Fernando Machado dos Santos

Controle de arroz-vermelho em dois genótipos de arroz (Oryza sativa) tolerantes a herbicidas do grupo das imidazolinonas

Red rice (Oryza spp.) is one of the main limiting factors to rice (O. sativa) yield. An experiment was carried out to evaluate red rice control and the behavior of two rice genotypes tolerant to the imidazolinone herbicides in response to imazethapyr (75 g L-1 ) + imazapic (25 g L1 ) application rates and timing. The experiment was conducted in Santa Maria-RS, Brazil in 2004/2005 and was arranged in a factorial scheme, in a randomized block design, with four replications. Factor A included the two rice genotypes tolerant to the imidazolinones, a cultivar (IRGA 422 CL) and a hybrid (Tuno CL); and factor D included the treatments for red rice control, which was a combination of rates and herbicide application timing. The hybrid was found to be more tolerant to the herbicide only than the cultivar. Application rates up to 200% on the hybrid genotype could be done without affecting rice yield. It is important to state that increasing the rate of herbicide application can create carryover problems to non-tolerant crops. Red rice control was total with split application of imazethapyr + imazapic in PRE and POST emergence with the total rate above 125%. The most efficient treatment was application of 75% in PRE followed by 50% in POST, which was the lowest rate promoting 100% control, with relatively low toxicity to the cultivar and without affecting rice yield.

Análise de coeficiente de trilha para os componentes de produção em arroz

Eighty eight rice genotypes were evaluated during four years aiming to study the relationship among yield components. In each year, the experimental design was a completely randomized block design with four replications and the variables studied were: plant height, seed yield, spikelet sterility, number of seeds per panicle, 1000 seeds weight and head grains. The estimation of correlations and the path coefficient analysis were conducted with the GENES software. The genotypes showed significant variability for all the variables analyzed within each one of years. It was concluded that variable selection must be carried out among the cultivars that are more similar and using a greater number of variables allows better inferences about rice yield components. Grain weight was the yield of component that most affected seed yield rice plants.

Controle químico de arroz-vermelho na cultura do arroz irrigado

Red rice (Oryza spp.) reduces rice (Oryza sativa L.) grain yield and quality. A field study was conducted to compare two red rice control tools, the first using the Clearfield™ system and the second using high rates of clomazone and rice seeds treated with safener to suppress red rice emergence. The treatments included: check control without herbicide application, three treatments for the formulated herbicide mixture (imazethapyr 75 g i.a. L-1 + imazapic 25 g i.a. L-1) under the Clearfield system, and three clomazone treatments (clomazone 500 g i.a. L-1). The most efficient treatment for red rice control was the formulated mixture of imazethapyr + imazapic (0.7 L ha-1 PRE followed by 0.7 L ha-1 POST). This treatment promoted 100% red rice control, without affecting plant stand and promoting high grain yield.

Qualidade da água no consórcio de peixes com arroz irrigado

The goal of the present work was to evaluate quality parameters of the water utilized in combination of the fish culture with irrigate rice. The experiment was carried in low land area, with rice pre-germinate system associated with farming of carps and silver catfish, where the levels of dissolved oxygen, temperature, pH, hardness, total alkalinity, ammonia, nitrite and water transparency were weekly monitored. The physical-chemical characteristics of the water (temperature, pH, hardness, total alkalinity, ammonia, and nitrite) do not affect the growth and development of the fish in combination with irrigate rice for cultived species (60% commom carp, 20% grass carp, 10% silver catfish, 5% silver carp and 5% bighead carp) Although, the quantities of fish utilized and time of entry fingerlings affect certain water quality parameters (dissolved oxygen and water transparency) in general they maintain in levels adequate to with the standard for these species.

Carryover of Imazethapyr and Imazapic to Nontolerant Rice

Abstract The present work aimed to evaluate plant injury caused by residues in the soil of the formulated mixture of imazethapyr and imazapic to a nontolerant genotype of rice (IRGA 417) drilled at 371 and 705 d after herbicide application (DAA). Herbicide carryover reduced up to 55% of the grain yield of the IRGA 417 drilled at 371 DAA, and plant injury was still evident at 705 DAA but without grain yield reduction. Nomenclature: Imazethapyr; imazapic; rice, Oryza sativa L. ‘IRGA 417’

Produção de novilhos de corte com suplementação em pastagem de azevém submetida a doses de nitrogênio

O experimento foi realizado em varzea sistematizada com o objetivo de comparar os efeitos do uso de doses de N em cobertura, associadas a niveis de suplementacao energetica, sobre o desempenho animal e a qualidade e producao de forragem. Os tratamentos foram: 300N+0,8S = adubacao com 300 kg de N/ha + suplementacao com grao de milho moido (0,8% do PV/dia); 200N+0,4S = adubacao com 200 kg de N/ha + suplementacao com grao de milho moido (0,4% do PV/dia); e 100N = adubacao com 100 kg de N/ha, sem suplementacao. Foram utilizados novilhos de corte da raca Charoles e suas cruzas com Nelore com idade inicial de 8 a 10 meses. A pastagem foi manejada sob lotacao continua e carga variavel, no periodo de 15/07 a 03/11/2000, totalizando 110 dias de utilizacao. O teor de PB, a digestibilidade in vitro da MO (DIVMO) e a oferta de forragem (OF) foram maiores no inicio do periodo de pastejo e apenas a OF diferiu entre os tratamentos. As doses de N em cobertura, associadas a niveis de suplementacao energetica em pastagem de azevem, nao alteraram o ganho medio diario dos animais, mas resultaram em maior carga animal e maior ganho de peso vivo por hectare.

Desempenho de genótipos de arroz irrigado cultivados no sistema pré-germinado com inundação contínua

No sistema pre-germinado de cultivo do arroz irrigado, adota-se o manejo de retirada da agua da lavoura, aproximadamente aos tres dias apos a semeadura, objetivando melhor estabelecimento das plântulas. No entanto, esta pratica acarreta perda de agua e nutrientes, alem da reinfestacao com plantas daninhas. A permanencia da lâmina de agua na lavoura, durante todo o ciclo da cultura, seria uma proposta de manejo capaz de minimizar estes problemas. Sendo assim, objetivou-se avaliar o desempenho de genotipos de arroz irrigado, quando submetidos ao cultivo em lâmina continua, especialmente quanto ao acamamento de plantas, aspecto considerado limitante neste manejo de irrigacao. Para tal, nos anos agricolas de 2000/01 a 2002/03, foram conduzidos experimentos em area de varzea sistematizada, em solo classificado como Planossolo Hidromorfico eutrofico arenico. Os tratamentos foram compostos por 8, 12 e 15 genotipos no primeiro, segundo e terceiro ano, respectivamente. No ano 1, a produtividade media foi de 7279kg ha-1, sendo o genotipo IRGA 1572-11-1F-1-4-4 (8297kg ha-1) o mais produtivo em valores absolutos. A porcentagem de acamamento variou entre 0 e 60% e a maioria dos tratamentos situou-se entre 0-20%. Todos os genotipos exibiram acamamento de plantas, exceto El Paso L 144. No ano 2, a produtividade media foi de 8492kg ha-1 e o genotipo BRS-Pelota o mais produtivo (9282kg ha-1), nao tendo sido verificado acamamento em nenhum dos genotipos. No ano 3, a produtividade media foi de 6202kg ha-1 e esteve relacionada a elevada porcentagem de plantas acamadas decorrente de intemperies climaticas, ocorridas na fase de maturacao. Constatou-se que a produtividade dos genotipos pode ser elevada neste manejo de irrigacao, mas o acamamento de plantas limita o potencial produtivo, dependendo das condicoes ambientais e do genotipo utilizado.

População de plantas, dose de nitrogênio e aplicação de fungicida na produção de arroz irrigado: II. Qualidade de grãos e sementes

This study was aimed at evaluating the effect of plant densities, nitrogen rates and foliar diseases control on the physical, physiological and sanitary qualities of rice seeds. The experiment was conducted during 2003/2004 growing seasons in Santa Maria-RS, Brazil. The treatments were: three plant densities (150, 260 and 380 plants m-2), five nitrogen rates (0, 40, 80, 120 and 160kg ha-1), and control or no control of foliage diseases. The nitrogen fertilizer was top-dressed, and split in two times. There was no triple interaction among the parameters evaluated. Increasing nitrogen rates resulted in higher seed protein content. The chemical control of diseases contributed for better physiological and sanitary qualities such as better germination and vigor and lower incidence of pathogens associated with seeds.

Herbicidas alternativos para o controle de Conyza sumatrensis (Retz.) E. H. Walker resistentes aos inibidores da ALS e EPSPs

Horseweed (Conyza sumatrensis), the major weed already identified in southern Brazil come presenting unsatisfactory control in response to application of herbicide chlorimuron-ethyl and glyphosate. In this context, the aim of this study was evaluating alternative herbicides for control of biotypes of C. sumatrensis with low-level resistance to the herbicide chlorimuron-ethyl and glyphosate-resistant. The experiment was carried out in a greenhouse, in a period during the interval April to August 2012, in Passo Fundo / RS. The experimental design was the completely randomized with four replications, with 15 herbicide treatments, plus an untreated control. The variables evaluated were percent control at 14, 21 and 28 days after treatment (DAT) and dry weight of shoot at 28 DAT. The results showed that the biotypes were 100% controlled at 28 DAT for alternative treatments of paraquat + diuron, ammonium glufosinate, glyphosate + 2,4-D, glyphosate and ammonium glufosinate; 2,4-D; tembotrione and tembotrione + atrazine. The biotype 17 showed less sensitivity to ALS-inhibiting herbicides, and biotypes 05, 17 and 20 were not controlled by glyphosate.