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
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
The present work aimed to evaluate the effect of different water stress levels on the development of both rice and barnyardgrass. The study was established into greenhouse, in completely randomized design, in factoria...The present work aimed to evaluate the effect of different water stress levels on the development of both rice and barnyardgrass. The study was established into greenhouse, in completely randomized design, in factorial scheme 2 × 5, with four replications. Factor “A” comprised the plant species (rice cv. BRS Querência, or the weed Echinochloa crusgalli), and factor “B” comprised the water stress levels: (T1) continuous flood (CF);(T2) 0 kPa (saturated soil);(T3) 10 kPa;(T4) 40 kPa;and (T5) 100 kPa. Plant emergence was assessed every day;plant length was measured 30 days after planting. At the end of the experiment, the number of leaves per plant, root length and shoot and root dry mass were determined. Our data supply evidence that under moderate water stress, up to approximately 40 kPa, rice tends to perform better than barnyardgrass in the initial stage of crop growth, when under equivalent plant density. However, barnyardgrass is usually present in much higher plant density than crop plants in fields traditionally cropped with rice. Thus, efficient control of barnyardgrass should be accomplished to avoid damage to rice crop by competition for environmental resources.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.
文摘The present work aimed to evaluate the effect of different water stress levels on the development of both rice and barnyardgrass. The study was established into greenhouse, in completely randomized design, in factorial scheme 2 × 5, with four replications. Factor “A” comprised the plant species (rice cv. BRS Querência, or the weed Echinochloa crusgalli), and factor “B” comprised the water stress levels: (T1) continuous flood (CF);(T2) 0 kPa (saturated soil);(T3) 10 kPa;(T4) 40 kPa;and (T5) 100 kPa. Plant emergence was assessed every day;plant length was measured 30 days after planting. At the end of the experiment, the number of leaves per plant, root length and shoot and root dry mass were determined. Our data supply evidence that under moderate water stress, up to approximately 40 kPa, rice tends to perform better than barnyardgrass in the initial stage of crop growth, when under equivalent plant density. However, barnyardgrass is usually present in much higher plant density than crop plants in fields traditionally cropped with rice. Thus, efficient control of barnyardgrass should be accomplished to avoid damage to rice crop by competition for environmental resources.
