Effects of soil salinity and mineral nitrogen on the acetylene reduction activity of Trifolium subterraneum

1984 ◽  
Vol 35 (1) ◽  
pp. 9 ◽  
Author(s):  
P Hopmans ◽  
LA Douglas ◽  
PM Chalk
Keyword(s):  
Linear Relationship ◽  
Soil Salinity ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Mineral Nitrogen ◽  
Acetylene Reduction Activity ◽  
Soil Mineral Nitrogen ◽  
Total N ◽  
Reduction Activity ◽  
C2h2 Reduction

Subterranean clover (Trifolium subrerraneum L.) was grown under controlled environmental conditions in pots containing a variety of soils. Non-destructive assays were used to measure rates of acetylene (C2H2) reduction by the plants. Soil mineral nitrogen (N) status and, to a lesser extent, soil salinity were found to be the most important soil properties relating to the development of C2H2reduction activity in subterranean clover. Application of KNO3 to pots resulted in an immediate decrease in the rate of C2H2reduction. A linear relationship was found between the loss in C,H, reduction activity and the amount of N applied up to 40 mg N kg-1 soil. Addition of salt (NaCl) to pots caused an immediate decrease in C2H2 reduction activity, followed by a gradual recovery. A linear relationship was found between the loss in C2H2 reduction activity and the level of soil salinity induced by salt addition. The loss in C2H2reduction \vas reflected in the lower total N content of the plants when soil salinity levels exceeded 4 mS cm-1.

Nitrogenase Activity by Subterranean Clover and Other Temperate Pasture Legumes

1988 ◽  
Vol 15 (5) ◽  
pp. 657 ◽  
Author(s):  
AG Davey ◽  
RJ Simpson
Keyword(s):  
Root Respiration ◽  
Nitrogenase Activity ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Acetylene Reduction Activity ◽  
Diffusion Resistance ◽  
Pasture Legumes ◽  
Reduction Activity ◽  
Decline Rate ◽  
Nodulated Root

Nitrogenase (C2H2-reduction) activity and nodulated root respiration of intact plants of subterranean clover (Trifolium subterraneum L.) cv. Seaton Park nodulated by Rhizobium trifolii WU95 were measured in a flow-through system. Simultaneous declines in nitrogenase activity and respiration were exhibited 2 min after 10% C2H2 had been introduced into the gas stream. Declines in nitrogenase activity and nodulated root respiration provided an estimate of the efficiency of nitrogenase activity (mol CO2 evolved/mol C2H4 produced). The pre-decline rate of nitrogenase activity at time zero was thus calculated as the product of the respiration associated with nitrogenase activity and the reciprocal of the efficiency of nitrogenase activity. Pre-decline rates of nitrogenase activity were similar to peak rates for several pasture legumes. However, post-decline rates of activity were as much as 70% lower than the pre-decline rate. The age of subterranean clover plants had an important influence on the magnitude of the C2H2-induced decline; young plants exhibited the largest C2H2-induced inhibition of nitrogenase activity. Neither sainfoin (Onobrychis viciifolia Scop.) cv. Othello nodulated by Rhizobium sp. CC1108 nor yellow serradella (Ornithopus compressus L.) cv. Pitman nodulated by R. lupini WU425 exhibited C2H2-induced declines in nitrogenase activity. Nitrogenase-linked respiration of subterranean clover at the 14-leaf stage accounted for 50% of total nodulated root respiration. The oxygen diffusion resistance of the nodules increased in the presence of C2H2 but the effect was reversible once C2H2 was removed from the gas atmosphere. The pre-decline rate of acetylene reduction activity of subterranean clover reached a maximum at 10% C2H2. The C2H2-induced decline in nitrogenase activity was lower at subsaturating pC2H2 and was not detected at 0.4% C2H2.

Responses of intensively grazed dairy pastures to applications of fertiliser nitrogen in south-western Australia

2007 ◽  
Vol 47 (8) ◽  
pp. 927 ◽  
Author(s):  
M. D. A. Bolland ◽  
I. F. Guthridge
Keyword(s):  
Western Australia ◽  
Dry Matter ◽  
Maximum Yield ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Growing Season ◽  
Mineral Elements ◽  
Italian Ryegrass ◽  
Total N ◽  
Dry Matter Digestibility

For the first time, we quantified pasture dry matter (DM) responses to applied fertiliser nitrogen (N) for intensively grazed, rain-fed, dairy pastures on sandy soils common in the Mediterranean-type climate of south-western Australia. The pastures are composed of subterranean clover (Trifolium subterraneum L.) and annual and Italian ryegrass (Lolium rigidum Gaud. and L. multiflorum Lam.). Six rates of N, as urea (46% N), were applied to 15 m by 15 m plots four times during 2002 and after each of the first 5–7 grazings in 2003 and 2004, throughout the typical April–October growing season. Total rates of N applied in the first year of the experiments were 0, 60, 120, 160, 200 and 320 kg N/ha, which were adjusted in subsequent years as detailed in the ‘Materials and methods’ section of this paper. The pastures in the experiments were rotationally grazed, by starting grazing when ryegrass plants had 2–3 leaves per tiller. The amount of pasture DM on each plot was measured before and after each grazing and was then used to estimate the amount of pasture DM consumed by the cows at each grazing for different times during the growing season. Linear increases (responses) of pasture DM to applied N occurred throughout the whole growing season when a total of up to 320 kg N/ha was applied in each year. No maximum yield plateaus were defined. Across all three experiments and years, on average in each year, a total of ~5 t/ha consumed DM was produced when no N was applied and ~7.5 t/ha was produced when a total of 200 kg N/ha was applied, giving ~2.5 t/ha increase in DM consumed and an N response efficiency of ~12.5 kg DM N/kg applied. As more fertiliser N was applied, the proportion of ryegrass in the pasture consistently increased, whereas clover content decreased. Concentrations of nitrate-N in the DM consistently increased as more N was applied, whereas concentrations of total N, and, therefore, concentration of crude protein in the DM, either increased or were unaffected by applied N. Application of N had no effect on concentrations of other mineral elements in DM and on dry matter digestibility and metabolisable energy of the DM. The results were generally consistent with findings of previous pasture N studies for perennial and annual temperate and subtropical pastures. We have shown that when pasture use for milk production has been maximised in the region, it is profitable to apply fertiliser N to grow extra DM consumed by dairy cows; conversely, it is a waste of money to apply N to undergrazed pastures to produce more unused DM.

Effects of early defoliation on the seedling growth of subterranean clover

1992 ◽  
Vol 43 (3) ◽  
pp. 717
Author(s):  
RC Rossiter
Keyword(s):  
Linear Relationship ◽  
Leaf Area ◽  
Seedling Growth ◽  
Shoot Growth ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Relative Reduction ◽  
Insect Damage ◽  
Leaf Production ◽  
Plant Densities

Two experiments were conducted in an open-sided glass shelter at Perth during winter. Subterranean clover (Trifolium subterraneum, L.) seedlings were grown in shallow seed boxes at low plant densities, 2 4 and 2 0 plants/dm2. The effects of a single defoliation involving mainly the removal of cotyledons only, on shoot growth and leaf production were measured at harvest, c. 5 weeks after sowing. Total shoot dry weights were reduced by 15-30% when 40-60% of the leaf area was removed by single defoliations from days 7 to 19 after planting. However, the growth was reduced by almost 70% when both cotyledons were removed (days 7 to 9) before emergence of the unifoliate leaf, i.e. when all of the leaf area was removed. In general, the relative reduction in growth largely depended on the percentage of leaf area removed, rather than on time of removal. Defoliation also reduced the size of trifoliate leaves, and total numbers of trifoliate leaves at harvest. There was a linear relationship between total leaf numbers and shoot dry weights. In the field, these findings are probably of more relevance in terms of insect damage, especially from redlegged earth mites, than for grazing by sheep.

Digesta flow studies in sheep fed two mature annual legumes

1994 ◽  
Vol 45 (4) ◽  
pp. 889
Author(s):  
X Li ◽  
RC Kellaway ◽  
RL Ison ◽  
G Annison
Keyword(s):  
Amino Acids ◽  
Dry Matter ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Apparent Digestibility ◽  
Total N ◽  
Flow Rates ◽  
Dietary Nitrogen ◽  
Nitrogen Intake ◽  
Trifolium Resupinatum

Mature subterranean clover (Trifolium subterraneum cv. Junee) and Persian clover (Trifolium resupinatum cv. Kyambro) were fed to cannulated sheep. Flow rates of dry matter and nitrogen in the abomasum and ileum were estimated using a double marker method. Contents of hemicellulosic polysaccharides (xylose and mannose monomers) were higher in Kyambro than in Junee. Although Junee contained higher levels of total N and amino acids, the relative concentrations of cystine and methionine were markedly higher in Kyambro. Dry matter intakes and flow rates in the abomasum, ileum and faeces were similar on Kyambro and Junee. Dietary nitrogen intake was lower and endogenous re-cycled nitrogen higher on Kyambro than on Junee. Ileal flow of nitrogen was similar to nitrogen intake on Kyambro. Apparent nitrogen digestibility was lower in the whole tract and higher in the intestines on Kyambro. The higher apparent digestibility of nitrogen in the intestines of sheep eating Kyambro was associated with a greater proportion of nitrogen leaving the stomach coming from endogenous sources. The lower nitrogen digestibility of Kyambro in the whole tract indicated lower digestibility of dietary nitrogen, which was associated with higher contents of xylose and mannose.

The long term effects of rotation, tillage and stubble management on soil mineral nitrogen supply to wheat

Soil Research ◽  
1992 ◽  
Vol 30 (6) ◽  
pp. 977 ◽  
Author(s):  
DP Heenan ◽  
KY Chan
Keyword(s):  
Soil Nitrogen ◽  
Subterranean Clover ◽  
Mineral Nitrogen ◽  
Wheat Crop ◽  
Wagga Wagga ◽  
Long Term Effects ◽  
Soil Mineral Nitrogen ◽  
Percent Recovery ◽  
Direct Drilling

Wheat was grown as a monoculture or in rotation with lupin or subterranean clover in a long-term rotation, stubble and tillage experiment established in 1979, on a red earth (Gn 2 . 12) at Wagga Wagga, N.S.W. The effect of rotation, tillage and stubble management on the supply of soil nitrogen, and amounts leached were studied by in situ sequential soil sampling during the wheat phase of the rotation in years 10 and 11. Of the rotations, grazed subterranean clover-wheat accumulated higher mineral nitrogen levels during the wheat phase than a lupin-wheat rotation, which in turn produced higher levels than wheat-wheat. The mean seasonal total of net soil nitrogen mineralized (0-15 cm) was 239 kg N ha-1 for subterranean clover-wheat, 165 kg N ha-1 for lupin-wheat and 99.5 kg N ha-1 for wheat-wheat. In a lupin-wheat rotation, retention of stubble increased the net amount of nitrogen mineralized in both seasons. Direct drilling also increased net mineralization in 1990 but the results were inconsistent in 1989. Losses from the surface 15 cm were closely related to the amounts mineralized, with the highest recorded in subterranean clover-wheat rotations. Percent recovery of soil mineralized nitrogen by the above-ground wheat crop following lupin ranged from 57% to 83%, with both direct drilling and stubble retention reducing recovery. While total plant uptake of nitrogen in a wheat-wheat rotation was low, percent recovery was high (77%), compared with that in a subterranean clover-wheat rotation (60%).

Invasion of clear-cuttings by the actinorhizal plant Comptoniaperegrina

1986 ◽  
Vol 16 (4) ◽  
pp. 872-874 ◽  
Author(s):  
O. Q. Hendrickson
Keyword(s):  
Forest Floor ◽  
Mineral Soil ◽  
Dry Weight ◽  
Significant Negative Correlation ◽  
Acetylene Reduction Activity ◽  
Total N ◽  
Reduction Activity ◽  
Site Disturbance ◽  
Harvest Site ◽  
Whole Tree

Three years after harvesting a mixed conifer–hardwood forest in Ontario, the density of sweet fern (Comptoniaperegrina (L.) Coult.) was far greater on a whole-tree harvest site (logging slash removed) than on an adjacent conventional harvest site (logging slash present). These differences were related to the degree of site disturbance, particularly forest floor removal. Nodule fixation rates also appeared to reflect the degree of disturbance, being highest in plants growing along a logging road where the sandy, nitrogen-poor mineral soil was exposed, and exceptionally low on the conventional harvest site (0.67 μmol C2H4 g dry weight−1 h−1). Overall, acetylene reduction activity showed a significant negative correlation (r = −0.77, p < 0.001) with total N.

Acetylene Reduction Rates by Selected Leguminous and Non-Leguminous Plants of Groote Eylandt, Northern Territory.

1981 ◽  
Vol 29 (1) ◽  
pp. 1 ◽  
Author(s):  
PJ Langkamp ◽  
GK Farnell ◽  
MJ Dalling
Keyword(s):  
Acetylene Reduction ◽  
Accretion Rate ◽  
Inorganic Nitrogen ◽  
Imperata Cylindrica ◽  
Acetylene Reduction Activity ◽  
Wet Season ◽  
Reduction Activity ◽  
C2h2 Reduction ◽  
Open Forest ◽  
Lag Period

Acetylene (C2H2) reduction associated with the roots of various grasses and sedges and by nodules of selected legumes was investigated in a Eucalyptus tetrodonta open-forest and a Melaleuca leucadendron open-forest swamp complex. High rates of non-legume C2H2 reduction, as measured by the excised root assay, were associated only with plants found in the swamp complex: the sedge Fimbristylis dichotoma and the grasses Imperata cylindrica and Paspalum vaginatum (70 ± 30, 161 ± 69 and 23 ± 15 nmol C2H4 g dry wt -1h-1 respectively). An initial lag period of 8 h before C2H2 reduction was detected was not eliminated or reduced by the addition of sucrose. Nearly all the C2H2 reduction activity was associated with the roots with very little activity in topsoil or subsoil. The addition of inorganic nitrogen or aspartic or citric acids stopped the reduction of C2H2, but addition of sucrose stimulated it. Current potential photosynthesis appeared to be related to C2H2 reduction ability. Acetylene reduction activity by rooted nodules of various leguminous species was distinctly seasonal, being greatest in the wet season. Members of the Mimosaceae had twice the wet season activity of those of the Caesalpiniaceae and Fabaceae (20.4 ± 2.9 and 10.1 ± 4.0 nmol mg fresh wt-1h-1 respectively). The results indicate that the nitrogen accretion rate in the E. tetrodonta open-forest will be low (0.05-1 kg Nha-1yr-1) and that mineralization of soil organic matter could account for all the nitrogen utilized by the ecosystem over a wet season.

Effects of temperature on germination, emergence and early seedling growth of swards of Mt Barker subterranean clover plants grown with and without nitrate

1984 ◽  
Vol 35 (4) ◽  
pp. 539 ◽  
Author(s):  
JH Silsbury ◽  
D Zuill ◽  
PH Brown
Keyword(s):  
N2 Fixation ◽  
Nitrogenase Activity ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Mineral Nitrogen ◽  
Mineral N ◽  
Area Index ◽  
Closed Canopy ◽  
Early Seedling

Effects of constant temperatures of 10, 15, 20, 25 and 30�C on the germination, emergence and early vegetative growth of Trifolium subterraneum L. cv. Mt Barker grown as swards were examined in temperature-controlled glasshouses and in a growth cabinet. Seedlings were established at a density of about 2000 plants m-2 and grown for up to 70 days. Plants were either inoculated and grown without mineral nitrogen (-N), or supplied with 7.5 mM NO-3 (+ N). Percentage germination and emergence were hardly affected by temperatures of 10-20�C, but at 25�C were reduced to 50%, and at 30�C to about 10%. The rates of germination and emergence were slowest at 10�C, but showed little change with temperature over the range 15-30�C. Time to closed canopy (leaf area index 3) and time to a dry weight of 133 g m-2 were shorter where plants were supplied with NO; than where mineral nitrogen was withheld and a symbiotic system established. Rates of N2-fixation, as measured by acetylene reduction assay, were not markedly affected by temperature over the range 10-25�C. Relative efficiency ranged from about 0.55 at 10, 15, and 20�C to about 0.66 at 25�C. At 30�C nodulation still occurred, but nitrogenase activity was very slight. It is concluded that, where swards of subterranean clover are grown in the absence of any mineral N, a period of N-starvation limits growth during the time taken for symbiotic N2-fixation to become established. Such retardation of growth is small at about 20�C, but becomes more marked at lower and higher temperatures. The establishment of subterranean clover swards in soils of low N status are likely to be retarded following an early (March) or a late (July) start in the growing season. In such cases a 'starter' application of mineral nitrogen may promote the early growth of the legume.

scholarly journals Calcium chloride extractable cadmium as an estimate of cadmium uptake by subterranean clover

Soil Research ◽  
1991 ◽  
Vol 29 (2) ◽  
pp. 215 ◽  
Author(s):  
MG Whitten ◽  
GSP Ritchie
Keyword(s):  
Linear Relationship ◽  
Calcium Chloride ◽  
Western Australia ◽  
Rock Phosphate ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Phosphate Fertilizer ◽  
Pot Experiment ◽  
Phosphate Fertilizers ◽  
The Past

Cadmium (Cd) may accumulate in soils which have been regularly fertilized with phosphate fertilizers which contain Cd originating in rock phosphate. Soil was taken from three sites in the wheatbelt of Western Australia which were estimated to have received different amounts of phosphate fertilizer over the past decade. The pH was adjusted with dilute HCl or CaCO3. No Cd was added experimentally. The concentration of Cd in the whole tops of Trifolium subterraneum cv Mt Barker grown in a glasshouse pot experiment increased from 0-2-0.8 �g g-1 dry wt at pH 6 -6-6.9 (1:50-01 M CaCl2) to 2-4 �g g-1 at pH 4.1-4.2. The highest concentration of Cd in the plant tops at any particular pH occurred on the soil which had the highest concentration of P in the CaCl2 extract. There was a linear relationship between the concentration of Cd in the whole tops of sub-clover and the concentration of Cd in the CaCl2 extracts which was independent of site. The concentration of Cd in the CaCl2 extracts was a function of pH and concentration of P in the CaCl2 extract.

Sign in / Sign up

Export Citation Format

Share Document