O objetivo do estudo foi identificar e descrever os sintomas visuais em mudas de tomate para processamento industrial, decorrentes da carência individual de macronutrientes e avaliar atributos biométricos nessa fase, bem como seu estado nutricional. O experimento foi conduzido em estufa agrícola, em blocos casualizados, com oito tratamentos e quatro repetições. Os tratamentos foram: solução nutritiva completa; soluções com omissão individual dos nutrientes N, P, K, Ca, Mg e S; e solução apenas com água deionizada. As sementes foram semeadas em bandejas com substrato e posteriormente transplantadas para bandejas com espuma fenólica. Diariamente aplicavam-se as soluções nutritivas. Durante 30 dias foram realizadas análise descritivas e registros da evolução dos sintomas de deficiência nutricional. Aos 30 dias após a semeadura, foram obtidas a leituras do Indice Relativo de Clorofila, altura, diâmetro do caule e o número de folhas das mudas dos híbridos (N901 e H9553) de tomate industrial e a parte aérea das mudas foram armazenadas para a determinação da matéria seca. As omissões promoveram alterações morfológicas, caracterizadas por sintomas visuais de deficiência nutricional, sendo a omissão de N, água deionizada e Ca os primeiros a apresentar os sinais de carência. As deficiências dos nutrientes N e Ca foram as mais limitantes para o desenvolvimento das mudas de tomate industrial. A carência de N e de Mg foram as que mais afetaram o IRC. O clorofilômetro pode ser utilizado para avaliar o estado nutricional das mudas de tomate industrial.

The objective of this work was to evaluate the effects of nitrogen fertilizers on the N dynamics and grain yield in flooded rice (Oryza sativa) cultivation in Brazilian tropical wetland. The experiment was carried out in a randomized complete block design with six treatments, as follows: common and protected urea; topdressing application of N doses (30, 70, and 150 kg ha-1); and one control treatment, without N fertilization. Emissions of N2O-N, global warming potential (pGWP), emission factors (EF) for mineral fertilizers, grain yield, emission intensity, nitrate, ammonium, pH, and potential redox were quantified. Gas sampling was carried out in two crop seasons of rice cultivation and in one off-season. During the flooded period of the two crop seasons, N2O fluxes did not exceed 862.41 μg m-2 h-1 N2O-N; in the off-season, the fluxes varied from -52.95 to 274.34 μg m-2 h-1 N2O-N. Consistent emission peaks were observed in soil draining before harvest, when the highest rate of both N sources was used, and also in the control treatment in the off-season. Protected urea does not reduce N2O emissions or EF. Nitrogen increases the grain yield. Protected urea does not have any effect on the pGWP. The concentrations of NO3- and NH4+ in the soil are not related to N2O fluxes.

The manganese (Mn) is an important nutrient to forage development; however, there is a lack of information regarding to adequate Mn-fertilizer rates for Guinea Grass (Panicum maximum) species growing in Brazilian soils. The objective of this research was to evaluate the effect of Mn on growth, nutrition and yield of Guinea Grass. The study was carried out under greenhouse conditions in a randomized block design, with five Mn rates (0, 15, 30, 60 and 120 mg dm -3 ) and four replicates, using manganese sulfate (35.5% Mn) as Mn source. Plant's growth parameters, dry mass production, Mn 2+ levels and accumulation in plant's tissues were measured and Mn efficiencies of absorption, transport and utilization were calculated. Enhancing Mn doses, there was a proportional increase of Mn 2+ levels in the leaves and the roots. Regarding to the growth parameters, the number of leaves and both root and aboveground dry mass were slightly affected by Mn application. The highest Mn efficiency of absorption and transport by Guinea Grass was ob using 30 mg dm -3 of Mn; however, the Mn utilization efficiency was higher when Mn was not applied. In this way, the Mn fertilization in Guinea Grass is economically viable using doses up to 30 mg dm -3 .