Movement of Alachlor and Metribuzin from Controlled Release Formulations in a Sandy Soil

Field and column experiments were conducted to determine the effect of controlled release formulations on weed control and leaching of alachlor and metribuzin on a Plainfield sand. Controlled release formulations including two starch encapsulations of both herbicides and a microencapsulation of alachlor were compared to emulsifiable concentrate and dry flowable formulations of alachlor and metribuzin, respectively. Herbicide movement was measured in laboratory columns and in the field throughout two growing seasons to a soil depth of 91 cm. Soybean injury and weed control were monitored. No significant differences in herbicide movement between starch-encapsulated and emulsifiable concentrate formulations were observed in either field or column experiments. Microencapsulation resulted in the greatest retention of alachlor in the soil surface in field and columns. Compared to the dry flowable formulation, starch encapsulation did not affect metribuzin distribution in the field but reduced leaching in columns. Controlled release formulations did not result in significant differences in weed control and soybean injury compared to the emulsifiable concentrate alachlor and dry flowable metribuzin formulations. Starch encapsulations had a limited effect on alachlor and metribuzin movement. Degradation appeared to be the primary mechanism for herbicide dissipation while leaching losses were minor.

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Efficacy of Controlled-Release Formulation of Trifluralin in No-Till Soybeans (Glycine max)

Weed Science ◽

10.1017/s004317450005390x ◽

1987 ◽

Vol 35 (3) ◽

pp. 407-411 ◽

Cited By ~ 7

Author(s):

Marvin M. Schreiber ◽

Michael D. White ◽

Baruch S. Shasha

Keyword(s):

Glycine Max ◽

Controlled Release ◽

Soil Surface ◽

Conventional Tillage ◽

Release Formulation ◽

Agricultural Industry ◽

Emulsifiable Concentrate ◽

Controlled Release Formulation ◽

No Till ◽

Series Of Experiments

A series of experiments were conducted from 1983 through 1986 to determine the efficacy of encapsulated starch formulations of trifluralin [2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine] in conventional and no-till soybean [Glycine max(L.) Merr.] production. The encapsulated starch formulations remaining on the soil surface were significantly more effective than the emulsifiable concentrate when applied in February, March, or April. Encapsulated trifluralin products prepared by both the starch xanthate and starch borate processes were as effective as the emulsifiable concentrate even when used in conventional-tillage systems for weed control and for maintaining soybean yields. Our data indicate that an effective and economical herbicide such as trifluralin need not be lost in no-till soybean production if new controlled-release formulation technology is used by the agricultural industry.

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Herbicide Effectiveness, Soil Residues, and Phytotoxicity to Peach Trees

Weed Science ◽

10.1017/s0043174500048839 ◽

1971 ◽

Vol 19 (3) ◽

pp. 257-260 ◽

Cited By ~ 7

Author(s):

W. A. Skroch ◽

T. J. Sheets ◽

J. W. Smith

Keyword(s):

Weed Control ◽

Prunus Persica ◽

Cynodon Dactylon ◽

Soil Depth ◽

Soil Layer ◽

Soil Surface ◽

The Third ◽

Low Concentrations ◽

Peach Trees ◽

Annual Application

Dichlobenil (2,6-dichlorobenzonitrile), 3-tert-butyl-5-chloro-6-methyluracil (terbacil), and 3-tert-butyl-5-bromo-6-methyluracil (hereinafter referred to as DP-733) were applied annually for 3 years as soil surface or incorporated treatments for weed control in young peach (Prunus persica(L.) Batsch., var. Redhaven) trees. Average monthly ratings showed significant increases in bermudagrass (Cynodon dactylon(L.) Pers.) control with incorporation of all three herbicides. Treetrunk diameters in incorporated dichlobenil plots were greater than those in surface-applied dichlobenil plots. Incorporation in the soil reduced loss of dichlobenil, terbacil, and DP-733. The herbicides did not accumulate in the 0 to 15-cm soil layer. Low concentrations were detected in the 30 to 60-cm soil depth 1 year after the third annual application of 6.72 kg/ha of dichlobenil and 4.48 kg/ha of DP-733. Terbacil was not present in detectable amounts at 30 to 60 cm but was present in the 15 to 30-cm layer of 4.48 kg/ha plots.

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Effect of soil incorporation and dose on control of field bindweed(Convolvulus arvensis)with the preemergence bioherbicidePhomopsis convolvulus

Weed Science ◽

10.1017/s0043174500089724 ◽

1998 ◽

Vol 46 (6) ◽

pp. 690-697 ◽

Cited By ~ 2

Author(s):

S. Vogelgsang ◽

A. K. Watson ◽

A. DiTommaso

Keyword(s):

Weed Control ◽

Aboveground Biomass ◽

Soil Surface ◽

Field Trials ◽

Field Conditions ◽

Effective Control ◽

Controlled Environment ◽

Convolvulus Arvensis ◽

Growing Seasons ◽

Field Bindweed

The preemergence efficacy of soil surface applications of aPhomopsis convolvulusgranular formulation to control field bindweed seedlings was compared with its efficacy when inoculum granules were incorporated in soil. In addition, the effect of different doses of soil-applied granules was also determined. Under controlled environment conditions, incorporation of the fungal granules resulted in aboveground biomass reductions between 88 and 96%, with no significant differences observed between incorporation depths of 1.5 and 3 cm. Granule applications on the soil surface were less effective, reducing aboveground biomass 40 to 83%. In a parallel field experiment conducted over two growing seasons, however, surface applications of inoculum granules resulted in greater weed control compared with soil incorporation of the granules. In spring and summer trials conducted in 1996, surface applications resulted in a 93 and 100% aboveground biomass reduction, respectively, whereas incorporated granules reduced biomass 62 and 97%. Similar trends were observed in 1997. Different soil-applied doses ofP. convolvulusdid not affect the level of weed control under both controlled environment and field conditions. In 1995 and 1996 field trials, all rates used (30, 20, and 10 g 0.25m−2plot) resulted in substantial (90 to 100%) field bindweed aboveground biomass reductions. Findings in this study indicate that under field conditions, preemergence applications of the bioherbicideP. convolvuluson the soil surface provide effective control of field bindweed.

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LYSIMETERS WITH RAINFALL AND SOIL WATER CONTROL

Hydrology Research ◽

10.2166/nh.1971.0006 ◽

1971 ◽

Vol 2 (2) ◽

pp. 79-92 ◽

Cited By ~ 17

Author(s):

K. J. KRISTENSEN ◽

H. C. ASLYNG

Keyword(s):

Soil Moisture Content ◽

Soil Depth ◽

Irrigation System ◽

Drainage System ◽

Soil Surface ◽

Trickle Irrigation ◽

Water Control ◽

Radiation Equipment ◽

Different Depths ◽

Growth Experiments

The lysimeter installation described comprises 36 concrete tanks each with a soil surface of 4 m2. The installation is useful for plant growth experiments under natural conditions involving different treatment combined with various controlled water supplies. The ground installation is at least 20 cm below the soil surface and tillage can be done with field implements. The lysimeter tanks are provided with a drainage system which can drain the soil at the bottom (100 cm depth) to a tension of up to 100 cm. A constant ground-water table at less than 100 cm soil depth can also be maintained. The soil moisture content at different depths is determined from an underground tunnel by use of gamma radiation equipment in metal tubes horizontally installed in the soil. Rainfall is prevented by a movable glass roof automatically operated and controlled by a special rain sensor. Water is applied to the soil surface with a special trickle irrigation system consisting of a set of plastic tubes for each lysimeter tank and controlled from the tunnel. Fertilizers in controlled amount can be applied with the irrigation water.

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Smallseed Falseflax (Camelina microcarpa) Management in Oklahoma Winter Wheat

Weed Technology ◽

10.1017/wet.2021.51 ◽

2021 ◽

pp. 1-14

Author(s):

Jodie A. Crose ◽

Misha R. Manuchehri ◽

Todd A. Baughman

Keyword(s):

Winter Wheat ◽

Weed Control ◽

Herbicide Resistance ◽

Wheat Yield ◽

Acetolactate Synthase ◽

Growing Season ◽

Time Of Application ◽

Adequate Control ◽

Growing Seasons

Abstract Three herbicide premixes have recently been introduced for weed control in wheat. These include: halauxifen + florasulam, thifensulfuron + fluroxypyr, and bromoxynil + bicyclopyrone. The objective of this study was to evaluate these herbicides along with older products for their control of smallseed falseflax in winter wheat in Oklahoma. Studies took place during the 2017, 2018, and 2020 winter wheat growing seasons. Weed control was visually estimated every two weeks throughout the growing season and wheat yield was collected in all three years. Smallseed falseflax size was approximately six cm in diameter at time of application in all years. Control ranged from 96 to 99% following all treatments with the exception of bicyclopyrone + bromoxynil and dicamba alone, which controlled falseflax 90%. All treatments containing an acetolactate synthase (ALS)-inhibiting herbicide achieved adequate control; therefore, resistance is not suspected in this population. Halauxifen + florasulam and thifensulfuron + fluroxypyr effectively controlled smallseed falseflax similarly to other standards recommended for broadleaf weed control in wheat in Oklahoma. Rotational use of these products allows producers flexibility in controlling smallseed falseflax and reduces the potential for development of herbicide resistance in this species.

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Impact of Weed Control by Hand Tools on Soil Erosion under a No-Tillage System Cultivation

Agronomy ◽

10.3390/agronomy11050974 ◽

2021 ◽

Vol 11 (5) ◽

pp. 974

Author(s):

Rafael Blanco-Sepúlveda ◽

Amilcar Aguilar-Carrillo ◽

Francisco Lima

Keyword(s):

Soil Erosion ◽

Weed Control ◽

Soil Cover ◽

Soil Surface ◽

Conservation Agriculture ◽

Soil Disturbance ◽

No Tillage ◽

Tropical Mountains ◽

Litter Cover ◽

Vegetal Cover

In conservation agriculture, the no-tillage cultivation system and the retention of permanent vegetal cover are crucial to the control of soil erosion by water. This paper analyses the cultivation of maize under no-tillage, with particular reference to the effect produced on soil erosion when weed control is performed by a hand tool (machete), which disturbs the surface of the soil, and to the behavior of the soil cover in these circumstances. The study area is located in the humid tropical mountains of northern Nicaragua (Peñas Blancas Massif Nature Reserve). The results obtained show that 59.2% of the soil surface was affected by appreciable levels of sheet and splash erosion, although the vegetal cover of the soil was relatively high (with average weed and litter cover of 33.9% and 33.8%, respectively). The use of machetes for weed control provoked considerable soil disturbance, which explained the high rates of erosion observed. Moreover, this form of soil management disturbs the litter layer, making it less effective in preventing erosion. The litter remains loose on the soil surface, and so an increase in soil cover does not achieve a proportionate reduction in the area affected by erosion; thus, even with 80–100% weed and litter cover, 42% of the cultivated area continued to present soil erosion.

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Simulated controlled-release mesotrione for turfgrass tolerance and weed control

Weed Technology ◽

10.1017/wet.2021.19 ◽

2021 ◽

pp. 1-25

Author(s):

Matthew J. R. Goddard ◽

Clebson G. Gonçalves ◽

Shawn D. Askew

Keyword(s):

Controlled Release ◽

Weed Control ◽

White Clover ◽

Tall Fescue ◽

Standard Treatment ◽

Creeping Bentgrass ◽

Control Efficacy ◽

Stepwise Change

Abstract Mesotrione typically requires multiple applications to control emerged weeds in turfgrass. Since it is absorbed by both foliage and roots, a controlled-release (CR) formulation could eliminate the need for multiple applications. Research was conducted evaluate simulated-release scenarios that mimic a potential CR mesotrione formulation. A soluble concentrate formulation of mesotrione was titrated to produce a stepwise change in mesotrione rates, which were applied daily to mimic predetermined release scenarios over a three-wk period. CR scenarios were compared to a broadcast treatment of mesotrione at 280 g ai ha-1 applied twice at three-wk intervals, and a nontreated. Mesotrione applied in three temporal release scenarios controlled creeping bentgrass, goosegrass, nimblewill, smooth crabgrass, and white clover equivalent to the standard sprayed mesotrione treatment in every comparison. However, each CR scenario injured tall fescue 2 to 7 times more than the standard treatment. Soil- and foliar-initiated repeat treatments were equivalent in most comparisons. Data indicates that mesotrione applied in a temporal range to simulate controlled release scenarios can deliver desired weed control efficacy comparable to sequential broadcast applications. More research is needed to elucidate proper timings and release scenarios to minimize turfgrass injury.

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Calcium Biogeochemical Cycle in a Typical Karst Forest: Evidence from Calcium Isotope Compositions

Forests ◽

10.3390/f12060666 ◽

2021 ◽

Vol 12 (6) ◽

pp. 666

Author(s):

Guilin Han ◽

Anton Eisenhauer ◽

Jie Zeng ◽

Man Liu

Keyword(s):

Soil Depth ◽

Isotope Composition ◽

Soil Surface ◽

Natural Soil ◽

Calcium Isotope ◽

Karst Forest ◽

Content Ratio ◽

The Difference ◽

Preferential Uptake ◽

Vital Factor

In order to better constrain calcium cycling in natural soil and in soil used for agriculture, we present the δ44/40Ca values measured in rainwater, groundwater, plants, soil, and bedrock samples from a representative karst forest in SW China. The δ44/40Ca values are found to differ by ≈3.0‰ in the karst forest ecosystem. The Ca isotope compositions and Ca contents of groundwater, rainwater, and bedrock suggest that the Ca of groundwater primarily originates from rainwater and bedrock. The δ44/40Ca values of plants are lower than that of soils, indicating the preferential uptake of light Ca isotopes by plants. The distribution of δ44/40Ca values in the soil profiles (increasing with soil depth) suggests that the recycling of crop-litter abundant with lighter Ca isotope has potential effects on soil Ca isotope composition. The soil Mg/Ca content ratio probably reflects the preferential plant uptake of Ca over Mg and the difference in soil maturity. Light Ca isotopes are more abundant in mature soils than nutrient-depleted soils. The relative abundance in the light Ca isotope (40Ca) is in the following order: farmland > burnt grassland > forests > grassland > shrubland. Our results further indicate that biological fractionation in a soil–plant system is a vital factor for Ca–geochemical transformations in soil surface systems.

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