Leandro Bortolon

Use of High-Yielding Bioenergy Plant Castor Bean (Ricinus communis L.) as a Potential Phytoremediator for Copper-Contaminated Soils

Abstract Copper (Cu) contamination in the environment has been increased during the years with agricultural and industrial activities. Biotechnological approaches are needed for bioremediation in these areas. The aims of this study were i) to evaluate the phytoremediation capacity of the high-yielding bioenergy plant castor bean (Ricinus communis L.) in vineyard soils (Inceptisol and Mollisol) contaminated with Cu and a Cu mining waste; ii) to characterize the castor bean as a Cu phytoremediation plant; and iii) to evaluate the nutrient uptake by castor bean. Castor bean plants cultivated in soil with toxic levels of Cu for 57 d exhibited high phytomass production, a high tolerance index of roots fresh mass and shoots dry mass, a high level of Cu phytoaccumulation in the roots and also, a robust capacity for Cu phytostabilization. Furthermore, castor bean plants did not significantly deplete soil nutrients (such as N, P, and Mg) during cultivation. Plants cultivated in Inceptisol, Mollisol and Cu mining waste exhibited a strong potential for Cu phytoaccumulation, with values of 5 900, 3 052 and 2 805 g ha−1, respectively. In addition, the castor beans elevated phytomass production and strong growth in Cu-contaminated soils indicated a high level of Cu phytoaccumulation and a potential application in biofuels. These findings indicate that the castor bean is a efficient hyperaccumulator of Cu and a potential candidate plant for the phytoremediation of Cu-contaminated soil.

Multielement Extraction from Southern Brazilian Soils

To evaluate the effectiveness of multielement extraction of Mehlich 1 and Mehlich 3 solutions in soils from southern Brazil, correlation studies are needed. The amounts of phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), copper (Cu), and zinc (Zn) extracted with Mehlich 1 solution, 1.0 M potassium chloride (KCl), and 0.1 M hydrochloric acid (HCl) for representative soil types of the Rio Grande do Sul state (Brazil) were compared with those extracted with Mehlich 3 solution. The amount of nutrients extracted with different methods indicated high correlation coefficients. On average, Mehlich 3 solution extracted greater amounts of P (50%) and K (20%) than Mehlich 1 solution. Calcium amounts extracted with all solutions were similar. Magnesium amounts extracted with Mehlich 3 solution were on average 20% less than the amounts extracted with 1.0 M KCl solution. Mehlich 3 solution extracted similar amounts of Cu as the 0.1 M HCl but lesser amounts of Zn. Simultaneous multielement soil-test methods such as Mehlich 1 and Mehlich 3 solutions are efficient in soils from southern Brazil and are a feasible alternative to improving the efficiency of soil-testing laboratories.

Caracterização, potencial agrícola e perspectivas de manejo de solos leves no Brasil

Light soils occupy 8% of the Brazilian territory and are especially expressive in the new and last agricultural frontier in Brazil: the Matopiba region – in the states of Maranhão, Tocantins, Piauí, and Bahia –, where they represent 20% of the area. These soils fit into the textural classes of sand and loamy sand or sandy loam, down to 0.75-m soil depth or deeper, and they are mainly represented by Neossolos Quartzarênicos (Quartzipsamments) and, partly, by Latossolos (Oxisols) and Argissolos (Ultisols). The understanding of soil functioning depends on the establishment of distinguishing criteria for: organic matter dynamics; content and mineralogy of the clay fraction; coarse sand and total sand contents, in relation to those of fine sand; mean diameter of the sand fraction; and water retention capacity. These criteria can contribute for the zoning and for the conservation and fertility management of light soils, as well as for the estimation of their agricultural potential. Integrated production systems, such as crop-livestock and crop-livestock-forestry integration, besides no-tillage with crop rotation, mixed forestry planting with legumes, and the use of green manure and cover crops are relevant for the proper management of these soils. The objective of this review was to characterize light soils and to highlight the main challenges regarding their agricultural potential and their conservation and fertility managements, in face of the expansion and consolidation of the new Brazilian agricultural frontier.

Evaluation of two Brazilian indigenous plants for phytostabilization and phytoremediation of copper-contaminated soils

Indigenous plants have been grown naturally and vigorously in copper contaminated soils. Thus, the aim of this study was to evaluate the phytoremediation ability of two indigenous plants naturally grown in two vineyard soils copper contaminated, and in a copper mining waste. However, it was evaluated the macro and micronutrient uptake and the potential of phytoremediation. So, a greenhouse study was carried out with Bidens pilosa and Plantago lanceolata in samples of vineyard soils (Inceptisol and Mollisol) copper contaminated, and in a copper mining waste. Plant growth, macro and micronutrient up take, tolerance index (TI), translocation factor (TF), metal extraction ratio (MER), bioaccumulation factor (BCF), plant effective number of the shoots (PENs), and plant effective number of the total plant (PENt) were analyzed. Both plants grown in vineyard soils showed high phytomass production and TI. P. lanceolata plants cultivated in the Inceptisol showed the highest copper concentrations in the shoots (142 mg kg-1), roots (964 mg kg-1) and entire plants (1,106 mg kg-1). High levels of copper were phytoaccumulated from the Inceptisol by B. pilosa and P. lanceolata with 3,500 and 2,200 g ha-1 respectively. Both B. pilosa and P. lanceolata plants showed characteristics of high copper hyperaccumulator. Results showed that both species play an important role in the natural copper phytoaccumulation in both vineyard soils contaminated with copper, being important to its phytoremediation.

Phytoremediation of vineyard copper-contaminated soil and copper mining waste by a high potential bioenergy crop (Helianthus annus L.).

Phytoremediation is a helpful technique to remediate copper-contaminated areas. The aim of this study was to evaluate sunflower phytoremediation capacity in two vineyard copper-contaminated soils (Inceptisol and Mollisol) and a copper mining waste. Nutrient uptake, copper phytoaccumulation, translocation factor (TF), and bioaccumulation factor (BCF) of sunflower were evaluated after 57 days of growth. Plants grown in both the Mollisol and Inceptisol soils showed high plant height. Fresh biomass was high in the Mollisol in the shoots and roots and also demonstrated the highest values on the tolerance index (TI). The BCF after growth in all three of the copper contaminated soils as Inceptisol, Mollisol, and copper mining waste showed reduction of this index value to 0.19, 0.24, and 0.03, respectively against native soil (Mollisol under natural conditions (4.71). Sunflowers have some important characteristics such as high phytomass production, copper phytoaccumulation, and potential use to biofuel. Thus, sunflower is a potential candidate to phytoremediation of vineyard copper-contaminated soils.

DECOMPOSIÇÃO DE RESÍDUOS INDUSTRIAIS NO SOLO

Waste disposal in soils is an efficient alternative to reduce environmentalnegative impact of industrial wastes and can be used as an important nutrientssource for the plants. Thus, the aim of this study was to evaluatethe decomposition rate of four industrial wastes applied in two differentsoils (Oxisol and Ultisol). The industrial wastes of treatment station were:(brewery – CERV; dairy products – LAT; plywood – AGL and textile – TEXT).It was evaluated the decomposition of the doses of these wastes throughthe microbial activity and N mineralization. The organic wastes evaluatedcan be used in agricultural soils, although, should be used nitrogen as additionalfertilization. The rate of the decomposition of the wastes in the bothevaluated soils, for the C-CO2 release and for the N accumulation in thesoils, increased in the following order: TEXT >LAT>CERV>AGL.

Produção de palha e desempenho agronômico de soja consorciada com espécies forrageiras em sistema plantio direto

The objective of this work was to evaluate the straw production and the agronomic performance of soybean intercropped with oversown forage species, in no-tillage system. A randomized complete block design was carried out with four replicates, in a 5×2+2 factorial arrangement, as follows: five forage species – Urochloa brizantha Marandu, Urochloa ruziziensis, Panicum maximum Mombaça, Panicum maximum Massai, and Pennisetum americanum –, intercropped with soybean over two crop years (2013/2014 and 2014/2015), plus two controls, with P. americanum sowed in succession to soybean or with soybean monocropping followed by winter fallow (traditional cultivation). Soybean yield components and forage straw yield were evaluated. None of the intercropping systems reduced soybean grain yield, compared with monocropped soybean. The oversown species can significantly improve soybean productivity, as is the case for soybean intercropped with P. maximum Mombaça, compared with soybean monocropping, followed or not by millet. Panicum maximum Mombaça is the most effective forage species for dry matter accumulation in the fall/spring period.

Fósforo remanescente para determinar a disponibilidade de fósforo em solos do Rio Grande do Sul

The objective of this work was to evaluate remaining P compared with soil clay content as a P buffer index to classify P extracted by the Mehlich-1 (M1) and Mehlich-3 (M3) methods in soils from the state of Rio Grande do Sul, Brazil. The experiment was carried out in a completely randomized design with five P2O5 rates (0, 50, 100, 200, and 400 mg kg-1) and two sucessive corn crops, and three replicates, in 20 representative soils of the state. P extracted by M1 and M3 before crop planting was adjusted to P contents in biomass, considering soil buffer capacity. The division of soils into different buffering classes, based on soil clay or remaining P, improved the capacity of estimating soil available P of both methods. However, there was no difference among the correlation coefficients obtained by classifying soils according to the evaluated indexes (remaining P or soil clay) for both M1 and M3 methods. Remaining P is a viable alternative to replace soil clay content to classify soil P extracted with the M1 and M3 methods.

Carbon Balance at the Regional Scale in Southern Brazil Estimated with the Century Model

Modeling of soil organic C (SOC) dynamics associated with GIS can be useful to estimates C emissions and sequestration as a function of the changes in the land use and soil management. A balance of C emissions and sequestration was made at the regional scale using the Century model and GIS. Santana district in Ijui, RS (28° 20′S and 53° 53′W) was selected where occur Hapludox, Orthents, Argiudolls, and Fluvents are common. We identified four homogeneous areas based on cropping systems, soil tillage systems, and native vegetation. These areas were converted into agriculture at different times. Soil samples were taken at 0–20 cm depth. The Century model was calibrated and validated based on the sampled areas and their estimates were generalized. We defined different simulation units that are similar zones in soil class, landscape elements (hilltops, slope, and depositional areas) and time of agricultural use (1901, 1957, 1965, 1976, and 1988). The agriculture use caused a 50 % reduction in SOC stocks from 1900 to 1986 (from 550.9 to 276.8 Mg × 103), by the end of most intensive soil management period, which corresponded to emissions of 2,277.5 × 103 Mg of CO2 into the atmosphere. Moreover the adoption of conservation agriculture management in 1987 enabled the recovery of C content of the soil. It is considered for 2007, compared with the original, recovery of the SOC stock in up to 60 % (337.7 × 103 Mg) when the soil C balance was positive in 276.5 × 103 Mg of CO2. These results shows the CO2 potential emission to the atmosphere by the forests removal and burning, as well as the potential of soil C sequestration by the adoption of soil conservation tillage systems. Century model adequately estimated the evolution of SOC stocks and CO2 balance due to the use, land use changes, and soil management.

Adjustment of the expedite method for clay content determination in Rondônia soils

Soil clay content is an important soil attribute and has been used to classification of phosphorus status in the soil in order to determinate the needing of phosphorus amounts to be applied to crops production. The aim of this research was to adjust the method for soil clay content determination, adopted by the laboratories of Southern Brazil (ROLAS-RS/SC), for soil clay content evaluation in Rondonia soils. The study was conducted using 50 soil samples from Rondonia State with wide range clay content. It was tested shaking periods (1.5, 2.0 and 2.5h) associated with periods for soil particles decantation (1.5 and 2.0h) to correlate with the standard method for soil texture testing, known as the pipette method. Clay content determined through this method was significantly correlated with pipette method. The better treatment was the combination of 2.0h of shaking and 1.5h of decantation, resulted in total period of 3.5h, which reduced the period to determine the soil clay content without loss of accuracy.