Biochar on Soil Chemical Properties and Beak Pepper (<i>Capsicun chinense</i>) Production

The transformation and recycling of poultry litter through the pyrolysis process produces a co-product called biochar which, applied to the soil, improves the chemical characteristics of the soil and is used as a soil fertilizer due to its high content of nutrients to plants. The objective of this study was to assess the effect of biochar, produced from poultry litter wastes on soil chemical properties and the culture of the beak pepper (Capsicun chinense). For this, the experimental units, corresponding to plastic vessels, were prepared with 5 kg of soil mixed with increasing doses of biochar: 0;2.5;5.0;7.5 and 10 t∙ha−1, with three replications. This material (soil + biochar) was incubated for 20 days keeping the humidity close to the field capacity. After this period, soil samples from the experimental units were collected and then chemically analyzed. The seedlings of pepper were produced in a greenhouse and transplanted to the experimental units when the seedlings were 15 cm tall. After 10 days of transplanting, thinning was done, leaving a plant/vessel. Biometric variables were analyzed at 120 DAS, after fruit harvesting: plant height (PH), stem diameter (SD), fresh shoot biomass (FSB), fresh fruit biomass (FFB), dry biomass of the aerial part (DSB) and the fruits (DFB). The results were submitted to analysis of variance and regression by orthogonal polynomials using the statistical program SISVAR. Biochar improved the soil chemical properties using as an acidity corrective and source of nutrients, mainly phosphorus and potassium. The doses used, in general, favored the development and production of the beak pepper, increasing the fresh shoot biomass, the fresh and dry fruit biomass. To improve the soil chemical properties, the highest biochar dose is recommended, that is, 10 ton∙ha−1, however, this dose can harm the production of pepper fruits, so for this crop 5 ton∙ha−1 should be recommended.

Crambe (<i>Crambe abyssinica</i>) Cultivation under Different Levels of Fertilization with Nitrogen, Phosphorus and Potassium

The effects of fertilization on crambe are poorly understood;in this sense, this study aimed to evaluate the crambe growth under different levels of nitrogen (0, 40, 80, 120 kg&#183;ha-1), phosphorus (0, 50, 100, 150 kg&#183;ha-1), and potassium (0, 30, 60, 90 kg&#183;ha-1) in a greenhouse. The height of the plants, the production of dried biomass and that of 1000 grains of crambe were evaluated. The height of the plants was impaired as a function of increasing doses of nitrogen. The interaction of nitrogen and phosphorus in the crambe crop increased the number of grains and dry shoot biomass. The growth and yield of the crop were not influenced by the use of potassium in mineral fertilization.

Influence of Bentonite and MB4 on the Chemical Characteristics of an Oxisol

The growing concern with the quality of life and the environment, due to the degradation of natural resources and their contamination, mainly with agrochemicals, led to the emergence of a sustainable or alternative agriculture. The objective of this study was to evaluate the effect of the addition of increasing doses of bentonite and MB4 on the availability of nutrients to the soil. The experiment consisted of a 4 × 4 factorial, bentonite doses (0, 30, 60 and 90 t&#8901;ha&#8722;1) and MB4 doses (0, 3, 6 and 9 t&#8901;ha&#8722;1) with three replications. The soil mixtures with the treatments were conditioned in the plastic pots, incubated for 90 days in a greenhouse, and chemically analyzed. Data were submitted to analysis of variance and comparison of means by the Tukey test. Increasing doses of bentonite and MB4 promoted an increase in the calcium (Ca), magnesium (Mg) in the soil sample either alone or the mixture of two factors, except for the mixture of the Ca Mg doses. Increasing doses of bentonite increased the cation exchange capacity of the soil, favoring the availability of nutrients in the soil. The increasing doses of MB4 favored the increase of the pH values and, consequently, decreased the soil potential acidity values for the applied bentonite doses. On the other hand, these treatments decreased the cation exchange capacity of the soil.

Effect of Copper, Zinc, Cadmium and Chromium in the Growth of Crambe

Crambe is a promising crop for biodiesel production. However, there is no much information available about techniques and research regarding the best performance in different regions to explore its potential. The objective of this study was to evaluate the effect of cadmium, chromium, copper and zinc in the development of crambe. The study was carried out in a greenhouse and it consisted of four independent experiments in completely randomized design, with three replications. Four metals with five levels were applied: 0, 10, 15, 20 and 25 mg·kg-1 for copper, cadmium, chromium;and 0, 20, 30, 40 and 50 mg·kg-1 for zinc, in order to evaluate the growth of crambe. Data were subjected to analysis of variance and comparison of means by Tukey test at 1 and 5% significance. Despite doses of cadmium, chromium, copper and zinc in growing crambe have influenced in some of the evaluated variables of the plants, in general, their development was similar in relation to doses and the metals applied. The importance of cultivating crambe is related to grain production, based on this, copper and cadmium decreased this production.

Bentonite Effects on Zinc Concentration in Plants Irrigated with Wastewater

A greenhouse study was conducted to investigate the effect of bentonite on zinc concentrations in radish and corn irrigated with wastewater. The experimental units were plastic pots with a capacity of 5 kg and 14 kg for radish and corn, respectively. The soil was mixed with increasing doses of bentonite equivalent to 0,?30,?60 and 90 t·ha-1. The plants were irrigated with poor quality water with a concentration of 5 mg·L-1?Zn. On the occasion of the harvest of radish and corn, that is, at 30 and 60 days after the emergence, respectively, the plants were separated in aerial part and roots, dried in a forced circulation oven, weighed and ground for analysis of zinc in the plant tissues. After these analyzes, the translocation factor (TF), the translocation index (TI), the bioaccumulation in the plant (BFP) and in the root (BFR) were calculated. According to the conditions of this research, the incorporation of bentonite to the soil irrigated with water of inferior quality favored the development of radish and corn;allowed the retention of the Zn metal in the soil, reducing the concentrations of this metal in the root of the radish and in the aerial part of the corn;decreased the transfer of zinc from the soil to the plants under study.