Crescimento e desenvolvimento de mudas de erva-mate associadas a diferentes coberturas vegetais de inverno

The lack of knowledge of management in the application of yerba mate is the reason for the present study, given the economic importance of this crop for family farming, the economy and also the culture in the southern region of Brazil. The objective of this work was to evaluate the effects of winter cover species on the morphophysiological characteristics of yerba mate seedlings. The experimental design was laid out in randomized blocks with four replicates. The weed species used were Avena strigosa, Lolium multiflorum, Vicia sativa, Raphanus sativus, Lupinus albus, Axonopus catharinensis, the consortium between A. strigosa and V. sativa, and the control treatment without cover. Physiological (photosynthesis, stomatal conductance, transpiration, internal CO2 concentration, water use efficiency, carboxylative efficiency, and chlorophyll) and morphological (plant height, stem diameter, leaf area, shoot and of root dry matter, in addition to cover dry matter) were evaluated. There was competition between the crop and the cover plants for the factors of light and water, and the control without cultivation did not affect the morphophysiological characteristics of yerba mate. The species A. catharinensis proved to be the best cover plant because it competed less with yerba mate. The growth and development of yerba mate were affected by the presence of A. strigosa.La escasez de conocimientos sobre el manejo en la aplicación de la yerba mate es la justificación del presente estudio, dada la importancia económica de este cultivo para la agricultura familiar, la economía y también para la cultura de la región sur de Brasil. El objetivo de este trabajo fue evaluar los efectos de especies de cobertura invernal sobre las características morfofisiológicas de plántulas de yerba mate. El diseño experimental fue en bloques al azar con cuatro repeticiones. Las especies de malezas utilizadas fueron Avena strigosa, Lolium multiflorum, Vicia sativa, Raphanus sativus, Lupinus albus, Axonopus catharinensis, el consorcio entre A. strigosa y V. sativa, y el tratamiento testigo sin cobertura. Se evaluaron las características fisiológicas (fotosíntesis, conductancia estomática, transpiración, concentración interna de CO2, eficiencia en el uso del agua, eficiencia de carboxilo y clorofila) y morfológicas (altura de la planta, diámetro del tallo, área foliar, parte aérea y materia seca de la hoja). a la materia seca de la cubierta) de las plantas. Hubo competencia entre el cultivo y los cultivos de cobertura por los factores luz y agua, y el testigo sin cultivo no afectó las características morfofisiológicas de la yerba mate. La especie A. catharinensis demostró ser la mejor planta de cobertura porque compite menos con la yerba mate. El crecimiento y desarrollo de la yerba mate se vieron afectados por la presencia de A. strigosa.A escassez de conhecimento sobre o manejo na aplicação da erva-mate é a justificativa do presente estudo, haja vista a importância econômica desta cultura para a agricultura familiar, economia e também para a cultura da região sul do Brasil. O objetivo deste trabalho foi avaliar os efeitos de espécies de cobertura de inverno sobre as características morfofisiológicas de mudas de erva-mate. O delineamento experimental foi em blocos casualizados com quatro repetições. As espécies daninhas utilizadas foram Avena strigosa, Lolium multiflorum, Vicia sativa, Raphanus sativus, Lupinus albus, Axonopus catharinensis, o consórcio entre A. strigosa e V. sativa, e o tratamento controle sem cobertura. Foram avaliadas as características fisiológicas (fotossíntese, condutância estomática, transpiração, concentração interna de CO2, eficiência do uso da água, eficiência carboxilativa e clorofila) e morfológicas (altura da planta, diâmetro do caule, área foliar, matéria seca da parte aérea e da raiz, além da matéria seca da cobertura) das plantas. Houve competição entre a cultura e as plantas de cobertura pelos fatores de luz e água, e o controle sem cultivo não afetou as características morfofisiológicas da erva-mate. A espécie A. catharinensis mostrou-se a melhor planta de cobertura por competir menos com a erva-mate. O crescimento e desenvolvimento da erva-mate foram afetados pela presença de A. strigosa

Morpho-physiological responses of potato cultivars under weed competition

Among the factors that affect potato productivity, the interference caused by weeds stands out as they may compete with the crop, release allelopathic substances to soil and host insects and diseases. Therefore, the objective of this work was to assess the competitive ability of white (Aghata) and pink (Asterix) potato cultivars when infested by Alexandergrass (Urochloa plantaginea) or wild poinsettia (Euphorbia heteroplylla). The experiment was carried out into greenhouse in randomized blocks design, with four replications. A single potato plant faced competition by either Alexandergrass or wild poinsettia, ranging from 0 to 64 plants per plot. Fifty days after seedling transplanting, variables related to the morphophysiology of potato cultivars and weeds were assessed. Potatoes have low competitive ability with both weed species, with wild poinsettia being the most aggressive in reducing the accumulation rates of leaf area and aboveground dry mass. Potato photosynthetic rate is negatively influenced by the presence of both weeds. Internal CO2 concentration, stomatal conductance, carboxylation efficiency and transpiration rates of potato varied depending on weed species and density. Morphological parameters are reduced when potato competed with Alexandergrass or wild poinsettia; however the physiological parameters are most sharply affected when under competition with wild poinsettia.Among the factors that affect potato productivity, the interference caused by weeds stands out as they may compete with the crop, release allelopathic substances to soil and host insects and diseases. Therefore, the objective of this work was to assess the competitive ability of white (Aghata) and pink (Asterix) potato cultivars when infested by Alexandergrass (Urochloa plantaginea) or wild poinsettia (Euphorbia heteroplylla). The experiment was carried out into greenhouse in randomized blocks design, with four replications. A single potato plant faced competition by either Alexandergrass or wild poinsettia, ranging from 0 to 64 plants per plot. Fifty days after seedling transplanting, variables related to the morphophysiology of potato cultivars and weeds were assessed. Potatoes have low competitive ability with both weed species, with wild poinsettia being the most aggressive in reducing the accumulation rates of leaf area and aboveground dry mass. Potato photosynthetic rate is negatively influenced by the presence of both weeds. Internal CO2 concentration, stomatal conductance, carboxylation efficiency and transpiration rates of potato varied depending on weed species and density. Morphological parameters are reduced when potato competed with Alexandergrass or wild poinsettia; however the physiological parameters are most sharply affected when under competition with wild poinsettia

Interação competitiva e nível de dano econômico de azevém daninho em híbridos de canola

In canola, yield and grain quality losses occur due to the interference caused by ryegrass (Lolium multiflorum) when infesting the crop. Thus, the objective was to evaluate the interference and identify explanatory variables seeking to determine the level of economic damage (NDE) of different densities of ryegrass infesting canola hybrids. The experiment was carried out in a randomized block design, with one replication. The treatments consisted of five canola hybrids (Hyola 433, Hyola 61, Alht B4, Hyola 575 CL and Hyola 76) and 12 ryegrass densities, from 0 to 260 plants m-2, in competition with the crop. At 50 days after plant emergence, the variables as plant densities, leaf area, soil cover and shoot dry matter of ryegrass plants were evaluated. Grain yield, control cost, grain price and control efficiency were determined in canola plants. The soil cover presented the best fit to the rectangular hyperbola model, adequately estimating the grain yield losses due to ryegrass interference. The canola hybrids Hyola 433 and Hyola 575 CL were the most competitive when compared to the others in the presence of the competitor, with higher values of EDL. The canola hybrids Hyola 433 and Hyola 575 CL showed the highest EDL values with 3.85 to 5.13 plants m-2 in all simulations performed, respectively. The lowest EDL values were obtained with hybrids Hyola 61, Alht B4 and Hyola 76 with average variations of 1.02 to 2.15 plants m-2, respectively. The canola grain yield, grain bag price, efficiency of the herbicide, and the reduction in the control cost cause variation in the economic damage level values.Na canola ocorrem perdas de produtividade e da qualidade de grãos em função da interferência causada pelo azevém (Lolium multiflorum). Diante disso, objetivou-se avaliar a interferência e identificar variáveis explicativas visando determinar o nível de dano econômico (NDE) de diferentes densidades do azevém infestante de híbridos de canola. O experimento foi instalado em delineamento de blocos casualizados, com uma repetição. Os tratamentos foram compostos pelos híbridos de canola (Hyola 433, Hyola 61, Alht B4, Hyola 575 CL e Hyola 76) e 12 densidades de azevém, de 0 até 260 plantas m-2, em competição com a cultura. Avaliou-se aos 50 dias após a emergência das plantas as variáveis densidades de plantas, área foliar, cobertura de solo e massa seca da parte aérea do azevém. A produtividade de grãos, custo de controle, preço de grãos e eficiência de controle foram determinados na canola. A cobertura do solo apresentou melhor ajuste ao modelo da hipérbole retangular estimando adequadamente as perdas de produtividades de grãos pela interferência do azevém. Os híbridos de canola Hyola 433, Hyola 575 CL e Hyola 76 foram os mais competitivos ao se comparar com os demais na presença do azevém, porém demonstraram as menores produtividades de grãos e também os que apresentaram os maiores valores de NDE. Os híbridos de canola Hyola 433 e Hyola 575 CL apresentaram os maiores valores de NDE com 3,85 a 5,13 plantas m-2 em todas as simulações realizadas, respectivamente. Os menores valores de NDE foram obtidos com os híbridos Hyola 61, Alht B4 e Hyola 76 com variações médias de 1,02 à 2,15 plantas m-2, respectivamente. A produtividade de grãos de canola, o preço da saca, a eficiência do herbicida e a redução no custo de controle, causam variação dos valores do NDE

Competitive ability of common bean cultivars in the presence of Urochloa plantaginea

Weeds are the main constraints tohigh bean productivity. Here, we aimed to investigate the competitive ability of black type bean cultivars BRS Campeiro and SCS Predileto in coexistence with alexandergrass,Urochloaplataginea. The experimental design employed a replacement series arrangement, and the experiments were conducted in a greenhouse using a randomized block design with four replicates. Once the appropriate plant density was determined, the experiments proceeded with the following ratios of bean to U. platagineaplants per pot: 20:00, 15:5, 10:10, 5:15, and 0:20. Fifty-five days after the emergenceof the plants, physiological and morphological traits were analyzed. Diagrams were made to analyze the relative productivity (RP),total relative productivity(TRP),and the competitiveness indices. Based on RP and TRP, a similar competitive mechanism for environmental resources was observed for both bean cultivarsin the presence of U. plataginea. Variables such as leaf area, dry matter, stem diameter,andplant height of the bean cultivarswere negatively affected by U. plataginea, indicating a superior competitive ability for environmental resources. However, considering only the 10:10 plants per plotratio,beans showedhigher relative growth than U. plataginea, represented by relative competition indices, relative clustering coefficients,and aggressiveness. Intraspecific competition was found to be more harmful than interspecific competition for both crop and weed species