Alvadi Antonio Balbinot Junior

Integração lavoura-pecuária: intensificação de uso de áreas agrícolas

Crop-livestock is a production system that succeeds, at the same area, pastures to animal production and vegetal crops, especially cereals. The objective of this work was to discuss the major presuppositions and characteristics of the crop-livestock system in Southern Brazil, and its effects on the soil quality and animal and vegetal yield. This production system can result in some advantages to farmers such as increase of rent per area, higher diversification, decrease of economic hazards and production costs. Moreover, the crop-livestock system can show biological advantages such as biodiversity increase and improved soil quality. Among the disadvantages, it can point out the possibility of superficial soil compaction in inappropriate pasture management. To success of crop-livestock system some presuppositions must be considered, such as crop rotation, use of no-tillage system, correction of soil acidity and fertility, use of improving vegetal and animal genotypes and, mainly, adequate pasture management.

Manejo de plantas daninhas na cultura de milho em função do arranjo espacial de plantas e características dos genótipos

Management practices contribute to reaching high grain yield in corn, which reduce negative effects of weed infestations. The competitive relationship between corn crop and weeds are usually modified by crop plant spatial arrangement and genotype morphophysiological characteristics. This literature review aims to discuss the influence of plant spatial arrangement and corn genotype characteristics in the competition relationship with weeds. Generally, equidistant plant arrangements, achieved through row width reduction, promote greater crop competitivity. Additionally, crop genotypes which present rapid initial growth, and suitable plant characteristics, particularly plant height, can tolerate interspecific plant competition better.

Competitividade de cultivares de arroz irrigado com cultivar simuladora de arroz-vermelho

(2) Resumo - Caracteristicas morfologicas e fisiologicas de plantas cultivadas podem afetar sua habilidade competitiva com plantas daninhas. Este trabalho objetivou investigar a competitividade de cultivares de arroz irrigado (Oryza sativa L.) com cultivar simuladora de arroz-vermelho. Investigou-se na safra 2000/2001 o comportamento de oito genotipos de arroz, cultivados na presenca ou ausencia da cultivar de arroz EEA 406, que simulou infestacao de arroz-vermelho. Aos 45 e aos 60 dias apos a semeadura, avaliou-se a resposta da simuladora em relacao as cultivares de arroz. Na colheita, foram determinados estatura de planta, componentes do rendimento e produtividade das plantas. A cultivar tardia IR 841 suprimiu o crescimento da simuladora, apresentando com a cultivar superprecoce Ligeirinho as meno- res reducoes de produtividade quando em competicao. Por sua vez, as cultivares IAS 12-9 Formosa e Bluebelle permitiram maior crescimento e producao de sementes pela concorrente, tambem sofrendo as maiores reducoes de produtividade de graos na condicao de competicao. Termos para indexacao: Oryza sativa, competicao vegetal, planta daninha, manejo da cultura. Competitiveness of flooded rice cultivars with a red rice simulating cultivar Abstract - Morphologic and physiologic characteristics of crop plants can affect their competitive ability with weeds. This research aimed to investigate competitiveness of flooded rice (Oryza sativa L.) cultivars with a red rice simulating genotype. It was investigated, during the 2000/2001 warm season, the behavior of eight rice genotypes, grown in presence or absence of the rice cultivar EEA 406, simulating a red rice infestation. At 45 and 60 days after rice seeding, it was evaluated the response of red rice mimicker genotype in relation to rice cultivars. At harvest, it was determined plant height, yield components, and grain yield of the cultivars. The late season genotype IR 841 suppressed growth of the simulative cultivar, presenting, together with the very-early cultivar Ligeirinho, the lowest reductions in grain yield under competition. In opposite, IAS 12-9 Formosa and Bluebelle cultivars allowed the greatest growth and seed production by the concurrent rice, also presenting the largest decreases of grain yield under the competition condition.

Interferência de picão-preto e guanxuma com a soja: efeitos da densidade de plantas e época relativa de emergência

The objective of this research was to evaluate the effects of hairy beggarticks (Bidens pilosa L.) and arrowleaf sida (Sida rhombifolia L.) densities and relative emergence time, on the degree of interference they may cause on soybeans. There were studies carried out under two conditions in Porto Alegre, RS, Brazil, in 1998/99 and 1999/00. The factors tested were weed species, emergence times, and weed densities. Weedsoybean associations occurred during the vegetative period of the crop. In pot assays, five weed emergence times were evaluated (11, 7, and 2 days before, and 4 and 8 days after soybean emergence). In microplot assays, three weed emergence times were compared in relation to soybeans (4 days before, at the same day, and 4 days after) and six weed densities (0, 4, 8, 16, 32 and 64 plants m -2). It was found that weed relative emergence time, in relation to soybeans, modifies competitive relations between these species, and that beggarticks performs greater competition effects on soybean and is less affected by the crop than is sida. Delay in soybean emergence in relation to weeds increases the negative effects of these species on the crop, which are potentialized by increase in weed density, mainly in presence of beggarticks.

Dano econômico como critério na decisão sobre manejo de genótipos de arroz concorrentes em arroz irrigado

The economic thresholds (ET) for weedy rice infestations in rice fields allow to decide the management of the rice crop, rationalizing herbicide use. The aim of this research was to estimate ET for red rice and for EEA 406 rice cultivar, mimicking red rice, when competing with flooded rice. Three field experiments were carried out, during the 1999/2000 and 2000/2001 growing seasons. The investigated factors were populations of the concurrents genotypes on the three experiments and red rice relative emergence times (first study), EEA 406 rice cultivar (second study) and rice cultivars and row widths (third experiment). ET values for red rice were lower than those for EEA 406 genotype. The ET values estimated for EEA 406 varied widely, according to environment (seasons), emergence time, rice cultivar and row width variables. Earlier emergence of concurrent genotypes in relation to the crop, increase in row width, and use of very early maturity cultivars decreased the ET values. Increases in grain yield, selling rice price and in control efficiency, and control cost reduction, decreased ET levels, making cost effective the adoption of management practices under lower concurrent genotype populations.

Velocidade de estabelecimento em cultivares de arroz irrigado como característica para aumentar a habilidade competitiva com plantas concorrentes

Plants that present fast establishment possess priority in utilizing environmental resources; therefore, they present advantage in competitive ability with their neighbours. The objective of this research was to detect variations in speed of establishment in flooded rice cultivars. This way, there were conducted three experiments, two of them in the greenhouse and the other in the field. In both conditions, it was investigated the behavior of nine cultivars. In order to characterize speed of establishment, there were evaluated: emergency velocity, plant height, leaf area, and aerial weight of the seedlings 15 days after sowing. The genotypes Ligeirinho and XL 6 showed characteristics that attribute them fast establishment; whereas, Bluebelle and Formosa presented characteristics indicative of slow seedling establishment.

Desempenho da cultura do feijão após diferentes formas de uso do solo no inverno

O uso e manejo do solo durante o inverno pode alterar as caracteristicas fisicas do solo, a cobertura remanescente e o desempenho da cultura semeada em sucessao. O objetivo deste trabalho foi avaliar o efeito de formas de uso do solo no inverno sobre essas variaveis, semeando-se a cultura do feijao em sucessao, manejada em plantio direto. Na safra 2007/08, foram conduzidos tres experimentos na regiao do Planalto Norte Catarinense, onde foram avaliadas cinco formas de uso do solo durante o inverno: 1) consorcio de aveia preta + azevem + ervilhaca + trevo vesiculoso manejado sem pastejo e sem adubacao nitrogenada (consorcio cobertura); 2) o mesmo consorcio, com pastejo e com 100kg ha-1 de N em cobertura (pastagem com N); 3) o mesmo consorcio, com pastejo e sem adubacao nitrogenada (pastagem sem N); 4) nabo forrageiro, sem pastejo e sem adubacao nitrogenada (nabo forrageiro); e 5) pousio, sem pastejo e sem adubacao nitrogenada (pousio). O consorcio cobertura proporciona maior quantidade de palha para o cultivo de feijao em sucessao, mas as formas de uso do solo no inverno estudadas nao afetam expressivamente a densidade e a macroporosidade do solo. O uso do solo no inverno com pastagem anual em sistema integracao lavoura-pecuaria, coberturas de solo e pousio nao afeta o desempenho da cultura do feijao semeada em sucessao, manejada em plantio direto.

Semeadura cruzada, espaçamento entre fileiras e densidade de semeadura influenciando o crescimento de duas cultivares de soja

This research aims to evaluate the growth of two soybean cultivars with determinate and indeterminate growth habits under different spatial plant arrangements, including crossed rows. Two experiments were conducted, one with BRS 294 RR cultivar, which has determinate growth habit and relative maturity of 6.3 and another with BRS 359 RR, which has indeterminate growth habit and relative maturity of 6.0. In both experiments, the randomized complete block design in a 2x2x2 factorial design with three replications was used. The treatments were formed by two row spacing (0.4 and 0.6 m), two seeding rates (375,000 and 562,500 seeds ha-1, with 81% germination) and two forms of sowing (crossed and uncrossed rows). The effect of plant arrangement on the soybean growth was different between cultivars. In general, for BRS 294 RR, vigorous vegetative growth and high branching, the growth of plant community was not affected by the spatial plant arrangement. However, the highest yield was observed in the 0.6 m row spacing. For BRS 359 RR, which has compact plant architecture, the highest plant density and the lowest row spacing promoted the growth and the soil cover by plant community, but did not affect the grain yield. In both cultivars, the soybean grain yield was not affected by crossed rows.