scholarly journals Nitrous oxide emissions from riparian forest buffers, warm-season and cool-season grass filters, and crop fields

2009 ◽  
Vol 6 (1) ◽  
pp. 607-650 ◽  
Author(s):  
D.-G. Kim ◽  
T. M. Isenhart ◽  
T. B. Parkin ◽  
R. C. Schultz ◽  
T. E. Loynachan ◽  
...  
Keyword(s):  
Warm Season ◽  
Fold Increase ◽  
N2o Emission ◽  
Riparian Buffers ◽  
N2o Emissions ◽  
Vegetation Types ◽  
Cool Season ◽  
Frozen Soils ◽  
Crop Field ◽  
Cool Season Grass

Abstract. Denitrification within riparian buffers may trade reduced nonpoint source pollution of surface waters for increased greenhouse gas emissions resulting from denitrification-produced nitrous oxide (N2O). However, little is known about the N2O emission within conservation buffers established for water quality improvement or of the importance of short-term N2O peak emission following rewetting dry soils and thawing frozen soils. Such estimates are important in reducing uncertainties in current Intergovernmental Panel on Climate Change (IPCC) methodologies estimating soil N2O emission which are based on N inputs. This study contrasts N2O emission from riparian buffer systems of three perennial vegetation types and an adjacent crop field, and compares measured N2O emission with estimates based on the IPCC methodology. We measured soil properties, N inputs, weather conditions and N2O fluxes from soils in forested riparian buffers, warm-season and cool-season grass filters, and a crop field located in the Bear Creek watershed in central Iowa, USA. Cumulative N2O emissions from soils in all riparian buffers (5.8 kg N2O-N ha−1 in 2006–2007) were significantly less than those from crop field soils (24.0 kg N2O-N ha−1 in 2006–2007), with no difference among the buffer vegetation types. While N2O peak emissions (up to 70-fold increase) following the rewetting of dry soils and thawing of frozen soils comprised 46–70% of the annual N2O emissions from soils in the crop field, soils in the riparian buffers were less sensitive to such events (3 to 10-fold increase). The ratio of N2O emission to N inputs within riparian buffers (0.02) was smaller than those of crop field (0.07). These results indicate that N2O emission from soils within the riparian buffers established for water quality improvement should not be considered a major source of N2O emission compared to crop field emission. The observed large difference between measured N2O emissions and those estimated using the IPCC's recommended methodology (i.e., 87% underestimation) in the crop field suggests that the IPCC methodology may underestimate N2O emission in the regions where soil rewetting and thawing are common, and that conditions predicted by future climate-change scenarios may increase N2O emissions.

scholarly journals Nitrate and dissolved nitrous oxide in groundwater within cropped fields and riparian buffers

2009 ◽  
Vol 6 (1) ◽  
pp. 651-685 ◽  
Author(s):  
D.-G. Kim ◽  
T. M. Isenhart ◽  
T. B. Parkin ◽  
R. C. Schultz ◽  
T. E. Loynachan
Keyword(s):  
Nitrous Oxide ◽  
N2o Emission ◽  
Riparian Buffers ◽  
Riparian Buffer ◽  
N2o Emissions ◽  
Cool Season ◽  
N2o Flux ◽  
Crop Fields ◽  
Ipcc Methodology ◽  
Cool Season Grass

Abstract. Transport and fate of dissolved nitrous oxide (N2O) in groundwater and its significance to nitrogen dynamics within agro-ecosystems are poorly known in spite of significant potential of N2O to global warming and ozone depletion. Increasing denitrification in riparian buffers may trade a reduction in nitrate (NO3−) transport to surface waters for increased N2O emissions resulting from denitrification-produced N2O dissolved in groundwater being emitted into the air when groundwater flows into a stream or a river. This study quantifies the transport and fate of NO3− and dissolved N2O moving from crop fields through riparian buffers, assesses whether groundwater exported from crop fields and riparian buffers is a significant source of dissolved N2O emissions, and evaluates the Intergovernmental Panel on Climate Change (IPCC) methodology to estimate dissolved N2O emission. We measured concentrations of NO3−; chloride (Cl−); pH; dissolved N2O, dissolved oxygen (DO), and organic carbon (DOC) in groundwater under a multi-species riparian buffer, a cool-season grass filter, and adjacent crop fields located in the Bear Creek watershed in central Iowa, USA. In both the multi-species riparian buffer and the cool-season grass filter, concentrations of dissolved N2O in the groundwater did not change as it passed through the sites, even when the concentrations of groundwater NO3− were decreased by 50% and 59%, respectively, over the same periods. The fraction of N lost to leaching and runoff (0.05) and the modified N2O emission factor, [ratio of dissolved N2O flux to N input (0.00002)] determined for the cropped fields indicate that the current IPCC methodology overestimates dissolved N2O flux in the sites. A low ratio between dissolved N2O flux and soil N2O emission (0.0003) was estimated in the cropped fields. These results suggest that the riparian buffers established adjacent to crop fields for water quality functions (enhanced denitrification) decreased NO3− and were not a source of dissolved N2O. Also, the flux of dissolved N2O from the cropped field was negligible in comparison to soil N2O emission in the crop fields.

Small mammal use of native warm-season and non-native cool-season grass forage fields

2014 ◽  
Vol 39 (1) ◽  
pp. 49-55
Author(s):  
Ryan L. Klimstra ◽  
Christopher E. Moorman ◽  
Sarah J. Converse ◽  
J. Andrew Royle ◽  
Craig A. Harper
Keyword(s):  
Small Mammal ◽  
Warm Season ◽  
Cool Season ◽  
Cool Season Grass

Ecological and Control Studies of Musk Thistle

Weed Science ◽  
1968 ◽  
Vol 16 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Israel Feldman ◽  
M. K. McCarty ◽  
C. J. Scifres
Keyword(s):  
Warm Season ◽  
Dichlorophenoxyacetic Acid ◽  
Cool Season ◽  
Carduus Nutans ◽  
Warm Season Grass ◽  
Excellent Control ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
And Control ◽  
Cool Season Grass ◽  
Thistle Plant

Herbicides applied April 30, May 10, or October 14 gave best control of musk thistle (Carduus nutansL.). The most effective herbicide at all dates and rates was 4-amino-3,5,6-trichloropicolinic acid (picloram). Two lb/A of 2-methoxy-3,6-dichlorobenzoic acid (dicamba) also was effective at all spring dates. Two lb/A of 2,4-dichlorophenoxyacetic acid (2,4-D) resulted in excellent control of musk thistle when applied May 10 or October 14.More musk thistle seedlings became established in nongrazed, cool season grass pastures than in nongrazed, mixed warm season grass pastures. Greater germination was attributed to the reserve moisture and accumulation of litter which served as an excellent germination medium. However, only one musk thistle plant remained in the nongrazed pastures 1 year after seeding. The remainder of the seedlings and young rosettes found in the protected areas in 1965 had succumbed to the heavy competition by 1966.

Breeding songbird use of native warm-season and non-native cool-season grass forage fields

2017 ◽  
Vol 41 (1) ◽  
pp. 42-48 ◽  
Author(s):  
Christopher E. Moorman ◽  
Ryan L. Klimstra ◽  
Craig A. Harper ◽  
Jeffrey F. Marcus ◽  
Clyde E. Sorenson
Keyword(s):  
Warm Season ◽  
Cool Season ◽  
Cool Season Grass

scholarly journals Seeding Rate Effects on Forage Mass and Vegetation Dynamics of Cool-Season Grass Sod Interseeded with Sorghum-Sudangrass

Agronomy ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2449
Author(s):  
John A. Guretzky ◽  
Daren D. Redfearn
Keyword(s):  
Vegetation Dynamics ◽  
Nutritive Value ◽  
Perennial Grass ◽  
Warm Season ◽  
Residual Effects ◽  
Control Treatment ◽  
Seeding Rate ◽  
Cool Season ◽  
Sorghum Sudangrass ◽  
Cool Season Grass

Interseeding annual warm-season grasses into perennial cool-season grasses has the potential to increase summer forage mass and nutritive value. Knowledge of how seeding rate affects annual warm-season grass establishment, forage mass, and vegetation dynamics remains limited. From 2016–2017, we conducted a field experiment evaluating the effects of seeding rates on sorghum-sudangrass (Sorghum bicolor × S. bicolor var. sudanense) density and forage mass and on the frequency of occurrence of plant species in cool-season grass sod in Lincoln, NE. The experiment had a completely randomized design consisting of six replicates of four seeding rates [0, 14, 28, and 35 kg pure live seed (PLS) ha−1] in sod mowed at a 2.5-cm height and one unseeded, non-mowed control treatment. Sorghum-sudangrass establishment increased with seeding rate from an average of 20 to 45 plants m−2 as the seeding rate increased from 14 to 35 kg PLS ha−1. Forage mass depended on a seeding rate × harvest interaction, showing positive linear and cubic responses to seeding rate in consecutive harvests at 45 and 90 d after interseeding. To increase forage mass in perennial cool-season grass sod, producers should interseed sorghum-sudangrass with at least 28 kg PLS ha−1. One-time seedings into cool-season, perennial grass sod have no residual effects on subsequent forage mass and vegetation dynamics.

Evaluating winter annual grass control and native species establishment following applications of indaziflam on rangeland

2020 ◽  
Vol 13 (3) ◽  
pp. 199-209
Author(s):  
Shannon L. Clark ◽  
Derek J. Sebastian ◽  
Scott J. Nissen ◽  
James R. Sebastian
Keyword(s):  
Plant Community ◽  
Weed Management ◽  
Native Species ◽  
Fold Increase ◽  
Native Plant ◽  
Cool Season ◽  
Species Establishment ◽  
Winter Annual ◽  
Cool Season Grass

AbstractIndaziflam, a PRE herbicide option for weed management on rangeland and natural areas, provides long-term control of invasive winter annual grasses (IWAGs). Because indaziflam only provides PRE control of IWAGs, POST herbicides such as glyphosate can be mixed with indaziflam to control germinated IWAG seedlings. Field trials were conducted at three sites on the Colorado Front Range to evaluate glyphosate dose required to provide adequate POST IWAG control and compare long-term downy brome (Bromus tectorum L.), Japanese brome (Bromus arvensis L.), and feral rye (Secale cereale L.) control with indaziflam and imazapic. Two of the three sites were void of desirable species, so species establishment through drill seeding was assessed, while the remnant native plant response was assessed at the third site. Herbicide applications were made March 2014 through April 2015, and two sites were drill seeded with native species 9 mo after herbicide application. Yearly visual control evaluations, biomass of all plant species, and drilled species stand counts were collected. Glyphosate at 474 g ae ha−1 reduced B. tectorum biomass to zero, while glyphosate at 631 g ae ha−1 was needed to reduce biomass to near zero at the S. cereale site. At all three sites, only indaziflam treatments had significant reductions in IWAG biomass compared with the nontreated check at 3 yr after treatment (YAT). By 3 YAT in the drill-seeded sites, cool-season grass frequency ranged from 37% to 69% within indaziflam treatments (73 and 102 g ai ha−1), while imazapic treatments ranged from 0% to 26% cool-season grass frequency. In the site with a remnant native plant community, indaziflam treatments resulted in a 3- to 4-fold increase in native grass biomass. These results indicate that the multiyear IWAG control provided by indaziflam can aid in desirable species reestablishment through drill seeding or response of the remnant plant community.

scholarly journals Leafy Spurge (Euphorbia esula) Response to AC 263,222

1998 ◽  
Vol 12 (4) ◽  
pp. 602-609 ◽  
Author(s):  
Robert A. Masters ◽  
Daniel D. Beran ◽  
Fernando Rivas-Pantoja
Keyword(s):  
Warm Season ◽  
Leafy Spurge ◽  
Euphorbia Esula ◽  
Stem Density ◽  
Single Application ◽  
Cool Season ◽  
Perennial Weed ◽  
Ac 263,222 ◽  
Cool Season Grass ◽  
Fall Application

Leafy spurge is an exotic perennial weed that infests more than 1 million ha in North America and reduces rangeland carrying capacity. Experiments were initiated on range sites in Nebraska and North Dakota in 1994 and 1995 to determine the response of leafy spurge and other vegetation to AC 263,222. Herbicide treatments evaluated included AC 263,222 at 0 to 280 g ai/ha, picloram at 560 g ai/ha plus 2,4-D at 1,120 g ae/ha, and quinclorac at 1,120 g ai/ha. In Nebraska, a single application of AC 263,222 in the fall at 140 g/ha provided ≥ 90% leafy spurge control 11 to 12 mo after treatment. At Jamestown, ND, leafy spurge control increased to almost 90% and stem density declined to two shoots/m212 mo after the second consecutive fall application of AC 263,222 at 140 g/ha. At Hankinson, ND, leafy spurge control was ≤ 50% when AC 263,222 was applied in the fall only, but increased to > 80% when AC 263,222 was applied in the fall and again at 70 or 140 g/ha in the spring. There were no differences in herbage biomass of established cool- and warm-season grasses where AC 263,222 at 140 g/ha, picloram plus 2,4-D, quinclorac, or no herbicide was applied in the fall. In contrast, application of AC 263,222 in the fall and again in the spring usually reduced cool-season grass biomass.

Transition From Overseeded Cool-Season Grass to Warm-Season Grass with Pronamide

Weed Science ◽  
1976 ◽  
Vol 24 (3) ◽  
pp. 309-311 ◽  
Author(s):  
B. J. Johnson
Keyword(s):  
Perennial Ryegrass ◽  
Field Experiments ◽  
Transition Period ◽  
Warm Season ◽  
Cool Season ◽  
Turf Quality ◽  
Warm Season Grass ◽  
Untreated Check ◽  
Cool Season Grass ◽  
Piedmont Region

Field experiments were conducted for 2 yr on pronamide [3,5-dichloro-N-(1,1-dimethyl-2-propynyl)benzamide] treatments in the Piedmont region of Georgia to aid the transition of overseeded cool-season turf to warm-season turf in early spring. Pronamide applied to overseeded perennial ryegrass (Lolium perenneL. ‘Game’ and ‘Manhattan’) gradually reduced the growth of perennial ryegrass and permitted bermudagrass [Cynodon dactylon(L.) Pers. ‘Tifdwarf’] to initiate spring growth with little competition. Total turfgrass cover and turf quality ratings in pronamide treated plots were lower than ratings for untreated plots during the transition period. However, the reduction in turf quality and stand was minimal when pronamide was applied March 20 at 0.8 kg/ha. The turf quality and stand was 76 and 88% of the untreated check on April 23 and May 9, respectively, but the turf fully recovered within 2 weeks. The turf quality was higher in plots treated with pronamide on March 20 than in untreated check throughout June. The optimum date of promanide treatment in the Piedmont Region for transition of cool-season grass to warm-season grass was March 20, when compared to applications made on February 28, April 9, or April 29.

Forage-Based Heifer Development Program for North Florida

EDIS ◽  
2018 ◽  
Vol 2018 (5) ◽  
Author(s):  
Jose C.B. Dubeux ◽  
Nicolas DiLorenzo ◽  
Kalyn Waters ◽  
Jane C. Griffin
Keyword(s):  
Development Program ◽  
Warm Season ◽  
Beef Cows ◽  
Good News ◽  
Cool Season ◽  
Beef Industry ◽  
Performance Targets ◽  
Grazing Systems ◽  
Heifer Development ◽  
Reducing Costs

Florida has 915,000 beef cows and 125,000 replacement heifers (USDA, 2016). Developing these heifers so that they can become productive females in the cow herd is a tremendous investment in a cow/calf operation, an investment that takes several years to make a return. The good news is that there are options to develop heifers on forage-based programs with the possibility of reducing costs while simultaneously meeting performance targets required by the beef industry. Mild winters in Florida allows utilization of cool-season forages that can significantly enhance the performance of grazing heifers. During the warm-season, integration of forage legumes into grazing systems will provide additional nutrients to meet the performance required to develop a replacement heifer to become pregnant and enter the mature cow herd. In this document, we will propose a model for replacement heifer development, based on forage research performed in trials at the NFREC Marianna.   

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