Field bindweed infests millions of hectares in the Great Plains greatly reducing productivity and... more Field bindweed infests millions of hectares in the Great Plains greatly reducing productivity and value of land. The standard practice for field bindweed control is sweep tillage at 3 wk intervals combined with one or two annual 2,4-D) applications during the 14 mo fallow period in a winter wheat-fallow crop rotation. This was compared to tillage and 2,4-D in conjunction with dicamba or a mixture of picloram+2,4-D applied once during the first October of the first 14 mo fallow period. Also, three no-tillage systems were included using glyphosate+2,4-D at monthly intervals. Two of the treatments were supplemented with dicamba, or picloram+2,4-D as in the sweep tillage system. All treatments controlled field bindweed in two fallow periods and two winter wheat crops, and increased winter wheat yields to about twice the control. Sweep tillage at 3 wk intervals combined with 2,4-D resulted in $36 ha−1profit for an owner-operator compared to $15 ha−1loss with no herbicide or tillage treatment. On average no-tillage lost $35 ha−1. Other treatments, although controlling field bindweed, lost from 35 to $186 ha−1. To determine if long-term benefit after control was achieved, average yields for the area were used to calculate profits using normal farming practices. Profits were 136, 78, and $-50 ha−1, respectively, for sweep tillage and 2,4-D, no-tillage, and the untreated check. In a standard 33:67 owner-tenant rental, profits to the owner for the control period were 90, −33, and $43 ha−1, respectively for tillage and 2,4-D, no-tillage, and untreated check. The tenant lost from $24 to 69 ha−1for the three systems indicating owners must modify rental agreements during a field bindweed control program.
Field and laboratory studies were conducted to examine the influence of previous pesticide use, n... more Field and laboratory studies were conducted to examine the influence of previous pesticide use, number of prior EPTC (S-ethyl dipropyl carbamothioate) and butylate [S-ethyl bis(2-methylpropyl)carbamothioate] applications, and pretreatment of soil with EPTC and butylate metabolites on EPTC and butylate degradation. EPTC degradation was enhanced in Clay Center and Scottsbluff soils following three annual EPTC, butylate, or vernolate (S-propyl dipropylcarbamothioate) applications, but was not affected in soils following three annual atrazine [6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine], cyanazine {2-[[4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl] amino]-2-methylpropanenitrile}, metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide], alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide], or cycloate (S-ethyl cyclohexylethylcarbamothioate) applications. EPTC degradation rate was not affected in a Scottsbluff soil following three annual carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate) applications, but was partially enhanced in a Clay Center soil. Self- and cross-enhanced degradation of EPTC and butylate did not change regardless of the number of prior annual applications of each herbicide. The degradation rates of EPTC and butylate were not affected by soil pretreated with butylate sulfone, but the degradation rates-were fully enhanced by pretreatment with the respective sulfoxides of each herbicide. In cross-enhancement testing, EPTC and butylate degradation was partially enhanced in Clay Center soil pretreated with the sulfoxides of each.
Summer annual forages are a practical roughage source for stocker cattle opera-tions because of t... more Summer annual forages are a practical roughage source for stocker cattle opera-tions because of their high yield potential. A 2-yr study was conducted to compare the performance of steers grazing 2 dif-ferent varieties of sorghum-sudangrass hybrids at different stocking rates. ...
Field and laboratory studies were conducted to examine the influence of continuous use and rotati... more Field and laboratory studies were conducted to examine the influence of continuous use and rotation of extenders on EPTC persistence in soils from Clay Center and Scottsbluff, NE. Rotation of EPTC + dietholate and EPTC + fonofos in soils with three prior annual treatments of each combination did not improve weed control compared to continuous use. SC-0058 was generally effective in slowing EPTC biodegradation in soils previously treated with EPTC, EPTC + dietholate, EPTC + fonofos, or EPTC + SC-0058. Dietholate was effective in slowing EPTC biodegradation in soil previously treated with EPTC or EPTC + SC-0058. SC-0058 appeared to have an inhibitory influence on the initial development of soil-enhanced EPTC biodegradation. Any enhanced biodegradation of dietholate or SC-0058 that may occur after repeated use was not a factor in enhanced EPTC degradation in EPTC + extender history soils.
Weed prevention consists of cultural practices to prevent the establishment of perennial weeds. I... more Weed prevention consists of cultural practices to prevent the establishment of perennial weeds. It is impossible to reclaim infested fields from perennial weeds if weeds are continuously reinvading clean croplands. Weed prevention includes control in surrounding noncrop areas, such as fence rows, playa lake beds, turn rows, and ditches. Every effort should be made to control small infested areas in a field. Spot treatments are generally much more effective and economical than trying to control perennial weeds over large areas. Planting weed-free crop seed and making sure tillage and harvesting equipment is free of weed seed and root segments are essential. Gin trash and feedlot manure are also potential sources of perennial weed seed.
Potential yield losses in grain sorghum due to weed interference based on quantitative data from ... more Potential yield losses in grain sorghum due to weed interference based on quantitative data from the major grain sorghum-growing areas of the United States are reported by the WSSA Weed Loss Committee. Weed scientists and extension specialists who researched weed control in grain sorghum provided data on grain sorghum yield loss due to weed interference in their region. Data were requested from up to 10 individual experiments per calendar year over 10 yr between 2007 and 2016. Based on the summarized information, farmers in Arkansas, Kansas, Missouri, Nebraska, South Dakota, and Texas would potentially lose an average of 37%, 38%, 30%, 56%, 61%, and 60% of their grain sorghum yield with no weed control, and have a corresponding annual monetary loss of US $19 million, 302 million, 7 million, 32 million, 25 million, and 314 million, respectively. The overall average yield loss due to weed interference was estimated to be 47% for this grain sorghum-growing region. Thus, US farmers would lose approximately 5,700 million kg of grain sorghum valued at approximately US $953 million annually if weeds are not controlled. With each dollar invested in weed management (based on estimated weed control cost of US $100 ha−1), there would be a return of US $3.80, highlighting the return on investment in weed management and the importance of continued weed science research for sustaining high grain sorghum yield and profitability in the United States.
Drought is an important factor limiting corn (Zea mays L.) yields in the Texas High Plains, and a... more Drought is an important factor limiting corn (Zea mays L.) yields in the Texas High Plains, and adoption of drought‐tolerant (DT) hybrids could be a management tool under water shortage. We conducted a 3‐yr field study to investigate yield, evapotranspiration (ET), and water use efficiency (WUE) in DT hybrids. One conventional (33D49) and 4 DT hybrids (P1151HR, P1324HR, P1498HR, and P1564HR) were grown at three water regimes (I100, I75, and I50, referring to 100, 75, and 50% ET requirement) and three planting densities (PD) (5.9, 7.4, and 8.4 plants m−2). Yield (13.56 Mg ha−1) and ET (719 mm) were the greatest at I100 but WUE (2.1 kg m−3) was the greatest at I75. Although DT hybrids did not always have greater yield and WUE than 33D49 at I100, hybrids P1151HR and P1564HR consistently had greater yield and WUE than 33D49 at I75 and I50. Compared to 33D49, P1151HR and P1564HR had 8.6 to 12.1% and 19.1% greater yield at I75 and I50, respectively. Correspondingly, WUE was 9.8 to 11.7% a...
Field studies were conducted in 2009 and 2010 to determine control of Palmer amaranth and crop in... more Field studies were conducted in 2009 and 2010 to determine control of Palmer amaranth and crop injury resulting from a postemergence (POST) premix application of pyrasulfotole + bromoxynil and various tank‐mix partners. The objectives were to (i) determine the effects of different pyrasulfotole + bromoxynil rates and tank‐mix partners applied at early and mid‐POST (EPOST and MPOST) on Palmer amaranth control; (ii) evaluate weed control following application at different Palmer amaranth sizes; and (iii) assess sorghum injury and yield as affected by herbicides applied at the 4‐leaf, 10‐leaf, and boot stages. At both EPOST and MPOST, pyrasulfotole + bromoxynil + atrazine alone or mixed with 2,4‐D or dicamba consistently provided better Palmer amaranth control (>98% at EPOST and >90% at MPOST) than bromoxynil + atrazine (94% at EPOST and 58% at MPOST). At EPOST, control of Palmer amaranth by pyrasulfotole + bromoxynil alone varied with year, but the control was 100% at 42 days af...
Texas planted 2.35 million acres of corn in 2009. Silage corn acreage in Texas has doubled from 7... more Texas planted 2.35 million acres of corn in 2009. Silage corn acreage in Texas has doubled from 70,000 acres since 1995. Most of this increase has occurred in the High Plains. The number of dairies located in this region has more than doubled since 2000. Seven of the top milk producing counties in Texas are now located in the region. Silage corn production will play an
Field bindweed infests millions of hectares in the Great Plains greatly reducing productivity and... more Field bindweed infests millions of hectares in the Great Plains greatly reducing productivity and value of land. The standard practice for field bindweed control is sweep tillage at 3 wk intervals combined with one or two annual 2,4-D) applications during the 14 mo fallow period in a winter wheat-fallow crop rotation. This was compared to tillage and 2,4-D in conjunction with dicamba or a mixture of picloram+2,4-D applied once during the first October of the first 14 mo fallow period. Also, three no-tillage systems were included using glyphosate+2,4-D at monthly intervals. Two of the treatments were supplemented with dicamba, or picloram+2,4-D as in the sweep tillage system. All treatments controlled field bindweed in two fallow periods and two winter wheat crops, and increased winter wheat yields to about twice the control. Sweep tillage at 3 wk intervals combined with 2,4-D resulted in $36 ha−1profit for an owner-operator compared to $15 ha−1loss with no herbicide or tillage treatment. On average no-tillage lost $35 ha−1. Other treatments, although controlling field bindweed, lost from 35 to $186 ha−1. To determine if long-term benefit after control was achieved, average yields for the area were used to calculate profits using normal farming practices. Profits were 136, 78, and $-50 ha−1, respectively, for sweep tillage and 2,4-D, no-tillage, and the untreated check. In a standard 33:67 owner-tenant rental, profits to the owner for the control period were 90, −33, and $43 ha−1, respectively for tillage and 2,4-D, no-tillage, and untreated check. The tenant lost from $24 to 69 ha−1for the three systems indicating owners must modify rental agreements during a field bindweed control program.
Field and laboratory studies were conducted to examine the influence of previous pesticide use, n... more Field and laboratory studies were conducted to examine the influence of previous pesticide use, number of prior EPTC (S-ethyl dipropyl carbamothioate) and butylate [S-ethyl bis(2-methylpropyl)carbamothioate] applications, and pretreatment of soil with EPTC and butylate metabolites on EPTC and butylate degradation. EPTC degradation was enhanced in Clay Center and Scottsbluff soils following three annual EPTC, butylate, or vernolate (S-propyl dipropylcarbamothioate) applications, but was not affected in soils following three annual atrazine [6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine], cyanazine {2-[[4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl] amino]-2-methylpropanenitrile}, metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide], alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide], or cycloate (S-ethyl cyclohexylethylcarbamothioate) applications. EPTC degradation rate was not affected in a Scottsbluff soil following three annual carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate) applications, but was partially enhanced in a Clay Center soil. Self- and cross-enhanced degradation of EPTC and butylate did not change regardless of the number of prior annual applications of each herbicide. The degradation rates of EPTC and butylate were not affected by soil pretreated with butylate sulfone, but the degradation rates-were fully enhanced by pretreatment with the respective sulfoxides of each herbicide. In cross-enhancement testing, EPTC and butylate degradation was partially enhanced in Clay Center soil pretreated with the sulfoxides of each.
Summer annual forages are a practical roughage source for stocker cattle opera-tions because of t... more Summer annual forages are a practical roughage source for stocker cattle opera-tions because of their high yield potential. A 2-yr study was conducted to compare the performance of steers grazing 2 dif-ferent varieties of sorghum-sudangrass hybrids at different stocking rates. ...
Field and laboratory studies were conducted to examine the influence of continuous use and rotati... more Field and laboratory studies were conducted to examine the influence of continuous use and rotation of extenders on EPTC persistence in soils from Clay Center and Scottsbluff, NE. Rotation of EPTC + dietholate and EPTC + fonofos in soils with three prior annual treatments of each combination did not improve weed control compared to continuous use. SC-0058 was generally effective in slowing EPTC biodegradation in soils previously treated with EPTC, EPTC + dietholate, EPTC + fonofos, or EPTC + SC-0058. Dietholate was effective in slowing EPTC biodegradation in soil previously treated with EPTC or EPTC + SC-0058. SC-0058 appeared to have an inhibitory influence on the initial development of soil-enhanced EPTC biodegradation. Any enhanced biodegradation of dietholate or SC-0058 that may occur after repeated use was not a factor in enhanced EPTC degradation in EPTC + extender history soils.
Weed prevention consists of cultural practices to prevent the establishment of perennial weeds. I... more Weed prevention consists of cultural practices to prevent the establishment of perennial weeds. It is impossible to reclaim infested fields from perennial weeds if weeds are continuously reinvading clean croplands. Weed prevention includes control in surrounding noncrop areas, such as fence rows, playa lake beds, turn rows, and ditches. Every effort should be made to control small infested areas in a field. Spot treatments are generally much more effective and economical than trying to control perennial weeds over large areas. Planting weed-free crop seed and making sure tillage and harvesting equipment is free of weed seed and root segments are essential. Gin trash and feedlot manure are also potential sources of perennial weed seed.
Potential yield losses in grain sorghum due to weed interference based on quantitative data from ... more Potential yield losses in grain sorghum due to weed interference based on quantitative data from the major grain sorghum-growing areas of the United States are reported by the WSSA Weed Loss Committee. Weed scientists and extension specialists who researched weed control in grain sorghum provided data on grain sorghum yield loss due to weed interference in their region. Data were requested from up to 10 individual experiments per calendar year over 10 yr between 2007 and 2016. Based on the summarized information, farmers in Arkansas, Kansas, Missouri, Nebraska, South Dakota, and Texas would potentially lose an average of 37%, 38%, 30%, 56%, 61%, and 60% of their grain sorghum yield with no weed control, and have a corresponding annual monetary loss of US $19 million, 302 million, 7 million, 32 million, 25 million, and 314 million, respectively. The overall average yield loss due to weed interference was estimated to be 47% for this grain sorghum-growing region. Thus, US farmers would lose approximately 5,700 million kg of grain sorghum valued at approximately US $953 million annually if weeds are not controlled. With each dollar invested in weed management (based on estimated weed control cost of US $100 ha−1), there would be a return of US $3.80, highlighting the return on investment in weed management and the importance of continued weed science research for sustaining high grain sorghum yield and profitability in the United States.
Drought is an important factor limiting corn (Zea mays L.) yields in the Texas High Plains, and a... more Drought is an important factor limiting corn (Zea mays L.) yields in the Texas High Plains, and adoption of drought‐tolerant (DT) hybrids could be a management tool under water shortage. We conducted a 3‐yr field study to investigate yield, evapotranspiration (ET), and water use efficiency (WUE) in DT hybrids. One conventional (33D49) and 4 DT hybrids (P1151HR, P1324HR, P1498HR, and P1564HR) were grown at three water regimes (I100, I75, and I50, referring to 100, 75, and 50% ET requirement) and three planting densities (PD) (5.9, 7.4, and 8.4 plants m−2). Yield (13.56 Mg ha−1) and ET (719 mm) were the greatest at I100 but WUE (2.1 kg m−3) was the greatest at I75. Although DT hybrids did not always have greater yield and WUE than 33D49 at I100, hybrids P1151HR and P1564HR consistently had greater yield and WUE than 33D49 at I75 and I50. Compared to 33D49, P1151HR and P1564HR had 8.6 to 12.1% and 19.1% greater yield at I75 and I50, respectively. Correspondingly, WUE was 9.8 to 11.7% a...
Field studies were conducted in 2009 and 2010 to determine control of Palmer amaranth and crop in... more Field studies were conducted in 2009 and 2010 to determine control of Palmer amaranth and crop injury resulting from a postemergence (POST) premix application of pyrasulfotole + bromoxynil and various tank‐mix partners. The objectives were to (i) determine the effects of different pyrasulfotole + bromoxynil rates and tank‐mix partners applied at early and mid‐POST (EPOST and MPOST) on Palmer amaranth control; (ii) evaluate weed control following application at different Palmer amaranth sizes; and (iii) assess sorghum injury and yield as affected by herbicides applied at the 4‐leaf, 10‐leaf, and boot stages. At both EPOST and MPOST, pyrasulfotole + bromoxynil + atrazine alone or mixed with 2,4‐D or dicamba consistently provided better Palmer amaranth control (>98% at EPOST and >90% at MPOST) than bromoxynil + atrazine (94% at EPOST and 58% at MPOST). At EPOST, control of Palmer amaranth by pyrasulfotole + bromoxynil alone varied with year, but the control was 100% at 42 days af...
Texas planted 2.35 million acres of corn in 2009. Silage corn acreage in Texas has doubled from 7... more Texas planted 2.35 million acres of corn in 2009. Silage corn acreage in Texas has doubled from 70,000 acres since 1995. Most of this increase has occurred in the High Plains. The number of dairies located in this region has more than doubled since 2000. Seven of the top milk producing counties in Texas are now located in the region. Silage corn production will play an
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