Influence of temperature on nutrient concentration and tetany potential of hardinggrass and tall fescue

Grass tetany (Hypomagnesemia) potential of TAM Wintergreen Hardinggrass and 16 tall fescue lines and varieties was estimated by determining the K, Ca and Mg concentrations in the herbage and the ratio of K/(Ca + Mg) (milliequivalent basis). Data were obtained at four dates during a two‐year period to determine the environmental conditions under which selections should be made to achieve the greatest progress in decreasing the tetany potential of tall fescue and to determine if either of the grasses have high tetany potential in the North Texas area. Hardinggrass had a greater potential to produce grass tetany than tall fescue when grown on the Northern Blackland Prairie of Texas. There were significant differences in K, Ca and Mg concentrations and K/(Ca + Mg) ratio among dates and tall fescue lines. The average temperature for the 30 days before harvest was related to the mineral content and to the K/(Ca + Mg) ratio in all varieties. The K(Ca + Mg) ratio was highest at approximately 18°C but the Mg content fell below the 0.18% required for lactating beef cows when the average temperature for the 30 days before harvest was 22.4°C. Progress could be made in breeding for low grass tetany proneness but selections should be made over a wide range of temperatures considering both the Mg content and ratio of K/(Ca + Mg).     

Effect of fertilization and harvest frequency on yield and quality of tall fescue and smooth bromegrass

Abstract

Fertilization and harvest frequency affect yield and quality of forages. The purposes of this experiment were to determine (i) the effects of fertilization and frequent harvesting on yield and quality of tall fescue (Festuca arundinacea Schreb.) and smooth bromegrass (Bromus inermis Leyss.) and (ii) the efficiency of N in animal waste as compared with inorganic N fertilizer for forage production of these cool season grasses. ‘Fawn’ tall fescue and ‘Southland’ smooth bromegrass were grown in the greenhouse on Pullman clay loam topsoil (fine, mixed thermic Torrertic Paleustoll) under eleven fertilizer treatments and two harvest regimes. Nitrogen fertilizer increased yields, N and K concentrations and K/(Ca + Mg) ratios and decreased P, Ca, and Mg concentrations. Phosphorus and K fertilizers did not affect yields but applied P increased P and tended to decrease N and Ca concentrations. Applied K tended to increase Ca concentrations. Recovery of N from feedlot manure ranged from 0.8 to 14%, whereas, recovery from NH₄NO₃ averaged 64%. Harvesting at 3‐week rather than at 6‐week intervals reduced yields 25%; however, N and P removal were higher under the 3‐week harvest regime. Even though forage production was reduced under heavy utilization, the grasses required more N fertilizer under heavy than under lighter utilization. The two grasses produced similar yields under the 3‐week cutting regime and at N rates through 340 kg/ha under the 6‐week cutting regime. Tall fescue yields were higher with the higher N rates under the 6‐week cutting regime. Smooth bromegrass forage was higher than tall fescue forage in N, K, and Ca, whereas tall fescue forage was higher in P and Mg.     

Calcium,magnesium, and potassium uptake by crested wheatgrass grown on calcareous soils

Abstract

Forage intake with potassium/(calcium + magnesium) [K/(Mg + Ca)] values in excess of 2.2 are associated with grass tetany and Mg deficiencies in ruminants. This study was conducted to determine the degree to which forage K and Mg concentrations and K/(Ca + Mg) ratios could be predicted from soil bicarbonate (HCO₃) extractable phosphate‐phosphorus (PO₄‐P), and saturation extract Ca, Mg, K, sodium (Na), and nitrate‐nitrogen (NO₃‐N) concentrations. Crested wheatgrass (Agropyron spp) strains and cultivars representing four ploidy levels were grown in the greenhouse on eight calcareous soils with different saturation extract Ca, Mg, K and K/Mg ratios. The plants were harvested three times. Soil solution K/(Ca + Mg) and K/Mg ratios were the only measured soil parameters that showed a consistent correlation with plant K/(Ca + Mg) ratios. Bicarbonate extractable soil P was positively related to plant P and K uptake in the first harvest, but was not related in the second and third harvests nor was soil P related to plant Ca or Mg content. There was a tendency for the higher ploidy level entries to have higher plant K/(Ca + Mg) ratios. It was concluded that soil K/(Ca + Mg) ratios can be used to predict relative forage K/(Ca + Mg) ratios for grasses grown under similar conditions.     

Effects of soil acidity and phosphorus on the yield and chemical composition of tall fescue

Abstract

Tall fescue (Festuca arundinacea) is assuming increasing importance as a pasture species in South Africa. Many of the soils on which fescue is grown are inherently high in exchangeable Al and are characterized by high P‐immobilization capacities. The responses of fescue to dolomitic lime and P were examined in a factorial field trial on a red clay (Kandiustalfic Eustrustox) having a pH(KCl) and acid saturation [100(Al+H)/(Al+H+Ca+Mg+K)] in the unlimed state of 4.1 and 48%, respectively. A significant, though very limited, dry‐matter yield response to lime was evident (yields in the absence of lime were approximately 80% of the yields obtained at high lime levels). This pattern in the response to lime remained consistent over the three seasons of experimentation, despite soil acidity levels being substantially increased through the periodic use of ammonium sulphate as the N source in the trial. A significant response to P was evident at the first harvest after establishment; thereafter, P treatments had no effect on yield. The lime and P response data obtained in this investigation indicate that tall fescue is much more tolerant of soil acidity and has substantially lower soil P requirements than other important crop and pasture species in this country, such as maize (Zea mays) and Italian ryegrass (Lolium multiflorum). Lime significantly increased herbage Mg levels yet, in general, did not influence Ca levels in the herbage. Concentrations of Mg in the herbage exceeded Ca concentrations at all lime rates. Luxury uptake of K resulted in the K/(Ca+Mg) equivalents ratio in the herbage frequently exceeding the tetany hazard threshold of 2.2.     

Yield and mineral concentration of HiMag compared to other tall fescue cultivars grown in the southern piedmont

HiMag is an experimental cultivar derived from Missouri 96 (Mo96) and Kentucky 31 (K31) tall fescue (Festuca arundinacea Schreb.) parentage for increased calcium (Ca), magnesium (Mg), and reduced potassium (K)/ (Ca+Mg). Our objective was to determine productivity and mineral characteristics of endophyte‐free (E‐) HiMag in relation to standard tall fescue cultivars when grown in the Southern Piedmont Land Resource Area. In experiment 1, HiMag (E‐) and K31 (E‐) were grown at two levels of phosphorus (P), K, and lime additions to both severely eroded, and non‐eroded Cecil soil (clayey, kaolinitic, thermic family of Typic Hapludults). Herbage Ca and Mg were greater and K/(Ca+ Mg) and yield were less for HiMag than for K31. Phosphorus and K concentrations were not different. Herbage yields, P, Ca, and Mg concentrations were increased by P, K, and lime additions. In experiment 2, HiMag(E‐), K31(E‐), endophyte‐infected K31(E+), Mo I(E+), Mo II (E+), and AU Triumph (E‐) were planted either in a prepared seedbed or planted without tillage into the Cecil soil. HiMag yields were not different from Mo‐I, Mo‐II or K31(E±), but were less than those of AU Triumph (E‐). HiMag yield response to no‐till planting, past soil erosion, and fertilizer level was similar to that of K31 (E±). Fertilizer level, and soil condition affected the magnitude of differences in mineral levels in HiMag and K31 (E±), but K/(Ca+Mg) values were more favorable in HiMag. All tall fescue cultivars established equally well in no‐till or prepared seedbeds. Aside from a slightly lower first harvest yield there were no important effects of planting no‐till versus planting in a prepared seedbed. HiMag's agronomic attributes, while not superior to other cultivars, were sufficient to justify further testing to improve Mg nutrition of grazing animals.     

Growth and magnesium uptake of tall fescue clones with varying root diameters

Abstract

A cool season perennial grass with a root system capable of penetrating hardpans and which can accumulate adequate Mg to prevent deficiencies in forage is needed in the Coastal Plain region. A greenhouse experiment was conducted to determine the effects of magnesium (Mg) concentration in nutrient solution and root diameter on Mg uptake and growth of tall fescue (Festuca arundinacea Schreb.). Propagules of two fescue clones with large root diameter (LDR >1 mm), two clones with small root diameter (SDR <0.8 mm), and a single clone from ‘Kentucky 31’ (Ky‐31) were transferred into 12‐liter tanks containing Mg concentrations of 3, 21, 42, 125, 250, and 500 μM as MgSO₄ and grown for 39 or 70 days. Leaf Mg concentration was increased linearly with Mg solution concentration in LDR clones for a 39‐day growth period (Harvest 1), but increased according to a cubic equation in the SDR clones and the Ky‐31. Predicted leaf Mg concentration as a function of solution Mg followed a cubic equation for a 70‐day growth period (Harvest 2) in all clones. Predicted root Mg concentration was linearly related to Mg solution concentration for the LDR clones and the Ky‐31, but followed a cubic equation for the SDR clones for the first growth period. For the second growth period, the root Mg concentration of the SDR clones and the Ky‐31 was increased linearly, while the LDR clones followed a quadratic equation. Magnesium uptake followed a cubic equation with Mg solution concentration for both growth periods on all tall fescue clones. This nonlinear variation of Mg uptake and plant Mg concentration with respect to solution Mg concentration strongly suggests that a dual uptake mechanism might have been present in tall fescue clones. Root volume was greater in the SDR than LDR clones or Ky‐31 for both growth periods. The Ky‐31 had the greatest leaf and root dry weight for both growth periods, while the LDR clones had the lowest.     

Grass species and cultivar differences in magnesium concentration

Abstract

Two rates of Mg, 0 and 56 kg/ha, were randomized within each of 43 cultivars that had previously been established in a randomized complete block design. The 43 cultivars consisted of 6 species. Forage samples were obtained in early spring and chemically analyzed for content of Ca, Mg and K.

Grass species and cultivars with species significantly differed in content of Ca, Mg and K and in the ratio meq K/(meq Ca + meq Mg). Significant interactions of Mg with species and Mg with cultivars within species were observed. At the relatively low level of soil Mg and Mg rate, no cultivar contained 0.20% Mg, a value often used to identify proneness to grass tetany. However, no cultivar had an average meq ratio, K/(Ca + Mg), greater than 2.2, a value often used in diagnosing potential tetany problems that might be associated with intake of low Mg forage.

The interaction of cultivar with Mg rate indicates that fertilizer Mg level influenced cultivar content of Mg, and that the effect was not consistent for all cultivars.     

Yield,quality and K/(Ca+Mg) ratio of tall fescue breeding lines on amended and nonamended minesoil

Abstract

Surface mineable coal is abundant beneath many farmland areas in Missouri. Presently, 90% of the electricity generated in the state is by coal powered plants. Surface strip‐mining laws now require reclamation of these lands after drastic disturbance. Tall fescue (Festuca arundinancea Schreb) cultivars and breeding lines have been evaluated for yield, nutrient composition and quality on undisturbed lands, but not for these qualities and for adaptability to revegetate drastically disturbed lands.

Six breeding lines and 2 cultivars of tall fescue were evaluated for yield, nutrient composition, crude protein and IVDMD on limed and unlisted minesoils in west‐central Missouri. The experimental design was a randomized split‐block with lime treatment the split‐block, 3‐replications, with individual plots 1.21 × 3.05 m. Agriculture lime with ENM index of 291 at rate of 19 mt/ha was incorporated, fescue seeded and the experimental area mulched during August‐September, 1978. The 1979 harvest samples were composited for crude protein, nutrient and IVDMD analyses and the 1980 harvest samples were analyzed for individual plots.

The 1979 yield was not significantly different between genetic materials, but mean yield from limed minesoil was significantly higher than from unlimed minesoil. Yield data evaluation suggest Kenny, WG3B, HMR to yield highest on unlimed minesoil and WG2B, LMR and HMR highest on limed minesoil, with MO‐96 lowest in yield limed or unlimed. The calculated K/(Ca+Mg) ratio of HMR and Kenhy was interpreted to be borderline for potential occurrence of grass tetany under limed environment. Differential divalent cation accumulation capacities of the breeding lines LMR and HMR was expressed on both the limed and unlimed minesoil. Potassium was not judged to reach a sufficiently high or Mg sufficiently low level to suggest potential problem of hypomagnesaema.

Lime increased IVDMD, but not crude protein. Crude protein varied by year, but IVDMD remained nearly constant. The genetic materials MO‐96 and H‐I accumulated higher quantities of Mg upon liming, but had lower IVDMD. Differences in yield were not significantly related to cation accumulation or forage quality on this minesoil, limed or unlimed.     

Yield,quality and k/(Ca+Mg) ratio of tall fescue beeeding lines on amended and nonamended minesoil

Abstract

Surface mineable coal is abundant beneath many farmland areas in Missouri. Presently, 90% of the electricity generated in the state is by coal powered plants. Surface strip‐mining laws now require reclamation of these lands after drastic disturbance. Tall fescue (Festuca arundinancea Schreb) cultivars and breeding lines have been evaluated for yield, nutrient composition and quality on undisturbed lands, but not for these qualities and for adaptability to revegetate drastically disturbed lands.

Six breeding lines and 2 cultivars of tall fescue were evaluated for yield, nutrient composition, crude protein and IVDMD on limed and unlimed minesoils in west‐central Missouri. The experimental dersign was a randomized split‐block with lime treatment the split‐block, 3‐replications, with individual plots 1.21 x 3.05 m. Agriculture lime with ENM index of 291 at rate of 19 mt/ha was incorporated, fescue seeded and the experimental area mulched during August‐September, 1978. The 1979 harvest samples were composited for crude protein, nutrient and IVDMD analyses and the 1980 harvest samples were analyzed for individual plots.

The 1979 yield was not significantly different between genetic materials, but mean yield from limed minesoil was significantly higher than from unlimed minesoil. Yield data evaluation suggest Kenhy, WG3B, HMR to yield highest on unlimed minesoil and WG2B, LMR and HMR highest on limed minesoil, with MO‐96 lowest in yield limed or unlimed. The calculated K/(Ca+Mg) ratio of HMR and Kenhy was interpreted to be borderline for potential occurrence of grass tetany under limed environment. Differential divalent cation accumulation capacities of the breeding lines LMR and HMR was expressed on both the limed and unlimed minesoil. Potassium was not judged to reach a sufficiently high or Mg sufficiently low level to suggest potential problem of hypomagnesaema.

Lime increased IVDMD, but not crude protein. Crude protein varied by year, but IVDMD remained nearly constant. The genetic materials MO‐96 and H‐I accumulated higher quantities of Mg upon liming, but had lower IVDMD. Differences in yield were not significantly related to cation accumulation or forage quality on this minesoil, limed or unlimed.     

Mineral composition of kenhy tall fescue as affected by nutrient solution concentrations of Mg and K

Four greenhouse sand culture experiments were conducted with Kenhy tall fescue, a Lolium multiflorum X Festuca arundinacea hybrid derivative. These experiments were conducted to characterize mg accumulation and the chemical composition of Kenhy under various combinations of Mg, K, and N solution concentrations. Of primary interest was the shape and magnitude of response of tissue Mg concentration to solution K levels and potential for Mg accumulation that exists in Kenhy under low solution K levels. Analyses were made for Mg, K, Ca, Na, N, and nitrate.

Increased Kg concentrations were observed with increased solution Mg. Increased solution K was in all cases associated with lower concentrations of Mg. Under conditions of low solution K (0.125 mM) and adequate Mg (0.25 mM), Mg accumulation exceeded 1.0%. Increased solution N was associated with decreased Mg concentrations. Both the linear and quadratic components of Mg solution concentration contributed significantly to increased tissue Mg. Hawever, the linear component of K solution concentration was sufficient to account for decreased tissue Mg. The reduction of tissue Mg to solution K was greater at higher concentrations of K.

Potassium accumulation significantly increased with increased solution K. Increased solution Mg was associated with lower tissue K in which the greatest reduction in K accumulation occurred with the first Mg addition.

Calcium accumulation decreased with increased solution K. Higher solution Mg was associated with lower tissue Ca levels while higher levels of N were associated with increased tissue Ca. Sodium accumulation was significantly reduced by increased K concentrations but neither Mg nor N was effective in consistently altering tissue Na concentrations.

From these experiments it is evident that Kenhy tall fescue has the absorptive capability for high levels of Mg under conditions of low levels of solution K. However, even small increments of solution K were shown to be capable of substantially reducing the Mg content, Thus, the selection of forage grasses for Mg absorptive capability must be conducted under conditions of high solution K, if large improvements on present forage materials are to be obtained. In addition, the inverse relationship between Mg and K present in Kenhy seedlings confirms the need to consider K fertilization recommendations in attempting to increase forage Mg durirg the grass tetany period.     

The use of carbonatite rock powder as a liming agent

Carbonatite rock powder, originating from the Lillebukt Alkaline Complex at Stjernøy in northern Norway, can potentially be used as a slow‐releasing lime and potassium (K) and magnesium (Mg) fertilizer due to a high concentration of the easily weathered minerals calcite (42%) and biotite (30%). However, the enrichment of barium (Ba) and strontium (Sr) may cause an undesired uptake to plants when carbonatite is applied to agroecosystems. A pot experiment was designed to investigate the liming and fertilization effects of carbonatite and the potential mobilization of Ba and Sr compared to a dolomite lime commonly used in Norwegian agriculture. These liming agents were mixed with a sandy soil applied to different amounts of peat, and the uptake of Ba, Sr, calcium (Ca), Mg, and K by Festuca arundinácea Schreb. Kora (tall fescue) and Trifolium repens L. Milkanova (white clover) was evaluated. The liming agents were generally incapable of buffering the acidifying effect from increased applications of peat, while the plant dry mass was unaffected. Compared to pots given dolomite and soluble K, the availability of K from carbonatite to plants was equally high or higher, and no difference in the K:(Ca + Mg) ratio in plants was observed. Carbonatite was a significant source to plant Ba and Sr, and the uptake seemed to follow the Ca uptake. Addition of peat amplified the uptake of Ba, Sr, Ca, Mg, and K to plants, probably an effect of organic acid‐induced weathering of carbonatite. White clover took up Ba, Sr, and Ca more effectively than tall fescue, but the Ba and Sr concentrations in plants were relatively moderate compared to concentrations reported from field investigations.     

Growth and nutrient uptake of temperate perennial pastures are influenced by grass species and fertilisation with a microbial consortium inoculant

Background: The low fertility of sandy soils in South‐Western Australia is challenging for the establishment of temperate perennial pastures. Aims: To assess whether microbial consortium inoculant may improve plant growth by increasing nutrient supply, root biomass and nutrient uptake capacity. Methods: Five temperate perennial pasture grasses–cocksfoot (Dactylis glomerata L. cv. Howlong), phalaris (Phalaris aquatica L. cv. Atlas PG), tall fescue (Festuca arundinacea L. cv. Prosper), tall wheatgrass (Thinopyrum ponticum L. cv. Dundas), and veldt grass (Ehrharta calycina Sm. cv. Mission) were tested in a controlled environment on the growth and nutrition with the microbial consortium inoculant and rock mineral fertiliser. Results: Veldt grass produced the highest shoot and root growth, while tall fescue yielded the lowest. Rock mineral fertiliser with or without microbial consortium inoculant significantly increased root and shoot biomass production across the grass species. The benefit of microbial consortium inoculation applied in conjunction with rock mineral fertiliser was significant regarding shoot N content in tall wheatgrass, cocksfoot and tall fescue. Shoot P and K concentrations also increased in the five grass species by microbial consortium inoculation combined with rock mineral fertiliser in comparison with the control treatment. Arbuscular mycorrhizal (AM) colonisation decreased with rock mineral fertilisation with or without microbial consortium inoculant except in cocksfoot. Conclusions: The response to microbial consortium inoculation, either alone or in combination with rock mineral fertiliser, was plant species‐dependent, indicating its potential use in pasture production.     

Effects of nitrogen carriers,nitrogen rates,and maturity on composition of smooth bromegrass

Abstract

Magnesium and Ca concentrations in smooth bromegrass (Bromus inermis L) were not affected by late‐winter applications of N. Magnesium concentrations were constant until rapid growth in mid‐May then they declined until early June harvest. Highest seasonal concentrations were found in the fall regrowth. Calcium concentrations declined as plants matured in spring. Highest seasonal Ca concentrations were found in the fall regrowth. Nitrogen, P, and K concentrations and K/(Ca+Mg) ratios were increased by N applications during early spring but did not differ significantly by early June harvest. Nitrogen and P concentrations decreased as plants matured in spring and fall. K concentrations and K/(Ca+Mg) ratios changed inconsistently from sampling date to sampling date. Forage yields were approximately doubled by 67 kg N/ha and tripled by 202 kg N/ha. Significant yield differences were related to different N carriers.     

Macronutrient variation in small grain forage as related to specie and variety

Abstract

Incidence of grass tetany on small grain pastures has been related to forage Mg content and K/Ca + Mg ratio. The objective of this study was to relate P, K, Ca, Mg, and the K/Ca + Mg ratio in winter forage to specie and variety. In one year on unlimed soil with low pH, rye forage tended to be higher in P than oats, barley, or wheat. P content increased the next year on higher pH soil with less specie differences. K differed little with specie, and was higher in November than later harvests. Rye tended to be higher in Ca both years, especially in the early harvest. Percent Mg was lower for wheat the first year on the low pH soil than the other species, and percent Mg increased in all species at all harvests the next year on higher pH soil with wheat having similar Mg levels to the other species. The K/Ca + Mg ratio of wheat was higher than rye, oats, and barley on the low pH soil. Liming reduced this ratio to near 2.2 on all species. Grass tetany has been reported more likely to occur when K/Ca + Mg is over 2.2, and this study suggests rye, followed closely by oats and barley, would maintain lower ratios than wheat under conditions of low Mg availability.     

Tall fescue aluminum tolerance is affected by neotyphodium coenophialum endophyte

Roots of endophyte‐infected (E+) tall fescue (Festuca arundinacea Schreb.) exude more phenolic‐like reductants than roots of endophyte‐free (E‐) plants when mineral stressed. Phenolic compounds are efficient chelators of aluminum (Al) and may influence Al tolerance in many plant species. The objective of our study was to determine if enhanced release of phenolic compounds by roots of E+ plants contributes to Al tolerance in tall fescue. Two cloned genotypes (DN2 and DN11) of tall fescue infected with their naturally occurring fungal endophyte Neotyphodium coenophialum (Morgan‐Jones and Gams) Glenn, Bacon and Hanlin and their noninfected isolines were grown in nutrient solutions at 0 μM Al (Al‐) and at 640 μM Al (Al+) under controlled environment conditions. Root and shoot dry matter (DM) of endophyte‐infected tall fescue was greater in E+ than E‐ plants by 57% and 40%, respectively, when plants were grown without Al. Endophyte infection did not affect root and shoot DM of tall fescue grown with Al but relative (to Al‐treatment) reduction in root and shoot DM was greater in E+ than E‐ plants. In response to Al stress, more Al (47%) and P (49%) could be desorbed from root surfaces of E+ than E‐ plants. Aluminum concentrations in roots of E+ plants were 35% greater and P concentrations were 10% less than those determined in roots of E‐plants. No differences in mineral concentrations were observed in shoots, regardless of endophyte status, or Al level in nutrient solution. Roots of E+ plants increased pH of both Al‐ and Al+ nutrient solutions to a greater extent than roots of E‐ plants in a 48 h interval. Our results show that more Al can be sequestered on root surfaces and in root tissues of endophyte‐infected tall fescue than in plants devoid of endophyte. Aluminum sequestration was greater on root surfaces and in root tissues of E+ than E‐ plants of a given tall fescue genotype. Our results suggest that increased exudation of phenolic‐like compounds from roots of endophyte‐infected tall fescue may be directly involved in Al tolerance and serves as a mechanism for widespread adaptability and success of endophyte‐tall fescue associations.     

Seasonal variations in nutrient and carbohydrate levels of tall fescue cultivars in Japan

Quality (color and density) of tall fescue (Festuca arundinacea Schreb.) as a turfgrass is reduced during both the winter and summer in Japan. Seasonal variations in nutrient and carbohydrate levels of six cultivars of tall fescue were measured to determine if these changes are related to the reduction in the turf quality. There were significant differences among the cultivars in nutrient and carbohydrate levels. The nutrient and carbohydrate levels of tall fescue cultivars changed seasonally. Levels of calcium (Ca) and zinc (Zn) were below the sufficiency, but the concentrations of other nutrients were sufficient during the summer suggesting that the reduction in the quality of tall fescue cultivars during the summer in Japan may not be related to the lack of these nutrients in the plant tissues. The nitrogen (N), Ca, magnesium (Mg), phosphorus (P), Zn, iron (Fe), and copper (Cu) levels in the plant tissues were below the adequate range in the spring which could be attributed to high growth rate since no deficiency symptom was observed. With exception of Ca content, plants contained sufficient or more than sufficient nutrients in their tissues during the fall. Though concentrations of other nutrients were sufficient in the plant tissues in the winter, levels of N, Ca, Mg, P, molybdenum (Mo), Zn, and Cu were lower than plant's requirement which could be due to low temperature since availability of the nutrients reduces under low temperature. There were no deficiency symptoms of these nutrients, but lack of N in the plant tissue could be the cause of the reduction in the color of the tall fescue cultivare in winter. Levels of glucose, fructose, sucrose, fructan, and starch in the summer were higher or equal to those carbohydrate levels in the spring or fall suggesting that decline in tall fescue quality in Japan during the summer may not be related to carbohydrates shortages. Though starch levels were lower in the winter than other seasons, other carbohydrate levels were equal or higher than the levels in the spring and the total carbohydrate content was much higher in the winter than other seasons, suggesting that reduction in tall fescue quality in Japan during the winter may not be related to carbohydrates shortages.     

Elemental and/or cation ratio efficiency of corn hybrids grown on an infertile soil inadequate in magnesium

Abstract

Magnesium deficiency in corn (Zea mays L.) is often attributed to the low levels of Mg in soils. This study was conducted to determine elemental and/or cation balance efficiency of corn hybrids grown on a soil low in available Mg, Among the 15 hybrids tested, no differential efficiency in ear leaf concentration of P was found at two planting dates. Leaf concentrations of Zn and Fe were influenced by planting date for all hybrids but interactions between hybrids and planting date were found only for K, Ca, Mg concentrations and the sum of the Meq Ca + Mg/100 g, the Meq K + Ca + Mg/100 g, and the K/Ca and K/Ca + Mg ratios. Planting dates did not Influence the K/Mg ratio among hybrids. Large differences in efficiency of K, Ca, and Mg were found but these cations were found to have large Interactions. Data show that Ca and Mg efficient hybrids are less efficient in K than Ca and Mg inefficient hybrids. It should be possible to breed corn hybrids for better cation balance efficiency for use on infertile soils low in avallable Mg.     

Effect of varying solution calcium or magnesium concentrations in the presence or absence of aluminum on yield and plant calcium or magnesium concentrations in wheat

The effect of varying solution calcium (Ca) and magnesium (Mg) concentrations in the absence or presence of 10 μM aluminum (Al) was investigated in several experiments using a low ionic strength (2.7 × 10^‐3 M) solution culture technique. Aluminium‐tolerant and Al‐sensitive lines of wheat (Triticum aestivum L.) were grown. In the absence of Al, top yields decreased when solution Ca concentrations were <50 μM or plant Ca concentrations were <2.0 mg/g. Top and root yields decreased when solution Mg concentrations were <50 μM or plant Mg concentrations were <1.5 mg/g. There were no differences between the lines in solution or plant concentrations at which yield declined. Increasing solution Ca concentrations decreased plant Mg concentrations in the tops (competitive ion effect) but increased plant Mg concentrations in the roots of wheat. This suggests that Ca is competing with Mg when Mg is transported from the roots. Increasing solution Mg concentrations decreased plant Ca concentrations in the tops and the roots (competitive ion effect). In the roots, increasing solution Mg concentrations decreased plant Ca concentrations at a lower solution Ca concentration in the Al‐sensitive line than the Al‐tolerant line. In the presence of Al, increasing solution Ca and Mg concentrations increased yield (Ca and Mg ameliorating Al toxicity). Yield increased until the sum of the solution concentrations of the divalent cations (Ca+Mg) was 2,000 μM for the Al‐tolerant line or 4,000 μM for the Al‐sensitive line. The exception was that yield decreased when solution Mg concentrations were > 1,500 μM and the solution Ca concentration was 100 μM (Mg exacerbating Al toxicity). The ameliorative effects of solution Ca or Mg on Al tolerance were not related to plant Ca or Mg concentrations per se.     

Neotyphodium endophytes trigger salt resistance in tall and meadow fescues

Infection with Neotyphodium spp. endophytes increases resistance to drought stress and soil mineral imbalances in tall fescue (Festuca arundinacea Schreb. = Lolium arundinaceum (Schreb.) S. J. Darbysh.) and meadow fescue (Festuca pratensis Huds. = Lolium pratense (Huds.) Darbysh.). We hypothesized that resistance of these grasses to salinity stress may also be attributed to endophyte infection. Two tall fescue genotypes, Fa75 and Fa83, and one meadow fescue genotype, Fp60, infected (E+) with their endophytic fungi, Neotyphodium coenophialum (Glenn, Bacon and Hanlin) and N. uncinatum (Glenn, Bacon and Hanlin), respectively, and their noninfected counterparts (E–) were cultured in nutrient solution at three salinity levels of 0, 85, and 170 mM NaCl. Except for genotype Fa75, E+ plants exhibited higher leaf survival rates than E– clones at a high salinity level (170 mM). Root dry matter was higher in E+ than in E– plants, but shoot dry matter was not affected by endophyte infection. This resulted in a lower shoot‐to‐root ratio in E+ plants (1.63) compared with E– plants (2.40). Sodium (Na⁺) and chloride (Cl^–) concentrations were greater in roots of E– than in E+ clones. In shoots, Na⁺ and Cl^– concentrations were not affected by the endophyte. In contrast, E+ plants accumulated more potassium (K⁺), which resulted in a greater K⁺ : Na⁺ ratio in shoots of E+ than in those of E– plants. Our results show that endophyte infection reduced Na⁺ and Cl^– concentrations in tall fescue and meadow fescue roots but increased K⁺ concentrations in the shoots. Based on these results, we conclude that endophyte‐infected grasses may thrive better in salinity‐stress environments.     

Neotyphodium coenophialum‐endophyte infection affects the ability of tall fescue to use sparingly available phosphorus

Neotyphodium coenophialum, (Morgan‐Jones & Gams) Glenn, Bacon & Hanlin, infected tall fescue (Festuca arundinacea Schreb.) plants perform better than non‐infected isolines on phosphorus (P)‐deficient soils. Our objective was to characterize growth and P uptake dynamics of tall fescue in response to endophyte infection and P source at low P availability in soil. Two tall fescue genotypes (DN2 and DN4) infected with their naturally occurring N. coenophialum strains (E+), and in noninfected (E‐) forms were grown in Lily soil (fine loamy siliceous, mesic Typic Hapludult) in a greenhouse for 20 weeks. Three soil P treatments were imposed: no P supplied (control) and P supplied as commercial fertilizer (PF) or as phosphate rock (PR) at the level of 25 mg P kg^‐1 soil. Interaction of tall fescue genotype and endophyte status had a significant influence on mineral element uptake suggesting high specificity of endophyte‐tall fescue associations. Endophyte infection did not affect root dry matter (DM) when no P was supplied but shoot DM was reduced by 20%. More biomass was produced and greater P uptake rate occurred in PR than PF treatment. Root DM was greater in E+ DN4 than E‐DN4 when supplied with either PF or PR. In contrast, endophyte infection did not affect root DM of DN2, regardless of P source. Relative growth rate (RGR) of E+ plants grown with PR was 16% greater than that of E‐plants. Endophyte infection did not improve growth or P uptake in PF treatment. When PR was supplied, P uptake rate was 24% greater in E+ DN2 than E‐ DN2, but endophyte infection did not benefit DN4. Phosphorus‐use efficiency was 6% less in E+ DN2 but 16% greater in E+ DN4 compared to E‐ plants, regardless of P source. Root exudates of E+ DN2, but not E+ DN4 solubilized more P from PR than those of E‐ plants. The correlation between root RGR and P uptake rate was relatively high for E‐ plants (r=0.76), but low for E+ plants (r=0.27) grown with PR. Results suggest that P uptake by E+ tall fescue might rely on mechanisms other than an increase in root biomass (surface area). Endophyte infection modified tall fescue responses to P source. This phenomenon was associated with modes of P acquisition which included enhanced activity of root exudates in releasing P from PR in E+ plants (DN2), and increased root biomass (DN4). The dominant means of P acquisition may be determined by a specific association of endophyte and tall fescue genomes. Endophyte‐tall fescue association plasticity contributes to widespread success of symbiotic in marginal resource conditions.