Simultaneous application of two herbicides and green compost in a field experiment: Implications on soil microbial community

Abstract

Highlights  Effects of herbicides and green compost on soil microbiology were evaluated at field scale  Green compost decreased the dissipation rate of triasulfuron, but no that of prosulfocarb  Combined application of triasulfuron and prosulfocarb modified soil microbial community  Green compost buffered the effects of herbicides on soil microbial activity and

Soil Microbial Community Changes in a Field Treatment with Chlorotoluron, Flufenacet and Diflufenican and Two Organic Amendments

“…No significant changes in DHA were observed simultaneously to the dissipation of herbicides applied as observed in S + H, and a non-significant relationship was found between herbicide residues and DHA values in the amended soils. This was probably due to the combination of herbicides applied with different adsorption and bioavailability rates in the amended soils, and the long persistence of some of them to produce more toxic effects on soil microbial biomass and activity than the single application of individual compounds [3,13]. Previous studies have reported this trend for one of the herbicides used here, namely, diflufenican, which mixed with glyphosate or with mesosulfuron-methyl and iodosulfuron methyl-sodium decreased DHA and other enzymatic activities [18,26].…”

“…This practice is often used to increase crop yields, improve soil quality and fertility, preserve the soil from degradation, mitigate pesticide leaching, and enhance soil microbial activity [6,11]. Organic residues with a potential value are those from agricultural, industrial, and urban activities, such as the composted spent mushroom substrate (SMS) and green compost (GC) [12,13]. The OM of these residues may modify the persistence, dynamics, and environmental fate of herbicides applied to amended soils [14,15].…”

“…Generally, organic amendments alter the biodegradation of pesticides, increasing sorption and reducing bioavailability to microorganisms by introducing exogenous microorganisms with biodegradation abilities, or by modifying soil properties, and consequently changing the structure and activity of native microbiota [13,16]. Some soil properties such as microbial biomass and enzymatic activities and in particular dehydrogenase activity (DHA) are used as bioindicators of changes in the soil after agricultural management practices involving the application of herbicides and organic amendments [6,[17][18][19].…”

“…Little is known about the effects these herbicides and organic residues have on the various groups of soil microorganisms when they are applied jointly. Most of the studies on soil microbial response to pesticides and organic residues have been assessed at laboratory or greenhouse scale [6,14,[22][23][24][25], but only a few assays have been performed at field scale [13,19]. Moreover, only one study has been found in the literature that refers to the impact on soil microbial activity of the combined application of the herbicide chlorotoluron with organic residues under field conditions [11].…”

Real‐time monitoring of greenhouse gas emissions with tall chambers reveals diurnal N2O variation and increased emissions of CO2and N2O fromMiscanthusfollowing compost addition

“…While some authors have reported no response (see Maughan et al, ; Teat, Neufeld, Gehl, & Gonzales, ), recently the balance of evidence suggests that fertilizer increases yields (Chen et al, ; Wang, Smyth, Crozier, Gehl, & Heitman, ; Xu, Gauder, Gruber, & Claupein, ). Emissions of the powerful greenhouse gas (GHG) nitrous oxide (N 2 O), derived from N fertilizer, are the biggest source of GHGs from agriculture after livestock methane (CH 4 ; FAO, ), and the use of fertilizer and composts can also lead to increased soil respiration ( R s ; Garcia‐Delgado et al, ; Ozlu & Kumar, ) and CH 4 emissions (Fernandez‐Luqueno et al, ; Thangarajan, Bolan, Tian, Naidu, & Kunhikrishnan, ), two other important components of a net GHG balance. Previous work has shown that GHG emissions, and especially N 2 O fluxes, from Miscanthus are much lower than conventional crop rotations (Drewer, Finch, Lloyd, Baggs, & Skiba, ), and this is key to its viability as a bioenergy crop (Whitaker et al, ).…”