Non-target effects of pretilachlor on microbial properties in tropical rice soil

Abstract

The use of herbicides has been questioned in recent past for their non-target effects. Therefore, we planned to study the effect of pretilachlor on growth and activities of microbes in tropical rice soil under controlled condition at National Rice Research Institute, Cuttack, India. Three pretilachlor treatments, namely, recommended dose at 600 g a.i. ha(-1) (RD), double the recommended dose at 1200 g a.i. ha(-1) (2RD), and ten times of the recommended dose at 6000 g a.i. ha(-1) (10RD) along with control, were imposed. The initial residue (after 2 h of spray) deposits in soil were 0.174, 0.968, and 3.35 μg g(-1) for recommended, double the recommended, and ten times of the recommended doses, respectively. No residue in soil was detected in RD treatment on day 45. The half life values were 16.90, 17.76, and 36.47 days for RD, 2RD, and 10RD treatments, respectively. Application of pretilachlor at 10RD, in general, had significantly reduced the number of bacteria, actinomycetes, fungi, nitrogen fixers, and microbial biomass carbon. Pretilachlor at RD did not record any significant changes in microbial properties compared to control. The results of the present study thus indicated that pretilachlor at RD can be safely used for controlling grassy weeds in rice fields.

Evaluation of soil health in organic vs. conventional farming of basmati rice in North India

“…Plenty of microbial substrates (C and nutrients) in composts can facilitate microbial population build up ( Witter and Kanal , ) and further stimulate them to produce enzymes responsible for the conversion of unavailable to an available form of nutrients ( Yadav et al, ). Conversely, application of agrochemicals reduced enzyme activities due to lack of microbial substrates which is also supported by other studies ( Saha et al, , ; Sahoo et al, , ).…”

Effects of fenclorim on rice physiology, gene transcription and pretilachlor detoxification ability

“…The safener fenclorim (4, 6-dichloro-2-phenylpyrimidine, Fen) was developed to reduce the injury to rice (Oryza sativa L.) caused by chloroacetanilide herbicides. To ensure the safety of early stage rice, Fen is often formulated with pretilachlor [2-chloro-2′, 6′-diethyl-N-(2propoxyethyl) acetanilide, Pre], which is one of the most widely used herbicides in rice fields in southeast Asian countries, but Pre represents phytotoxicity risk to rice [16]. Fen protects rice from injury by Pre mainly due to the acceleration of the metabolism of Pre [17].…”

Evaluation of Side Effects of Pre-Plant Incorporated Herbicides on The Population of Root-Knot Nematode in Cucumber Plants Under Field Conditions الأثار الجانبیة لبعض مبیدات الحشائش على نیماتودا تعقد الجذور Meloidogyne javanicaالتی تصیب نباتات الخیار فی ظروف الحقل المفتوح

“…So the mutual influence of nematode and weed management have many ways, based on understanding of the link between them (Kumar et al, 2017) which the most widely recognized is by providing plant parasitic nematodes with additional substrate is alternative hosts his alternative host seduces the efficacy of management techniques designed to lower plant-parasitic nematode populations and there by enhances crop in jury that is proportional to the size of the nematode population (Riggs, 1992 ). Other directed effects of weeds include protection of certain nematodes from pesticides or the environment (Schroeder et al, 1993 andThomas et al, 2005), nematode suppression by antagonistic weeds or by the incorporation of weed biomass into soil (Yeates et al, 1999), and perhaps through host-induced change in future nematode biotic potential (Thomas et al 1997), or as the chemicals added to the soil environment can be said it changed the nature of the soil through the temperature and humidity may reflected negatively on the population of plant parasitic nematodes as a one of soil bio-community in soil (Sahoo et al, 2016). In this study results showed the variation and difference in the effect of tested pre-plant incorporated herbicides on root-knot nematode outside the usual pattern of the developmental stages population during the life cycle , so if excepting the difference in the active ingredient materials perhaps due to most it have a deleterious effect by enhancing populations or the adaptability plant parasitic nematodes (Westwood et al, 2010), or below-ground weed biomass may help protect endoparasites from pesticides and the factors of environment (Norris, 2005), which corresponds with Browde et al, (1994) and (Riggs and Oliver, 1982), where reported that positive effecting of herbicides in plant parasitic nematodes reduction and referred to inconsistencies in its herbicide's ability to influence in some different stages of life.…”