Relationship between P and N concentrations in timothy

1999 ◽  
Vol 79 (1) ◽  
pp. 65-70 ◽  
Author(s):  
G. Bélanger ◽  
J. E. Richards
Keyword(s):  
N Fertilization ◽  
Phleum Pratense ◽  
Growth And Yield ◽  
Shoot Biomass ◽  
P Deficiency ◽  
P Concentration ◽  
N Concentration ◽  
Critical P Concentration ◽  
The Relationship ◽  
Phleum Pratense L

Tools quantifying the status of N and P in plants may help to achieve efficient management of these nutrients and to optimize crop growth and yield. The objective of this study was to establish the relationship between P and N concentrations during the regrowth of timothy (Phleum pratense L.) and, in particular, to estimate the critical P concentration required to diagnose P deficiency. The relationship between P and N concentrations was determined for timothy grown in two experiments conducted with early- and late-maturing cultivars under non-limiting N conditions in spring of 1991 and 1992, and in two experiments with four rates of N fertilization conducted in the spring of 1993 and the summer of 1994. Shoot biomass and P and N concentrations were determined weekly during each regrowth cycle. The P and N concentrations decreased with time in all four experiments. The decrease in P concentration with increasing shoot biomass was generally similar to the decrease in N concentration. The relationship between P concentration and shoot biomass was not different for early- and late-maturing timothy cultivars. This relationship, however, was affected by N fertilization. For a given shoot biomass, increasing N fertilization rates increased P concentration. The relationship between P and N concentrations under non-limiting N conditions is described by a linear relationship (P = 1.46 + 0.069N, R2 = 0.79, P < 0.001, n = 48) in which P concentration (P) and N concentration (N) are expressed in g kg−1 DM. The relationship between P and N concentrations was different under N limiting conditions. For a given N concentration, the P concentration was greater under limiting N conditions than under non-limiting N conditions. Our results show that the critical P concentration for shoot growth is a function of the N concentration in the shoot biomass and the level of N deficiency. The present study provides the relationship required to estimate the critical P concentration which is essential for quantifying levels of P deficiency in timothy, and in developing models to predict the quantity of fertilizer P needed to correct that deficiency. Key words: Phleum pratense L., timothy, nitrogen, phosphorus, grasses

Growth analysis of timothy grown with varying N nutrition

1997 ◽  
Vol 77 (3) ◽  
pp. 373-380 ◽  
Author(s):  
G. Bélanger ◽  
J. E. Richards
Keyword(s):  
Growth Rates ◽  
Shoot Growth ◽  
N Fertilization ◽  
Phleum Pratense ◽  
Radiation Use Efficiency ◽  
Radiation Interception ◽  
N Concentration ◽  
Use Efficiency ◽  
Radiation Use ◽  
Phleum Pratense L

Nitrogen fertilization increases yield of timothy (Phleum pratense L.) but little knowledge exists on the effect of N fertilization on the growth processes of field-grown timothy. The objective of this study was to analyze the growth of timothy fertilized with increasing rates of N in spring and summer and, in particular, to determine the relative importance of radiation interception and radiation-use efficiency in explaining the differences in shoot growth caused by N deficiency. In two separate experiments conducted in spring 1993 and summer 1994, shoot growth, leaf area development, radiation interception and radiation-use efficiency of timothy grown with four N rates (0, 70, 140 and 210 kg N ha−1 in 1993; 0, 60, 120 and 180 kg N ha−1 in 1994) were determined using weekly sampling. Maximum leaf photosynthesis was also measured. The maximum shoot growth and LAI were reached with 140 kg N ha−1 in the spring of 1993 and 120 kg N ha−1 in the summer of 1994. The rates of N fertilization required to produce these maximum values of shoot growth were those that resulted in shoot N concentration equal to or greater than the optimal N concentration. The concept of an optimum N concentration was therefore useful in identifying situations of N deficiencies. When no N was applied, the growth rates were 32 and 33% of the maximum growth rates in spring and summer, respectively. The impact of the N deficiency was greater on RUE than on cumulative intercepted PAR. When no N was applied, the RUE and cumulative intercepted PAR were respectively 45 and 61% of their maximum values in spring, and 52% and 80% of their maximum values in summer. A general and synthetic expression of the effect of crop N concentration on shoot growth was developed using the concept of an optimal N concentration. Key words: Phleum pratense L., timothy, growth, radiation, photosynthesis, nitrogen

Leaf and stem nutritive value of timothy grown with varying N nutrition in spring and summer

1999 ◽  
Vol 79 (2) ◽  
pp. 223-229 ◽  
Author(s):  
G. Bélanger ◽  
R. E. McQueen
Keyword(s):  
Cell Wall ◽  
Nutritive Value ◽  
Nitrogen Deficiency ◽  
Phleum Pratense ◽  
Shoot Biomass ◽  
Negative Effect ◽  
N Deficiency ◽  
Rate Of Decline ◽  
Phleum Pratense L

Nitrogen fertilization is known to have a limited effect on the digestibility of grasses. In a previous paper, however, we reported that N deficiency increased the proportion of leaves in the shoot biomass, and hence, indirectly increased the digestibility of timothy (Phleum pratense L). This was mitigated by the direct negative effect of N deficiency on the digestibility of leaves or stems or both early in the regrowth. The objective of this study was to determine the direct effect of N deficiency on three parameters of nutritive value of leaves and stems of timothy cv. Champ. The evolution of leaf and stem in vitro true digestibility (IVTD), in vitro cell wall digestibility (IVCWD), and neutral detergent fiber (NDF) concentration of field-grown timothy fertilized with four rates of N was studied during a spring and summer regrowth cycle by sampling at weekly intervals. The rate of decline in leaf nutritive value in spring was greater than that in summer, and was less than the rate of decline in stem nutritive value during spring. Nitrogen deficiency consistently increased the NDF concentration of leaves but had a lesser effect on the NDF concentration of stems. Nitrogen deficiency decreased leaf IVCWD when the leaf-to-weight ratio (LWR) was high early in the spring and summer regrowth cycles. At the end of regrowth when LWR values were low, leaf IVCWD was greatest when no N was applied. As a result, the negative effect of N deficiency on the leaf IVTD during the early part of the spring and summer regrowth cycles diminished as the regrowth cycles progressed. Nitrogen deficiency had a limited effect on stem IVCWD. We concluded that the direct negative effect of N deficiency on the digestibility of the timothy shoot biomass can be attributed primarily to its effect on the NDF concentration and cell wall digestibility of leaves. Key words: Phleum pratense L., grasses, digestibility, cell wall, nitrogen

Leaf and stem nutritive value of timothy genotypes under varying N fertilization

2004 ◽  
Vol 84 (4) ◽  
pp. 1101-1104 ◽  
Author(s):  
G. Bélanger ◽  
A. Brégard ◽  
R. Michaud ◽  
G. F. Tremblay
Keyword(s):  
Cell Wall ◽  
Nutritive Value ◽  
N Fertilization ◽  
Phleum Pratense ◽  
Neutral Detergent Fiber ◽  
Acid Detergent Fiber ◽  
True Digestibility ◽  
Sib Families ◽  
Phleum Pratense L

Populations and half-sib families of timothy (Phleum pratense L.), contrasting in forage N concentration, were studied in two experiments conducted in growth rooms with varying N applications. They differed in leaf and stem in vitro true digestibility (IVTD) of DM and in vitro cell wall digestibility (IVCWD), and in stem neutral detergent fiber (NDF) concentration; this confirms the presence of genetic variability for leaf and stem nutritive value in timothy under both limiting and non-limiting N conditions. Key words: Digestibility, grasses, Phleum pratense, neutral detergent fiber, acid detergent fiber

Assessment of the phosphorus status of oilseed rape by plant analysis

1989 ◽  
Vol 29 (6) ◽  
pp. 861 ◽  
Author(s):  
A Pinkerton ◽  
K Spencer ◽  
AG Govaars
Keyword(s):  
Field Experiments ◽  
Maximum Yield ◽  
Plant Part ◽  
Plant Analysis ◽  
Triple Superphosphate ◽  
P Deficiency ◽  
P Concentration ◽  
Critical P Concentration ◽  
Phosphorus Status ◽  
P Supply

Phosphorus (P) concentrations in young plants of rapeseed (Brassica napus cv. Wesway) were related to seed and oil yields to develop a tissue test for the diagnosis of P deficiency. Critical P concentrations were defined as those concentrations required to sustain 90% of maximum yield. In 2 field experiments in successive seasons on a P-deficient soil, rates of triple superphosphate from 2.5 to 120 kg/ha were banded with the seed. The lowest P concentration in young shoots (17-19 weeks from sowing) associated with a P supply that was adequate for plant growth was approximately 0.31%. The youngest fully-expanded leaf was a reliable plant part to sample, its P concentration being about 0.05% lower than the concentration of the whole shoot. Critical P concentrations in young plants for sustaining 90% of maximum seed and oil yields were higher, namely 0.33 and 0.28% for whole shoots and youngest fully-expanded leaves respectively. The critical P concentration in seeds was about 0.35%.

Selection for nitrogen use efficiency and N concentration in timothy

1998 ◽  
Vol 78 (4) ◽  
pp. 611-613 ◽  
Author(s):  
R. Michaud ◽  
G. Bélanger ◽  
A. Brégard ◽  
J. Surprenant
Keyword(s):  
Nitrogen Use Efficiency ◽  
N Uptake ◽  
Genetic Selection ◽  
Phleum Pratense ◽  
N Use Efficiency ◽  
Nitrogen Use ◽  
N Concentration ◽  
Use Efficiency ◽  
Phleum Pratense L ◽  
N Use

Improvement of N use efficiency of timothy (Phleum pratense L.) involves higher DM yield but, for feeding purposes, N concentration should also be considered. Differences in N use efficiency were found among 40 genotypes of timothy. The analysis of residues of the linear regression between N uptake and DM yield of all genotypes allowed for the selection of genotypes with both high N use efficiency and contrasted N concentrations. Key words: Phleum pratense L., timothy, genetic selection, nitrogen use efficiency

Nitrogen utilization by forage grasses

2000 ◽  
Vol 80 (1) ◽  
pp. 11-20 ◽  
Author(s):  
G. Bélanger ◽  
F. Gastal
Keyword(s):  
Crop Growth ◽  
Utilization Efficiency ◽  
Shoot Biomass ◽  
Forage Grasses ◽  
N Nutrition ◽  
N Concentration ◽  
N Utilization ◽  
Grass Growth ◽  
The Relationship ◽  
Critical N Concentration

The efficient utilization of nitrogen (N) in grass production is essential to reduce the risks of water and air pollution, and the costs of production. Recent findings in grass physiology and agronomy should help in developing new tools to improve N utilization efficiency. A model of N dilution describing the decrease in plant N concentration with increasing shoot biomass under non-limiting N supply is used to define a critical N concentration in grasses required to reach maximum shoot growth and yield. The index of N nutrition (INN) is then calculated as the measured N concentration in a given situation divided by the critical N concentration. The INN is a diagnostic tool to quantify the level of N deficiency during growth cycles, and can also be used in crop modelling and in the interpretation of results from studies conducted over many sites and years. The "universality" of the model of N dilution is based on the increased proportion of structural to metabolic components during crop growth combined with the fact that the structural component has a lower N concentration. Inter- and intra-species differences in N concentration at a given shoot biomass can be related to differences in the proportion of leaves which are assumed to be equivalent to the metabolic component. Under N-deficient conditions, the reduction in grass growth is due to a reduction in the interception of solar radiation primarily through reduced leaf extension, and to a reduction in the conversion efficiency of intercepted radiation into shoot biomass primarily through an effect on biomass partitioning between roots and shoots. The concept of the critical N concentration based on the relationship between plant N concentration and shoot biomass is used to derive general and synthetic expressions of the effect of plant N nutrition on crop growth and crop growth processes. These recent findings on the relationship between N nutrition and the growth of forage grasses should result in the improvement of the efficiency of N utilization by a more precise fertilizer management and the development of more N efficient cultivars. Key words: Physiology, growth, photosynthesis, leaf, partitioning, model

INFLUENCE DE LA FERTILISATION AZOTEE SUR LE RENDEMENT, LA VALEUR NUTRITIVE ET LA TENEUR EN DIVERSES FRACTIONS AZOTEES DE TROIS CULTIVARS DE LA FLEOLE DES PRES

1979 ◽  
Vol 59 (3) ◽  
pp. 839-846 ◽  
Author(s):  
S. P. GUERTIN ◽  
J. C. ST-PIERRE ◽  
P. GERVAIS
Keyword(s):  
Nutritive Value ◽  
Nitrate Nitrogen ◽  
N Fertilization ◽  
Phleum Pratense ◽  
N Fertilizer ◽  
Protein Nitrogen ◽  
Second Growth ◽  
Significant Difference ◽  
Nitrogen Contents ◽  
Phleum Pratense L

A 3-yr study on rates of nitgoren fertilization of timothy (Phleum pratense L.) showed that dry matter yield increased significantly with each increment of N fertilizer up to 448 kg/ha. Bounty outyielded Climax and Clair cultivars. Forage nutritive value index (NVI) was reduced by N fertilization but no significant difference was found among cultivars over the three growth cycles. Third cut forage had the highest and first cut forage the lowest NVI. Total, protein and non-protein nitrogen contents reached their highest values in first and second growth at highest rates of N fertilizer. Potentially toxic levels of nitrate-nitrogen were attained at each harvest only at rates of 448 and 896 kg/ha of N. On average over the season, Climax had the highest and Clair the lowest percentages of total and protein nitrogen while there was no significant difference among cultivars in the non-protein and nitrate nitrogen contents.

INFLUENCE OF WEED CONTROL AND N FERTILIZATION AT ESTABLISHMENT ON GROWTH AND NODULATION OF BIRDSFOOT TREFOIL

1974 ◽  
Vol 54 (2) ◽  
pp. 259-264 ◽  
Author(s):  
H. T. KUNELIUS
Keyword(s):  
Weed Control ◽  
N Fertilization ◽  
Phleum Pratense ◽  
Birdsfoot Trefoil ◽  
Forage Legume ◽  
Hordeum Vulgare L ◽  
Weed Growth ◽  
The Mean ◽  
N Treatment ◽  
Phleum Pratense L

Leo birdsfoot trefoil (Lotus corniculatus L.) was established on check (no weed control), handweeded, and 4-(2,4-dichlorophenoxy)butyric acid (2,4-DB)-2,2-dichloroproprionic acid (dalapon)-treated plots with N applied at 0, 25, 50, or 100 kg/ha as NH4NO3 at the emergence of forage legume. The preceding crops were barley (Hordeum vulgare L.) and timothy (Phleum pratense L.) in locations 1 (soil OM 3.4%) and 2 (soil OM 3.8%), respectively. In the year of seeding, N. applications increased dry matter (DM) yields of birdsfoot trefoil up to 115% over zero N treatment in location 1. Similarly, the growth of weeds was increased up to 69% applied N in location 1. In location 2, applied N did not influence the growth of birdsfoot trefoil and weeds. A 2,4-DB-dalapon treatment in both locations controlled the weeds, but it also suppressed the growth of birdsfoot trefoil. The mean number of birdsfoot trefoil plants/m2 in location 1 was decreased both by N fertilization and by 2,4-DB-dalapon treatment. The growth of birdsfoot trefoil in the 2nd yr was not influenced by N fertilizer applied at establishment. Heavy weed growth in location 2 during the 1st yr resulted in low DM yields of birdsfoot trefoil the following year. Nodulation of birdsfoot trefoil was promoted in location 1 by small N applications (25 kg/ha). In location 2, nodulation was reduced by fertilizer N, as compared to zero N treatment. Treatment with 2,4-DB-dalapon caused some reduction in the nodulation of birdsfoot trefoil as compared to check or handweeded plots in location 1. It is concluded that applied N may improve the early growth of birdsfoot trefoil only where soil N level is low and almost no weeds are present.

EFFECTS OF N AND K FERTILIZATION ON THE PROTEIN, NITRATE AND NONPROTEIN REDUCED N FRACTIONS OF TIMOTHY AND BROMEGRASS

1974 ◽  
Vol 54 (2) ◽  
pp. 331-341 ◽  
Author(s):  
L. B. MacLEOD ◽  
J. A. MacLEOD
Keyword(s):  
Field Experiments ◽  
Application Rate ◽  
Phleum Pratense ◽  
Bromus Inermis ◽  
N Application ◽  
Nitrate N ◽  
N Concentration ◽  
Phleum Pratense L ◽  
K Fertilization ◽  
N Fractions

Timothy (Phleum pratense L.) and bromegrass (Bromus inermis Leyss.) were grown in field experiments to evaluate the effects of N and K fertilization on protein, nitrate and nonprotein reduced N concentration in the forage. Concentrations of all N fractions studied generally increased as the rate of N application was increased. At high rates of N application (448 and 896 kg N/ha) nitrate N concentrations increased when rates of K application were increased from 56 to 440 kg/ha. Highest nitrate N concentrations were 0.37 and 0.43% for timothy and bromegrass, respectively. These were obtained at highest rates of N and K application (896 kg N/ha and 440 kg K/ha). Highest concentrations of nonprotein reduced N were 1.20 and 1.11% for timothy and bromegrass, respectively. Although the highest concentrations of nonprotein reduced N were obtained at highest rates of N and K application, rate of K application had no significant effect on this fraction.

Digestibility and cell wall concentration of early- and late-maturing timothy (Phleum pratense L.) cultivars

1996 ◽  
Vol 76 (1) ◽  
pp. 107-112 ◽  
Author(s):  
G. Bélanger ◽  
R. E. McQueen
Keyword(s):  
Cell Wall ◽  
Nutritive Value ◽  
Field Experiments ◽  
Weight Ratio ◽  
Phleum Pratense ◽  
Early Maturing ◽  
Mathematical Relationships ◽  
The Relationship ◽  
Phleum Pratense L

Ear emergence or heading of early- and late-maturing cultivars of timothy (Phleum pratense L.) in the spring varies by as much as 3 wk. Two field experiments were conducted to describe the evolution of digestibility and cell-wall concentration of early- and late-maturing timothy cultivars during primary growth and to analyze the relationship between parameters of nutritive value and the leaf blade to biomass weight ratio (LWR). Compared with late-maturing cultivars of timothy on a given date, early-maturing cultivars had lower in vitro true digestibilities of DM and cell wall and a greater NDF concentration. Differences in in vitro true DM digestibility and NDF concentration between early- and late-maturing cultivars were not only related to the proportion of leaf blades in the biomass. Different parameters are, therefore, required to describe the mathematical relationships between digestibility and NDF concentration and LWR of early- and late-maturing cultivars. Key words:Phleum pratense, timothy, cultivars, digestibility, cell wall

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