The effect of interval between harvests and nitrogen application on the concentration of nitrate-nitrogen in the total herbage, green leaf and ‘stem’ of grasses

Wilman, D.; Wright, P. T.

doi:10.1017/s0021859600063346

Cited by 13 publications

(11 citation statements)

References 20 publications

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“…This is consistent with data for Italian ryegrass (Wilman and Wright 1986), perennial ryegrasses (Reid 1983), tropical grasses (Henzell 1963) and oats . The only exception was the Kairi site in 1994, where levels remained high throughout the year.…”

Section: What Are the Most Effective Rates Of Nitrogen For Annual Ryesupporting

confidence: 91%

“…This suggests that there may have been a substantial N pool resident in the soil organic matter, which became available during the growing season. Wilman and Wright (1986) suggest that the N concentration of ryegrass is determined by the amount of N applied divided by the number of days between N application and sampling, moderated by time of season effects; our data agree with this supposition. Our range of values for N concentration is similar to those recorded in South Africa by Eckard (1990a), with average N concentrations in the highest yielding treatments of about 4.8%.…”

Section: What Are the Most Effective Rates Of Nitrogen For Annual Ryesupporting

confidence: 87%

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Comparative productivity of irrigated short-term ryegrass (Lolium multiflorum) pasture receiving nitrogen, grown alone or in a mixture with white (Trifolium repens) and Persian (T. resupinatum) clovers

Lowe

Fulkerson

Walker

et al. 2005

Aust. J. Exp. Agric.

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Dairy farms in subtropical Australia use irrigated, annually sown short-term ryegrass (Lolium multiflorum) or mixtures of short-term ryegrass and white (Trifolium repens) and Persian (shaftal) (T. resupinatum) clover during the winter–spring period in all-year-round milk production systems. A series of small plot cutting experiments was conducted in 3 dairying regions (tropical upland, north Queensland, and subtropical southeast Queensland and northern New South Wales) to determine the most effective rate and frequency of application of nitrogen (N) fertiliser. The experiments were not grazed, nor was harvested material returned to the plots, after sampling. Rates up to 100 kg N/ha.month (as urea or calcium ammonium nitrate) and up to 200 kg N/ha every 2 months (as urea) were applied to pure stands of ryegrass in 1991. In 1993 and 1994, urea, at rates up to 150 kg N/ha.month and to 200 kg N/ha every 2 months, was applied to pure stands of ryegrass; urea, at rates up to 50 kg N/ha.month, was also applied to ryegrass–clover mixtures. The results indicate that applications of 50–85 kg N/ha.month can be recommended for short-term ryegrass pastures throughout the subtropics and tropical uplands of eastern Australia, irrespective of soil type. At this rate, dry matter yields will reach about 90% of their potential, forage nitrogen concentration will be increased, there is minimal risk to stock from nitrate poisoning and there will be no substantial increase in soil N. The rate of N for ryegrass–clover pastures is slightly higher than for pure ryegrass but, at these rates, the clover component will be suppressed. However, increased ryegrass yields and higher forage nitrogen concentrations will compensate for the reduced clover component. At application rates up to 100 kg N/ha.month, build-up of NO3–-N and NH4+-N in soil was generally restricted to the surface layers (0–20 cm) of the soil, but there was a substantial increase throughout the soil profile at 150 kg N/ha.month. The build-up of NO3–-N and NH4+-N was greater and was found at lower rates on the lighter soil compared with heavy clays. Generally, most of the soil N was in the NO3–-N form and most was in the top 20 cm.

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Section: What Are the Most Effective Rates Of Nitrogen For Annual Ryesupporting

confidence: 91%

Section: What Are the Most Effective Rates Of Nitrogen For Annual Ryesupporting

confidence: 87%

Comparative productivity of irrigated short-term ryegrass (Lolium multiflorum) pasture receiving nitrogen, grown alone or in a mixture with white (Trifolium repens) and Persian (T. resupinatum) clovers

Lowe

Fulkerson

Walker

et al. 2005

Aust. J. Exp. Agric.

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“…Other studies reported maxima from 10 to 15% with nitrate-N concentrations from 3700 to 6500 mg N kg -1 (Reid 1966;MacLeod and MacLeod 1974;Prins and van Burg 1979;Nicolson et al 1985;Wilman and Wright 1986). These calculations must take into account the method for measuring "total" N. The Kjeldahl procedure does not quantitatively include nitrate unless the sample is pretreated (e.g., reduced iron) (Bremner and Mulvaney 1982); however, the dry combustion method includes nitrate.…”

Section: Discussionmentioning

confidence: 95%

Within-season grass herbage crude-protein- and nitrate-N concentrations as affected by rates and seasonal distribution of fertilizer nitrogen in a high yearly rainfall climate

Bittman¹,

Kowalenko²

2000

Can. J. Plant Sci.

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.25 proportions prior to four cut intervals examined crude-protein-N and nitrate-N concentrations in grass herbage at each cut in three trials. Crude-protein-N concentration frequently increased to a greater degree and in a different pattern (based on cut) than yield as the rate of N application increased. This showed that crude-protein-N by itself cannot be used as a method for determining the N sufficiency status of grass. Both rate and distribution of fertilizer N strongly influenced plant nitrate-N concentration; the degree of change varied considerably among cuts and trials. Plant nitrate-N concentration in the control did not correspond to yield responsiveness to N application, making it a poor indicator of the plant's need for fertilizer applications. Residual effects of N applications on plant nitrate-N were noted into the last cut of the season from a single spring application. The effect of N rate and distribution, then, was a function of immediate and residual effects of the applications. There was some evidence that N present in the soil in nitrate-N form enhanced the potential for high nitrate-N in the plant. Plant nitrate-N concentrations accounted for up to 29% of the total N in the plant with concentrations greater than 4000 mg N kg -1 at the highest N application rates. Plant nitrate-N did not exceed 1000 mg N kg -1 , a concentration considered safe for ruminants, when 75 kg N ha -1 or less ammonium nitrate was applied as a single application prior to a growth interval for all cuts. Since grass protein-and nitrate-N concentrations respond differently than yield to N applications, a specific combination of rate and distribution of fertilizer will not necessarily produce maximum herbage quantity and quality simultaneously. L'expérience était réalisée à trois emplacements. La concentration de PB augmentait souvent davantage que le rendement, suivant un mode de répartition différent selon les coupes, à mesure qu'on accroissait la dose d'é-pandage de N. Ce qui montre que la teneur en N total ne peut à elle seule servir pour déterminer le niveau de suffisance de N nitrique dans le fourrage. La concentration de N nitrique dans les plantes était fortement dépendante de la dose totale et du fractionnement du N de fumure, l'amplitude de sa réaction variant considérablement d'une récolte et d'un champ et à l'autre. La teneur en N nitrique du fourrage dans le traitement témoin ne correspondait pas à l'effet de la fumure N sur le rendement herbager et n'é-tait donc pas un indicateur de la dose de N de fumure requise par la culture. Les arrière-effets d'un apport de N unique au printemps sur le contenu en N nitrique des plantes persistaient observés jusqu'à la dernière récolte de la saison. L'effet de la dose et du fractionnement de la fumure était donc fonction des effets immédiats et des arrière-effets des épandages. Il appert que l'azote présent dans le sol sous forme nitrique accroîtrait les risques de concentrations en nitrate élevées dans l'herbage. En effet, le N nitrique représentait jusqu'à 29 % du N...

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“…3. This value represents an average N concentration across multiple published datasets (Whitehead 1995) and also the average N concentration measured for 3-cut and 4-cut systems (Table 1).…”

Section: N Uptake Calculation Methodologiesmentioning

confidence: 99%

Improved estimation of nitrogen uptake in grasslands using the nitrogen dilution curve

Reyes

Schellberg

Siebert

et al. 2015

Agron. Sustain. Dev.

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The nitrogen (N) dilution curve is a useful tool for farmers to assess the effectiveness of fertilizer application. The N dilution curve describes the decrease in plant N as biomass increases. This concept has not yet been tested for its applicability and robustness under different cutting regimes in grasslands. We conducted a principal components analysis on biomass yield and N concentration data to discern relationships among experimental, climatic, and management factors. Next, two N dilution curve parameters were calibrated for different cutting frequencies. We compared N uptake using four different methods utilizing calibrated N dilution curves, a reference curve, and different cutting regimes representing different physiological ages of the crops at cutting. Our results show that excluding cutting frequency information overestimates values of N uptake. Calibration of the N dilution curve according to cutting frequency improves N uptake estimates relative to observed values. Therefore, N uptake is better estimated using both the N dilution curve and the cutting regime information.

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The effect of interval between harvests and nitrogen application on the concentration of nitrate-nitrogen in the total herbage, green leaf and ‘stem’ of grasses

Cited by 13 publications

References 20 publications

Comparative productivity of irrigated short-term ryegrass (Lolium multiflorum) pasture receiving nitrogen, grown alone or in a mixture with white (Trifolium repens) and Persian (T. resupinatum) clovers

Comparative productivity of irrigated short-term ryegrass (Lolium multiflorum) pasture receiving nitrogen, grown alone or in a mixture with white (Trifolium repens) and Persian (T. resupinatum) clovers

Within-season grass herbage crude-protein- and nitrate-N concentrations as affected by rates and seasonal distribution of fertilizer nitrogen in a high yearly rainfall climate

Improved estimation of nitrogen uptake in grasslands using the nitrogen dilution curve

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