This work aimed at evaluating the influence of different levels of aluminum on the physiological parameters of the citrus rootstock Swingle Citrumelo in hydroponic solution. The experiment was carried out with a completely randomized design with three replications, subdivided in several lots. The levels of aluminum used were: 0, 7.5, 15, 22.5 and 30 mg L-1 in form of AlCl3.6H2O in nutrient solution. Following physiological parameters were evaluated: specific and relative foliar area, relative foliar mass, and the ratio of aerial part dry matter/root system dry matter. The results showed that aluminum did not influence the parameters evaluated except the specific foliar area, which decreased starting at the 7.5 mg L-1 level.

The objective was to verify the performance of spectral techniques as well as validation models in the prediction of nitrogen, total organic carbon, and humic fractions under different cultivation conditions. Chemical analyses for the determination of nitrate, total nitrogen, total organic carbon, and the chemical fractionation of soil organic matter were performed, as well as spectral analyses by Vis-NIR-SWIR and X-ray fluorescence. The results of the spectroscopy were processed using RStudio v. 4.1.3, and PLSR and support vector machine learning algorithms were applied to validate the models. The Vis-NIR-SWIR and XRF spectroscopic techniques showed high performance and are indicated for the prediction of nitrogen, total organic carbon, and humic fractions in Ferralsols of medium sandy texture. However, it is important to highlight that each technique has its own characteristic mechanism of action: Vis-NIR-SWIR detects the element based on harmonic tones, while XRF is based on the atomic number of the element or elemental association. The PLSR and SVM models showed excellent validation results, allowing them to fit the experimental data, emphasizing that they are different statistical methods.

Swine wastewaters (SW) present organic load and nutrient content, what have caused degradation of water quality in many watercourses. Thus, the aquatic macrophytes represent an alternative for the depollution of these wastewaters, due to the high recovery power. The aim of this study was to evaluate the performance of the Eichhornia crassipes (Mart.) Solms, Pistia stratiotes L. and Salvinia auriculata Aubl. in improving the physicochemical targets of SW, as well as to quantify the total ammoniacal nitrogen (NH4+) and total phosphorus (total P) in the plant tissue of the macrophytes and the dry matter biomass (DMB) in two seasons of the year (spring and winter). The experiment was designed in a randomized block design, with 4 treatments (T) with 4 replicates: T1 = Control (without plants); T2 = E. crassipes; T3 = P. stratiotes; and T4 = S. auriculata, submitted to a SW diluted in 50% water. The monitoring is done in tanks during a period of 30 days of each season. Electrical conductivity (EC), dissolved oxygen (DO), turbidity, NH4+ and dissolved phosphorus (P) were analyzed in the SW. In the plants, the contents of NH4+, total P and DMB were determined. It was verified that, in the spring, the plants showed higher production of DMB and a more significant reduction of EC, NH4+ and P, when compared to the plants managed in the SW in the winter. E. crassipes was more efficient at removing P (39%) and total NH4+ (80.2%), and EC reducing (92%) of SW and DMB production in the spring. The results demonstrated that the NH4+ uptake by E. crassipes contributed to a considerable removal of NH4+ and P from SW.

Soils of tropical regions are more weathered and in need of conservation managements to maintain and improve the quality of its components. The objective of this study was to evaluate the availability of K, the organic matter content and the stock of total carbon of an Argisol after vinasse application and manual and mechanized harvesting of burnt and raw sugarcane, in western São Paulo.The data collection was done in the 2012/2013 harvest, in a bioenergy company in Presidente Prudente/SP. The research was arranged out following a split-plot scheme in a 5x5 factorial design, characterized by four management systems: without vinasse application and harvest without burning; with vinasse application and harvest without burning; with vinasse application and harvest after burning; without vinasse application and harvest after burning; plus native forest, and five soil sampling depths (0-10 10-20, 20-30, 30-40, 40-50 cm), with four replications. In each treatment, the K content in the soil and accumulated in the remaining dry biomass in the area, the levels of organic matter, organic carbon and soil carbon stock were determined. The mean values were compared by Tukey test. The vinasse application associated with the harvest without burning increased the K content in soil layers up to 40 cm deep. The managements without vinasse application and manual harvest after burning, and without vinasse application with mechanical harvesting without burning did not increase the levels of organic matter, organic carbon and stock of total soil organic carbon, while the vinasse application and harvest after burning and without burning increased the levels of these attributes in the depth of 0-10 cm.

O trabalho foi desenvolvido com o objetivo de avaliar o acúmulo de Pb no tecido vegetal de mucuna preta (Mucuna aterrima Piper & Tracy.) em solo contaminado e verificar o potencial de remediação do solo. As plantas foram cultivadas em vasos com capacidade para 9 dm3 de solo. Os tratamentos consistiram em adição nos recipientes de 18,8 mg kg-1; 37,5 mg kg-1; 75 mg kg-1; 150 mg kg-1; 300 mg kg-1; 600 mg kg-1 e 1.200 mg kg-1 de Pb na forma de (Pb(NO3)2). Os tratamentos foram distribuídos de acordo com delineamento estatístico inteiramente casualizado. Amostras do solo e do tecido vegetal foram coletadas noventa dias após a semeadura para a quantificação das massas das matérias secas da parte aérea e raízes para a determinação do acúmulo de chumbo nos tecidos vegetais. Os parâmetros avaliados foram submetidos à análise de variância avaliando-se o efeito dos tratamentos pelo teste de Tukey a nível de 5% de probabilidade. Os resultados significativos apresentados pelo Teste F foram submetidos à regressão polinomial. As plantas de mucuna preta apresentaram maior acúmulo de Pb em sua parte aérea, em função da massa de matéria seca produzida; não houve alteração significativa na produção da massa de matéria seca das raízes e da parte aérea em função das doses de Pb no solo; as plantas de mucuna preta manejadas com a dose de 1.200 mg kg-1 de Pb no solo acumularam o maior teor de Pb tanto na parte aérea quanto nas raízes.

O objetivo do presente estudo foi caracterizar matérias-primas e biocarvões produzidos em condições de laboratório, além de fornecer informações referentes a viabilidade de uso do biocarvão no solo. Assim, numa primeira etapa o biocarvão foi produzido a partir da amostra seca de biossólido (BP) e de bagaço de cana-de-açúcar (BCP), por meio da pirólise lenta a temperatura de 350°C por 30 minutos. Numa segunda etapa foi realizado a caracterização das matérias-primas e seus respectivos biocarvões. Foi utilizado um delineamento com cinco repetições, sendo que os tratamentos foram constituídos por: biossólido puro; bagaço de cana-de-açúcar puro; biocarvão de biossólido (BB); biocarvão do bagaço de cana-de-açúcar (BBC). Onde a avaliação dos resíduos foi por meio das análises de: rendimento de massas, imediatas, potencial hidrogeniônico, capacidade de troca catiônica, teor de nutrientes, espectrometria de fluorescência de raio x, bromatológica, densidade e tamanho de partículas. Os dados obtidos foram submetidos à análise de variância (ANOVA) pelo programa SISVAR. Para comparação de médias, foi utilizado o teste de Tukey a 5% de probabilidade (p<0,05). Conclui-se que tanto as matérias-primas quanto os biocarvões, produzidos por pirólise lenta a 350ºC, apresentaram características propícias para o uso agrícola, principalmente em termos de fertilidade.