METHODS OF USING A COMPOSITION COMPRISING AN ANIONIC PESTICIDE AND A BUFFER

Abstract

The present invention relates to methods of and compositions for reducing loss in pesticide application, the method comprising the steps of a) combining an anionic pesticide and a buffer, and b) applying the resulting composition to plants or to seed, soil, or habitat of said plants.

Claims

1. A method of reducing loss in pesticide application, comprising a) combining an anionic pesticide and a buffer, and b) applying the resulting composition to a plant, seed, soil, or habitat of said plant.

2. The method as claimed in claim 1, wherein the reduced loss is observed as reduced crop phytotoxicity in comparison to the anionic pesticide without buffer.

3. The method as claimed in claim 2, wherein the crop is soy or cotton.

4. The method as claimed in claim 1, wherein the reduced loss is observed in improved equipment clean-out in comparison to the anionic pesticide without buffer.

5. The method as claimed in claim 1, wherein the anionic pesticide is selected from the group consisting of dicamba, dicamba-sodium, dicamba-potassium, dicamba diglycolamine, dicamba-dimethylamine, dicamba-monoethanolamine, dicamba-choline, and dicamba-N,N-bis(3-aminopropyl)methylamine.

6. The method as claimed in claim 1, wherein the anionic pesticide is selected from the group consisting of dicamba-potassium, dicamba diglycolamine, dicamba-dimethylamine, and dicamba-N,N-bis(3-aminopropyl)methylamine.

7. The method as claimed in claim 1, wherein the anionic pesticide is dicamba-N,N-bis(3-aminopropyl)methylamine.

8. The method as claimed in claim 1, wherein in step a) the anionic pesticide and the buffer are combined with a further pesticide.

9. The method as claimed in claim 8, wherein the further pesticide is a herbicide selected from the group consisting from glyphosate, glufosinate, L-glufosinate, 2,4-D, and their salts and esters.

10. The method as claimed in claim 8, wherein the further pesticide is a herbicide selected from glyphosate and its salts.

11. The method as claimed in claim 8, wherein the further pesticide is a herbicide selected from glufosinate, L-glufosinate, and their salts.

12. The method as claimed in claim 1, wherein in step a) the anionic pesticide and the buffer are combined with a nitrogen fertilizer.

13. The method as claimed in claim 12, wherein the nitrogen fertilizer is ammonium sulfate.

14. The method as claimed in claim 1, wherein the buffer is an inorganic base or an organic base.

15. The method as claimed in claim 14, wherein the buffer is a carbonate, a phosphate, a citrate, or a mixture thereof.

16. The method as claimed in claim 14, wherein the buffer is potassium carbonate, potassium citrate, or a mixture thereof.

17. The method as claimed in claim 1, wherein the anionic pesticide is selected from the group consisting of dicamba, dicamba-sodium, dicamba-potassium, dicamba diglycolamine, dicamba-dimethylamine, dicamba-monoethanolamine, dicamba-choline, and dicamba-N,N-bis(3-aminopropyl)methylamine; the buffer is potassium carbonate, potassium citrate, or a mixture thereof; and wherein the anionic pesticide is applied with an application rate from 128 to 1120 g active equivalents per hectare; and wherein the buffer is applied with an application rate from 100 to 800 g per hectare.

18. The method as claimed in claim 17, wherein in step a) the anionic pesticide and the buffer are combined with a further pesticide selected from glyphosate, glufosinate, L-glufosinate, 2,4-D, and their salts and esters.

19. The method as claimed in claim 17, wherein in step a) the anionic pesticide and the buffer are combined with a nitrogen fertilizer.

20. The method as claimed in claim 1, wherein the anionic pesticide is selected from the group consisting of dicamba, dicamba-sodium, dicamba-potassium, dicamba diglycolamine, dicamba-dimethylamine, dicamba-monoethanolamine, dicamba-choline, and dicamba-N,N-bis(3-aminopropyl)methylamine; and wherein the buffer is potassium carbonate, potassium citrate, or a mixture thereof; and wherein the anionic pesticide and the buffer are combined in a ratio of 10:1 to 1:5.

21. The method as claimed in claim 20, wherein in step a) the anionic pesticide and the buffer are combined with a further pesticide selected from glyphosate, glufosinate, L-glufosinate, 2,4-D, and their salts and esters.

22. The method as claimed in claim 20, wherein in step a) the anionic pesticide and the buffer are combined with a nitrogen fertilizer.

23. A composition for reducing loss in pesticide application, comprising (a) 5-45% w/w are dicamba, dicamba-sodium, dicamba-potassium, dicamba diglycolamine, dicamba-dimethylamine, dicamba-monoethanolamine, dicamba-choline, or dicamba-N,N-bis(3-aminopropyl)methylamine; (b) 2-20% w/w potassium carbonate, potassium citrate, or a mixture thereof; (c) 3-50% w/w surfactant; and optionally. (d) 4-10% w/w ammonium sulfate or urea ammonium nitrate.

24. The composition as claimed in claim 23, additionally comprising (e) 6-67% w/w glyphosate, glufosinate, L-glufosinate, 2,4-D, or their salts and esters.

Description

EXAMPLE 1

[0190] A quantitative humidome study provides a measurement of relative secondary loss in a dynamic, contained environment via air sampling and quantitative analysis (an indication of potential volatile or particulate loss from a treated substrate; usually measured as the amount of dicamba captured in an air sampling filter per air volume or ng/m3).

[0191] The method of a quantitative humidome study utilizes a treated substrate (e.g. glass, soil, potting mix or plants) placed in a plastic tray covered with a clear plastic humidome (overall size 25 cm wide×50 cm long×20 cm tall; source: Hummert) fitted with an air sampling filter cassette (fiberglass and cotton pad filter media; source: SKC) connected to a vacuum pump (flow rate: 2 L/min). Individual humidomes representing different study treatments and replicates are placed in a controlled growth chamber environment (typical temperature at 35° C. and 25 to 40% RH).

[0192] After 24 hours, filters are collected, extracted and analyzed for dicamba content using GC-MS. The total amount of dicamba captured is then divided by total volume of the air flow through the filter to calculate total dicamba (ng), average dicamba concentration ng/m3 and % relative loss or improvement compared to a standard treatment. Lower loss of dicamba indicates a better or improved secondary loss profile for a given treatment.

[0193] Table 1 details a quantitative humidome study conducted in a growth chamber to compare secondary loss profiles of selected dicamba candidates. Aqueous solutions of the candidates were prepared by dissolving the components as indicated in Table 1 in water at room temperature while stirring. Dicamba was used as dicamba N,N-bis(3-aminopropyl)methylamine salt (“dicamba-BAPMA”). The samples were clear solutions. They remained clear solution after storage for at least four weeks at room temperature.

TABLE-US-00003 TABLE 1 % reduction in K.sub.2CO.sub.3 secondary loss Dicamba buffer relative to Dicamba candidates +/− rate rate Dicamba-BAPMA + tank mix partner (g ae/ha) (g/ha) K-glyphosate Dicamba-BAPMA 560 0 — Dicamba-BAPMA + K.sub.2CO.sub.3 560 200 87 buffer (tank mix) Dicamba-BAPMA + built in 560 175 83 K.sub.2CO.sub.3 buffer Dicamba-BAPMA + built in 560 187 87 K.sub.2CO.sub.3 buffer Dicamba-BAPMA + built in 560 200 88 K.sub.2CO.sub.3 buffer All treatments included 0.25% v/v non-ionic surfactant (Induce from Helena Chemical) and K-glyphosate at 1120 g ae/ha Substrate media: 8 glass petri plates, total area 594 cm.sup.2

[0194] According to the results in Table 1, all treatments containing the K2CO3 buffer at rates of 175 to 200 g/ha whether as a tank mix or premix formulation provided a significant reduction (83-88%) in potential dicamba secondary loss relative to the treatment without buffer.

EXAMPLE 2

[0195] A bioassay humidome study provides a measurement of secondary loss in a static, contained environment using sensitive soybean plants as a biological indicator (an indication of potential volatile or particulate loss from a treated substrate; usually measured as a visual 0-100 percent assessment of soybean injury where more injury indicates higher potential loss (exposure)).

[0196] The method of a bioassay humidome study utilizes a treated substrate (e.g. glass, soil, potting mix or plants) placed in a plastic tray covered with a clear plastic humidome (overall size 25 cm wide×50 cm long×20 cm tall; source: Hummert) along with 2 dicamba sensitive soybean plants (1-2 true leaves). Individual humidomes representing different study treatments and replicates are placed in a greenhouse environment (with a typical diurnal temperature range of 25 to 40 C and 75 to 98 % RH).

[0197] After 18 to 24 hours, the sensitive soybean plants are removed from the humidomes and placed on a greenhouse bench for observation and visual response or injury assessment over a 2-3 weeks period. The level of injury to soybean plants is an indirect measurement of amount of dicamba exposure from treated substrate. Lower injury to plants indicates a relatively better or improved secondary loss treatment profile.

[0198] Table 2 details a bioassay humidome study conducted in a greenhouse to compare secondary loss profiles of selected dicamba candidates. Aqueous solutions of the candidates were prepared by dissolving the components as indicated in Table 2 in water at room temperature while stirring. Dicamba was used as dicamba-BAPMA. The samples were clear solutions. They remained clear solution after storage for at least four weeks at room temperature.

TABLE-US-00004 TABLE 2 % reduction in K.sub.2CO.sub.3 secondary loss Dicamba buffer relative to Dicamba candidates +/− rate rate Dicamba-BAPMA + tank mix partner (g ae/ha) (g/ha) K-glyphosate Dicamba-BAPMA 560 0 — Dicamba-BAPMA + K.sub.2CO.sub.3 560 200 56 buffer (tank mix) Dicamba-BAPMA + built in 560 175 53 K.sub.2CO.sub.3 buffer Dicamba-BAPMA + built in 560 187 54 K.sub.2CO.sub.3 buffer Dicamba-BAPMA + built in 560 200 47 K.sub.2CO.sub.3 buffer Dicamba-BAPMA + built in 560 225 56 K.sub.2CO.sub.3 buffer All treatments included 0.25% v/v non-ionic surfactant (Induce from Helena Chemical) and K-glyphosate at 1120 g ae/ha. Substrate media: 2 large glass plates, total area 620 cm.sup.2

[0199] According to the results in Table 2, all treatments containing the K2CO3 buffer at rates of 175 to 225 g/ha whether as a tank mix or premix formulation provided a significant reduction (47-56%) in soybean injury related to dicamba secondary loss relative to the treatment without buffer.

EXAMPLE 3

[0200] Table 3 details a bioassay humidome study conducted in a greenhouse to compare secondary loss profiles of selected dicamba candidates. This experiment utilized 2× rates of dicamba-BAPMA (1120 g ae/ha) and K.sub.2CO.sub.3 buffer at 234 and 350 g/ha. Aqueous solutions of the candidates were prepared by dissolving the components as indicated in Table 3 in water at room temperature while stirring. Dicamba was used as dicamba-BAPMA. The samples were clear solutions. They remained clear solutions after storage for at least four weeks at room temperature.

TABLE-US-00005 TABLE 3 K.sub.2CO.sub.3 % reduction in Dicamba buffer secondary loss rate rate relative to Dicamba candidates (g ae/ha) (g/ha) Dicamba-BAPMA Dicamba-BAPMA 1120 0 — Dicamba-BAPMA + built in 1120 234 72 K.sub.2CO.sub.3 buffer Dicamba-BAPMA + built in 1120 350 95 K.sub.2CO.sub.3 buffer All treatments included 0.25% v/v non-ionic surfactant (Induce from Helena Chemical)

[0201] According to the results in Table 3, all treatments containing the K.sub.2CO.sub.3 buffer provided a significant reduction (72-95%) in soybean injury related to dicamba secondary loss relative to the treatment without buffer. The improvement or reduction in secondary loss potential is consistent whether the dicamba formulation is mixed with another herbicide such as glyphosate or not.

EXAMPLE 4

[0202] Field off-target simulation study methodology provides a measurement of potential secondary loss via air sampling in an open field environment following a spray application. Since the materials are applied as a spray application it is impossible to completely isolate primary and secondary loss. To favor measurement of secondary loss, care is taken during the application to minimize fine droplets (the typical source of spray drift or primary loss) and air sampling is delayed 30 to 45 min until most droplets are likely to have settled on foliage or soil.

[0203] While field studies cannot entirely separate various primary and secondary loss effects, they are useful for evaluating the relative difference in off-target effects between treatments. For each treatment, a 40×40 ft area is treated in the center of a 300×300 ft plot in a soybean field. Four to five low volume air samplers (source: SKC) with filter cassettes (placed 3-5″ above soybean canopy) containing layers of fiberglass+a cotton support pad (source: SKC) are placed in each treatment area. Thirty to forty-five minutes after application, the air samplers are started and allowed to run for 18-24 hours. Filter cassettes are collected after the sampling period, extracted and analyzed for dicamba content using GC-MS. The total amount of dicamba captured is then divided by total volume of the air sampled in the 18-24 hr period to calculate the relative average concentration of dicamba as ng/m3. This allows a calculation of the relative % reduction in loss (improvement) compared to a standard treatment. Lower loss of dicamba indicates a relatively better secondary loss treatment profile.

[0204] Table 4 details a field off-target simulation study comparing the secondary loss profile of selected dicamba candidates. Aqueous solutions of the candidates were prepared by dissolving the components as indicated in Table 4 in water at room temperature while stirring. Dicamba was used as dicamba-BAPMA. The samples were clear solutions. They remained clear solutions after storage for at least four weeks at room temperature.

TABLE-US-00006 TABLE 4 % reduction in K.sub.2CO.sub.3 secondary loss Dicamba buffer relative to Dicamba candidates +/− rate rate Dicamba-BAPMA + tank mix partner (g ae/ha) (g/ha) K-glyphosate Dicamba-BAPMA 560 0 — Dicamba-BAPMA + K.sub.2CO.sub.3 560 200 42 buffer (tank mix) Dicamba-BAPMA + built in 560 175 48 K.sub.2CO.sub.3 buffer Dicamba-BAPMA + built in 560 187 50 K.sub.2CO.sub.3 buffer Dicamba-BAPMA + built in 560 200 51 K.sub.2CO.sub.3 buffer All treatments included 0.25% v/v non-ionic surfactant (Induce from Helena Chemical) and K-glyphosate at 1120 g ae/ha. Substrate media: DT-soybean foliage (treated area = 40 × 40 ft plot)

[0205] According to the results in Table 4, all treatments containing a K.sub.2CO.sub.3 buffer at rates of 175 to 200 g/ha whether as a tank mix or premix formulation provided a significant reduction (42-51%) in dicamba secondary loss from treated soybean plot relative to the treatment without buffer.

EXAMPLE 5

[0206] Spray equipment cleanout hose assay methodology provides a relative measurement of dicamba retained on spray equipment using EPDM rubber spray hose (source: Apache) as a model equipment surface. Dicamba retention is measured by determining the amount of dicamba removed from treated hose using an effective solvent (i.e. methanol); a lower amount in the methanol wash indicates less retention or contamination and better cleanout efficiency.

[0207] For the hose assay, a solo dicamba formulation or herbicide mixture with or without a K2CO3 buffer addition is prepared simulating a 147 L/ha spray dilution and is allowed to incubate overnight in 28 cm long EPDM rubber hose sections. After approximately 24 hours, the hose sections are drained of the herbicide solution and rinsed with 25 ml of water. Then the hoses are rinsed with 25 ml of pure methanol which is collected and analyzed for dicamba using H PLC.

[0208] Table 5 details hose assay studies to compare ease of cleanout for selected dicamba candidates. Aqueous solutions of the candidates were prepared by dissolving the components as indicated in Table 5 in water at room temperature while stirring. Dicamba was used as dicamba-BAPMA. The samples were clear solutions. They remained clear solutions after storage for at least four weeks at room temperature.

TABLE-US-00007 TABLE 5 Dicamba K.sub.2CO.sub.3 % improvement in hose Dicamba candidates +/− rate buffer rate cleanout relative to Study tank mix partner (g ae/ha) (g/ha) Dicamba-BAPMA + K-glyphosate 1 Dicamba-BAPMA 560 0 — Dicamba-BAPMA + K.sub.2CO.sub.3 560 117 49 buffer (tank mix) Dicamba-BAPMA + K.sub.2CO.sub.3 560 150 43 buffer (tank mix) Dicamba-BAPMA + K.sub.2CO.sub.3 560 175 59 buffer (tank mix) Dicamba-BAPMA + built in 560 175 51 K.sub.2CO.sub.3 buffer 2 Dicamba-BAPMA 560 0 — Dicamba-BAPMA + K.sub.2CO.sub.3 560 100 45 buffer (tank mix) Dicamba-BAPMA + K.sub.2CO.sub.3 560 200 58 buffer (tank mix) buffer (tank mix) 560 300 59 Dicamba-BAPMA + K.sub.2CO.sub.3 560 400 62 buffer (tank mix) All treatments included 0.25% v/v non-ionic surfactant (Induce from Helena Chemical) and K-glyphosate at 1120 g ae/ha

[0209] According to the results in Table 5, the addition of a K.sub.2CO.sub.3 buffer to the spray solution at a rate of 100 to 400 g/ha reduces potential retention of dicamba on equipment (hose) surfaces by approximately 50% (43 to 62%). This reduction in retention should ease cleanout of dicamba from spray equipment, reducing potential equipment contamination and inadvertent later application to sensitive crops.

EXAMPLE 6

[0210] Table 6 describes a bioassay humidome study conducted in a greenhouse to compare secondary loss profiles of selected dicamba salt candidates. Aqueous solutions of the candidates were prepared by dissolving the components as indicated in Table 6 in water at room temperature while stirring. Dicamba was used as dicamba N,N-bis(3-aminopropyl)methylamine salt (“dicamba-BAPMA”), dicamba dimethylamine (“dicamba-DMA”) and dicamba diglycolamine (“dicamba-DGA”). Additional treatments included combinations with ammonium sulfate (AMS, 99.5%). Higher than normal rates of dicamba and buffer were used to examine the range of the buffer effect on the dicamba salts alone and in the presence of AMS. Previous work had shown that AMS had a negative effect on dicamba secondary loss. The samples were clear solutions. They remained clear solution after storage for at least four weeks at room temperature.

TABLE-US-00008 TABLE 6 Dicamba AMS K.sub.2CO.sub.3 % bioassay % reduction in Dicamba candidates +/− rate rate buffer rate soybean secondary loss relative tank mix partner (g ae/ha) (g/ha) (g/ha) response on soybean response Dicamba-DMA 2240 45 — Dicamba-DMA + AMS 2240 917 72 −59 Dicamba-DMA + K.sub.2CO.sub.3 2240 4000 11 76 buffer Dicamba-DMA + AMS + 2240 917 4000 6 87 K.sub.2CO.sub.3 buffer Dicamba-DGA 2240 22 — Dicamba-DGA + AMS 2240 917 71 −227 Dicamba-DGA + K.sub.2CO.sub.3 2240 4000 5 78 buffer Dicamba-DGA + AMS + 2240 917 4000 2 92 K.sub.2CO.sub.3 buffer Dicamba-BAPMA 2240 9 — Dicamba-BAPMA + AMS 2240 917 74 −773 Dicamba-BAPMA + 2240 4000 3 71 K.sub.2CO.sub.3 buffer Dicamba-BAPMA + AMS + 2240 917 4000 4 51 K.sub.2CO.sub.3 buffer All treatments included 0.25% v/v non-ionic surfactant (Preference from Winfield United). Substrate media: 8 glass petri plates, total area 594 cm.sup.2

[0211] According to the results in Table 6, dicamba-BAPMA provided lower soybean response than dicamba-DGA or dicamba-DMA. Bioassay soybean response increased when AMS was added. The additional of the K.sub.2CO.sub.3 buffer provided a significant reduction in soybean response to each dicamba salt candidate alone or when combined with AMS.

EXAMPLE 7

[0212] Table 7 details a field off-target simulation study comparing the secondary loss profile of tank mixed dicamba+glufosinate with and without a K.sub.2CO.sub.3 buffer. This study included 3 test locations; one on soybean in Illinois and 2 cotton locations in Georgia and Texas. An average of the results from the 3 locations are presented in Table 7. Aqueous solutions of the candidates were prepared by dissolving the components as indicated in Table 7 in water at room temperature while stirring. Dicamba was used as dicamba-BAPMA. Glufosinate was used as glufosinate-ammonium (280 g a/l SL, BASF). The samples were clear solutions. They remained clear solutions after storage for at least four weeks at room temperature. Treatment test solution pH ranged from 7 to 9.5.

TABLE-US-00009 TABLE 7 Dicamba Glufosinate K.sub.2CO.sub.3 % reduction in rate Rate buffer rate secondary loss relative to Dicamba + Glufosinate +/− Buffer (g ae/ha) (g a/ha) (g/ha) Dicamba-BAPMA + glufosinate-ammonium Dicamba + Glufosinate 560 655 0 — Dicamba + Glufosinate + Buffer 560 655 200 76 Dicamba + Glufosinate + Buffer 560 655 300 86 Dicamba + Glufosinate + Buffer 560 655 400 88 All treatments also included 0.25% v/v non-ionic surfactant (Induce from Helena Chemical) Substrate media: DT-soybean (IL) and DT-cotton (GA, TX) foliage (treated area = 40 × 40 ft plot)

[0213] According to the results in Table 7, all treatments containing a K.sub.2CO.sub.3 buffer at rates of 200 to 400 g/ha provided a significant reduction (76 to 88%) in dicamba secondary loss from treated soybean and cotton plots relative to the treatment without buffer, measured by air sampling as described in Example 4.

EXAMPLE 8

[0214] Table 8 details a quantitative humidome study conducted in a growth chamber to compare secondary loss profiles of selected dicamba candidates. Aqueous solutions of the candidates were prepared by dissolving the components as indicated in Table 8 in water at room temperature while stirring. Dicamba-DGA was used.

TABLE-US-00010 TABLE 8 K.sub.2CO.sub.3 % reduction in Dicamba buffer secondary loss Dicamba candidates +/− rate rate relative to tank mix partner (g ae/ha) (g/ha) Dicamba-DGA Dicamba-DGA 560 0 — Dicamba-DGA + K.sub.2CO.sub.3 560 150 83 buffer (tank mix) Dicamba-DGA + K.sub.2CO.sub.3 560 300 96 buffer (tank mix) All treatments included 0.25% v/v non-ionic surfactant (Induce from Helena Chemical) Substrate media: 2 large glass plates, total area 620 cm.sup.2

[0215] According to the results in Table 8, all treatments containing the K.sub.2CO.sub.3 buffer at rates of 150 to 300 g/ha as a tank mix provided a significant reduction (83-96%) in potential dicamba secondary loss relative to the treatment without buffer.

EXAMPLE 9

[0216] Table 9 details a quantitative humidome study conducted in a growth chamber to compare secondary loss profiles of selected dicamba candidates. Aqueous solutions of the candidates were prepared by dissolving the components as indicated in Table 9 in water at room temperature while stirring. Dicamba-DGA was used.

TABLE-US-00011 TABLE 9 % reduction in K.sub.2CO.sub.3 secondary loss Dicamba buffer relative to Dicamba candidates +/− rate rate Dicamba-DGA + tank mix partner (g ae/ha) (g/ha) K-glyphosate Dicamba-DGA 560 0 — Dicamba-DGA + K.sub.2CO.sub.3 560 150 72 buffer (tank mix) Dicamba-DGA + K.sub.2CO.sub.3 560 300 94 buffer (tank mix) All treatments included 0.25% v/v non-ionic surfactant (Induce from Helena Chemical) and K-glyphosate at 1120 g ae/ha Substrate media: 2 large glass plates, total area 620 cm.sup.2

[0217] According to the results in Table 9, all treatments containing the K.sub.2CO.sub.3 buffer at rates of 150 to 300 g/ha as a tank mix provided a significant reduction (72-94%) in potential dicamba secondary loss relative to the treatment without buffer.

EXAMPLE 10

[0218] Table 10 details a quantitative humidome study conducted in a growth chamber to compare secondary loss profiles of selected dicamba candidates. Aqueous solutions of the candidates were prepared by dissolving the components as indicated in Table 10 in water at room temperature while stirring. Dicamba was used as dicamba potassium salt (“dicamba-K”).

TABLE-US-00012 TABLE 10 K.sub.2CO.sub.3 % reduction in Dicamba buffer secondary loss Dicamba candidates +/− rate rate relative to tank mix partner (g ae/ha) (g/ha) Dicamba-K Dicamba-K 560 0 — Dicamba-K + K.sub.2CO.sub.3 560 150 94 buffer (tank mix) Dicamba-K + K.sub.2CO.sub.3 560 300 94 buffer (tank mix) All treatments included 0.25% v/v non-ionic surfactant (Induce from Helena Chemical) Substrate media: 2 large glass plates, total area 620 cm.sup.2

[0219] According to the results in Table 10, all treatments containing the K.sub.2CO.sub.3 buffer at rates of 150 to 300 g/ha as a tank mix provided a significant reduction (94%) in in potential dicamba secondary loss relative to the treatment without buffer.

EXAMPLE 11

[0220] Table 11 details a quantitative humidome study conducted in a growth chamber to compare secondary loss profiles of selected dicamba candidates. Aqueous solutions of the candidates were prepared by dissolving the components as indicated in Table 11 in water at room temperature while stirring. Dicamba-K was used.

TABLE-US-00013 TABLE 11 % reduction in K.sub.2CO.sub.3 secondary loss Dicamba buffer relative to Dicamba candidates +/− rate rate Dicamba-K + tank mix partner (g ae/ha) (g/ha) K-glyphosate Dicamba-K 560 0 — Dicamba-K + K.sub.2CO.sub.3 560 150 89 buffer (tank mix) Dicamba-K + K.sub.2CO.sub.3 560 300 96 buffer (tank mix) All treatments included 0.25% v/v non-ionic surfactant (Induce from Helena Chemical) and K-glyphosate at 1120 g ae/ha Substrate media: 2 large glass plates, total area 620 cm.sup.2

[0221] According to the results in Table 11, all treatments containing the K.sub.2CO.sub.3 buffer at rates of 150 to 300 g/ha as a tank mix provided a significant reduction (89-96%) in in potential dicamba secondary loss relative to the treatment without buffer.

EXAMPLE 12

[0222] Table 12 details a quantitative humidome study conducted in a growth chamber to compare secondary loss profiles of selected dicamba+pyroxasulfone candidate formulations. Aqueous solutions of the candidates were prepared by dissolving or dispersing the components as indicated in Table 12 in water at room temperature while stirring. The dicamba-BAPMA salt form of dicamba was used throughout the study. The commercial Engenia® formulation of dicamba-BAPMA (600 g ae/l SL, BASF) and the Zidua® formulation of pyroxasulfone (500 g a/l SC, BASF) were used for the tank mix treatment. The reduction in secondary loss of dicamba was compared between mixtures containing the K.sub.2CO.sub.3 (potassium carbonate) or K.sub.2CO.sub.3+C.sub.6H.sub.5K.sub.3O.sub.7 (potassium citrate) buffer or without a buffer.

TABLE-US-00014 TABLE 12 Dicamba Pyroxasulfone buffer % reduction in secondary Dicamba candidates +/− rate rate rate loss relative to Dicamba-BAPMA + tank mix partner(s) (g ae/ha) (g/ha) (g/ha) Pyroxasulfone + K-glyphosate Dicamba-BAPMA + 560 120 0 — Pyroxasulfone (tank mix) Dicamba-BAPMA + 560 120 187 K.sub.2CO.sub.3 87 Pyroxasulfone + built in K.sub.2CO.sub.3 buffer (premix) Premix of Dicamba-BAPMA + 560 120 146 + 44 81 Pyroxasulfone + built in K.sub.2CO.sub.3 + K.sub.2CO.sub.3 and C.sub.6H.sub.5K.sub.3O.sub.7 buffer C.sub.6H.sub.5K.sub.3O.sub.7 (premix) All treatments included 0.25% v/v non-ionic surfactant (Induce from Helena Chemical) and K-glyphosate at 1120 g ae/ha. Substrate media: 2 large glass plates, total area 620 cm.sup.2

[0223] According to the results in Table 12, dicamba-BAPMA+pyroxasulfone treatments containing the K.sub.2CO.sub.3 or K.sub.2CO.sub.3+C.sub.6H.sub.5K.sub.3O.sub.7 buffer at rates of 187 or 146+44 g/ha provided a reduction (87-81%) in potential dicamba secondary loss relative to the treatment without buffer.

EXAMPLE 13

[0224] Table 13 describes a quantitative humidome study conducted in a growth chamber to compare secondary loss profiles of selected dicamba-BAPMA mixtures with a C.sub.6H.sub.5K.sub.3O.sub.7 (potassium citrate) buffer. Aqueous solutions of the candidates were prepared by dissolving the components as indicated in Table 13 in water at room temperature while stirring. The reduction in secondary loss of dicamba was compared between mixtures containing various rates of the C.sub.6H.sub.5K.sub.3O.sub.7 (potassium citrate) buffer.

TABLE-US-00015 TABLE 13 % reduction in C.sub.6H.sub.5K.sub.3O.sub.7 secondary loss Dicamba buffer relative to Dicamba candidates +/− rate rate Dicamba-BAPMA + tank mix partner (g ae/ha) (g/ha) K-glyphosate Dicamba-BAPMA 560 0 — Dicamba-BAPMA + 560 175 38 C.sub.6H.sub.5K.sub.3O.sub.7 buffer (tank mix) All treatments included 0.25% v/v non-ionic surfactant (Induce from Helena Chemical) and K-glyphosate at 1120 g ae/ha Substrate media: 8 glass petri plates, total area 594 cm.sup.2

[0225] According to the results in Table 13, the dicamba-BAPMA treatment containing the C.sub.6H.sub.5K.sub.3O.sub.7 buffer at a rate of 175 g/ha provided a reduction of 38% in dicamba secondary loss relative to the treatment without buffer.