ABSTRACT The objective of this study was to investigate the acidic soil physical and chemical alteration associated to vinasse application under laboratory conditions. The experiment was distributed in a factorial scheme (5 × 3), in a completely randomized design, with four replicates. The beneficial effects of five vinasse doses (without vinasse [0, only water], 50, 100, 150, and 200 m3/ha) in enhancing the physical and chemical properties of three acidic soils: Oxisol (SO), Ultisol (SU), and Argisol (SA) were studied after 30 days of incubation. Soil samples were collected in the 0-20 cm depth layer to determine physical and chemical properties such as pH (CaCl2), total acidity (AT), exchangeable acidity (Al3+), base cations (K+, Ca2+, and Mg2+), sums of bases (SB), cations exchange capacity (CIC), base saturation index (V%), and saturation of potassium (K), calcium (Ca), magnesium (Mg), and aluminum (Al). Results indicated that vinasse application enhanced the physical and chemical properties of the studied soils, since pH, base cations, SB, CIC, V%, and saturation of K, Ca, and Mg were increased, while AT, Al3+, and Al saturation were decreased. The most important effects in the improvement of physical and chemical properties of acidic soils were observed with a dose of 200 m3/ha of vinasse. The findings of this study suggest that vinasse could be a low-cost effective strategy as an alternative source for balancing soil acidity and would be an appropriate option for minimizing environmental pollution.

RESUMEN El objetivo de este estudio fue investigar las alteraciones físicas y químicas de los suelos ácidos asociadas a la aplicación de vinaza en condiciones de laboratorio. Los efectos beneficiosos de cinco dosis de vinaza (sin vinaza [0, solamente agua], 50, 100, 150 y 200 m3/ha), fueron estudiadas en el mejoramiento de las propiedades físicas y químicas de tres suelos ácidos: Oxisol (SO), Ultisol (SU) y Argisol (SA), después de 30 días de incubación. Las muestras de suelos fueron recolectadas en la capa de 0-20 cm de profundidad para la determinación de propiedades físicas y químicas como pH (CaCl2), acidez total (AT), acidez intercambiable (Al3+), cationes bases (K+, Ca2+ y Mg2+), suma de bases (SB), capacidad de intercambio catiónico (CIC), índice de saturación de las bases (V%), y saturación de potasio (K), calcio (Ca), magnesio (Mg) y aluminio (Al). Los resultados indicaron que la aplicación de vinaza mejoró las propiedades físicas y químicas de los suelos estudiados, porque se incrementaron tanto el pH como los cationes bases, la SB, la CIC, el V% y la saturación de K, Ca y Mg, y disminuyeron la AT, Al3+ y saturación de Al. Además, los efectos más importantes en el mejoramiento de las propiedades físicas y químicas de los suelos ácidos se observaron en la dosis de 200 m3/ha de vinaza. Los hallazgos de este estudio sugieren que la vinaza podría ser una estrategia efectiva de bajo costo como fuente alternativa para balancear la acidez del suelo y constituiría una opción apropiada para disminuir la contaminación ambiental.

The diamondback moth, Plutella xylostella (L.), is the most important pest of brassicaceous crops worldwide. Since temperature is the major abiotic factor influencing insect development and thermal requirements may vary among insect populations, it is important to know the effect of temperature on development and survival of a subtropical strain of P. xylostella. Development and survival of the diamondback moth was evaluated under seven constant temperatures ranging from 10°C to 35°C. Development was completed between 10°C and 32.5°C, but at 35°C all individuals died in the larval stage. Data were fitted to one linear and five nonlinear models. Considering as criteria the goodness of fit and the ability to estimate parameters of biological significance, the models Briere-1 and Briere-2 were the most adequate to describe the relationship between temperature and development of P. xylostella. The linear model demonstrated that P. xylostella required 312.5 degree-days above a lower threshold of 6.3°C to complete development. The degree-day model showed that the number of diamondback moth generations in the tropical region of Brazil is nearly twice the number in the subtropical region of the country. This result explains, at least in part, the higher population levels of this species in the tropical region of Brazil, and also demonstrates that P. xylostella is tolerant to a wide range of temperatures (6.1-32.5°C). Therefore, temperature cannot be considered a limiting factor for the occurrence of diamondback moth throughout the year in most regions of Brazil.