Modeling Herbicide Bioconcentration Factor in Sugarcane Juice

Ciência Rural, 2015

Sugarcane is an important crop for sugar and biofuel production in Brazil. Growers depend greatly on herbicides to produce it. This experiment used herbicide physical-chemical and sugarcane plant physiological properties to simulate herbicide uptake and estimate the bioconcentration factor (BCF). The (BCF) was calculated for the steady state chemical equilibrium between the plant herbicide concentration and soil solution. Plantwater partition coefficient (sugarcane bagasse-water partition coefficient), herbicide dilution rate, metabolism and dissipation in the soil-plant system, as well as total plant biomass factors were used. In addition, we added Tebuthiuron at rate of 5.0kg a.i. ha -1 to physically test the model. In conclusion, the model showed the following ranking of herbicide uptake: sulfentrazone > picloram >tebuthiuron > hexazinone > metribuzin > simazine > ametryn > diuron > clomazone > acetochlor. Furthermore, the highest BCF herbicides showed higher Groundwater Ubiquity Score (GUS) index indicating high leaching potential. We did not find tebuthiuron in plants after three months of herbicide application.

Chemical control is used to restrain the attack of weeds on cultivated crops in Brazil; however, the overuse of chemical products can cause damage to the crops. This study aimed to evaluate the phytotoxicity caused by pre-emergence (PRE) and post-emergence (POST) herbicides in sugarcane cultivars and their influence in agronomic and technological traits as well as to verify the existence of correlation between the herbicides effect and the measured traits. The experiment was carried out in a randomized complete block design with three replications, considering the factorial combination of five sugarcane cultivars and five control strategies, being four herbicides and one control. The sensitivity was evaluated at 30, 60 and 90 days after application, through a scale of intoxication symptoms. The herbicides with active ingredients diuron + hexazinone and ametryn presented more phytotoxicity effect; the cultivars RB867515 and SP81-3250 showed greater toxicity symptoms when exposed to the agrochemicals. Plant height was the only trait influenced by the herbicides. It was observed a significant correlation between the trait number of stems and phytotoxicity effect.

Journal of Cleaner Production, 2020

The concept of gray water footprint (GWF) was introduced as an indicator of the volume of freshwater required to dilute the total pollutant load, generated from a particular production process, to maintain water quality standards. In crop production, for example, the theoretical calculation of the GWF can be employed as a sound tool for assessing the environmental impacts due to the use of pesticides. In this context, we compared two models for estimating the GWF of pesticide mixtures applied to the soil in a sugarcane crop, in Pernambuco, Brazil. One model was proposed by Hoekstra et al. (2011) and calculates the GWF based on the maximum concentration limit acceptable in water. The other one was designed by Paraiba et al. (2014) and employs the concept of Concentration Addition. This latter model also takes into account the effect of toxicity of pesticide mixtures on aquatic organisms and water quality, considering the characteristics of the soil and cultivation data obtained through the field and physical-chemical tests pesticides used in agricultural activities. The model of Paraiba et al. (2014) has shown to be more conservative in determining the GWF of the pesticide mixtures (2.00 Â 10 7 m 3 ha À1) in the aquatic ecosystem, than the model of Hoekstra et al. (2011) (6.25 Â 10 5 m 3 ha À1 for Sulfentrazone). The results presented and discussed in this study reinforce the use of the GWF as an indicator of water quality for agricultural sustainability. Our work also contributes to a better understanding of the advantages and limitations of each model approach in the assessment of the volume of freshwater needed to dilute the contaminant load in agriculture activities as, for instance, in sugarcane crops.

Revista Brasileira de Tecnologia Aplicada nas Ciências Agrárias, 2013

Reduction of spraying rate can be an alternative to reduce costs in pesticide application. The aim of this study was to evaluate the distribution of fan and droplet size with different spraying rate and concentration of adjuvant on spraying liquid of herbicide to control Ipomoea spp. on sugarcane crop. The experiment was carried out at fully randomized plots, 3 x 4 + 1 factorial scheme. The factors were application volumes (80, 130 and 180 L ha-1) preemergence application of herbicide sulfentrazone, and concentrations of adjuvant (0; 0.5; 1.5 and 4.5%). The variables were: Angle of the jet spray (degrees), flow of nozzles (L min-1), coefficient of variation of fan distribution (CV), volume median diameter (VMD), coefficient of uniformity for static nozzles (SPAN), drift (percentage of volume in droplets smaller than 200 microns) and control of Ipomoea spp. (%), analyzed with statistical process control tool (CEP). The reduction of spraying volume did not change the control of Ipomoea spp. and have resulted in standardization of the droplet size when the concentration of adjuvant in spraying liquid was bigger than 1.5%.

Journal of Sohag Agriscience (JSAS) (Print), 2017

The present study was carried out at Kom-Ombo Agricultural Research Station Farm, Aswan Governorate, Agricultural Research Centre, Giza, Egypt, to evaluate the herbicide treatments on different weed species in sugarcane fields and their control methods on yield and quality of sugarcane. The obtained results revealed that, the weed species observed in the sugarcane field were twelve weed species belonging to nine families. Out of them three species belong to the broad leaved perennial weeds (Convolulus arvensis L., Sesbania sesban L., and Ipomoea cairica L.) while six species belong to the broad-leaved annual weeds (Hibiscus trionum L. , Corchorus sp, Euphorbia geniculate L., Portulaca oleraceae L. , Sida alba L., and Datura stramonium L.) were observed. The grass perennial weeds were presented by two species (Cyperus rotundus L. , and Cynodon dactylon L.), while only one grass annual weed species were found (Digitaria sanguinalis L.). Weed control treatments had a significant affected on broad leaved, narrow, and total weeds (g/m 2) in both seasons. The application of herbicides affected the weed type and density but the response of different types of weeds varied to different herbicides. In addition, weeds control by herbicides treatments had a significant effect on cane, and sugarcane yield , brix, sucrose , purity and sugar recovery percentages in sugarcane .

Chemosphere, 2007

The model presented allows simulating the pesticide concentration evolution in fruit trees and estimating the pesticide bioconcentration factor in fruits. Pesticides are non-ionic organic compounds that are degraded in soils cropped with woody species, fruit trees and other perennials. The model allows estimating the pesticide uptake by plants through the water transpiration stream and also the time in which maximum pesticide concentration occur in the fruits. The equation proposed presents the relationships between bioconcentration factor (BCF) and the following variables: plant water transpiration volume (Q), pesticide transpiration stream concentration factor (TSCF), pesticide stem-water partition coefficient (K Wood,W ), stem dry biomass (M) and pesticide dissipation rate in the soil-plant system (k EGS ). The modeling started and was developed from a previous model ''Fruit Tree Model'' (FTM), reported by Trapp and collaborators in 2003, to which was added the hypothesis that the pesticide degradation in the soil follows a first order kinetic equation. The FTM model for pesticides (FTM-p) was applied to a hypothetic mango plant cropping (Mangifera indica) treated with paclobutrazol (growth regulator) added to the soil. The model fitness was evaluated through the sensitivity analysis of the pesticide BCF values in fruits with respect to the model entry data variability.

Egypt. J. of Appl. Sci., 2019

Field experiments were carried out at El-Mattana Research Station (latitude of 25.25°N and longitude of 32.31°E), Agricultural Research Center, Luxor Governorate, Egypt, in plant can and 1st ratoon crops grown during 2016/2017 and 2017/2018 seasons to study the effect of different herbicides and hand hoeing on weeds in sugarcane varieties (G.T.54-9, G.2003-47 and G.2003-49) .The treatments were Starane (fluroxypyr 20 % EC) and Lumax (s-metalachlor +atrazine + mesotorine 53.75 % WP) applied as pre-emergence ,whereas Garlon (triclopyr 20 % EC) and Clomedy (clomazone 50 % EC) applied as post-emergence and hand hoeing twice at 30 and 45 days after planting in comparison with untreated control. Obtained results showed that the predominant broad-leaved weeds were Atropa belladonna, convolvulus arvensis, Corichorius olitorius, Euphorbia astiqourumand and portulaca oliricea, in sugarcane field during the two studied seasons. Results also indicated that all the tested herbicides and hand hoeing significantly gave high weed control efficiency of weeds as well as highest increase in cane growth, yield and quality of sugarcane over untreated control. Among the tested herbicidal treatments , Lumax, Garlon and Starane showed maximum herbicidal activity against broad-leaved weeds, improve cane growth, and increase yield and quality of sugarcane varieties in sugarcane field than the other treatments compared to weedy check.

The Bioscan, 2016

The study was carried out during the spring seasons of 2011-12 and 2012-13 to the effect of sequential application of herbicides on weeds and productivity of spring planted sugarcane (Saccharum officinarum L.). Results showed that the minimum weed density at 90 DAP, weed control efficiency (94.53%) at 90 DAP and weed index were significantly highest with conventional practice (three hoeings) at 30, 60 and 90 DAP. Weight of millable cane, cane yield (135.32 t/ha), green tops yield, trash yield, biological yield and harvest index were found highest under conventional practice (three hoeings) at 30, 60 and 90 days after planting of sugarcane. Among the herbicides, the sequential application of ametryne @ 2.4 kg a.i./ha at 30 DAP fb 2,4-D @ 1.0 kg a.i./ha at 60 DAP of sugarcane observed as the second best treatment with lower weed density at 90 DAP, weed control efficiency (85.61%) at 90 DAP weed index (8.61%) and cane yield (123.66 t/ha).

Chemosphere, 2008

We presented a model that estimates the bioconcentration factor (BCF) of pesticides in potatoes supposing that the pesticide in the soil solution is absorbed by the potato by passive diffusion, following Fick's second law. The pesticides in the model are nonionic organic substances, traditionally used in potato crops that degrade in the soil according to a first-order kinetic equation. This presents an expression that relates BCF with the pesticide elimination rate by the potato, with the pesticide accumulation rate within the potato, with the rate of growth of the potato and with the pesticide degradation rate in the soil. BCF was estimated supposing steady state equilibrium of the quotient between the pesticide concentration in the potato and the pesticide concentration in the soil solution. It is suggested that a negative correlation exists between the pesticide BCF and the soil sorption partition coefficient. The model was built based on the work of Trapp et al. . Diffusion of PAH in potato and carrot slices and application for a potato model. Environ. Sci. Technol. 41 (9), 3103-3108], in which an expression to calculate the diffusivity of persistent organic substances in potatoes is presented. The model consists in adding to the expression of . Diffusion of PAH in potato and carrot slices and application for a potato model. Environ. Sci. Technol. 41 (9), 3103-3108] the hypothesis that the pesticide degrades in the soil. The value of BCF suggests which pesticides should be monitored in potatoes.

VOLUME 17, Nº 02 ABR./JUN., 2018

À luz de uma perspectiva ético-filosófica cosmopolita e solidarista de mundo, o presente ensaio visa analisar a questão dos refugiados e dos migrantes traçando diretrizes teóricas ao assunto clarificar a posição dos refugiados e migrantes como não só importantes atores sociais, mas, sobretudo, como sujeitos de direito que são. Após, visa verificar como tais vertentes vem sendo aplicadas na prática cotidiana do Brasil. As fontes usadas foram o tripé jurídico doutrina-legislação-jurisprudência, com destaque para o uso de documentos teóricos outros, especialmente da seara das Relações Internacionais, como base teórica necessária ao entendimento aprofundado do assunto