Average net nitrification rate in glyphosate-free and glyphosate-treated soils under two fertilization histories over a 15-days incubation period at 22°C.

<p>Different letters indicate a significant difference according to Tukey HSD test (<i>P</i> < 0.05). CK: glyphosate-free, FR: field rate, 100FR: 100 × field rate, N+: N-fertilized for 6 years, N0: unfertilized for 6 years.</p

Summary of the measured effects of glyphosate application / nitrogen history combinations on soil biological and chemical parameters at 15 days following glyphosate application in the laboratory incubation.

<p>Effects of treatments on variables are coloured by green as positive, and red as negative while the absence of clear effect was coloured by blue. DH: dehydrogenase activity, AlP: alkaline phosphatase activity, URE: urease activity, AWCD: average well color development, <i>H</i>’: Shannon index, PO₄: available phosphorus content, NO₃: nitrate content, NIT: average net nitrification rate.</p

Does nitrogen fertilization history affects short-term microbial responses and chemical properties of soils submitted to different glyphosate concentrations? - Fig 2

<p><b>Values of (A) average well color development and (B) Shannon diversity index <i>H</i>’ of culturable microbial communities on BIOLOG ecoplates of glyphosate-free and glyphosate-treated soils under two N fertilization histories.</b> Different letters denote significant differences according to Tukey HSD test (<i>P</i> < 0.05) among all fertilization and herbicide treatments at each incubation time (1, 8, 15 days). CK: glyphosate-free, FR: field rate, 100FR: 100 × field rate, N+: N-fertilized for 6 years, N0: unfertilized for 6 years.</p

Soil chemical properties measured at each incubation time (1, 8, 15 days) under two N fertilization histories and three doses of glyphosate application.

<p>Soil chemical properties measured at each incubation time (1, 8, 15 days) under two N fertilization histories and three doses of glyphosate application.</p

Principal component analysis based on correlations between soil microbial and chemical parameters at each incubation time (1, 8, 15 days).

<p>N+\CK: fertilized soils and glyphosate-free (black circles), N+\FR: fertilized soils and field application rate of glyphosate (black triangles), N+\100FR: fertilized soils and 100 times the field application rate of glyphosate (black squares), N0\CK: unfertilized soils and glyphosate-free (white circles), N0\FR: unfertilized soils and field application rate of glyphosate (white triangles), N0\100FR: unfertilized soils and 100 times the field application rate of glyphosate (white squares), DH: dehydrogenase activity, AlP: alkaline phosphatase activity, URE: urease activity, AWCD: average well color development, <i>H</i>’: Shannon index, CEC: cation exchange capacity, TOC: total carbon organic, TN: total nitrogen, Soil.C.N: soil C:N ratio, pH: hydrogen potential, PO₄: available phosphorus content, NO₃: nitrate content, NIT: average net nitrification rate, Moisture: soil moisture.</p

Principal component analysis based on the data of the carbon substrates groups from Biolog EcoPlates at each incubation time (1, 8, 15 days).

<p>N+\CK: fertilized soils and glyphosate-free (black circles), N+\FR: fertilized soils and field application rate of glyphosate (black triangles), N+\100FR: fertilized soils and 100 times the field application rate of glyphosate (black squares), N0\CK: unfertilized soils and glyphosate-free (white circles), N0\FR: unfertilized soils and field application rate of glyphosate (white triangles), N0\100FR: unfertilized soils and 100 times the field application rate of glyphosate (white squares).</p