Effect of Fall-Applied Residual Herbicides on Rice Growth and Yield

Abstract

Glyphosate-resistant (GR) Italian ryegrass is one of the most troublesome weeds in Mississippi row crop production. Fall-applied residual herbicide applications are recommended for control of GR Italian ryegrass. However, carryover of residual herbicides applied in fields for rice production can have a negative impact on rice performance. Field studies were conducted in Stoneville, MS, to determine the effects of fall-applied residual herbicides on rice growth and yield. Herbicide treatments included suggested use rates (1×) of clomazone at 840 g ai ha–1, pyroxasulfone 170 g ai ha–1,S-metolachlor 1,420 g ai ha–1, and trifluralin 1,680 g ai ha–1, and two times (2×) the suggested use rates in the fall before rice seeding. Pooled across application rate, pyroxasulfone,S-metolachlor, and trifluralin injured rice to an extent 28% to 36% greater than clomazone 14 d after emergence (DAE). Rice seedling density and height 14 DAE and rice maturity were negatively affected by all fall-applied herbicides except clomazone. Applications at 2× rates reduced rough rice yields in plots treated with pyroxasulfone,S-metolachlor, and trifluralin compared with clomazone. Pyroxasulfone applied at the 2× rate reduced rough rice yield 22% compared with the 1× rate. Rough rice yield was 90% or greater of the nontreated control in plots treated with either rate ofS-metolachlor, and these were comparable with rough rice yields from plots treated with both rates of trifluralin and the 1× rate of pyroxasulfone. Early-season injury and reductions in seedling density and height 14 DAE, would preclude even 1× applications of pyroxasulfone,S-metolachlor, and trifluralin from being viable options for residual herbicide treatments targeting GR Italian ryegrass in the fall before rice seeding. Of the herbicides evaluated, only clomazone should be utilized as a fall-applied residual herbicide treatment targeting GR Italian ryegrass before seeding rice.

Persistence of S-metolachlor in the soil as affected by moisture content

“…In another study of field conditions, injury of rice plants from 9 to 30% was verified in the 2010-11 and 2011-12 season (Lawrence et al, 2018). In this study, the residual period of S-metolachlor was 185 and 190 days (2010-11 and 2011-12 seasons, respectively), and soil moisture was close to the water holding capacity condition (Lawrence et al, 2018).…”

Efficacy of fall-applied residual herbicides on weedy rice control in rice (Oryza sativa L.)

“…The most significant rice injury was observed in response to the high rates of acetochlor and pyroxasulfone, which caused 10% and 20% injury, respectively (Table 3). Lawrence et al (2018) also observed rice injury after fall applications of pyroxasulfone, although to a greater extent. Reduced pyroxasulfone injury in the current study was likely because herbicide applications were made on September 28 and October 9 in 2016 and 2017, respectively, in comparison to an early November application in the Lawrence et al (2018) study, which may have allowed more herbicide degradation before planting rice.…”

“…However, these application timings also pose significant risk to growers because severe crop injury can result when rainfall occurs soon after application. Lawrence et al (2018) evaluated the effect of fall-applied clomazone, pyroxasulfone, S-metolachlor, and trifluralin on rice growth and yield. At 14 d after emergence (DAE), rice seedling density and height were negatively affected by all herbicides except clomazone.…”

Multifunctional β-Cyclodextrin MOF-Derived Porous Carbon as Efficient Herbicides Adsorbent and Potassium Fertilizer

“…On the basis of previous study, the amide herbicides have been frequently detected in the aqueous environment, and the residue metolachlor could cause harm for rice seedlings, which is a typical crop needing plenty of water from irrigation. 34 In this work, four amide herbicides were chosen as typical pollutants in agricultural wastewater to explore the adsorptive removal performance of β-CD MOF-NPC.…”