Forage Grass Production Research Articles

Late Growing-Season Fire Effects in Mid-Successional Tallgrass Prairies

Wildfire in the growing season is relatively frequent and interest is increasing in using growing-season fire in management of tallgrass prairie. However, the influence of fire in the growing season on forage production and species composition, especially in mid-successional tallgrass prairie, is largely unknown. Our objective was to compare vegetation composition and production on Loamy Prairie and Very Shallow ecological sites in mid-successional stages in response to late growing-season fire at different frequencies. We applied 4 burning treatments (no burn, or 1, 2, or 3 burns in 5 years) in the late growing season in southern Oklahoma during a series of years of above-average precipitation. The sites were dominated at the beginning of the study by early- and mid-successional species including prairie threeawn (Aristida oligantha (Michx)), a species indicating a disturbance history. After the initial burns in 1990, tallgrasses, little bluestem, and perennial grasses were reduced by burning on the Loamy site. Forbs were more productive on burned plots (1,980 kg ha-1) than on plots that were not burned (1,290 kg ha-1) averaged across sites. Total production was not reduced by burning in 1990. Growing-season burns in 2 consecutive years had little influence on species composition or production as compared to a single burn in 2 years. Warm-season perennial grasses other than tallgrasses and little bluestem increased on the Loamy site, but decreased on the Shallow site. Production of cool-season perennial grasses increased to almost 40% of total production on twice-burned plots averaged across sites. Other than the effect on cool-season perennial grasses, 2 burns over a two-year period had little effect beyond the first growing season after the second burn. Twice-burned plots and plots burned 3 times produced more forbs than either plots that were burned once or not burned. Production of perennial grasses was opposite that of forb production. Total production was not reduced on either site regardless of fire frequency. Results indicate managers may expect a short-term reduction in production of forage grasses and an increase in forbs following late growing-season fire in mid-successional tallgrass prairies.

Tiller Development Influences Seasonal Change in Cell Wall Digestibility of Big Bluestem(Andropogon gerardii)

The productivity of cool-season forage grasses declines during mid-summer in the southern corn belt of the USA. Warm-season grasses are productive during this time, but their digestibility decreases from spring to summer. The objective of this study was to investigate cell wall factors contributing to the decline in in vitro dry matter digestibility (IVDMD) of big bluestem (Andropogon gerardii Vitman) leaf blades from late spring (May) to mid-summer (July) under three harvest regimens. Under frequent defoliation, decrease in cell wall digestibility accounted for much of the change in IVDMD. Among cell wall constituents, only xylose and alkali-labile phenolic acids increased significantly from spring to summer. Change in p-coumaric acid content and the ratio of p-coumaric acid to ferulic acid were both negatively correlated with the decrease in cell wall digestibility. While glucose and uronic acid digestibility decreased from spring to summer, xylose was consistently the least digestible of the cell wall monomers. In warm-season grasses grown under constant environments, tiller development causes an increase in leaf structural tissue, and the data suggest that the seasonal decline in leaf blade cell wall digestibility was partially due to tiller development.

Coupling of dry matter and nutrient accumulation in forage grass

Abstract The logistic model has proven very useful in relating dry matter production of forage grasses to applied nitrogen. A recent extension of the model coupled dry matter and plant ? accumulation through a common response coefficient c. The objective of this analysis was to establish the validity of the extended model for each of the three major nutrients (?, ?, ?), with a common coefficient c between dry matter and each applied nutrient. Analysis of variance established the validity of this hypothesis. The model accurately described response of dry matter, plant nutrient removal, and plant nutrient concentration to applied nutrient, with overall correlation coefficients of 0.9928, 0.9972, and 0.9975 for applied N, P, and K, respectively. Furthermore, the model closely described the relationship between yield and plant nutrient removal, as well as between plant nutrient concentration and plant nutrient removal, for each nutrient. This work confirmed earlier results for applied ? with various grasses a...

Coupling of dry matter and nitrogen accumulation in ryegrass

The logistic model has proven very useful in relating dry matter production of warm season perennial forage grasses to applied nitrogen. A recent extension of the model coupled dry matter and plant N accumulation through a common response coefficient c. The objective of this analysis was to apply the extended logistic model to cool season Gulf annual ryegrass (Lolium multiflorum Lam.) and to establish a common response coefficient c between accumulation of dry matter and plant N. Analysis of variance established the validity of this hypothesis. The model accurately described response of dry matter, plant N removal, and plant N concentration to applied N, with an overall correlation coefficient of 0.9954. Furthermore, the model closely described the relationship between yield and plant N removal, as well as between plant N concentration and plant N removal. The logistic equation is well-behaved and simple to use on a pocket calculator. It can be used to estimate yields and plant N removal in evaluation of agricultural production and environmental quality.

An Extended Model of Forage Grass Response to Applied Nitrogen

AbstractA simple model is needed that relates forage grass production (yield and N removal) to management factors (applied N, harvest interval, and water availability). The objective of this analysis was to extend a previous model to include quantitative coupling between yield and N removal in response to applied N for perennial grasses. The extended model was developed from three postulates: (1) annual dry matter yield follows logistic response to applied N, (2) annual plant N removal follows logistic response to applied N, and (3) the N response coefficients are the same for both. Three additional consequences derive from these postulates: (i) plant N concentration response to applied N follows a ratio of logistic functions, (ii) annual dry matter yield and plant N removal are related by a hyperbolic equation, and (iii) plant N concentration and plant N removal follow a linear relationship. Data from a field study in Louisiana with dallisgrass [Paspalum dilatation Poir.] grown on Olivier silt loam (fine‐silty, mixed, thermic Aquic Fragiudalf) were used to demonstrate applicability of the model and to illustrate procedures. Analysis of variance supported Postulate 3 for these data, with an overall correlation coefficient of 0.9990. Plant N concentration (Nc for this study was bounded by 11.8 <Nc< 27.5 g kg−1. Maximum yield for the study reached 57% of potential yield at plant N removal of 427 kg ha−1. Potential yield of 27.5 Mg ha−1 appears to be in the range of values reported in the literature. Further use of this model should provide added insight into the coupling among various mechanisms that control forage production.

Effects of Plant Growth Regulators and Fertilization on Dry Matter Production of Green Panic(Panicum maximum Jacq. var. trichoglume Eyles).

The effects of applications of plant growth regulators and additional fertilizer on dry matter production of green panic (Panicum maximum Jacq. var. trichoglume Eyles), cv. Petrie were investigated for the first growth during 26 days after application and the aftermath without any applications during 42 days. The application of GA3 (90 mL/m2 of 200 ppm solution) and of PP-333 (90 mL/m2 of 860 ppm solution) suppressed dry matter production of green panic by inhibiting tiller production in the former and tiller elongation in the latter. Dry matter production under aftermath in GA3-plot was enhanced due to the growth of many tillers from the tiller buds, the growth of which had been suppressed by GA3 application. The inhibition of tiller elongation by PP-333 application increased the number of tillers with apex in stubble at cutting. These tillers produced many daughter tillers after cutting, contributing to the enhancement of dry matter production under aftermath. The application of additional fertilizer (10 g/m2 each of N, P2O5 and K2O) enhanced dry matter production under direct effect by stimulating tiller growth. However, the stubble had no advantageous characteristics for tiller production, so dry matter production was not enhanced under aftermath. The above results gained in green panic may be applicable to the control of seasonal changes in dry matter production of forage grasses.

Landscape-Level Interactions Among Ungulates, Vegetation, and Large-Scale Fires in Northern Yellowstone National Park

The scale of the 1988 fires in Yellowstone National Park (YNP) raised numerous questions for the management of natural areas subject to large, infrequent disturbances. An important management issue in YNP involves the interaction of large-scale fire with the large assemblage of native ungulates and vegetation dynamics in the landscape. We used landscape modeling and field studies to address basic questions about the effects of fire scale and heterogeneity on resource utilization and survival of free-ranging elk (Cervus elaphus) and bison (Bison bison), and the production and regeneration of preferred forage grasses and aspen in northern Yellowstone Park. More specifically, we asked (1) how fire size interacts with winter severity to control ungulate feeding behavior and survival, both in the initial postfire winter, when fire reduces forage, and in later postfire winters, when fire augments forage; (2) how fire pattern (e.g., clumped vs. dispersed burn sites) modifies the effects of fire size; (3) which environmental factors, including fire, influence selection of feeding areas by wintering ungulates at a variety of scales, from a single feeding station to the entire northern winter range; and (4) how the size and spatial pattern of burning influence regeneration of aspen (Populus tremuloides), a preferred and heavily browsed species in YNP. We focus on elk and bison because these are by far the most numerous ungulates in the area (Houston 1982), and we have chosen to examine winter grazing and browsing for several reasons. Winter range conditions are the primary determinant of ungulate survival and reproduction in Yellowstone, and winter utilization of the vegetation by ungulates appears to be intense in some areas. Ungulates make distinct foraging choices in the winter as in the rest of the year, and burn patterns may influence those choices in ways that we represent as hypotheses described later. In addition, the activities of animals can be readily monitored in the winter, and the exact locations of feeding and bedding sites can be determined. Travel routes are easily monitored, and the ability to sight animals is high; therefore, group locations and sizes can be readily determined. This research complements ongoing studies in Yellowstone by expanding the spatial scale at which plant-herbivore dynamics are considered and by explicitly addressing the effects of spatial heterogeneity. We produced a spatially explicit simulation model of the winter range that predicts plant and ungulate dynamics under varying fire sizes, fire patterns, winter weather scenarios. The model and field studies will generate quantitative comparisons of the effects of large and small fires on ungulate survival and will thereby permit the simulation of the effects of alternative fire management scenarios.

Landscape-Level Interactions Among Ungulates, Vegetation, and Large-Scale Fires in Northern Yellowstone National Park

The scale of the 1988 fires in Yellowstone National Park (YNP) raised numerous questions for the management of natural areas subject to large, infrequent disturbances. An important management issue in YNP involves the interaction of large-scale fire with the large assemblage of native ungulates and vegetation dynamics in the landscape. In this 2-year research project, we are using landscape modeling and field studies to address basic questions about the effects of fire scale and heterogeneity on (1) resource utilization and survival of free-ranging elk (Cervus elaphus) and bison (Bison bison) and (2) the production and regeneration of preferred forage grasses and aspen in northern YNP. We are testing a series of eight hypotheses within the framework of two basic questions. First, we ask whether there are thresholds in fire size that interact with winter severity and ungulate density to determine ungulate resource use and survival on the winter range in northern YNP. This question focuses on the effects of fire size, regardless of the spatial pattern of burning. Second we ask, if large fires occur, does the spatial distribution of burned areas (and hence of higher quality forage) influence ungulate resource use during winters subsequent to the first post-fire year. In this question, we are addressing the effects of spatial pattern on herbivory. We focus on elk and bison because these are by far the most numerous ungulates in the area (Houston 1982), and we have chosen to examine winter grazing and browsing for several reasons. Winter range conditions are the primary determinant of ungulate survival and reproduction in Yellowstone, and winter utilization of the vegetation by ungulates appears to be intense in some areas. Ungulates make distinct foraging choices in the winter as in the rest of the year, and burn patterns may influence those choices in ways that we represent as hypotheses described later. In addition, the activities of animals can be readily monitored in the winter, and the exact locations of feeding and bedding sites can be determined. Travel routes are easily monitored, and the ability to sight animals is high; therefore, group locations and sizes can be readily determined. This research complements ongoing studies in YNP by expanding the spatial scale at which plant-herbivore dynamics are considered and by explicitly addressing the effects of spatial heterogeneity. Our research will produce a spatially explicit simulation model of the 78,000 ha winter range that predicts plant and ungulate dynamics under varying fire sizes, fire patterns, winter weather scenarios, and ungulate densities. The model and field studies will allow quantitative comparisons of the effects of large and small fires on ungulate survival and will thereby permit the simulation of the effects of alternative fire management scenarios.

Cultivar and Clonal Differences for Water‐use Efficiency and Yield in Four Forage Grasses

Available water is a major factor limiting productivity of forage grasses grown in the northern Great Plains of the USA. Cultivars with greater water‐use efficiency (WUE) would be beneficial to forage production and utilization in this semiarid region. Our objective was to assess variability in forage yield and WUE among genotypes of four common forage grasses. Four clones with contrasting phenotypes were selected from each of three cultivars or strains of crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Shult.], western wheatgrass [Pascopyrum smithii Rybd. (Löve)], intermediate wheatgrass [Thinopyrum Intermedium (Host) Barkworth and Dewey], and reed canarygrass (Phalaris arundinacea L.). Soil water content was determined by neutron probe for 5 yr on clonal plots grown on a Parshall sandy loam soil (coarse‐loamy, mixed Pachic Haploboroll) near Mandan, ND. A single forage harvest was taken each year when plants were at soft dough stage of seed development. Forage yield and WUE increased the first 2 yr of the study, then decreased for the next 2 yr. Increases and decreases in forage yield were associated with total available water (soil water plus growing season precipitation) prior to harvest and effects of stress in one year on subsequent years. There were no significant (P≥0.05) differences among entries for total water used before harvest. Environmental effects (years and replications) on yield and WUE in each species were large compared with genotypic effects. Genotypic mean squares were from 2 to over 35 times larger than experimental error mean squares for yield and WUE. Broad sense heritability estimates ranged from 71 to 95% for yield and from 69 to 94% for WUE over the four species, which indicated that gain from selection may be possible. However, because of the large year effects, extensive testing will be necessary to evaluate yield and WUE in the four grasses we studied. Development of more effective screening techniques will be necessary to reduce resource input required for evaluating WUE.

Exploitation of the incompatibility mechanism for the production of F1 hybrid forage grasses

The utility of the two locus (SZ) incompatibility system for the production of F1 hybrids in forage grasses is examined in relation to its mode of action at the tetraploid level and in dihaploids. Schemes are proposed for producing tetraploid populations with a high level of within population incompatibility or of single or double cross hybrids from the dihaploids.

Selecting for nutrient use efficiency within forage grass species: I. Development of a screening system

Abstract One means of achieving increased forage grass production on infertile soils is to select plant genotypes which grow efficiently at low levels of available nutrients. This requires methods to identify variability in individual plant nutrient response from among large populations of plants grown under controlled environmental conditions. A compact, containerized system, partially developed for growing large numbers of forage grass seedlings for use in automatic machine transplanter research, was adapted as the basis for such a screening technique. Three trials were made with 100‐plant samples of a kleingrass‐75 (Panicum coloratum L.) population to test the utility of the system. Results of these trials showed that differences in nutrient use efficiency (= reciprocal of nutrient concentration in the plant tissue, or milligrams dry matter produced per milligram nutrient absorbed) among the grass plants could be effectively identified by using the system in conjunction with laboratory analysis of the ...

Comparison of Dry Matter Production in Forage Grass Species

Dry matter production was compared between the two groups of four grass species which differ in photosynthetic capacity and optimum temperature for growth. The species were oats, Avena sativa L. Italian rye grass, Lolium multiflorum, (species of low photosynthetic capacity and low optimum temparature), barnyard grass, Panicum Crus-galli var. echinata and sorgo, Sorghum vulgare (species of high photosynthetic capacity and high optimum temperature). Experiments were carried out from summer to autumn in 1966 for 74 days with two sowing densities and for spring in 1967 for 51 days with one sowing density. The results of high density plot only were described. Panicum and Sorghum produced much higher dry matter and had higher crop growth rate (CGR) then Avena and Lolium (Fig. 1 and 4) in the experiment in 1966. It was shown that the former species had the higher leaf area indeces (LAI) in an early growth stage (Fig. 2) and had the higher net assimilation rate (NAR) even in the growth stage of high LAI than the latter species (Fig. 3). The comparison was also made in dry weight ratio of nonphotosynthetic system to photosynthetic system and specific leaf area, but no consistent result with dry matter production was obtained (Table 3). In the experiment in 1967, which was carried out for a period of lower temperature, longer day length and for younger stage, than the one of 1966, sorghum showed higher CGR, higher relative growth rate, higher relative leaf growth rate and higher NAR than Lolium (Table 5). It was noticed that NAR was one of the most important factor for dry matter production in the young stage with low LAI. From these results, the significance of NAR or photosynthetic capacity per unit leaf area (P) in dry matter production was discussed. It was concluded that not only leaf area but NAR or P were important and that the high dry matter production of forage grasses could be achieved with the species which possess both the ability of high NAR or P and of high growth rate in leaf area simultaneously.

Floral Induction and Development in Poa pratensis L.1

Crop ScienceVolume 4, Issue 5 cropsci1964.0011183X000400050033x p. 540-544 Article Floral Induction and Development in Poa pratensis L.1 K. E. Lindsey, K. E. LindseySearch for more papers by this authorM. L. Peterson, M. L. Peterson Graduate Student, University of California, Davis, and Professor of Agronomy, University of California Berkeley.Search for more papers by this author K. E. Lindsey, K. E. LindseySearch for more papers by this authorM. L. Peterson, M. L. Peterson Graduate Student, University of California, Davis, and Professor of Agronomy, University of California Berkeley.Search for more papers by this author First published: 01 September 1964 https://doi.org/10.2135/cropsci1964.0011183X000400050033xCitations: 9 1 Contribution from the Department of Agronomy, University of California, Davis. This work was supported in part through a USDA Research and Marketing Contract No. 12-14-100-1011 (34) on Forage Grass and Legume Seed Production Research. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume4, Issue5September–October 1964Pages 540-544 RelatedInformation

High Temperature Suppression of Flowering in Poa Pratensis L.1

Crop ScienceVolume 2, Issue 1 cropsci1962.0011183X000200010023x p. 72-74 Article High Temperature Suppression of Flowering in Poa Pratensis L.1 K. E. Lindsey, K. E. LindseySearch for more papers by this authorM. L. Peterson, M. L. Peterson Graduate Research Assistant and Professor of Agronomy, respectively, University of California.Search for more papers by this author K. E. Lindsey, K. E. LindseySearch for more papers by this authorM. L. Peterson, M. L. Peterson Graduate Research Assistant and Professor of Agronomy, respectively, University of California.Search for more papers by this author First published: 01 January 1962 https://doi.org/10.2135/cropsci1962.0011183X000200010023xCitations: 1 1 Contribution from the Department of Agronomy, University of California, Davis. This work was supported in part through a U. S. D. A. Research and Marketing Contract No. 12-14-100-1011 (34) on Forage Grass and Legume Seed Production Research. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume2, Issue1January–February 1962Pages 72-74 RelatedInformation