Luis Osmar Braga Schuch

Vigor de sementes e competição intra-específica em soja

The objective of this research was to evaluate the effect of high and low vigor soybean seeds combinations distribution in the planting row on individual plants and different communities performance. The cultivar BRS 154 was used. Six seed vigor combinations were used. Plants from high vigor seeds had higher leaf area, dry matter accumulation and seed yield than plants from low vigor seeds. Plants from high vigor seeds do not have dominance effect on plants from low vigor adjacent in the row. The increases in proportion of high vigor seeds in the establishment of the plants communities provided linears increments in leaf area index, dry matter production and seeds yield. The population established with all plants from of high vigor seeds out yield in more than 30% the population established only with plants from low vigor seeds.The objective of this research was to evaluate the effect of high and low vigor soybean seeds combinations distribution in the planting row on individual plants and different communities performance. The cultivar BRS 154 was used. Six seed vigor combinations were used. Plants from high vigor seeds had higher leaf area, dry matter accumulation and seed yield than plants from low vigor seeds. Plants from high vigor seeds do not have dominance effect on plants from low vigor adjacent in the row. The increases in proportion of high vigor seeds in the establishment of the plants communities provided linears increments in leaf area index, dry matter production and seeds yield. The population established with all plants from of high vigor seeds out yield in more than 30% the population established only with plants from low vigor seeds.

Qualidade fisiológica e produtividade de sementes de soja

There is currently intense research on obtaining information about higher soybean productivity and, in this context, using high quality seeds is extremely important to farmers. With the objective of evaluating the effects of soybean seed vigor on productivity, seed lots with high and low vigor were sown at three different densities: the certified germination %, the certified germination % plus 15% as a correction factor and, from the result of field emergence. The seedling population after emergence was not changed so that the field condition that farmers face when sowing variable quality seeds could be reproduced. During plant development, the following parameters were evaluated: initial stand, plant height at 21 and 75 days after sowing, number of pods and seeds per plant, weight of one thousand seeds, and yield/area. The results showed that: the yield/area of high vigor seed lots is on average up to 9% higher; the seedlings from high vigor seeds are taller at 21 days after sowing.

Vigor de sementes e análise de crescimento de aveia preta

This study was carried out in Capao do Leao, RS, Brazil, with the objective of evaluating the effect of seed vigor on the growth of two cultivars of cultivated black oats (Avena strigosa Schreb), as well as to verify possible interactions with plant population (150, 300 and 450 pl m-2). Seed vigor and plant population affected dry matter production during the vegetative period. The effects were reduced progressively in the growing season, with no more difference after anthesis. The extreme levels of seed vigor and plant population produced differences in dry matter yield of 410 kg ha-1 and 480 kg ha-1, respectively, at the 75th day after emergence, these effects were due to differences in crop growth rates. A compensatory effect of the plant population on dry matter production was verified, so that the effect of low seed vigor could be compensated by an increase in plant population; the lower the seed vigor level, the greater was the plant population required. High vigor seeds also compensated the effects of low plant populations.

Comportamento individual de plantas originadas de sementes com diferentes níveis de qualidade fisiológica em populações de arroz irrigado

L.), constituidas de diferentescombinacoes de distribuicao ao longo da linha de semeadura, foi conduzido este estudo. Oexperimento constou de diferentes combinacoes de distribuicao de sementes de arroz, cv. BR-IRGA 410, oriundas de lotes de alto e baixo vigor, semeadas em ambiente controlado e, apos,transplantadas ao campo para garantir o estande de plantas e o arranjo da semeadura. Para tal,foram avaliados altura, materia seca da planta e numero de perfilhos aos 60, 102 e 134 dias apostransplante ao campo e numero de paniculas por planta, rendimento de graos e indice de colheita,ao final do ciclo. As plantas originadas de sementes de alto vigor apresentaram desempenhosuperior para todas as caracteristicas avaliadas, independentemente do sistema de distribuicaodas plantas ao longo da linha de semeadura. As plantas originadas de sementes de alto vigorapresentaram rendimento medio de graos superior ao das plantas originadas de sementes de baixovigor. Plantas de arroz originadas de sementes de alto vigor nao apresentam desempenho dominantesobre as plantas adjacentes de baixo vigor na linha de semeadura.Termos para indexacao:

Avaliação de espaçamentos e populações de plantas de feijão visando à colheita mecanizada direta

8 RESUMO - O trabalho foi conduzido na safra 1992/93, no Centro Agropecuario Palma (CAP)/Univer- sidade Federal de Pelotas (UFPel), objetivando avaliar o efeito da variacao do espacamento entre linhas e da populacao de plantas sobre caracteristicas agronomicas relacionadas com a colheita mecanizada de feijoeiro (Phaseolus vulgaris L.). Foram testados tres espacamentos entre linhas (25, 50 e 75 cm) e quatro populacoes de plantas/ha (100, 200, 350 e 500 mil), utilizando como reagente a cultivar Pampa, de habito de crescimento indeterminado, tipo II. O delineamento experimental foi em blocos casualizados, com quatro repeticoes. Somente ocorreu interacao entre os fatores para o indice de acamamento, onde o aumento da populacao tendeu a reduzi-lo. A combinacao do maior espacamento com a menor populacao provocou o maior acamamento. A reducao no espacamento entre linhas, apesar de reduzir a altura de plantas, a altura de insercao de vagens e o rendimento de graos, provocou aumento na altura da ponta da vagem mais baixa ate o solo, e reducao na porcentagem de plantas com vagens encostando no solo. O aumento na populacao de plantas, apesar de nao afetar a maioria das caracteristicas agronomicas das plantas, provocou reducao na porcentagem de plantas com vagens encostando no solo, e nao provocou modificacoes no rendimento de graos. Termos para indexacao: Phaseolus vulgaris, acamamento, insercao de vagens. SPACING AND PLANT POPULATION FOR DRY BEAN HARVEST MECHANIZATION ABSTRACT - The experiment was conducted in 1992/93 season at Centro Agropecuario da Palma (CAP) of the Universidade Federal de Pelotas (UFPel), in Pelotas, Brazil, to evaluate the effect of spacing variations between rows and plant populations on agronomic characteristics related to mechanized harvest for dry bean (Phaseolus vulgaris L.). Three different row spacing (25, 50 and 75 cm) and four different plant populations/ha (100, 200, 350 and 500 thousand) were used, utilizing the cultivar Pampa, indeterminate growth habit type II as reagent. The field trial was in randomized blocks, with four replications. Positive interaction between factors was observed for the lodging index, where the increase in the plant population tended to reduce it. The combination of larger spacing with smaller plant population resulted in a higher lodging index. The reduction in the row spacings, in spite of reducing the plant height, the pod insertion height and the grain yield, resulted in an increase of the lowest pod tip height and in a reduction of the percentage of plants with pods touching the soil surface. The increase in the plant population, despite of not affecting the majority of the agronomic characteristics of the plant, resulted in a reduction of the percentage of plants with pods touching the soil and did not cause any alteration in the grain yield.The experiment was conducted in 1992/93 season at Centro Agropecuario da Palma (CAP) of the Universidade Federal de Pelotas (UFPel), in Pelotas, Brazil, to evaluate the effect of spacing variations between rows and plant populations on agronomic characteristics related to mechanized harvest for dry bean (Phaseolus vulgaris L.). Three different row spacing (25, 50 and 75 cm) and four different plant populations/ha (100, 200, 350 and 500 thousand) were used, utilizing the cultivar Pampa, indeterminate growth habit type II as reagent. The field trial was in randomized blocks, with four replications. Positive interaction between factors was observed for the lodging index, where the increase in the plant population tended to reduce it. The combination of larger spacing with smaller plant population resulted in a higher lodging index. The reduction in the row spacings, in spite of reducing the plant height, the pod insertion height and the grain yield, resulted in an increase of the lowest pod tip height and in a reduction of the percentage of plants with pods touching the soil surface. The increase in the plant population, despite of not affecting the majority of the agronomic characteristics of the plant, resulted in a reduction of the percentage of plants with pods touching the soil and did not cause any alteration in the grain yield.

Efeito da qualidade fisiológica das sementes e da densidade de semeadura sobre o rendimento de grãos e qualidade industrial em arroz

An experiment was conducted in the Centro Agropecuario da Palma, at the Universidade Federal de Pelotas (CAP/UFPel) with the objective of evaluating the effect of rice seed physiological quality and seeding rate upon grain yield and grain integrity percentage. It was tested in a factorial combination in two crop years (2000/2001 and 2001/2002), two physiological quality levels and different seeding rates. Seed lots of the cultivar IRGA 417 were obtained from official seed growers of Rio Grande do Sul State, Brazil. Seeding rates were 80, 140 and 200 kg per hectare in 2000/2001 and 80 and 150 kg in 2001/2002. The use of high physiological quality level seed lots propitiated yield increases of 8,2% and 9,0% in 2000/2001 and 2001/2002, corresponding to 622 kg ha-1 and 660 kg ha-1, respectivelly. Otherwise, different seeding rates did not affect grain yield.The use of lots of low seed physiological quality caused uneven maturation, reduction in 1000 grain weight. On the other hand, grain integrity percentage and index of harvesting were not affected. The variation in the seeding rate did not affect maturation uniformity, grain integrity yield and weight of 1000 grains.

Desempenho individual e de populações de plantas de arroz híbrido em função da qualidade fisiológica das sementes

The work had the objective of evaluating the individual behavior of plants originated from seeds of high and low vigor of hybrid rice, inside of populations and behavior of populations of hybrid rice plants that were constituted by different ratio of plants derived from seeds of high and low physiological quality. The experiment was conducted in the experimental area of the agronomy school. It was used seeds of hybrid rice of the cultivar Avaxi, which belongs to the Ricetec®, consisting 5 treatments ( ratio of 0, 25, 50, 75 and 100% plants originated from seeds of high vigor in the population) including two lots characterized as low and high vigor. After the emergence of the plants in the trays, a looping was proceeded in order to remove the undesirable plants, removing the precocious plants in the low vigor lot and the delayed plants in the high vigor lot, intending to use the emerged plants of the day with higher frequencies of emergency on each one of the vigor levels. The transplant was carried out 20 days after sowing. The experiment was developed by a randomized complete block design, with 3 repetitions. It was evaluated: the plants height at 60 DAT, number of panicles per plant at 115 DAT, number of tiller at 60 DAT, leaf area, number of grains per panicle, number of grains per plant, weight of 1000 seeds and plant yield. Seeds of high vigor originated plants with better performance on all evaluations, independing ong the seedline distribuition. The use of high vigor seeds on the establishment of hybrid rice populations provided increases over than 30% on the yield.

Sustentabilidade de sistemas de rotação e sucessão de culturas em solos de várzea no Sul do Brasil

The quantitative analysis with different types of indicators is crucial in determining the sustainability of crop succession. This study aimed to appraise that in tilled plain areas. The research was carried out in Pelotas, RS, Brazil at Embrapa Clima Temperado research area. The treatments consisted of successions of winter and spring-summer crops species for five years, followed by two years of fallow and three years of rice cropping. The spring-summer crops were corn and soybean, besides rice; the winter crops were cereals, leguminous pastures, mixtures species, turnip and native grass species. Seeding was performed either by no-till (NT) or conventional (CT). The experiment was planned in a split-plot randomized blocks design with three replications, where the summer crops occupied the plots, while the winters species were allocated to the subplots. The parameters measured were transformed into index to standardize the variables, each one in relation to the better measurement behavior, and arranged in four categories of analysis: (a) Agronomics indices (dry weight and grain yield); (b) Environmental indicators (soil fertility); (c) Energy Indicators (gain and energy efficiency); d) Economic Indicators (profitability and gross value of production). Through harmonic average rates calculated for each indicator, comparisons to the crop succession were then performed, and its sustainability inferred. Analyses of contrasts between the crop successions were accomplished too. The results provided the following conclusions: (a) All crop succession which had maize participation had a higher index sustainability; (b) the crops successions S1 [Cereals x soybean x rice(NT)] and S4 [Turnip x soybean x rice(NT)] had, respectively, the highest and the lowest sustainability among the ones with the soybean crop participation; (c) S5 [Native grass x soybean x rice(CT)] showed the lowest sustainability level, (d) S8 [Species mixtures x corn x rice(NT)] presented the best distribution and balance between the different classes of sustainability considered; (e) S10 [Native grass x corn x rice(CT)] has the worst performance, regarding the sustainability of the ones which included maize; (f) the NT system gives greater sustainability to the crop succession.

Vigor de sementes de populações de aveia preta: II. Desempenho e utilização de nitrogênio

O efeito do vigor das sementes e das possiveis interacoes com a variacao na populacao de plantas (150, 300 e 450 pl/m2), sobre o desempenho a campo de dois cultivares de aveia preta (Avena strigosa Schreb), e sobre alguns componentes envolvidos na utilizacao do nitrogenio, foi avaliado neste trabalho. O rendimento biologico na antese e na maturacao, a remobilizacao de nitrogenio, a eficiencia de remobilizacao e de utilizacao de nitrogenio, a concentracao de nitrogenio nos tecidos na maturacao e a qualidade fisiologica das sementes produzidas, nao foram afetados pela diferenca nos niveis de vigor das sementes e pela variacao na populacao de plantas. O rendimento de graos e os componentes do rendimento nao foram afetados pelo nivel de vigor das sementes, embora as baixas populacoes de plantas tenham reduzido o rendimento de graos. As plantas provenientes de sementes de menor vigor foram mais eficientes na alocacao de produtos da fotossintese nas sementes. A cultivar Embrapa 29 foi menos eficientes na acumulacao de nitrogenio na biomassa da parte aerea na epoca da antese, e na biomassa da parte vegetativa aerea na epoca da maturacao, do que a cultivar Embrapa 140. Ocorreram diferencas genotipicas na resposta ao vigor das sementes para algumas caracteristicas ligadas a eficiencia no uso de nitrogenio. Nao foram observadas interacoes entre niveis de vigor de sementes e populacoes de plantas.

Desempenho em campo de plantas isoladas de arroz híbrido em função da qualidade fisiológica das sementes

The work had the objective of evaluating the effects of seed vigor over several agronomic characteristics of hybrid rice plants. The experiment was conducted in the didactic experimental area of the Federal University of Pelotas (UFPEL). It was used two seed lots, which belong to the Ricetec®, characterized by presenting low and high vigor. The sowing was conducted directly on the field, in hollows distant 50 cm from each other, in order to isolate the plants. It was sowed 10 seed per hollow to allow posterior looping, leaving one plant per hollow at the end. The experiment was developed by a randomized completely block design, with 20 repetitions. Two treatments were tested; plants which were originated from low and high vigor seeds, formatting parcels constituted by only one plant. The soil fertility correction was accomplished by analyzing the soil, and the weed control was accomplished manually. The following parameters were evaluated: plant height at 60 and 115 days after plants emergence number of panicles per plant, leaf area, dry matter of the aerial part, number of grains per panicle, number of grains per plant, weight of 1000 seeds and plant yield. It was concluded that the seed physiological quality used for the plants establishment affected the performance of the adult plants. Seeds of high vigor originated plants with higher physiological potential which reflected on a higher growing and yield per plant.