fertilizantes e reguladores de crescimento fornecidos via sementes já é uma realidade na agricultura e com resultados bem promissores. É importante destacar que as repostas à aplicação desses produtos dependem de uma série de fatores como espécie em estudo, composição das substâncias presentes nos produtos, das condições do ambiente e formas de aplicação, fatos estes que justificam mais estudos no setor.