Relationship between P and N concentrations in timothy

Abstract

. Relationship between P and N concentrations in timothy. Can. J. Plant Sci. 79: 65-70. 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 latematuring 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, R 2 = 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 Bélanger, G. et Richards, J. E. 1999. Relation entre les teneurs en P et N de la fléole des prés. Can. J. Plant Sci. 79: 65-70. Le développement d'outils permettant de quantifier le statut de nutrition en N et P dans les plantes est une étape essentielle pour atteindre une gestion efficace de ces éléments nutritifs, et pour optimiser la croissance et le rendement. L'objectif de cette étude était d'établir la relation entre les teneurs en P et N au cours de repousses de fléole des prés (Phleum pratense L.), et plus particulière-ment, de déterminer la teneur critique en P laquelle pourrait être utilisée pour diagnostiquer les déficiences en P. Cette relation entre les teneurs en P et N a été développée à partir de deux expériences avec des cult...

Switchgrass (Panicum virgatum L.) Cultivar Adaptation, Biomass Production, and Cellulose Concentration as Affected by Latitude of Origin

“…Meanwhile, OMD was positively correlated with cultivar differences in N concentration (Table 7). Nitrogen concentration was positively correlated with P concentration at Brandon as has been reported for other grasses such as timothy (Phleum pratense L.) [29]. The relationship between latitude of origin and OMD digestibility differed between Brandon and Swift Current (Figure 3).…”

Rendement et valeur nutritive de la fétuque élevée cultivée en régions à faibles degrés-jours de croissance

“…L'augmentation de la concentration en P est reliée à l'augmentation de la concentration en PB. Bélanger et Richards (1999) ont rapporté qu'il existe une relation étroite entre les concentrations en N et en P chez la fléole des prés. Ainsi, une augmentation de la concentration en N due à une récolte plus hâtive ou à la fertilisation azotée se traduit par une augmentation de la concentration en P. Contrairement à la concentration en P, K et Mg, celle en Ca a diminué avec l'augmentation du nombre de coupes.…”

The importance of early season phosphorus nutrition

“…The P concentration in tissue of annual plants generally declines with advancing plant age/stage of growth (Racz et al 1965;Bélanger and Richards 1999), as do critical nutrient concentrations (Bélanger and Richards 1999). Thus, highest tissue P concentrations are required at early growth stages.…”