Zinc is the micronutrient that presents the greatest response in corn grain production. However, the mode of application and the dose used are decisive factors with respect to fertilizer efficiency in the crop. Thus, ...Zinc is the micronutrient that presents the greatest response in corn grain production. However, the mode of application and the dose used are decisive factors with respect to fertilizer efficiency in the crop. Thus, the objective of the present study was to evaluate the residual effect of zinc application methods and rates on corn nutrition and productivity. The experiment was conducted in the experimental area of the Teaching, Research and Production Farm of the FCAV/UNESP. Soil in the area is classified as dystrophic Dark-Red Latosol (dRL). The experimental setup consisted of a randomized complete block design with four replications. Treatments included three localized Zn doses applied to the soil (planting row);three Zn doses incorporated into the soil at depth of 0 - 20 cm;foliar application, seed application and treatment without addition of Zn. Two evaluations of growth during cultivation were performed. Grain productivity of the crop and the zinc content in soil, leaves and seeds were evaluated. Foliar spraying with Zn simultaneously promoted increased leaf Zn content and basal diameter of the plant. The Zn contents in grains and in the soil, as well as grain yield, were not affected by the Zn application methods or the applied doses. The residual effect of incorporated Zn doses was observed only in the basal diameter and number of leaves at 60 days after emergence.展开更多
Available information of the effects of manganese nutrition on the forage genus Urochloa is scarce. In the context, this study aims to evaluate the tolerance of Urochloa brizantha cv. MG5 to Mn toxicity. The experimen...Available information of the effects of manganese nutrition on the forage genus Urochloa is scarce. In the context, this study aims to evaluate the tolerance of Urochloa brizantha cv. MG5 to Mn toxicity. The experiment was conducted in a greenhouse at the University of the State of Sao Paulo (UNESP) in the city of Jaboticabal, SP. Plants were cultivated in vases (3.5 L) filled with soil according to a completely randomized experimental design comprising of five levels of Mn (0, 15, 30, 60 and 120 mg?dm?3) and four replications and cut in two periods: one is 42 days after sowing and the other is 30 days after the first one. Samples from both cuts were evaluated as to plant height, number of leaves and tillers, dry weight, Mn content and accumulation, and the green index was determined in the last cut. Manganese addition to soil caused an increase in chlorophyll content at the dosage of 68 mg?dm?3 observed in the second plant cut. Dosages of Mn above 15 mg?dm?3 did not induce increases in nutrient accumulation and in the number of leaves in the first and second cuts of the grass, and tillers in the first cut. The highest concentrations of manganese in the shoots did not produce visual symptoms of damage or a decrease in forage productivity demonstrating that Urochloa brizantha cv. MG5 has high tolerance to manganese toxicity.展开更多
文摘Zinc is the micronutrient that presents the greatest response in corn grain production. However, the mode of application and the dose used are decisive factors with respect to fertilizer efficiency in the crop. Thus, the objective of the present study was to evaluate the residual effect of zinc application methods and rates on corn nutrition and productivity. The experiment was conducted in the experimental area of the Teaching, Research and Production Farm of the FCAV/UNESP. Soil in the area is classified as dystrophic Dark-Red Latosol (dRL). The experimental setup consisted of a randomized complete block design with four replications. Treatments included three localized Zn doses applied to the soil (planting row);three Zn doses incorporated into the soil at depth of 0 - 20 cm;foliar application, seed application and treatment without addition of Zn. Two evaluations of growth during cultivation were performed. Grain productivity of the crop and the zinc content in soil, leaves and seeds were evaluated. Foliar spraying with Zn simultaneously promoted increased leaf Zn content and basal diameter of the plant. The Zn contents in grains and in the soil, as well as grain yield, were not affected by the Zn application methods or the applied doses. The residual effect of incorporated Zn doses was observed only in the basal diameter and number of leaves at 60 days after emergence.
文摘Available information of the effects of manganese nutrition on the forage genus Urochloa is scarce. In the context, this study aims to evaluate the tolerance of Urochloa brizantha cv. MG5 to Mn toxicity. The experiment was conducted in a greenhouse at the University of the State of Sao Paulo (UNESP) in the city of Jaboticabal, SP. Plants were cultivated in vases (3.5 L) filled with soil according to a completely randomized experimental design comprising of five levels of Mn (0, 15, 30, 60 and 120 mg?dm?3) and four replications and cut in two periods: one is 42 days after sowing and the other is 30 days after the first one. Samples from both cuts were evaluated as to plant height, number of leaves and tillers, dry weight, Mn content and accumulation, and the green index was determined in the last cut. Manganese addition to soil caused an increase in chlorophyll content at the dosage of 68 mg?dm?3 observed in the second plant cut. Dosages of Mn above 15 mg?dm?3 did not induce increases in nutrient accumulation and in the number of leaves in the first and second cuts of the grass, and tillers in the first cut. The highest concentrations of manganese in the shoots did not produce visual symptoms of damage or a decrease in forage productivity demonstrating that Urochloa brizantha cv. MG5 has high tolerance to manganese toxicity.
