Photosynthetic and Stomatal Responses to Variable Light in a Cool-Season and a Warm-Season Prairie Forb

1996 ◽  
Vol 157 (3) ◽  
pp. 303-308 ◽  
Author(s):  
Philip A. Fay ◽  
Alan K. Knapp
Keyword(s):  
Warm Season ◽  
Cool Season ◽  
Stomatal Responses ◽  
Variable Light

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.   

scholarly journals Milk Production, Body Weight, Body Condition Score, Activity, and Rumination of Organic Dairy Cattle Grazing Two Different Pasture Systems Incorporating Cool- and Warm-Season Forages

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 264
Author(s):  
Kathryn E. Ritz ◽  
Bradley J. Heins ◽  
Roger D. Moon ◽  
Craig C. Sheaffer ◽  
Sharon L. Weyers
Keyword(s):  
Body Weight ◽  
Milk Production ◽  
Body Condition Score ◽  
Warm Season ◽  
Cool Season ◽  
Organic Dairy ◽  
Condition Score ◽  
Annual Grasses ◽  
System 2 ◽  
System 1

Organic dairy cows were used to evaluate the effect of two organic pasture production systems (temperate grass species and warm-season annual grasses and cool-season annuals compared with temperate grasses only) across two grazing seasons (May to October of 2014 and 2015) on milk production, milk components (fat, protein, milk urea nitrogen (MUN), somatic cell score (SCS)), body weight, body condition score (BCS), and activity and rumination (min/day). Cows were assigned to two pasture systems across the grazing season at an organic research dairy in Morris, Minnesota. Pasture System 1 was cool-season perennials (CSP) and Pasture System 2 was a combination of System 1 and warm-season grasses and cool-season annuals. System 1 and System 2 cows had similar milk production (14.7 and 14.8 kg d−1), fat percentage (3.92% vs. 3.80%), protein percentage (3.21% vs. 3.17%), MUN (12.5 and 11.5 mg dL−1), and SCS (4.05 and 4.07), respectively. Cows in System 1 had greater daily rumination (530 min/day) compared to cows in System 2 (470 min/day). In summary, warm-season annual grasses may be incorporated into grazing systems for pastured dairy cattle.

Herbicides for Postemergence Control of Annual Grass Weeds in Seedling Forage Grasses

Weed Science ◽  
1989 ◽  
Vol 37 (3) ◽  
pp. 375-379 ◽  
Author(s):  
Thomas J. Peters ◽  
Russell S. Moomaw ◽  
Alex R. Martin
Keyword(s):  
Warm Season ◽  
Big Bluestem ◽  
Forage Grasses ◽  
Annual Grass ◽  
Cool Season ◽  
Intermediate Wheatgrass ◽  
Green Foxtail ◽  
Annual Grasses ◽  
Large Crabgrass ◽  
Warm Season Grasses

The control of three summer annual grass weeds with herbicides during establishment of forage grasses was studied near Concord and Mead, NE, in 1984, 1985, and 1986. Three cool-season forage grasses, intermediate wheatgrass, tall fescue, and smooth bromegrass, and two warm-season grasses, big bluestem and switchgrass, were included. The control of three major summer annual grasses, green foxtail, barnyardgrass, and large crabgrass, was excellent with fenoxaprop at 0.22 kg ai/ha. Slight to moderate injury to cool-season forage grasses and severe injury to warm-season grasses were evident. Sethoxydim at 0.22 kg ai/ha and haloxyfop at 0.11 kg ai/ha controlled green foxtail and large crabgrass, but not barnyardgrass. Sulfometuron-treated big bluestem and switchgrass plots had the best forage stand frequencies and yields and, at the rate used, sulfometuron satisfactorily controlled green foxtail but only marginally controlled barnyardgrass and large crabgrass.

Seasonal and temperature effects on mycorrhizal activity and dependence of cool- and warm-season tallgrass prairie grasses

1992 ◽  
Vol 70 (8) ◽  
pp. 1596-1602 ◽  
Author(s):  
S. P. Bentivenga ◽  
B. A. D. Hetrick
Keyword(s):  
Tallgrass Prairie ◽  
Mycorrhizal Fungi ◽  
Warm Season ◽  
Growing Season ◽  
Cool Temperature ◽  
Cool Season ◽  
Fungal Activity ◽  
Prairie Grasses ◽  
Vesicular Arbuscular ◽  
Warm Season Grasses

Previous research on North American tallgrass prairie grasses has shown that warm-season grasses rely heavily on vesicular–arbuscular mycorrhizal symbiosis, while cool-season grasses are less dependent on the symbiosis (i.e., receive less benefit). This led to the hypothesis that cool-season grasses are less dependent on the symbiosis, because the growth of these plants occurs when mycorrhizal fungi are inactive. Field studies were performed to assess the effect of phenology of cool- and warm-season grasses on mycorrhizal fungal activity and fungal species composition. Mycorrhizal fungal activity in field samples was assessed using the vital stain nitro blue tetrazolium in addition to traditional staining techniques. Mycorrhizal activity was greater in cool-season grasses than in warm-season grasses early (April and May) and late (December) in the growing season, while mycorrhizal activity in roots of the warm-season grasses was greater (compared with cool-season grasses) in midseason (July and August). Active mycorrhizal colonization was relatively high in both groups of grasses late in the growing season, suggesting that mycorrhizal fungi may proliferate internally or may be parasitic at this time. Total Glomales sporulation was generally greater in the rhizosphere of cool-season grasses in June and in the rhizosphere of the warm-season grasses in October. A growth chamber experiment was conducted to examine the effect of temperature on mycorrhizal dependence of cool- and warm-season grasses. For both groups of grasses, mycorrhizal dependence was greatest at the temperature that favored growth of the host. The results suggest that mycorrhizal fungi are active in roots when cool-season grasses are growing and that cool-season grasses may receive benefit from the symbiosis under relatively cool temperature regimes. Key words: cool-season grasses, tallgrass prairie, vesicular–arbuscular mycorrhizae, warm-season grasses.

Establishment Stage Competition between Exotic Crimson Fountaingrass (Pennisetum setaceum, C4) and Native Purple Needlegrass (Stipa pulchra, C3)

2015 ◽  
Vol 8 (2) ◽  
pp. 139-150 ◽  
Author(s):  
Lynn C. Sweet ◽  
Jodie S. Holt
Keyword(s):  
Southern California ◽  
Niche Partitioning ◽  
Winter Season ◽  
Warm Season ◽  
Summer Rainfall ◽  
Summer Season ◽  
Initial Growth ◽  
Cool Season ◽  
California Grasslands ◽  
Pennisetum Setaceum

Southern California grasslands have largely been type-converted to dominance by exotic annual grasses, leading to displacement of many native grass and forb species. Crimson fountaingrass, Pennisetum setaceum, an exotic perennial C4 species and a relatively new invader to California, is expanding to areas currently occupied by purple needlegrass, Stipa pulchra, a C3 native. We predicted that fountaingrass seedlings might withstand cool season competition in California's Mediterranean-type climate and establish in Stipa pulchra grasslands due to less competition during the warm, dry summer season, and that interactions might be influenced by density. A field experiment was conducted to examine competitive interactions of the two species from the cool winter season to the warm summer season. As predicted, Stipa produced greater aboveground biomass in the cool season and showed strong intraspecific competition, as well as interspecific suppression of Pennisetum growth, whereas Pennisetum showed no suppression of Stipa. In the warm season, Stipa showed relatively less suppression of Pennisetum, erasing significant differences, and Pennisetum showed increased growth. Results of this study show that C3Stipa can suppress initial growth of C4Pennisetum in the cool season, but in warmer months, Pennisetum can overcome this initial suppression at both low and high densities, even within a Mediterranean-type climate with little to no summer rainfall. Thus, in southern California, temporal niche partitioning due to photosynthetic pathway in these two species can allow Pennisetum invasion. Given the similarity in life history and growth form of Stipa and Pennisetum, few options exist for controlling Pennisetum in habitats where Stipa occurs. In these cases, restoration plantings of desirable species are essential in order to reestablish competitive vegetation that will be more resistant to invasion.

scholarly journals Drought Relief and Reversal over North America from 1500 to 2016

2021 ◽  
Vol 25 (1) ◽  
pp. 94-107
Author(s):  
M. C. A. Torbenson ◽  
D. W. Stahle ◽  
I. M. Howard ◽  
D. J. Burnette ◽  
D. Griffin ◽  
...  
Keyword(s):  
Soil Moisture ◽  
North America ◽  
Land Surface ◽  
Large Scale ◽  
Temporal Stability ◽  
Warm Season ◽  
Cool Season ◽  
Continental Scale ◽  
The North ◽  
Drought Relief

Abstract Season-to-season persistence of soil moisture drought varies across North America. Such interseasonal autocorrelation can have modest skill in forecasting future conditions several months in advance. Because robust instrumental observations of precipitation span less than 100 years, the temporal stability of the relationship between seasonal moisture anomalies is uncertain. The North American Seasonal Precipitation Atlas (NASPA) is a gridded network of separately reconstructed cool-season (December–April) and warm-season (May–July) precipitation series and offers new insights on the intra-annual changes in drought for up to 2000 years. Here, the NASPA precipitation reconstructions are rescaled to represent the long-term soil moisture balance during the cool season and 3-month-long atmospheric moisture during the warm season. These rescaled seasonal reconstructions are then used to quantify the frequency, magnitude, and spatial extent of cool-season drought that was relieved or reversed during the following summer months. The adjusted seasonal reconstructions reproduce the general patterns of large-scale drought amelioration and termination in the instrumental record during the twentieth century and are used to estimate relief and reversals for the most skillfully reconstructed past 500 years. Subcontinental-to-continental-scale reversals of cool-season drought in the following warm season have been rare, but the reconstructions display periods prior to the instrumental data of increased reversal probabilities for the mid-Atlantic region and the U.S. Southwest. Drought relief at the continental scale may arise in part from macroscale ocean–atmosphere processes, whereas the smaller-scale regional reversals may reflect land surface feedbacks and stochastic variability.

scholarly journals Effects of dry or wet conditions during the preweaning phase on subsequent feedlot performance and carcass composition of beef cattle

2018 ◽  
Vol 3 (1) ◽  
pp. 247-255
Author(s):  
Garth A Gatson ◽  
Patrick J Gunn ◽  
W Darrell Busby ◽  
Bryon R Wiegand ◽  
Brian L Vander Ley ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Fixed Effects ◽  
Average Daily Gain ◽  
Warm Season ◽  
Carcass Composition ◽  
Drought Severity ◽  
Cool Season ◽  
Feedlot Performance ◽  
Dry And Wet Conditions ◽  
Normal Class

Abstract Our objective was to determine the effects of dry and wet conditions during the preweaning on subsequent feedlot performance and carcass characteristics of beef cattle. Steers (n = 7,432) and heifers (n = 2,361) finished in 16 feedlots in southwestern Iowa through the Tri-County Steer Carcass Futurity Cooperative were used for a retrospective analysis. Cattle originated in the Midwest (Iowa, Missouri, Indiana, Illinois, and Minnesota) and were born in February, March, or April of 2002 through 2013. Feedlot performance and carcass composition data were obtained for each animal. Palmer Drought Severity Index (PDSI) values were obtained for each animal’s preweaning environment on a monthly basis. Mean PDSI values were used to classify conditions as dry (≤−2.0), normal (>−2.0 and <2.0), or wet (≥2.0) for the cool (April and May), warm (June through August), and combined (April through August) forage growing seasons preweaning. Mixed models were used to evaluate the effects of PDSI class on subsequent performance. Calf sex, date of birth (as day of year), year, and feedlot were also included as fixed effects. When considering PDSI class during the cool season, cattle from normal and wet classes had a greater feedlot delivery BW (P < 0.0001) than dry. Dry and normal classes had greater (P ≤ 0.02) delivery BW than wet during the warm and combined seasons, however. For the cool season, average daily gain was greater (P < 0.0001) for the dry class than normal and wet. Cattle from the normal class for the cool season had greater (P = 0.001) final BW than wet, but the wet class had the greatest (P < 0.04) and dry class had the lowest (P < 0.01) final BW during the warm season. During the cool season, HCW was greater (P < 0.007) for the normal than wet class, although HCW was greater (P ≤ 0.02) for wet compared with dry and normal during the warm season. Calculated yield grade was lower (P ≤ 0.006) for the normal class during the cool season compared with dry and wet. For both the warm and combined seasons, the dry class had lower (P ≤ 0.004) calculated yield grade compared with normal and wet. Carcasses from cattle that experienced normal or wet warm seasons had greater (P ≤ 0.0005) marbling scores than dry, and normal had greater (P = 0.0009) marbling score than dry for the combined seasons. In conclusion, these data indicate that both dry and wet conditions during the preweaning phase may impact ultimate feedlot performance and carcass composition.

scholarly journals Seasonal Variations in Temperature–Suicide Associations across South Korea

2019 ◽  
Vol 11 (4) ◽  
pp. 731-739
Author(s):  
Adam J. Kalkstein ◽  
Miloslav Belorid ◽  
P. Grady Dixon ◽  
Kyu Rang Kim ◽  
Keith A. Bremer
Keyword(s):  
South Korea ◽  
Nonlinear Modeling ◽  
Warm Season ◽  
Cool Season ◽  
Delayed Effects ◽  
Distributed Lag ◽  
Significant Relationships ◽  
Linear Relationships ◽  
Significant Temperature ◽  
Seasonal Signal

Abstract South Korea has among the highest rates of suicide in the world, and previous research suggests that suicide frequency increases with anomalously high temperatures, possibly as a result of increased sunshine. However, it is unclear whether this temperature–suicide association exists throughout the entire year. Using distributed lag nonlinear modeling, which effectively controls for nonlinear and delayed effects, we examine temperature–suicide associations for both a warm season (April–September) and a cool season (October–March) for three cities across South Korea: Seoul, Daegu, and Busan. We find consistent, statistically significant, mostly linear relationships between relative risk of suicide and daily temperature in the cool season but few associations in the warm season. This seasonal signal of statistically significant temperature–suicide associations only in the cool season exists among all age segments, but especially for those 35 and older, along with both males and females. We further use distributed lag nonlinear modeling to examine cloud cover–suicide associations and find few significant relationships. This result suggests that that high daily temperatures in the cool season, and not exposure to sun, are responsible for the strong temperature–suicide associations found in South Korea.

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