Simazine dynamics in a vineyard soil at Casablanca valley, Chile

Field dissipation, soil movement and laboratory leaching studies were performed to elucidate the effect of two rainfall amounts in the behaviour and environmental fate of simazine under climatic conditions at Casablanca Valley, Chile. Dissipation and soil movement were studied in a field vineyard with a sandy loam soil (Inceptisol; 74.08% sand; 14.87% silt and 11.04% clay). Simazine was applied to bare soil at 2.0 kg AI ha(-1), and its concentration was measured using immunoassay (ELISA) at 0, 10, 20, 40 and 90 days after application under two rainfall amounts, natural field conditions (39 mm) and modified conditions (39 + 180 mm). Simazine leaching was studied using soil core PVC lysimeters (0.9 m height; 0.22 m diameter). Field dissipation data were adjusted with a bi-exponential model. Half-life (DT(50)) values varied between 31.3 (+/-2.5) and 19.0 (+/-4.2) days under natural and modified conditions, respectively. Simazine K(d) varied from 0.42 to 2.15 (K(oc) 32.6-216.2) in the soil profile. Simazine was detected at a 90-cm soil depth in concentrations of 0.0085 (+/-0.0043) mg kg(-1) and 0.0321 (+/-0.001) mg kg(-1) under field and modified conditions, respectively. The maximum simazine leachate concentrations were 0.013 (+/-0.00084) mg litre(-1) (0.012% of total applied simazine) and 0.0084 (+/-0.00082) mg litre(-1) (0.11% of total applied simazine) for field and modified conditions respectively. These data indicate that water quantity has a significant effect on the DT(50) and the amount of simazine that moved through the soil profile, but not on the soil depth reached by this herbicide.     

丙炔氟草胺除草活性及对棉花的安全性

丙炔氟草胺是一种以原卟啉原氧化酶为作用标靶的N-苯基肽酰亚胺类除草剂。为探究其在棉花田的应用前景,通过温室盆栽法对丙炔氟草胺的杀草谱、除草活性及其对棉花的安全性进行了测定。结果表明:丙炔氟草胺对棉田常见阔叶杂草有较好防效,处理剂量为有效成分15 g/hm2时,对马齿苋Portulaca oleracea、反枝苋Amaranthus retroflexus、藜Chenopodium album、小藜Chenopodium serotinum和鳢肠Eclipta prostrata的鲜重防效均高于90%,对野油菜Rorippa indica、苣荬菜Sonchus arvensis、小飞蓬Conyza canadensis、龙葵Solanum nigrum、马唐Digitaria sanguinalis和牛筋草Eleusine indica等的鲜重防效高于80%;丙炔氟草胺对棉田4种常见阔叶杂草马齿苋、反枝苋、龙葵和藜的除草活性均显著高于二甲戊灵;丙炔氟草胺在鲁棉研28号与马齿苋、反枝苋、龙葵和藜之间的选择性指数依次为79.1、38.1、32.1和112.6,均显著高于二甲戊灵的12.0、9.9、5.8和9.2;鲁棉研37号、鑫秋4号与杂草间的选择性指数,与鲁棉研28号的相近。试验结果表明,丙炔氟草胺可作为棉田苗前防除阔叶杂草的候选药剂之一。     

Sorption and desorption of flumioxazin to soil, clay minerals and ion-exchange resin

Flumioxazin adsorption kinetics were described using a Greenville sandy clay loam soil. Adsorption kinetics experiments showed that 72% of total herbicide was absorbed after 1 h of continuous shaking and continued to increase to 78% after 72 h. Flumioxazin adsorption was then tested on seven agriculturally important soils throughout the southern USA. Adsorption isotherms for all soils had K(f) (Freundlich distribution coefficient) values that ranged from 8.8 to 0.4, with many near 1.5. Soil organic matter content was the parameter most highly correlated with flumioxazin adsorption (r(2) = 0.95, P < 0.001). Sorption to clay minerals had K(f) values ranging from 50 for bentonite to 4.7 for kaolinite. However, normalizing K(f) for sorbent surface area revealed that aluminum hydroxide (gibbsite) possessed the greatest flumioxazin sorption per unit area. Sorption to anionic exchange resin (K(f) 676) was greater than cationic exchange resin (K(f) 42). Molecular model calculations were performed to elucidate why sorption was greater to anionic exchangers. These calculations indicated that a region of dense electronegativity exists on the 3-dione moiety of the molecule. This would lead to greater flumioxazin sorption by positively charged surface sites. Desorption isotherms from soil exhibited no effect of hysteresis. Desorption from clay minerals was very rapid and flumioxazin in solution was undetectable after three desorption steps. From these data it was concluded that flumioxazin can become readily available in soil solution with increase in soil water content.     

Effect of long‐term field application of pendimethalin: enhanced degradation in soil

The effect of long‐term application of pendimethalin in a maize–wheat rotation on herbicide persistence was investigated. Pendimethalin was applied at 1.5 kg AI ha⁻¹ separately as one or two annual applications for five consecutive years in the same plots. Residues of pendimethalin were determined by gas chromatography. Harvest‐time residues of the herbicide decreased gradually over the years and at the end of five years less than 3% of applied pendimethalin was recovered from soil as against 18% in the first year. Residues were found distributed in the soil profile up to 90 cm depth at the end of the experiment with peak distribution of 0.03 µg g⁻¹ in the surface layer of soil treated with 10 herbicide applications. The minimum distribution was, however, in the deepest soil (75–90 cm) profile. Some of the metabolites of pendimethalin ie dealkylated pendimethalin derivative, partially reduced derivative and cyclized product were also traced in surface and sub‐surface soils up to 90 cm. A study of the rate of degradation of pendimethalin in field‐treated soils under laboratory conditions revealed faster degradation compared to control soils. Only the surface soil (0–15 cm) showed this enhanced degradation of the herbicide, which could be due to the adaptability of the aerobic micro‐organisms to degrade pendimethalin. Microbes capable of degrading herbicide were isolated, identified and pendimethalin degradation was confirmed in nutrient broth. © 2000 Society of Chemical Industry     

Persistence and movement of terbacil in peach orchard soil after repeated annual applications*

Terbacil (5-chloro-6-methyl-3-butyluracil) residues did not accumulate in peach orchard soil after seven consecutive annual spring applications of the herbicide at the rate of 4.5 kg/ha although carry-over of terbacil from year to year occurred. Terbacil was lost by degradation and leaching and the time required for a 50% decrease in surface soil concentration was 5–7 months in the sandy loam soil. The major part of the residues was found in the upper 15 cm of the soil profile and smaller amounts were detected to a depth of 60 cm. Terbacil leached readily in prepared columns of sandy loam soil in proportion to the amount of water added. The residual levels of terbacil in the orchard were phytotoxic to oats planted 3 years after the last application.     

Persistence and leaching of beta-cyfluthrin in alluvial soil of India

Persistence as affected by rate of application and moisture regimes and leaching of beta-cyfluthrin was studied in alluvial soil under laboratory conditions. The effects of rate of application and moisture regimes on persistence were studied by incubating fortified soil at 0.1, 1.0 and 10.0 mg kg(-1) under air-dry, field capacity and submerged moisture regimes. The initial deposits of 0.09, 1.11 and 10.1 mg kg(-1) dissipated with time and 78.4-100% loss was recorded at 90 days. The half-life values varied from 7.8 to 41.8 days. The rate of dissipation decreased as the rate of application increased under field capacity and submerged conditions. However, under air-dry conditions, the effect was less pronounced, and half-life values showed a reverse trend. Persistence of beta-cyfluthrin under different moisture regimes followed the trend: air-dry > field capacity > submerged. The trend could be attributed to the effect of moisture on number and type of microbes. Leaching was studied in a packed soil column under saturated flow conditions. beta-Cyfluthrin was found to be highly immobile in alluvial soil. No residues were detected in any leachate fraction under the experimental conditions. In column soil, residues were detected at 0-10 cm depth and the major amount (>99%) was recovered from 0-5 cm depth. Although beta-cyfluthrin showed moderate persistence in alluvial soil, the possibility of its leaching to ground water is negligible as a result of its immobility.     

Aminocyclopyrachlor sorption–desorption and leaching in soil amended with organic materials from sugar cane cultivation

The correct application of a new herbicide depends on knowledge concerning its behaviour within the cultivation system. The objective of this study was to evaluate the sorption–desorption process of aminocyclopyrachlor in soils with the addition of three aged organic materials from sugar cane and their transport via leaching. Sugar cane straw (12 t/ha), filter cake (90 t/ha) and vinasse (200 m³/ha) were added to a clayey soil 15, 30 and 60 days before herbicide application. Sorption and desorption were evaluated by the batch equilibrium method. For leaching assessments, the materials were applied to the soil surface. Sorption was relatively low in all treatments (K_d = 0.17–0.41 L/kg), although significantly higher in soil without organic material addition. A negative correlation between herbicide sorption and increased soil base saturation was observed, indicating competition for sorption sites. With the addition of vinasse, 71% of the herbicide reached the leachate, while <50% reached the leachate in the other treatments. Aminocyclopyrachlor availability was not reduced with organic material addition to the soil, which may be favourable for weed control. However, the presence of vinasse leads to the risk of leaching to deeper soil layers than the seed bank.     

莠去津在土壤中的残留动态和淋溶动态

利用HPLC法对土壤中莠去津的残留动态、淋溶动态进行了研究。结果显示,莠去津以有效成分2.25 kg/hm2和4.50 kg/hm2的剂量施用时,在土壤中的半衰期分别为19.1 d和18.1 d,即其半衰期与莠去津的施用浓度无关,属于典型的一级动力学反应。在120 d的玉米生长期中,土壤中莠去津在不断降解代谢的同时,逐渐向深层土壤中淋溶,多数莠去津持留在表层土壤中。施用莠去津27 d后,高浓度处理小区莠去津的淋溶深度超过30 cm,深度为10~15 cm处的土壤在施用后27 d莠去津的浓度最大。同一土壤深度,莠去津在高浓度处理小区的残留量要远高于低浓度处理小区。这些结果显示,减小莠去津的用量可以减少莠去津在土壤中的移动,表明低剂量施用莠去津是保护地下水免受污染的一种有效措施。影响莠去津的淋溶作用的主要因素包括使用量和土壤的理化特性。     

Long-term tillage and crop rotation effects on weed seedbank size and composition

Size and composition of the weed seedbank was assessed after 12 years of application of four tillage systems in two crop rotations. Mouldboard and chisel ploughing at 45 cm, minimum tillage at 15 cm and no tillage were compared in continuous winter wheat and a pigeon bean/winter wheat 2-year rotation. Weed control was based upon post-emergence herbicide application. Weed seedling emergence from soil samples taken at 0–15, 15–30 and 30–45 cm depths was assessed in a non-heated glasshouse for 12 months. The tillage system influenced weed seedbank size and composition to a much greater extent than crop rotation. Total weed seedling density was higher in no tillage, minimum tillage and chisel ploughing plots in the 0–15, 15–30 and 30–45 cm layers respectively. Density in the whole (0–45 cm) layer did not differ significantly among tillage systems. With no tillage, more than 60% of the total seedlings emerged from the surface layer, compared with an average 43% in the other tillage systems. Crop rotation did not influence either weed seedbank size or seedling distribution among soil layers, and only had a small influence on major species abundance. The weed seedbank was dominated (>66%) by Conyza canadensis (L.) Cronq. and Amaranthus retroflexus (L.), which thrived in chisel ploughing and no tillage respectively. Results suggested that crop rotation and substitution of mouldboard ploughing by non-inversion tillage (especially by minimum tillage) would not result in increased weed problems, whereas use of no tillage might increase weed infestations because of higher seedling recruitment from the topsoil.     

覆盖地膜栽培烤烟地的杂草防除研究

作者于1992～1995年对盖透明膜烟地杂草发生规律、化学除草和覆盖有色膜控草进行了研究。烟地以一年生杂草为主。灌水后盖膜,杂草发生多集中在盖膜后10～20天,发生率达64.6％,而不盖膜的同期只发生17.8％,直到下透雨烟苗移栽60天后才出现明显的高峰,说明杂草萌发与土壤水分关系密切。试验筛选出高效、经济的除草剂及其用量等应用技术,并进行了示范验证。试验和示范结果表明,深黑膜控草效果最好,达90％以上。     

Effect of allelopathic rice varieties combined with cultural management options on paddy field weeds

BACKGROUND: A number of techniques, including cultural management, allelopathy and bioherbicide, have been considered as alternatives for synthetic herbicides, but successful weed control will require the careful integration of these multiple techniques. This study was conducted to assess the use of allelopathic rice varieties in combination with cultural management options on paddy weeds, in order to develop an allelopathy-based technique to reduce herbicide use in paddies. RESULTS: The weed-suppressive effects of the rice varieties tested varied highly with allelopathic trait, planting pattern and cultural management including planting density, flooding depth and duration and supply of nitrogen. Allelopathic rice varieties PI312777 and Huagan-1 demonstrated much stronger weed suppression than the non-allelopathic variety Huajianxian under the same planting pattern and cultural management. Their weed-suppressive effect was increased with cultural management options. In particular, if integrated cultural management options of allelopathic rice varieties included a low-dose (bensulfuron-methyl, 25 g AI ha(-1), a third of the recommended dose) herbicide application, the emergence and growth of most weeds found in paddy fields was completely controlled. No grain yield reduction for allelopathic varieties occurred under integrated cultural management options, whereas with the non-allelopathic variety a reduction of up to 45-60% was measurable even with the low-dose herbicide application. CONCLUSION: The allelopathic potential of rice varieties will likely have a great impact on paddy weed control if integrated with cultural management options and application of low doses of herbicides. Therefore, it is feasible to reduce herbicide input in paddies if allelopathic rice is grown under integrated cultural management practices.     

除草剂使用问题及对策

在除草剂使用中存在苗前用量偏低或低 ,整地质量差 ,施药过晚 ,土壤干旱 ;苗后施药期天气干旱 ,高温或喷液量过大 ,施药时期偏晚 ,混用不当 ;喷洒器械及喷洒技术落后等影响了药效 ,苗前除草剂应根据土壤有机质及质地确定用药量。采用混土施药法适期施药 ,苗后应因杂草叶龄确定施药时期。混用除草剂选择比例 ,干旱条件下施药时药液中加植物油喷雾助剂 ,选择合适的喷洒器械 ,使用前应进行调整     

丙炔氟草胺与二甲戊灵混配使用对棉田杂草的防除效果及棉花安全性研究

为明确丙炔氟草胺与二甲戊灵混配使用防除新疆覆膜棉田杂草的效果及其对棉花的安全性,在新疆南北疆进行了田间药效试验。结果表明,50%丙炔氟草胺WP 45~120 g/hm2+33%二甲戊灵EC 742.5/1 237.5 g/hm2对龙葵Solanum nigrum、藜Chenopodium album、灰绿藜C.glaucum、反枝苋Amaranthus retroflexus和稗草Echinochloa crus-galli等一年生杂草防除效果理想,持效期45～60 d,对苘麻Abutilon theophrasti、田旋花Convolvulus arvensis有一定的防效,但对其生长抑制作用不佳,对榆树Ulmus pumila 苗防效差。50%丙炔氟草胺WP+33%二甲戊灵EC高剂量处理或在持续低温多雨情况下,对棉花出苗和生长有一定影响。在农业生产中,应重视完善和优化丙炔氟草胺与二甲戊灵混配使用的田间应用技术,避免和降低除草剂药害风险。     

Herbicide leaching as affected by macropore flow and within-storm rainfall intensity variation: a RZWQM simulation

Within-event variability in rainfall intensity may affect pesticide leaching rates in soil, but most laboratory studies of pesticide leaching use a rainfall simulator operating at constant rainfall intensity, or cover the soil with ponded water. This is especially true in experiments where macropores are present--macroporous soils present experimental complexities enough without the added complexity of variable rainfall intensity. One way to get around this difficulty is to use a suitable pesticide transport model, calibrate it to describe accurately a fixed-intensity experiment, and then explore the affects of within-event rainfall intensity variation on pesticide leaching through macropores. We used the Root Zone Water Quality Model (RZWQM) to investigate the effect of variable rainfall intensity on alachlor and atrazine transport through macropores. Data were used from an experiment in which atrazine and alachlor were surface-applied to 30 x 30 x 30 cm undisturbed blocks of two macroporous silt loam soils from glacial till regions. One hour later the blocks were subjected to 30-mm simulated rain with constant intensity for 0.5 h. Percolate was collected and analyzed from 64 square cells at the base of the blocks. RZWQM was calibrated to describe accurately the atrazine and alachlor leaching data, and then a median Mid-west variable-intensity storm, in which the initial intensity was high, was simulated. The variable-intensity storm more than quadrupled alachlor losses and almost doubled atrazine losses in one soil over the constant-intensity storm of the same total depth. Also rainfall intensity may affect percolate-producing macroporosity and consequently pesticide transport through macropores. For example, under variable rainfall intensity RZWQM predicted the alachlor concentration to be 2.7 microg ml(-1) with an effective macroporosity of 2.2 E(-4) cm(3) cm(-3) and 1.4 microg ml(-1) with an effective macroporosity of 4.6 E(-4) cm(3) cm(-3). Percolate-producing macroporosity and herbicide leaching under different rainfall intensity patterns, however, are not well understood. Clearly, further investigation of rainfall intensity variation on pesticide leaching through macropores is needed.     

Action of two herbicides on the microbial activity of soil cultivated with common bean (Phaseolus vulgaris) in conventional-till and no-till systems

The effects of application of the herbicides fluazifop‐p‐butyl and fomesafen and the commercial mixture of these herbicides on the microbial activity of a soil, cultivated with common bean under no‐till (NTS) and conventional‐till (CTS) systems, were evaluated. Microbial respiration was monitored for 63 days after application (DAA) of the herbicides, and the following evaluated at 12 and 51 DAA: microbial biomass carbon (MBC), microbial quotient (qMIC), metabolic quotient (qCO₂), percentage of bean root colonisation by mycorrhizal fungi and grain yield at the end of the cycle. A greater microbial respiratory rate was observed under NTS, with fluazifop‐p‐butyl providing the lowest respiration. At 12 DAA, MBC and qMIC were most affected negatively by fomesafen and by the commercial mixture of the two herbicides. Mycorrhizal colonisation was affected by the herbicides only at 12 DAA under CTS; however, in both periods, the highest value was found under NTS. All the herbicides caused a decrease in the MBC and qMIC values at 51 DAA; the qCO₂, which is related to the soil system stability, indicated a greater NTS balance over CTS. The herbicide fomesafen induced lower stability in the system. Lower grain yield was obtained without weed control (no herbicides) and with fomesafen‐only treatments, which may be attributed to the high weed infestation in the experimental area.     

Regenerative capacity and response to pre‐emergent herbicides by stolon fragments of triquetrous murdannia (Murdannia triquetra) in rice

Triquetrous murdannia is an annual stoloniferous weed commonly found in wheat‐rice rotation fields in China. Disturbance after wheat harvesting can fragment stolons of triquetrous murdannia, and the regeneration of these fragments may contribute to the spread of this weed. In this study, the regenerate capacity and response to pre‐emergence (PRE) herbicides of stolon fragment of triquetrous murdannia were evaluated in a screenhouse. The experiment consisted of two types of single node fragments (2‐cm stolon node and five‐leaf stolon tips) placed under different floating, flooding and burial depth conditions. Results indicated that floating depth did not influence the survival of the two types of fragments but significantly decreased their growth (stolon length, number of branches, and biomass). The stolon nodes were more sensitive to flooding than stolon tips; no stolon node survived at a flooding depth of 6 cm. The highest survival was observed for fragments placed on the soil surface, and no fragments buried to a depth of 2 cm survived. PRE application of benzobicyclon, butachlor, metazosulfuron, and triafamone significantly decreased the branching and biomass of the stolon nodes; however, only triafamone and metazosulfuron significantly inhibited the regeneration of the stolon tips. These results suggest that stolon fragments with one node are likely to promote vegetative reproduction in triquetrous murdannia, and thus, disturbance may contribute to the spread of this weed. Tillage to bury fragments below their maximum regeneration depth and application of an effective PRE herbicide could serve as important tools for managing triquetrous murdannia.     

丙炔氟草胺在大豆和土壤中的残留及消解动态

通过在山东德州、黑龙江哈尔滨和辽宁海城2年3地的田间试验,采用QuEChERS-高效液相色谱-串联质谱 (QuEChERS-HPLC-MS/MS) 法,研究了丙炔氟草胺在大豆和土壤中的残留及消解动态。结果表明: 在0.000 3、0.01和0.1 mg/kg添加水平下,丙炔氟草胺在大豆植株、青大豆、大豆籽粒和土壤中的日内平均添加回收率为89%~112%,日内相对标准偏差(RSD) (n = 5) 为1.3%~5.3%;日间平均添加回收率为85%~110%,日间RSD (n = 15) 为0.40%~4.8%。丙炔氟草胺在大豆植株、青大豆、大豆籽粒和土壤中的定量限 (LOQ) 均为0.000 3 mg/kg,能够满足农药残留限量标准的要求。丙炔氟草胺在大豆植株和土壤中的消解动态均符合一级反应动力学方程,在大豆植株和土壤中的消解半衰期分别为 5.8~11.8 d和 15.8~24.8 d。采用480 g/L丙炔氟草胺悬浮剂按推荐高剂量 (有效成分60 g/hm2) 及其1.5倍推存剂量 (有效成分90 g/hm2) 于播后苗前施药1次,收获期采样时,丙炔氟草胺在大豆植株、青大豆、大豆籽粒和土壤中的最终残留量均低于中国国家标准中规定的丙炔氟草胺在大豆上的最大残留限量 (0.02 mg/kg)。     

施肥对麦田杂草发生、生长及危害的影响

应用微区试验研究了在种植小麦的情况下,不同施肥水平对杂草及其防除效果的影响。结果表明,在缺磷土壤上单施氮肥,杂草发生和生长受到抑制;增施磷肥,氮肥效应得到充分发挥,杂草发生和生长迅猛提高。杂草根系发达,对钾肥不敏感。有机肥养分完全,显著促进杂草发生和生长。在不施肥(对照)及适合杂草和小麦生长的平衡施肥处理区(NP和NPK),麦田杂草的危害(小麦减产百分率)最为严重。杂草危害程度和施除草剂的增产效果均与小麦长势呈极显著负相关(相关系数分别是-0.5121、-0.5418,n=27)。肥料对甲磺隆钠盐杂草防效的影响与施药时间有关。在小麦苗前至苗后早期施药,防效高,且不受施肥影响;施药过迟,杂草长大,防效下降。研究结果还表明,杂草发生和生长在受施肥影响的同时,也受小麦长势和长相的影响。     

Absorption and translocation of glyphosate in Spermacoce verticillata and alternative herbicide control

Glyphosate has been associated with control failures for Spermacoce verticillata in some Brazilian States. The objective of this work was to evaluate and determine the possible causes of this and propose alternative herbicides to use. Glyphosate was applied at three plant stages of development (2–4 leaves, 4–6 leaves and full bloom) where foliar absorption and translocation of glyphosate to various plants parts and time were analysed using the ¹⁴C technique. Data were submitted to nonlinear regressions and analysis of variance, where means were compared by a Tukey test at 5% probability. Plant control by the application of different herbicides (19) in the same three stages of development of weed was evaluated. Twenty‐one days after herbicide application, control was visually evaluated and data analysed and means were compared. Due to absorption and/or translocation problems, S. verticillata plants were not controlled by glyphosate. Plants with 4–6 leaves showed lower absorption and translocation of the herbicide to the leaf/root regions compared with plants at the beginning of their development. Plants at full bloom showed lower translocation of the herbicide to the root. In addition to the application of glyphosate at early stages of development, the application of paraquat, flumioxazin and mixtures of glyphosate with flumioxazin or cloransulam is recommended. Late applications could result in poor control, principally if glyphosate is used. Therefore, early applications are strongly recommended for control of this species.     

Hydrolysis and photolysis of flumioxazin in aqueous buffer solutions

To determine the degradation rates and degradation products of the herbicide flumioxazin in aqueous buffer solutions (pH 5, 7 and 9), its hydrolysis and photolysis were investigated at 30 degrees C in the dark, and in a growth chamber fitted with fluorescent lamps simulating the UV output of sunlight. The rate of hydrolysis of flumioxazin was accelerated by increasing pH. The t(1/2) values at pH 5, 7 and 9 were 16.4, 9.1 and 0.25 h, respectively. Two degradation products were detected and their structural assignments were made on the basis of LC-MS data. Degradation product I was detected in all buffer solutions while degradation product II was detected in acidic buffer only. Both degradation products appeared to be stable to further hydrolysis. After correcting for the effects of hydrolysis, the photolytic degradation rate also increased as a function of pH and was approximately 10 times higher at pH 7 than that at pH 5, showing t(1/2) values of 4.9 and 41.5 h, respectively. Degradation products formed by photolysis were the same as those formed by hydrolysis. Flumioxazin was degraded more extensively at high pH and should degrade in surface water.