Table 1.
Chemical and physical properties of the experimental soils.
Table 2.
Diuron herbicide rates as the commercial product (Nufarm- Diurex WG 900 g kg-1) (g ha-1) and their equivalent rates of active ingredient (a.i., mg kg-1 soil) applied to loamy sand (bulk density-1.4 g cm-3) and washed sand (bulk density-1.6 g cm-3).
Table 3.
Analysis of variance results (mean sum of squares and significance) for the effect of soil types, crop species, and diuron doses on plant and their interactions on crop growth responses.
Table 4.
Plant biomass and growth inhibition (%) relative to control at the recommended application rate of diuron.
Value are means of three replicates ± SE (n = 3).
Fig 1.
A. Diuron dose–response curves in sand for root biomass inhibition of chickpea. Regression lines were calculated by using four-parameter log-logistic model (LL.4), three and four-parameter Weibull type 2 (W2.3 and W2.4) models, and three-parameter log-logistic model (LL.3). P values larger than 0.05 represented better fitting of the models by lack-of-fit test. B. Comparison of sigmoid models for estimation of diuron effective dose values (ED20 and ED50). Bars on each column represent standard error.
Fig 2.
Diuron dose–response curves in sand and loamy sand determined after 28 days for shoot and root dry biomass bioassay for: (A, D) canola, (B, E) chickpea, and (C, F) wheat. Regression lines were calculated by using four-parameter log logistic model and the parameter values are shown in Table 5.—Diuron residue level estimated in Western Australia paddocks [30]. L.R—Label rate.
Fig 3.
Diuron dose–response curves in sand and loamy sand determined after 28 days for shoot and root length bioassay for: (A, D) canola, (B, E) chickpea, and (C, F) wheat. Regression lines were calculated by using four-parameter log logistic model and the parameter values are shown in Table 5.—Diuron residue level estimated in Western Australia paddocks [30]. L.R—Label rate.
Table 5.
Herbicide doses corresponding to 20 and 50% plant growth reduction of canola, chickpea, and wheat.