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Animals influence nutrient cycling within grazed systems, and the effect may be greater with tall fescue (Festuca arundinacea Schreb.) because of endophyte-produced alkaloids that cause fescue toxicosis and alter animal behavior. Twelve grazed tall fescue pastures, established in a Cecil sandy loam (fine, kaolinitic, thermic Typic Kanhapludult) soil near Watkinsville, GA were used to measure fertility (134-15-56 and 336-37-139 kg N-P-K ha -1 yr -1 ) and endophyte (low, 0 to 29% and high, 65 to 94%) effects on P and K distribution. Soil samples were collected in winter 1997 at distances of 1, 10, 30, 50, and 80 m from permanently located shade and water sources at eight depth increments down to 1.5 m. Nutrient accumulation was greatest 1 m from shade and water sources where P, K, and Mg concentrations were 1.7 to 8, 2.5 to 15, and 1.1 to L5 times greater than average concentrations at the remaining distances, depending on depth and fertility level. Accumulation of P, K, and Mg in the area 10 to 80 m from shade and water was limited. When summed for the 0- to 300-mm depth and estimated on a per hectare basis, extractable P was 64% greater in high than in low endophyte-infected tall fescue pastures at 1 m from shade and water sources (703 vs. 428 kg ha -1 , LSD = 93) and averaged 252 kg ha -1 for remaining distances. Endophyte levels did not affect K distribution and only affected Mg distribution under the low-fertility treatment. Endophyte effects accrued over a long time period, which would indicate that altering grazing and pasture management (movement of animals, fertilizer and lime applications, and location of shade and water sources) to reduce these effects would be needed only occasionally to reduce potential environmental risks.

Recycled paper treated with boric acid (BA) is gaining acceptance as bedding in broiler houses. Applying this litter to Kentucky 31 (K‐31) tall fescue, Festuca Arundinacea Shreb, pastures raises the issue of potential boron (B) toxicity. There is also the question of nitrogen (N) availability from composts made with borated paper and broiler manure. The effect of five N sources at 224, 448, and 896 kg N/ha in a factorial arrangement plus an unfertilized control and high nitrogen‐phosphorus‐potassium (NPK) + additional boron at 45 kg B/ha on growth and NPKB uptake of K‐31 tall fescue was determined in a greenhouse during the spring of 1992. The five N sources were (1) inorganic salts, (2) compost made from hen manure, broiler manure, fescue hay and bark (M1), (3) fresh broiler litter (M2), (4) compost made from broiler manure and borated paper bedding (M3), (5) compost from hen manure, oak leaves, broiler litter (M4). The soil was Cecil sandy clay loam subsoil. Six harvests were made at 4‐cm cutti...

Recycled paper treated with boric acid (BA) is gaining acceptance as bedding in broiler production houses. Applying this litter, or compost made from this litter, to turf raises an issue of boron (B) toxicity. There is also the question of nitrogen (N) availability from composts made from borated paper and broiler manure. The objective of this study was to determine if broiler house litter containing recycled BA‐treated paper poses a toxicity hazard to bermudagrass turf (Cynodon dactylon L. pers x C. Transvaalensis, Burtt‐Davis) when applied at agronomic N rates. The effects of five N sources at rates equivalent to 224, 448, and 896 kg N/ha in a factorial arrangement plus an unfertilized control and a high nitrogen‐phosphorus‐potassium (NPK) treatment with B at 22 kg B/ha on bermudagrass were determined in pot culture during the summer of 1992. The five NPKB sources were (M1) compost made from broiler manure, BA‐treated paper and yard refuse; (M2) fresh broiler manure with BA paper bedding; (M3) ...

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...

Dry matter yields and plant nutrient uptake of forage grasses are influenced by levels of applied nitrogen (N), phosphorus (P), and potassium (K). Response to one element generally depends on levels of the other two. In this article, a mathematical model is presented which includes the major elements, N, P, and K as inputs. It consists of triple logistic equations with a total of thirteen parameters. The model is evaluated for Kentucky 31 (KY 31) and Kenwell tall fescue (Festuca arundinacea Schreb.) grown at Watkinsville, GA on Cecil sandy loam (clayey, kaolinitic, thermic, Typic Hapludult). Procedures are described for parameter estimation. The model provides high correlation between yields and plant uptake of N, P, and K with applied N, P, and K for both cultivars of tall fescue, as demonstrated in response graphs and scatter diagrams. Intercept and N response coefficients from this study agree closely with those from previous work. Data from this study support the hyperbolic relationship betwe...

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.

A 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 [...]

Models can be used to describe yield response of grasses to applied N and other management factors. This analysis was performed to show interactions between applied N and overseeded clover on dry matter yield, and to estimate equivalent N supplied by clover. Data from three locations were used. At Watkinsville, GA both Coastal' and common bermudagrass [Cynodon dactylon (L.) Pers.] were overseeded with crimson clover (Trifolium incarnatum L.). At Eagle Lake, TX, both Coastal bermudagrass and Pensacola' bahiagrass (Paspalum notatum Flugge) were overseeded with Yuchi' arrowleaf (Trifolium vesiculosum Savi) and Mt. Barker' subterranean (Trifolium subterranean L.) clovers. At Jat, FL both Coastal bermudagrass and Pensacola bahiagrass were overseeded with crimson clover []

Field studies on response of forage grasses to management factors (such as applied N) are generally conducted over multiple years to insure reliability of treatment responses measured. The increased number of observations enhances statistical analysis and separation of means. The question of system behavior over time naturally occurs. Data from a three year study at Watkinsville, GA with coastal and common bermuda ‐grass [Cynodon dactylon (L) Pers.] were analyzed with the logistic model to estimate approach to steady state. Model parameters (A, b, c) showed an exponential shift with time, approaching 90 % of steady state in the third year. The model provided high correlation ( R > 0.98 ) between dry matter yield and applied N.

Models can be used to estimate yield response of grasses to applied N. This analysis was conducted to show variation of model parameters among grasses at the same location and differences among locations. The logistic equation was used to relate annual dry matter yield to applied N for four locations (Blairsville, GA; Fayetteville, AR; Thorsby, AL; jay, FL) and five perennial grasses [bermudagrass (Cynodon dactylon L., Pers.), bahiagrass (Paspalum notatum Flugge), tall fescue (Festuca arundinacea Schreb.), dallisgrass (Paspalum dilatatum Poir.), and orchardgrass (Dactylis glomerata L.)] (...)

A field study was conducted from 1983 through 1986 to ascertain the effect of endophyte (Acremonium coenophialum), nitrogen fertility and tall fescue (Festuca arundiancea) genotype upon the soluble carbohydrate content of tall fescue from grazed paddocks. Non-grazed paddock exclosures were evaluated for 1984 and 1985. Plant tissues were extracted with 0·1 mol 1−1 H2SO4 to obtain acid-extractable carbohydrate (AEC). The AEC concentration and yield (concentration × dry matter) varied among and within years, generally was not influenced by endophyte, and was influenced by N fertility and cultivar. The AEC concentration from non-grazed exclosures was inversely related to AEC yield. Grazed paddock AEC concentration and yield were not significantly correlated. Grazed paddock AEC concentration remained fairly constant over the growing season, whereas AEC yield was greatest during periods of ample rainfall. The cultivar Johnstone generally had the greatest AEC concentration when compared with AU Triumph and KY-31. Even though endophyte is a carbohydrate sink, sward scale effects on AEC, as influenced by endophyte, were virtually undetected, suggesting that presence of endophyte is not detrimental to the fescue host. Grazed and non-grazed tall fescue AEC concentration and yield patterns differ and indicate the need to interpret non-grazed quality and management data carefully.

A logistic equation was used to relate annual dry matter yield of Coastal bermudagrass [Cynodon dactylon (L.) Pers.] to applied N, P, and K. Yield data from 4 × 4 × 4 (N × P × K) factorial experiment were analyzed. The second order Newton-Raphson procedure for nonlinear regression was used to estimate the seven parameters of the model. A correlation coefficient of 0.9884 was obtained with the model for the 64 data points. A response surface for yield as related to N and K at P = 100 kg ha −1 was drawn from the model. Isoquants (constant yield) were drawn for annual yield of 10Mg ha −1 (...)

A logistic equation was used to relate forage yield to applied N for bermudagrass [Cynodon dactylon (L.) Pers.] and bahiagrass [Paspalum notatum Flugge]. It was shown that the equation could be factored into a triple product-one term each for water availability, harvest interval and applied N. The equation provides high correlation (R ≥ 0.98) between yield and applied N for all levels of water availability and harvest interval. Appropriate statistical procedures for nonlinear regression were utilized in the analysis. These results are useful for estimating effects of management factors on forage production

Equations were developed to estimate concentration of nitrogen for bermudagrass forage [Cynodon dactylon, (L.) Pers.] as related to applied nitrogen level and harvest interval. Data from six field studies were used in the analysis. Estimates of N concentration in forage obtained with these equations agreed with data from other studies with fertilizer and waste application to bermudagrass (correlation coefficient of 0.94). Concentration of nitrogen decreased linearly with harvest interval (up to 6 weeks) and increased exponentially with nitrogen level. These equations should provide relevant information for crop production and environmental quality.

Equations were developed to estimate concentrations of phosphorus and potassium for Coastal bermudagrass [Cynodon dactylon, (L.) Pers.] as related to applied nutrient level and harvest interval. Data from several field studies were used in the analysis. Estimates from these agronomic studies agreed with data from fertilizer and waste application for several locations. Concentrations of phosphorus and potassium decreased linearly with harvest interval (up to 6 weeks) and increased exponentially with nutrient level. This information should be relevant to crop production and environmental quality.

Models can be used to estimate yields and nutrient utilization by forage grasses. The objective of this study was to model response of three cultivars of tall fescue (Festuca arundinacea Schreb.) to applied N over a 3-yr period at Watkinsville, GA. The procedure uses analysis of variance to evaluate linear parameter A and the exponential parameters b and c for the logistic equation. It was shown that yields could be averaged across years and that all differences among cultivars could be assigned to the b (intercept) parameter. 'AU-Triumph' proved to he more efficient at converting soil N to dry matter without applied N than either 'Johnstone' or 'Kentucky 31' cultivars. Endophyte (Acremonium coenophialum Morgan-Jones & Gams) infection did not affect dry matter response relationships of Kentucky 31 [...]

A study was designed to evaluate yield, quality and composition of tall fescue (Festuaa arundinaaea Schreb.) as influenced by water stress under 0, 100, and 400 kg N·ha‐1 during autumn in the southeastern U.S. Four replicates of each treatment were imposed in a completely random design in the field. The experiment was conducted in two successive years with treatments applied to an adjacent area to eliminate residual or carry‐over effects. Water status was verified by gypsum block, tensiometer, and determination of leaf stomatal resistance. Plant tissue was harvested three times during autumn and again in the following spring. Forage yield total was not significantly affected by soil water stress, apparently due to compensatory growth during recovery periods. Soil water appeared to be more rapidly depleted under 400 kg N·ha‐1 than other N treatments. Increasing N fertilizer significantly increased leaf area, leaf number, and was inversely related to the number of senesced leaves. Stomatal resistan...

On a determine les effets de deux niveaux de fertilisation et de l'infection par un champignon endophyte, chez le cultivar «Kentucky-31», sur les distributions laterale et verticale du potassium du sol apres trois ans de pâturage. On a etudie les effets du pâturage, du repos et d'autres comportements des animaux sur les transferts de potassium

The influence of limestone and N:P:K fertilizer rates on elemental composition of Coastal bermudagrass forage was determined to evaluate causes for high yield responses to dolomitic limestone at high N:P:K rates, as well as severe stand loss, and chlorosis of bermudagrass in the unlimed treatments. Increasing N:P:K fertilization resulted in severe Mg deficiency. Maximum yields (when limed with dolomitic limestone) were associated with Mg concentrations of 1.0 g/kg plant tops. Magnesium lost to plant removal, Mg loss to enhanced leaching under N fertilization, and K interference associated with excess K accumulation at high rates of NK inputs all contributed to Mg deficiency. However, the accumulation of excess K, which interfered with Mg uptake when high rates of N and K were applied, was considered to be the primary cause of the observed Mg deficiency.

A multispecies no-tillage system was designed to produce supplemental forage for year-round grazing while maintaining a viable tall fescue sod for erosion control. This system offers the potential to improve forage quantity and quality for low yielding tall fescue (Festuca arundinacea Schreb.) pastures in the South. Sorghum ✕ sudangrass hybrid, cv. ‘Pennington's summergrazer’ (Sorghum bicolor L. Moench ✕ Sorghum bicolor L. Moench) (SS hybrid), was seeded into tall fescue sod after the flush of spring growth, and rye (Secale cereale L.) seeded in early October after the end of the summer growing season for 3 consecutive years. Tall fescue sod kill treatments of no kill, 25, 50, and 100% of the surface area were obtained with 0.28 and 0.56 kg paraquat (1, 1'-dimethyl-4, 4'bipyridimium ion) per ha. Nine treatments were applied in a randomized block design replicated four times on Cecil sandy loam (Typic Hapludult, clayey, kaolinitic thermic). Phosphorus and K fertilizer was applied to satisfy soil test recommendations, while N fertilizer was applied in split applications across all treatments. Summer forage was harvested and separated by cutting height into tall fescue and SS hybrid, while winter yield was represented by tall fescue or tall fescue plus rye. The higher rate of paraquat gave no significant yield advantage to sod-seeded species at a given level of tall fescue sod control. A tall fescue sod monoculture yielded 7,405 kg dry matter/ha annually (3-year average). Inclusion of SS hybrid and rye in the tall fescue system with 50% sod kill increased total average forage yield to 11,115 kg/ha and improved distribution of yield over the year. Sorghum ✕ sudangrass hybrid accounted for 48%, (5,283 kg dry matter/ha) of the average yearly total yield for 50% sod kill. Yearly total forage yields were not significantly different far 50 and 100% levels of tall fescue sod kill seeded with both SS hybrid and rye. Thus, it was feasible to increase and improve distribution of forage yield and provide species diversity, while maintaining tall fescue sod as an integral part of the system.

Endophyte (Acremonium cotnophiaJum Morgan-Jones et Gams) -Infected tall fescue (Festuca arundinacea Schreb.) produces ergopeptiDe alkaloids (EP) that may be associated with fescue toxicosis symptoms in cattle (B03 taurus). A study was conducted during 1983 and 1984 at Watkinsville, GA, to determine the effects of endophyte infection, season, and N fertilization on EP concentration and Steer average daily gain (ADG) in grazed O.7-ha tall fescue paddocks. Treatments included iow (LF) and high (HF) endophyte infectioo frequency lKentucky-31' (KY·31) tall fescue fertilized with 134 or 336 kg N ha I (2x2 factorial) replicated three times. The cuJtivars AU Triumph and Johnstone were also evaluated. Animals were managed using put-and-take grazing system. Ergopeptine alkaloid concentration (ergovaline was 80% of total) was greater in HF KY~ 31 than LF KY·31 in both years. Peak ergovaline concentrations occurred In spring and again in autumn (1984) when concentrations in HF KY·31 approached 1 mk kg-I. Mid·summer concentrations were about one-third the autumn maximum Cor HF and LF KY~31. Nitrogen fertilization had minimal effect on ergovaline concentration in the spring·summer of 1983 but increased concentrations in LF KY-31 in 1984. Ergopeptine alkaloids were not detected in endophyte-free AU Triumph~ and were detected in low amounts « 0.1 mg kg I) in a pre-varietal release of Johnstone containing 7 to 10% endophyte. Increased ergovaline was associated with decreased ADG in the spring·summer of 1983 and 1984; howel'er, there was no sig. nificant association between ergovaline and ADG when the entire (April-December) 1984 growing season was considered, suggesting that ergopeptine alkaloids may operate in conjunction with other environmental and nutritional factors to elicit fescue toxicosis symptoms.

Tall rescue (Festuca arundinacae) was seeded into dormant Coastal bermudagrass (Cynodon dactylon L.), fertilized at five levels of N, and clipped at 5.1 and 10.2 cm over a 3-year period to evaluate the influence of these factors on its persistence in competition with Coastal. The experiment was conducted at two adjacent locations, with one irrigated and the other not irrigated. Tall rescue persisted and contributed to yield at N levels up to 420 kg N/ha per year at the 5.1-cm clip height, and at N levels up to 560 kg N/ha per year at 10.2-cm clip height. Nitrogen fertilization decreased rescue content, whereas, the higher clipping increased rescue content of the harvested forage. Fescue content was high in the spring and fall and low in summer. Fescue growth during summer was better at the irrigated location. High N fertilization gave the highest yields, with little rescue in the harvested forage. Tall fescue-Coastal associations have potential in grazing systems for cow-calf operations where even seasonal distribution of forage may be important.

SynopsisBiuret was toxic to germinating seeds and caused injury to developing corn seedlings. Hyponasty, frayed leaf margins, and interveinal leaf chlorosis in immature leaves were symptoms associated with this injury. Crystalline urea did not cause this injury to developing corn seedlings. Placement away from seed minimized the probability of biuret injury.

Forage utilization could affect soil nutrient dynamics and depth distribution, potentially changing long-term productivity and environmental quality. The effect of forage utilization on nutrient cycling might also be altered depending upon the source and quantity of nutrients applied. We evaluated changes in soil pH and extractable-soil nutrient cations during the first 5 yr of bermudagrass [Cynodon dactylon (L.) Pers.] management varying in fertilization (three different sources targeted to supply 200 kg N ha(-1) yr(-1)) and forage utilization (four levels). Chicken (Gallus gallus) broiler litter (5.4 Mg ha(-1) yr(-1)) was a significant source of nutrient cations in addition to N and P and therefore, at the end of 5 yr, resulted in extractable-soil concentrations (0- to 15-cm depth) that were 1.5 +/- 0.1 times greater for K, 1.6 +/- 0.2 times greater for Mn, 4.3 +/- 2.2 times greater for Zn, and 7.5 +/- 0.8 times greater for Cu than under inorganic and clover (Trifolium incarnatum L.) + inorganic fertilization regimes. The increases in extractable-soil K, Zn, Mn, and Cu concentrations with broiler litter, however, were only 13 +/- 42% of nutrients applied. Removal of forage as hay resulted in significant declines in extractable-soil K and Mg under all fertilization regimes and in extractable-soil Ca and Mn with inorganic and clover + inorganic fertilization. Cattle (Bos taurus) grazing resulted in greater nutrient cycling within the paddock domain, and the more diverse and higher quantity of several nutrient cations applied with broiler litter either prevented a decline or contributed to an increase in concentrations with time.

Productivity, quality, and persistence of 'Coastal' bermudagrass [Cynodon dactylon (L.) Pers.] pastures are affected by fertilization, but possible interactions with defoliation regime including animal grazing are not fully known. We evaluated three sources of fertilization with equivalent N rates [inorganic, crimson clover (Trifolium incarnatum L.) cover crop plus inorganic, and chicken (Gallus gallus) broiler litter] factorially arranged with four defoliation regimes [unharvested, cattle (Bos taurus) grazing to maintain high (4.5 ± 1.6 Mg ha -1 ) and low (2.5 ± 1.1 Mg ha -1 ) forage mass, and hayed monthly] on estimated forage dry matter production, forage and surface residue C/N ratio, and ground cover of pastures on a Typic Kanhapludult in Georgia during 5 yr. Mean annual forage dry matter production was 7.5 ± 0.7 Mg ha -1 with hay harvest but declined (1.3 Mg ha -1 yr -1 ) significantly with time as a result of lower precipitation. With grazing, estimated production was 8.3 ± 1.0 Mg ha -1 and did not change with time, suggesting that grazing cattle sustained forage productivity by recycling nutrients and creating better surface soil conditions. Coastal bermudagrass as a percentage of ground cover (initially 81%) declined 5 ± 2% yr -1 with unharvested and grazing to maintain low forage mass, declined 3 ± 1% yr -1 with haying, and remained unchanged (-1 ± 1% yr -1 ) with grazing to maintain high forage mass. Pastures with high forage mass were more productive than with low forage mass (9.2 ± 1.6 vs. 7.5 ± 1.1 Mg ha -1 ) from a forage sustainability perspective, primarily by avoiding encroachment of undesirable plant species.