Effect of plant growth-promoting Bacillus sp. on color and clipping yield of three turfgrass species

A two-year irrigated field study was conducted to determine the effects of plant growth-promoting rhizobacteria (PGPR; Bacillus subtilis OSU-142 and Bacillus megaterium M3) as biofertilizer, and in combination with a chemical nitrogen (N) fertilizer, on turf color and clipping yield, and interaction of biofertilizer and chemical N fertilizers in perennial ryegrass (Lolium perenne L.), tall fescue (Festuca arundinacea L. Schreb.), and Kentucky bluegrass (Poa pratensis L.). The three turf species were tested separately in split-plot design experiments with three replications. Three fertilizer sources (ammonium nitrate only, ammonium nitrate + B. megaterium M3, and ammonium nitrate + B. subtilis OSU-142) were the main plots. N applications with monthly applications of 0.0, 2.5, 5.0, and 7.5 g N/m² were the subplots. Color ratings and clipping yields increased with increasing chemical N fertilizers in all species. Both Bacillus sp. significantly increased color ratings and clipping yields in perennial ryegrass and tall fescue. However, there were no significant differences among the three fertilizer sources in color and clipping yield of Kentucky bluegrass. The experiments showed that there is a small but significant benefit from applying biofertilizers for turf color, and that N fertilization may be reduced in some turf species when biofertilization are made for this purpose.     

EFFECTS OF NITROGEN APPLICATION TIMING ON GROWTH AND QUALITY OF A TURFGRASS MIXTURE

A 3-year field study was conducted to determine the influence of nitrogen (N) application timing on the growth and quality of a turfgrass mixture consisting of perennial ryegrass (Lolium perenne L.), Kentucky bluegrass (Poa pratensis L.), creeping red fescue (Festuca rubra var. rubra L.), and chewings fescue (Festuca rubra var. commutata Gaud.) under irrigated conditions. Nitrogen was applied annually at the rate of 30 g m^?2 year^?1, with six application regimes: control (no N), single spring (30 g m^?2), single fall (30 g m^?2), spring + fall (15 + 15 g m^?2), spring + summer + fall (10 + 10 + 10 g m^?2), and monthly from April through September (5 g m^?2).

Color, turf quality, clipping weights, and shoot density were correlated with fertilizer rates and application timing in this study. Fertilization monthly or every 2 months resulted in more uniform color and turf quality and less clipping weights than with comparable heavy spring and fall fertilizations. Heavy N applications in the fall did not cause winter injury and produced significantly darker color and more uniform appearance in early spring than other N applications. All N-fertilization regimes increased shoot density, but spring fertilization stimulated density the most. Nitrogen applied monthly or every 2 months was enough to enhance the color, turf quality, and shoot density of the turf during the growing season but did not greatly affect the growth rate.     

Effect of Nitrogen Fertilization on Quality Characteristics of Four Turf Mixtures Under Different Wear Treatments

ABSTRACT

The effect of three nitrogen (N) application regimes on the color, turf quality, cover, and clipping weights of four different sports type mixtures were evaluated under different wear frequencies for three years in an irrigated field. Nitrogen was applied monthly at rates of low (2.5 g N m^{? 2}), medium (5.0 g N m^{? 2}), and high (7.5 g N m^{? 2}). The turf mixtures were subjected to four different wear treatments at frequencies of zero (control), once per week, once biweekly, and once per month for approximately eight months each experimental year. Wear treatments reduced turf color and quality, cover percentage, and clipping yield. Application of wear every week was detrimental to turf characteristics, whereas wear once every month generally had no significant effect. Nitrogen fertilization resulted in improved color and quality, and increased cover percentage and clipping yield.     

北京地区常用草坪草的耗水规律及适宜灌溉量研究

研究了在北京地区不同供水条件下，草地早熟禾、高羊茅、多年生黑麦草、野牛草、结缕草和狗牙根整个生长季的蒸散量差异和耗水规律。结果表明，蒸散量主要与草坪草的生物学特性有关，受水分条件影响；冷季型草坪草中多年生黑麦草耗水最少，暖季型草坪草中结缕草耗水最少；通过比较坪草和北方主要农作物的K_C值，得出草坪与大田作物的需水量相当；北京地区常用草坪草整个生长季的适宜灌溉量为：高羊茅(391.8 mm)>草地早熟禾(368.3 mm)>多年生黑麦草(315.1 mm)>狗牙根(300.7 mm)>野牛草(184.0 mm)>结缕草(110.5 mm)。     

Response of turfgrass to urea-based fertilizers formulated to reduce ammonia volatilization and nitrate conversion

Stabilized urea fertilizers are currently being marketed for use in turfgrass, as a more efficient alternative to standard urea that minimizes adverse impacts on the environment. These fertilizers have been evaluated for reducing N losses and increasing grain yield in crop plants, but their effects in turf are not well characterized. The efficacy of two stabilized urea fertilizers containing urease and nitrification inhibitors, N-(n-butyl) thiophosphoric triamide and dicyandiamide or butenedioc-methylenesuccinic acid copolymer, in reducing N losses was studied for a 56-day period in a mixed stand of Kentucky bluegrass (Poa pratensis L.) and perennial ryegrass (Lolium perenne L.) using ¹⁵?N-enriched fertilizers. Turf responded to a 49-kg ha^?1 N input with increased color, quality, and biomass production. No benefit of nitrification and urease inhibitors compared to urea was observed for clipping production, N use efficiency, or turfgrass color and quality. Though the efficacy of urease and nitrification inhibitors has been demonstrated both in the laboratory and for row crops, inhibitors appear to be of limited value for enhancing N use efficiency in turf.     

Rhizodeposition of nitrogen by red clover,white clover and ryegrass leys

Correct assessment of the rhizodeposition of N in grassland is essential for the evaluation of biological N₂-fixation of legumes, for the total N balance of agro-ecosystems, and for the pre-cropping value of grasslands. Using a leaf-feeding technique by which plants were ¹⁵N labelled while growing in mezotrons in the field, the rhizodeposition of N by unfertilised red clover, white clover and perennial ryegrass growing in pure stands was shown to amount to 64, 71 and 9 g N m⁻², respectively, over two complete growing seasons. The corresponding values for red clover and white clover growing in mixtures with ryegrass were 89 and 32 g N m⁻², respectively. The rhizodeposited N compounds, including fine roots, constituted more than 80% of the total plant-derived N in the soil, and in all cases exceeded the amount of N present in stubble. In the mixtures of red clover–ryegrass and white clover–ryegrass and the pure stands of red clover, white clover and ryegrass, respectively, the rhizodeposition constituted a 1.05, 1.52, 1.26, 2.21 and 2.77 fold increase over the total N in the shoots harvested during the two production years. In pure stands and mixtures of clover, 84 and 92%, respectively, of this N derived from biological N₂ fixation. It is concluded that rhizodeposition provides a very substantial input of N to the legume-based grassland systems with great consequences for ecosystem N balance and turnover. Furthermore, the amount of atmospheric-derived N in the rhizodeposits may exceed that in the harvested shoots.     

Efficiency of Foliar Versus Granular Fertilization: A Field Study of Creeping Bentgrass Performance

ABSTRACT

Limited information comparing foliar versus granular fertilization of turfgrasses is available. The objective of this research was to evaluate liquid and/or granular N fertilization on turfgrass quality, clipping yield, and root biomass of ‘L-93’ creeping bentgrass. Treatments consisted of two annual nitrogen (N) inputs, 127 and 190 kg ha^?1, using 100% granular urea fertilizer, 50% granular urea + 50% liquid urea fertilizer, or 100% liquid urea fertilizer. These results suggest a rate of at least 190 kg N ha^?1 yr^?1 is needed to maintain acceptable bentgrass quality in the transition zone of the U.S. Combining both liquid and granular methods appear superior compared to relying on one method exclusively.     

Response of photosynthesis and superoxide dismutase to silica applied to creeping bentgrass grown under two fertility levels

Abstract

Responses of photosynthesis, Superoxide dismutase activity, and disease tolerance of creeping bentgrass (Agrostis palustris Huds. A.) to soluble potassium silicate (20.8% SiO₂) treatments was investigated under two fertilization regimes during 1997 and 1998. Potassium silicate was applied twice a month at 603 and 1205 mL 100 m^?2 under high or low fertilization regimes in the field, sampled from which were subjected to low soil moisture in a greenhouse environment. Foliar application of silicate stimulated antioxidant superoxide dismutase (SOD) activity in the bentgarss, especially under the high fertilization regime. Silicate increased photosynthetic capacity (PC) and chlorophyll content when applied at 603 mL 100 m^?2. Dollarspot disease incidence was significantly reduced with silicate treatment regardless of fertilization regime. Silicate did not significantly impact clipping weight. Under low soil moisture (‐0.05 MPa), silicate also enhanced SOD activity, PC, and chlorophyll content as well as root mass of bentgrass. Results suggest silicate may be used to enhance turfgrass drought and disease tolerance of turfgrass.     

Forage Production,Nitrogen Fixation,and Soil N Accumulation of White Clover in the Hill Farming System of Azad Jammu and Kashmir

Quantitative measurements of plant growth characteristics, forage production, nitrogen (N) fixation, and soil N accumulation by white clover were determined in a field experiment at the subhumid hilly region of Rawalakot, Azad Jammu and Kashmir (AJK). Three indigenous and two exotic ecotypes of white clover were used in the study. Indigenous ecotypes were collected from three different locations (i.e., Tollipir, Banjosa, and Rawalakot), whereas exotic ecotypes (NuSiral and Irrigation) were collected from New South Wales Agricultural Research and Advisory Station, Australia. Data were collected for two seasons (spring 2004–autumn 2004). Total average values for height, number of stolons, length of stolons, number of leaves, and leaf area were 13–50 cm, 9–20, 2–4 cm, 23–81, and 7–16 cm², respectively. The morphological characteristics of exotic ecotypes were significantly higher than the indigenous ecotypes, and the percentage increase in different plant characteristics was +6% to 214%. Total herbage dry‐matter yield (DMY) in the indigenous and exotic ecotypes varied between 0.5–2.3 and 3.6–4 Mg ha^?1, respectively. All the ecotypes showed substantial nodulation potential, and the number of nodules in plant roots ranged from 65 to 119, confirming the presence of indigenous Rhizobium population in the soil. The N contents of harvested herbage of white clover were 2.3–3.0% compared to 0.85% in the grass, and the estimated rates of N₂ fixation were 26 kg N ha^?1 in the indigenous to 79 kg N ha^?1 in the exotic ecotypes. Amount of N₂ fixed was strongly correlated with DMY, suggesting that crop DM can be used as an indicator of N₂ fixation in white clover. Protein content of white clover was 14–19%, compared to 5% in the indigenous grass species. Total organic carbon (C) and N in control soil were 8.5 and 0.75 g kg^?1, which increased significantly to 13.1 and 0.93 g kg^?1 in soil under white clover. It is concluded that white clover has substantial potential for growth and establishment in the subhumid hilly regions and can be used to recuperate degraded soils because of its ability to sustain high level of pasture production and increase the N status of soil. These benefits could be of particular use for small‐scale resource‐poor farmers.     

Response of Kentucky bluegrass turf to fertilizers containing dicyandiamide

Abstract

Nitrogen fertilization is of major importance in maintaining turfgrass stands. Although rates and sources of N may vary on different turfgrass areas, efficient utilization of N applications is always important. This research was conducted in the field to determine the value of dicyandiamide (DCD) as a nitrification inhibitor and as a slow‐release N source in turfgrass fertilization. The inhibitory effect was studied by applying ammonium sulfate (AS), urea, and a complete fertilizer alone and with 10 and/or 15% of the N replaced with DCD‐N to stands of Kentucky bluegrass. Single and split rates totaling up to 196 kgN/ha/yr were used. Soil NO₃‐N and NH₄‐N analyses sometimes indicated decreased nitrification; however, turfgrass yield and color were essentially unaffected by these rates of DCD. To assess the slow‐release effect of DCD, various ratios of AS‐N or urea‐N to DCD‐N were used to fertilize turf in two experiments. Initial response decreased as the proportion of DCD‐N increased, and in one experiment, a residual effect was noted a year after application when DCD comprised 80 or 100% of the N. Severe, but short‐lived, phytotoxicity from DCD was noted in the other experiment when more than 40% of the N was from DCD. Under the conditions of this research, DCD appeared to have little value in increasing the efficiency of N fertilization.     

Comparing cultivars of three cool‐season turf‐grasses for potassium uptake kinetics and potassium recovery in the field

Efficient use of potassium (K) by turf depends on the ability of roots to absorb a high proportion of the fertilizer K applied to the soil. Among turfgrass genotypes, variation in K absorption kinetics of roots and its inheritance is important in the development of genotypes that are more efficient in K absorption from the soil. Therefore, K uptake kinetics of six cultivars each of Kentucky bluegrass (Poa pratensis L.), perennial ryegrass (Lolium perenne L.), and tall fescue (Festuca arundinacea Schreb.) were compared under greenhouse conditions. In 1990 and 1991, field studies of the same cultivars were conducted comparing clipping production rate, leaf blade K concentration, K recovery rate in clippings, K efficiency ratio and visual quality under a moderate K fertilization of 59 kg K/ha/year. Significant differences among species and cultivars were obtained for both absorption kinetics and field recovery of K. Significant correlations between some K uptake parameters and field performance were identified. These results show that genetic differences exist among turfgrasses for K utilization at both the interspecific and intraspecific levels and suggest that a screening program could be developed to identify turfgrass genotypes possessing superior K utilization.     

Uptake and Distribution of Nitrogen in Perennial Ryegrass: Effect of Additional Applications at Vegetative Growth

Abstract

Nitrogen (N) fertilization rate, form, and timing in perennial ryegrass (Lolium perenne L.) vary according to the purpose of the grass. Double or triple spring N applications are required in forage production of perennial ryegrass. Whereas in perennial ryegrass grown for seed production the effect of more than one application has not received much attention. The hypothesis is that in perennial ryegrass grown for seed production the utilization of applied N depends on the current N status. Perennial ryegrass was grown in a hydroponic system with two N rates: low‐N (0.2 mM) and high‐N (6.0 mM). After 47 days of growth, additional N was applied as double‐labeled ¹⁵NO₃ ^{? 15}NH₄ ⁺ on four successive occasions in order to distinguish between the recoveries of the initial N applications and the additional N applied. Growth parameters and N content were analyzed on five harvesting occasions. Additional N applications to plants with low N status were primarily used to increase both N content in all organs as well as shoot number. By contrast, in high‐N treatments, the additional N supplied was primarily used to increase total‐N content in leaves. In all treatments, leaves were the preferable storage organs for N, however, the results from the high‐N treatments suggest a shift to pseudo‐stems as the preferable storage organ when additional N was supplied. It is suggested that the current N concentration in perennial ryegrass determines the potential of the plants to utilize additional applied N.     

Utilisation by white clover and ryegrass of sulphur from 35s‐Labelled Gypsum

Abstract

This investigation reports the uptake of S from a surface application of ³⁵S‐labelled gypsum by a ryegrass‐white clover mixture sward and by a pure ryegrass stand, each growing at three levels of N in the field. Nitrogen stimulated ryegrass growth, reducing the contribution of white clover to the total yield, whereas S did not influence the yield of either species. Gypsum, while not increasing the total S in the white clover, contributed 23 to 50% of the total S concentration. In contrast, gypsum increased the total S in the ryegrass. The level of N nutrition did not alter the fertiliser S in white clover, but depressed the total S in the ryegrass. Nitrogen enhanced the fertiliser S in ryegrass at the first harvest, however, at the second harvest N depressed the fertiliser S.

Recovery of applied S was increased by N, reaching a maximum value of 19.8% by two harvest, and was decreased with increasing rate of gypsum. Without ‐N the white clover accounted for 50% and 27% of the S recovery by the mixture at the 1st and 2nd harvests respectively, the proportion dropping to less than 20% for each harvest at a high level of N.

There was no apparent competitive advantage of ryegrass over white clover when grown in association although the data indicated a greater ability by ryegrass to absorb S from a surface application. Under conditions of incipient S deficiency the reduction in the contribution of white clover to production with increasing N supply was considered to be due to factors other than the availability of S in the environment.     

Seasonal variations of soil microbial biomass and activity in warm- and cool-season turfgrass systems

Plant growth can be an important factor regulating seasonal variations of soil microbial biomass and activity. We investigated soil microbial biomass, microbial respiration, net N mineralization, and soil enzyme activity in turfgrass systems of three cool-season species (tall fescue, Festuca arundinacea Schreb., Kentucky bluegrass, Poa pratensis L., and creeping bentgrass, Agrostis palustris L.) and three warm-season species (centipedegrass, Eremochloa ophiuroides (Munro.) Hack, zoysiagrass, Zoysia japonica Steud, and bermudagrass, Cynodon dactylon (L.) Pers.). Microbial biomass and respiration were higher in warm- than the cool-season turfgrass systems, but net N mineralization was generally lower in warm-season turfgrass systems. Soil microbial biomass C and N varied seasonally, being lower in September and higher in May and December, independent of turfgrass physiological types. Seasonal variations in microbial respiration, net N mineralization, and cellulase activity were also similar between warm- and cool-season turfgrass systems. The lower microbial biomass and activity in September were associated with lower soil available N, possibly caused by turfgrass competition for this resource. Microbial biomass and activity (i.e., microbial respiration and net N mineralization determined in a laboratory incubation experiment) increased in soil samples collected during late fall and winter when turfgrasses grew slowly and their competition for soil N was weak. These results suggest that N availability rather than climate is the primary determinant of seasonal dynamics of soil microbial biomass and activity in turfgrass systems, located in the humid and warm region.     

Leaf morphology explains the disparity between annual bluegrass and creeping bentgrass growth under foliar fertilization

On golf courses planted to creeping bentgrass, invasion of annual bluegrass is a constant concern. To analyze if nitrogen fertilization manipulation could bias growth to creeping bentgrass, both grasses were fertilized either through foliar or soil application with either urea or ammonium sulfate and the impact on shoot and root growth measured. Ammonium sulfate resulted in greater overall growth for both species. Foliar application resulted in greater shoot growth for annual bluegrass and soil application resulted in greater root growth for creeping bentgrass. Leaf samples, as well as multiple leaf samples collected from golf courses, were examined microscopically for potential routes for foliar nutrient uptake: stomata and aqueous pores. No statistical difference was observed in the stomatal number between the two species but annual bluegrass possessed more aqueous pores. The enhanced ability of annual bluegrass to benefit from foliar fertilization may aid in its encroachment on highly managed golf greens.     

Manganese Supply and pH Influence Growth,Carboxylate Exudation and Peroxidase Activity of Ryegrass and White Clover

ABSTRACT

The effects of differential manganese (Mn) supply (0 to 355 μ M) and pH (4.8 and 6.0) on dry weight (DW), tissue concentrations of Mn, exudation of carboxylates, and the peroxidase activity were studied in ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) grown in nutrient solution. In both plant species, the increase in Mn supply caused a significant reduction in DW due to severe Mn toxicity, especially at pH 4.8. The critical toxicity concentration of Mn in shoots was 421 mg kg^{? 1} for ryegrass and 283 mg kg^{? 1} for white clover. For both plant species, an increase in Mn supply levels stimulated the exudation of carboxylates and the activity of peroxidase, which was related to stress conditions. The highest amount of carboxylates was exuded at pH 4.8. There was no clear effect of carboxylates on the complexation of Mn^{2 +}.     

Green Manuring with Clover and Ryegrass Catch Crops Undersown in Small Grains: Effects on Soil Mineral Nitrogen in Field and Laboratory Experiments

Abstract

In three field trials in southern Norway, Italian ryegrass (Lolium multiflorum Lam.), white clover (Trifolium repens L.) or subterranean clover (T. subterraneuni L.) was undersown in spring grain at three N fertilizer rates and ploughed under in late October as a green manure for a succeeding spring grain crop. The content of topsoil (0-20 cm) mineral nitrogen was determined during the growth of the grain crop, after grain harvest and after ploughing. In addition, mineralization of nitrogen and carbon was measured in green-manured soil incubated at 15°C and controlled moisture conditions. During grain crop growth, ryegrass tended to reduce soil mineral N compared with the other treatments. After grain harvest, in a small-plot experiment where extra nitrate was added, ryegrass reduced soil nitrate N (0-18 cm) from 4.2 to 0.4 g m^?2 within 13 days, while the clovers had negligible effect compared with bare soil. Up to 9.4 g N m^?2 was present in above-plus below-ground ryegrass biomass at ploughing. In incubated ryegrass soil, there was a temporary net N immobilization of up to 0.9 g N m^?2 as compared with unamended soil. In clover-amended soil, mineral N exceeded that in unamended soil by up to 5 g N m^?2.     

Salt influence on germination and seedling survival of six cool season turfgrass species

Abstract

‘Merion’ Kentucky bluegrass (Poa pratensis L.), ‘Pennfine’ perennial ryegrass (Lolium perenne L.), ‘Seaside’ creeping bent‐grass (Agrostis palustris Huds.), ‘Dawson’ slender creeping red fescue (Festuca rubra trichophylla (L.) Gaud.), ‘Fults’ weeping alkaligrass (Puccinellia distans (L.) Parl.), and ‘common’ Lemmon alkaligrass (Puccinellia lemmoni (Vasey) Scribn.) were evaluated for germination and seedling survival in the greenhouse and laboratory under saline conditions. Overall results indicated that weeping and Lemmon alkaligrass were superior performers under saline and/or sodic conditions. Among the remaining four species, none appeared clearly superior in overall performance.     

Kura Clover Response to Potassium Fertilization

Kura clover (Trifolium ambiguum M.B.) is a persistent perennial forage legume that produces high-quality herbage for grazing, but its response to potassium (K), an essential plant nutrient, is unknown. Our objective was to determine the effect of four dipotassium oxide (K₂O) rates on forage yields and stands of Kura clover compared to birdsfoot trefoil (Lotus corniculatus L.) and alfalfa (Medicago sativa L.). There was a significant linear response in Kura clover and alfalfa forage yields to K₂O fertilization each year. Averaged over 4 years, Kura clover forage yield increased by 0.024 Mg ha^–1 per kg of K₂O applied, and the yield response was similar for alfalfa. Birdsfoot trefoil forage yield response to K₂O fertilization was less than those of alfalfa and Kura clover. In the first 2 years after seeding, Kura clover forage yields were consistently less than for alfalfa at all rates of K₂O fertilizer, but in subsequent years Kura clover yields were similar to or exceeded those of alfalfa. Final groundcover values, an estimate of stand density, of unfertilized (0 K₂O rate) Kura clover, birdsfoot trefoil, and alfalfa were 86, 35, and 21%, respectively. Final groundcover of Kura clover and alfalfa was increased by K₂O fertilization. We conclude that Kura clover has good persistence with low soil K fertility but stands and yields can be increased by fertilization.     

Velvet bentgrass (Agrostis canina L.) is the likely ancestral diploid maternal parent of allotetraploid creeping bentgrass (Agrostis stolonifera L.)

Understanding genetic relationships among the three most important Agrostis species will be important in breeding and genomic studies aimed at cultivar improvement. Creeping, colonial, and velvet bentgrasses (Agrostis stolonifera L., A. capillaris L., and A. canina L., respectively) are commercially important turfgrass species often used on golf courses. Velvet bentgrass is a diploid and creeping and colonial bentgrasses are both allotetraploids. A model for the genomic relationships among these species was previously developed from cytological evidence. The genome designations were A₁A₁ for velvet bentgrass, A₁A₁A₂A₂ for colonial bentgrass, and A₂A₂A₃A₃ for creeping bentgrass. Here we used phylogenetic analysis based on DNA sequences of nuclear ITS and protein coding genes and the plastid trnK intron and matK gene to reexamine these relationships. In contrast to the previous model, the DNA sequence analysis suggested that velvet bentgrass was closely related to creeping bentgrass and it is likely the maternal parent of creeping bentgrass. Phylogenetic analysis of some conserved nuclear genes revealed a close relationship of the velvet bentgrass sequences with the A₂ subgenome sequences of creeping bentgrass. We therefore propose that velvet bentgrass be designated as having the A₂ genome, rather than the A₁ genome as in the previous model.