The crop yield is related to several factors, among these, soil tillage, soil compaction and crop rotation. This study aimed to evaluate the winter cover crops and crop rotation influence on soil physical properties a...The crop yield is related to several factors, among these, soil tillage, soil compaction and crop rotation. This study aimed to evaluate the winter cover crops and crop rotation influence on soil physical properties and grain yield of dry beans, maize and soybean for two growing seasons. Three experiments were conducted, corresponding to dry beans, maize and soybean crops. It was used the randomized block design with three treatments and four replications consisted by 3 × 10 m plots. The treatments were: two cover crops systems and crop rotation in no-till, and the control, consisting of winter fallow and conventional tillage. The cover crop dry matter, soil physical properties and grain yield for dry beans, maize and soybean in the two growing seasons were evaluated. Crop rotation systems and cover crops showed a trend to increase maize and soybean yields. Crop rotation in no-till increases soil compaction in the superficial layer compared to conventional tillage, but does not reduce the dry beans, maize and soybean yields.展开更多
Competition between crops and weeds interfere on growth and development with harm to one or both, in different ways. To quantify these differences in competition, additive and replacement series study methods are most...Competition between crops and weeds interfere on growth and development with harm to one or both, in different ways. To quantify these differences in competition, additive and replacement series study methods are most often used, each with different characteristics and goals. Therefore, we aimed with this work to study inter-specific competition between plants of soybean and corn against the weeds Bidens pilosa (beggartick) and Digitaria insularis (sourgrass), by two experimental methods of study: additive and replacement series (substitutive) experiments. Initial tests were performed prior to the installation of replacement series experiments to describe the intra-specific competition features for all species. For additive experiments these are unnecessary. To compare the methods of study, there were two sets of trials (an additive and a substitutive) installed under greenhouse, during the growing season 2013/14. Variables analyzed were leaf area and dry weight of shoots of crops and weeds, at 50 days after emergence. The results were analyzed according to the methods used, these being compared. It was found that the additive method supplied results most prone to be applied in the field, while the replacement series (substitutive) method was more appropriate for studies that aimed to provide detailed scientific information regarding the proportions of plants and coefficients describing the behavior of the species community.展开更多
The erva-mate (Ilex paraguariensis) represents an alternative crop for agricultural exploitation in South Brazilian farms with potential to export the harvested product. However, there is scarce information about the ...The erva-mate (Ilex paraguariensis) represents an alternative crop for agricultural exploitation in South Brazilian farms with potential to export the harvested product. However, there is scarce information about the interference caused by weeds on this crop. The objective of this work was to evaluate the interference of weed species on the morphophysiological and nutritional characteristics of erva-mate. The experiment was installed in greenhouse at the Federal University of Fronteira Sul (UFFS), Campus Erechim/RS, Brazil, in randomized blocks design, arranged in a 4 × 6 factorial scheme, with four replications. In factor A, weed species (Urochloa plantaginea—Alexandergrass, Bidens pilosa—Hairy beggarticks, Ipomoea indivisa—Morning glory and Conyza bonariensis—Hairy fleabane) were allocated, and in B the populations of these species competing with the erva-mate (0, 1, 2, 3, 4 and 5 plants per pot) were considered. The variables evaluated in erva-mate were sub-stomatal CO2 concentration, photosynthetic rate, CO2 consumed, stomatal conductance, transpiration rate, water use efficiency, height, stem diameter, leaf area and shoot dry mass. Concentrations of nitrogen (N), phosphorus (P), calcium (Ca) and magnesium (Mg) were also evaluated. Overall, all weed species and densities among the tested ones harmed the development of erva-mate plants, which was considered as low competitive with weeds.展开更多
文摘The crop yield is related to several factors, among these, soil tillage, soil compaction and crop rotation. This study aimed to evaluate the winter cover crops and crop rotation influence on soil physical properties and grain yield of dry beans, maize and soybean for two growing seasons. Three experiments were conducted, corresponding to dry beans, maize and soybean crops. It was used the randomized block design with three treatments and four replications consisted by 3 × 10 m plots. The treatments were: two cover crops systems and crop rotation in no-till, and the control, consisting of winter fallow and conventional tillage. The cover crop dry matter, soil physical properties and grain yield for dry beans, maize and soybean in the two growing seasons were evaluated. Crop rotation systems and cover crops showed a trend to increase maize and soybean yields. Crop rotation in no-till increases soil compaction in the superficial layer compared to conventional tillage, but does not reduce the dry beans, maize and soybean yields.
文摘Competition between crops and weeds interfere on growth and development with harm to one or both, in different ways. To quantify these differences in competition, additive and replacement series study methods are most often used, each with different characteristics and goals. Therefore, we aimed with this work to study inter-specific competition between plants of soybean and corn against the weeds Bidens pilosa (beggartick) and Digitaria insularis (sourgrass), by two experimental methods of study: additive and replacement series (substitutive) experiments. Initial tests were performed prior to the installation of replacement series experiments to describe the intra-specific competition features for all species. For additive experiments these are unnecessary. To compare the methods of study, there were two sets of trials (an additive and a substitutive) installed under greenhouse, during the growing season 2013/14. Variables analyzed were leaf area and dry weight of shoots of crops and weeds, at 50 days after emergence. The results were analyzed according to the methods used, these being compared. It was found that the additive method supplied results most prone to be applied in the field, while the replacement series (substitutive) method was more appropriate for studies that aimed to provide detailed scientific information regarding the proportions of plants and coefficients describing the behavior of the species community.
文摘The erva-mate (Ilex paraguariensis) represents an alternative crop for agricultural exploitation in South Brazilian farms with potential to export the harvested product. However, there is scarce information about the interference caused by weeds on this crop. The objective of this work was to evaluate the interference of weed species on the morphophysiological and nutritional characteristics of erva-mate. The experiment was installed in greenhouse at the Federal University of Fronteira Sul (UFFS), Campus Erechim/RS, Brazil, in randomized blocks design, arranged in a 4 × 6 factorial scheme, with four replications. In factor A, weed species (Urochloa plantaginea—Alexandergrass, Bidens pilosa—Hairy beggarticks, Ipomoea indivisa—Morning glory and Conyza bonariensis—Hairy fleabane) were allocated, and in B the populations of these species competing with the erva-mate (0, 1, 2, 3, 4 and 5 plants per pot) were considered. The variables evaluated in erva-mate were sub-stomatal CO2 concentration, photosynthetic rate, CO2 consumed, stomatal conductance, transpiration rate, water use efficiency, height, stem diameter, leaf area and shoot dry mass. Concentrations of nitrogen (N), phosphorus (P), calcium (Ca) and magnesium (Mg) were also evaluated. Overall, all weed species and densities among the tested ones harmed the development of erva-mate plants, which was considered as low competitive with weeds.
