Cácio Luiz Boechat

Industrial and urban organic wastes increase soil microbial activity and biomass

Microbial processes have been used as indicators of soil quality, due to the high sensitivity to small changes in management to evaluate, e.g., the impact of applying organic residues to the soil. In an experiment in a completely randomized factorial design 6 x 13 + 4, (pot without soil and residue or absolute control) the effect of following organic wastes was evaluated: pulp mill sludge, petrochemical complex sludge, municipal sewage sludge, dairy factory sewage sludge, waste from pulp industry and control (soil without organic waste) after 2, 4, 6, 12, 14, 20, 28, 36, 44, 60, 74, 86, and 98 days of incubation on some soil microbial properties, with four replications. The soil microbial activity was highly sensitive to the carbon/nitrogen ratio of the organic wastes. The amount of mineralized carbon was proportional to the quantity of soil-applied carbon. The average carbon dioxide emanating from the soil with pulp mill sludge, corresponding to soil basal respiration, was 0.141 mg C-CO2 100 g-1 soil h-1. This value is 6.4 times higher than in the control, resulting in a significant increase in the metabolic quotient from 0.005 in the control to 0.025 mg C-CO2 g-1 Cmic h-1 in the soil with pulp mill sludge. The metabolic quotient in the other treatments did not differ from the control (p < 0.01), demonstrating that these organic wastes cause no disturbance in the microbial community.

Efeito das interações entre os íons amônio e nitrato na fisiologia do crescimento do amendoinzeiro

Peanut is a crop of great importance for the Northeast region, as it is usually grown by small farmers, who on average, do not exceed 10 ha of cultivated area and aim to increase its profitability and diversify the production. This study aimed to evaluate the effect of the relationship between nitrogen forms (ammonium and nitrate) in the initial growth of peanuts. Complete nutrient solution was used with a single concentration of 210 mg N L-1 provided in five proportions of NH4+:NO3-: 100:0, 75:25, 50:50, 25:75 and 0:100. The experimental units were arranged in completely randomized design, with four replications. The variables evaluated were: shoot length, root length, leaf number, stem diameter, fresh and dry shoot and fresh weight and dry root. The 100:0, 75:25 and 50:50 ratio resulted in decreasing peanut phytomass by ammonium toxicity. However, the 0:100 ratio, nitrate caused a smaller decreased compared to reductions in the highest ammonium concentrations. In the 25:75 and 0:100 ratio, plants grow normally with higher phytomass. The supply of nitrogen in the NH4+ form only is not a good option for the nutrition of peanuts in early growth stages.

Treated Industrial Wastewater Effects on Chemical Constitution Maize Biomass, Physicochemical Soil Properties, and Economic Balance

ABSTRACT Irrigation with treated wastewaters can improve nutrient levels and yield of crops planted on degraded soils. This study evaluated how irrigation with treated industrial wastewater affected biomass production and nutrition of maize plants and physio-chemical properties of a degraded soil. The experiment was conducted in a greenhouse using PVC columns. Treatments consisted of 8 treatments irrigated with clean water and increasing doses of N and P, and 8 treatments with 4 proportions of wastewater irrigation (25%, 50%, 75% and 100% v/v). In general, maize biomass did not differ between irrigation water sources. Differences were largely associated with N nutrition. We observed increases in concentrations of N, P, K, S, Mn, Na, Cu, and Zn in tissue of maize under irrigation with wastewater. The addition of treated wastewater increased the P and Na concentrations, and EC values in the soil without affecting clay dispersion in water. An associated economic analysis indicated that wastewater irrigation would not be economically feasible without including environmental benefits. In southern Brazil, the proportion of irrigation water that is wastewater should not exceed 50%.

Heavy Metals and Nutrients Uptake by Medicinal Plants Cultivated on Multi-metal Contaminated Soil Samples from an Abandoned Gold Ore Processing Site

Heavy metal extraction from soils is one of the functions of plants which is widely studied and applied worldwide. However, little is known to what extent medicinal plants can accumulate these metals and cause problems to human health. This study aimed to evaluate the accumulation of heavy metal/loid in plant tissues, nutritional imbalance, and the effect of heavy metal concentrations in soil on the medicinal plants. The experiment was conducted in a factorial scheme with three contaminated soil samples and a soil sample from an uncontaminated field and three medicinal species: Cynara scolymus, Ocimum basilicum, and Rosmarinus officinalis. The heavy metal content in the biomass increased with increasing soil samples concentration. Biomass production, nutritional imbalance by nutrients did not show consistent results according to soil contamination criteria and are not good indicators of heavy metals presence in plant tissues, since they did not allow predicting the presence of metal in the plants, due to the different behavior of elements and plant species. There was a high concentration of Cd, Cr, Pb, and As and micronutrients Fe, Zn, and Cu in the plant tissues, above the limits recommended by the World Health Organization. Therefore, as the components of C. scolymus, O. basilicum, and R. officinaliss are used to prepare teas, condiments, or consumed raw, coupled with the ability of such species to concentrate toxic metals, the continued use of these plant products containing these metals can pose a potential health concern.

Agua salobre: una opción para la producción de Capsicum annuum hidropónicos en flujo laminar de nutrientes minerales

Sweet pepper plants were grown using a Nutrient Film Technique (NFT) hydroponic system. This study aimed to evaluate the effect of using brackish water on fruit production. The experiment was carried out in a randomized block design with seven treatments and five replications. The electrical conductivity of the water was 0.29, 1.39, 2.75, 4.49, 5.90, 6.76, and 7.09 dS m -1 in the treatments; this water was used for both the nutrient solution preparation and replenishment of crop evapotranspiration. The plant parameters: fruit diameter, fruit length, number of fruits per plant, mean fruit weight, total fruit weight per plant and fruit length/diameter ratio were evaluated 69 days after the transplanting. The use of brackish water with high electric conductivity values did not directly interfere with the sweet pepper production in NFT hydroponic systems, as long as these values did not exceed the sweet pepper salt tolerance of 1.5 to 1.8 dS m -1 .

Impact of Treated Industrial Effluent on Physical and Chemical Properties of Three Subtropical Soils and Millet Nutrition

ABSTRACT The use of treated industrial effluents to irrigate plants is an alternative, because of nutrients that can increase yield of the agricultural crops. This study was conducted to determine irrigation with treated effluent and gypsum application, which changes the chemical and physical characteristics of soils and the growth and nutrition of millet (Pennisetum glaucum). Thus, an experiment was conducted on PVC columns with three soil classes, Typic Hapludox, Typic Hapludult, and Arenic Hapludult. Nutrient and Na+ concentrations in the millet biomass reflected concentrations of elements in the effluent and soil. In the control, low N levels were found in the biomass, while higher leaf N concentrations were observed, due to irrigation with treated effluent. In the short term, irrigation with treated industrial effluent by controlled application could be an alternative and a complementary source of nutrients for plants, reducing the volume of nutrients and organic materials discharged into water bodies.

Changes in physiological qualities of castor bean seeds caused by herbicides.

Ricinus communis is a highly weed-sensitive crop, and this competition generates reduced economic yields. The use of herbicides may be a viable alternative. However, herbicides may become phytotoxic to germination processes and plant growth. In this study, we aimed to evaluate the selectivity and efficiency of herbicides that inhibit cell division and photosynthesis, respectively, in castor culture. We used a completely randomized block experimental design with four replications. Treatments consisted of control (manual weeding), 2.4 and 4.0 L ha of Diuron herbicide, and 5.0 and 7.0 L ha of Alachlor herbicide. We concluded that Diuron can be recommended to castor bean culture; however, Alachlor is not recommended because it affects the germination process and reduces the emergence speed of castor bean seedlings. Alterações na qualidade fisiológica de sementes de mamoneira provocadas por herbicidas Changes in physiological qualities of castor bean seeds caused by herbicides Adaílton Conceição dos Santos1 Cácio Luiz Boechat2* José Carlos de Cerqueira Moraes3 Maria de Fátima da Silva Pinto Peixoto1 Lucas De Oliveira Ribeiro1 1Universidade Federal do Recôncavo da Bahia – UFRB, Centro de Ciências Agrárias, Ambientais e Biológicas, Campus Universitário, 44380-000, Cruz das Almas, BA, Brasil 2Universidade Federal do Rio Grande do Sul – UFRGS, Faculdade de Agronomia, Av. Bento Gonçalves, 7712, Agronomia, 91540-000, Porto Alegre, RS, Brasil 3Colégio Estadual Alberto Torres, Secretaria Estadual de Educação, Rua Rui Barbosa, Centro, 44380-000, Cruz das Almas, BA, Brasil Autor Correspondente: *E-mail: clboechat@hotmail.com PALAVRAS-CHAVE Planta daninha Fitotoxicidade Germinação Ricinus communis L.