Effect of diazotrophic bacterium inoculation and organic fertilization on yield of Champaka pineapple intercropped with irrigated sapota.

The purpose of this study was to evaluate the response of the Champaka pineapple to inoculation with the diazotrophic bacterium Asaia bogorensis (strain 219) when grown with organic fertilizer in an irrigated sapota orchard. Plantlets were transplanted to tubes containing a mixture of worm compost and vermiculite and inoculated with 108 bacterial cells. After five and a half months of acclimatization the plantlets were transplanted in furrows in the sapota orchard. Fertilizer was placed at the bottom of the furrows and covered with three doses (2.5; 5.0 and 7.5 L linear m−1 row) of three organic composts. The successful association of the plantlets with the diazo-trophic bacterium was confirmed by most probable number analysis before transferring to the field. Plants inoculated with strain AB219 showed the greatest initial leaf growth and produced the heaviest fruits compared to uninoculated plants. Plant growth and fruit yield increased with increasing compost dosages. The results suggested that Champaka pineapple benefited from the association of A. bogorensis (strain 219) when grown under irrigation and with organic fertilizer.

Alleles of organic acid transporter genes are highly correlated with wheat resistance to acidic soil in field conditions.

2016

Degradation and sorption of fipronil and atrazine in Latossols with organic residues from sugarcane crop.

ABSTRACT: Organic residues from sugarcane crop and processing (vinasse, boiler ash, cake filter, and straw) are commonly applied or left on the soil to enhance its fertility. However, they can influence pesticide degradation and sorption. The objective of this study was to assess the effect of adding these organic residues on the degradation and sorption of fipronil and atrazine in two soils of the State of Mato Grosso do Sul, MS, Brazil. The degradation experiment was carried out with laboratory-incubated (40 days; 28°C; 70% field capacity) soils (0-10cm). The batch equilibration method was used to determine sorption. Fipronil (half-life values of 15-105 days) showed to be more persistent than atrazine (7-17 days). Vinasse application to the soil favored fipronil and atrazine degradation, whereas cake filter application decreased the degradation rates for both pesticides. Values for sorption coefficients (Kd) were determined for fipronil (5.1-13.2mL g-1) and atrazine (0.5-1.5mL g-1). Only straw and cake filter residues enhanced fipronil sorption when added to the soil, whereas all sugarcane residues increased atrazine sorption. RESUMO: Resíduos orgânicos do cultivo e processamento da cana-de-açúcar (vinhaça, cinzas, torta de filtro e palha) são usualmente aplicados ou deixados no solo para aumentar sua fertilidade, mas eles podem influenciar na degradação e sorção de agrotóxicos. O objetivo deste estudo foi avaliar o efeito da adição desses resíduos orgânicos no solo sobre a degradação e sorção do fipronil e da atrazina em dois solos no Estado de Mato Grosso do Sul, MS, Brasil. O experimento de degradação foi realizado com solos (0-10cm) incubados em laboratório (40 dias; 28°C; 70% da capacidade de campo). Para determinar a sorção, foi usado o método da batelada. Fipronil mostrou ser mais persistente (valores de meia-vida entre 15-105 dias) que atrazina (7-17 dias). O solo com adição de vinhaça favoreceu a degradação de fipronil e atrazina, enquanto adição da torta de filtro desacelerou o processo. Os valores do coeficiente de sorção (Kd) foram determinados para fipronil (5,1-13,2mL g-1) e atrazina (0,5-1,5mL g-1). Apenas os resíduos palha e torta de filtro aumentaram a sorção de fipronil quando adicionados ao solo, enquanto todos os resíduos aumentaram a sorção de atrazina.