Influence of time of application on the fate of<sup>15</sup>N-labelled urea applied to dairy pasture

Ledgard, S. F.; Steele, K. W.; Feyter, C.

doi:10.1080/00288233.1988.10421368

Cited by 36 publications

(14 citation statements)

References 7 publications

(10 reference statements)

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“…This suggests that N was stored in the soil in a form not measured as soil extractable inorganic N and/or plant material remaining in the plot. Tracer studies have shown that considerable fertilizer N can be incorporated into organic fractions in the soil (Bristow et al 1987;Ledgard et al 1988;Malhi 1995;Stevens et al 1986), and that the sizes of these fractions increase with time. Whitehead et al (1990) estimated N released by mineralization in the first year after cultivation increased from 70 kg N ha -1 in a 1-yr-old stand to 300 kg N ha -1 in a 15-yr-old stand.…”

Section: Discussionmentioning

confidence: 99%

Within-season grass yield and nitrogen uptake, and soil nitrogen as affected by nitrogen applied at various rates and distributions in a high rainfall environment

Kowalenko¹,

Bittman²

2000

Can. J. Plant Sci.

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S. 2000. Within-season grass yield and nitrogen uptake, and soil nitrogen as affected by nitrogen applied at various rates and distributions in a high rainfall environment. Can. J. Plant Sci. 80: 287-301. A study was conducted to assess the effect of rates of nitrogen (N) fertilizer, and to compare the effectiveness of single and split applications of N on yield and quality of forage grass and on the potential for nitrate leaching. Three field trials were conducted at different sites in successive years, with plant and soil measurements made at each of four harvests. Extractable inorganic N was measured to 0.6 m in three depth increments prior to spring N application and after each cut in order to evaluate immediate and residual effects of the N fertilizer on plant growth, and the environmental implications of the applications. Response of yield and N uptake to N applications differed in the three trials. In all trials, the effect of N rate was greater than the effect of N distribution during the growing season. Although there were only small, whole-season yield increases associated with distributing the N over the season, the distribution of yield within the season was changed considerably. Soil data showed relatively little leaching of N during the growing season under contrasting weather conditions of the three growing seasons. Retention of N within the soil root zone contributed to residual effects on yield and plant uptake, and these effects frequently lasted to the end of the growing season. Crop response to N applications was apparently influenced by the N supplying capacity of the soil and the effect of weather on crop growth rate. Soil nitrate at harvest did not vary consistently with N application treatments in the three trials, other than having highest concentrations at the highest fertilizer rate. Soil nitrate was greatest after cut 1 and decreased sharply toward the end of the season following the single spring applications, whereas plots receiving equal distributions of N through the season had relatively high concentrations at all sampling times during the season. Soil extractable ammonium concentration was influenced by high rates of N application, but the effect was small and largely confined to the sampling after cut 1. The soil always contained about 10-15 mg kg -1 extractable ammonium in surface 0.3 m depth, with a tendency for slightly greater concentrations in early spring. Soil ammonium appears to be involved in soil and plant processes, but the exact magnitude and significance of its involvement could not be determined from the measurements made. The redistribution of grass yield by splitting the application of fertilizer N within the growing season would be beneficial for grazing systems. Unfortunately, soil inorganic N measurements will not greatly assist in determining the precise rate and distribution of fertilizer for varying field conditions. Key words: N response, N uptake, residual N effect, soil extractable N, N leaching Kowalenko, C. G. et Bittman, S. 2000. Influence de la dos...

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Section: Discussionmentioning

confidence: 99%

Within-season grass yield and nitrogen uptake, and soil nitrogen as affected by nitrogen applied at various rates and distributions in a high rainfall environment

Kowalenko¹,

Bittman²

2000

Can. J. Plant Sci.

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“…At the second harvest, the 600-900 mm depth was also sampled for the 200kgNha ~ treatment. Subsamples were dried (60°C), digested using a reduced iron method to include nitrate and analysed for total N and 15N (Ledgard et al, 1988). Subsamples of moist soil were also extracted with 2 M KCI and analysed for inorganic N and ~SN (Ledgard et al, 1988).…”

Section: Soil Sampling and Analysismentioning

confidence: 99%

Fate of 15N-labelled nitrogen fertilizer applied to kiwifruit (Actinidia deliciosa) vines

1992

Self Cite

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The fate of 15N-labelled ammonium fertilizer applied once to six-year-old field-grown kiwifruit (Actinidia deliciosa 'Hayward') vines was measured over three years. The three main treatments were nitrogen (N) applied singularly at 100 or 200 kg N ha -~ in early spring (two weeks before bud burst) or split with 100 kg N ha -I (unlabelled) in early spring and 100 kg N ha -1 (lSN-labelled) ten weeks later. All N treatments were applied to vines with a history of either 50 or 200 kg N ha -~ yr -1. For three years after ~SN application, components of the vines and soil (0-600 mm depth) were sampled at harvest in late autumn and the N and 15N contents determined.By the first harvest, all plant uptake of ~SN had occurred and this represented 48-53% of the 15N applied. There was no significant effect of current N fertilizer treatment or of N history on ~SN recovery by vines. Removal of 15N in harvested fruit was small at 5-6% in the first year and 8% over 3 years. After 2-3 years, most plant 15N occurred in the roots and this component declined only slowly over time. In contrast, there was a large temporal decline in ~SN in above-ground plant components due to the annual 'removal' in leaf fall and pruning. An associated experiment showed that when 15N-labelled prunings and leaves were mulched and returned to the soil, only about 9% was recovered by plants within 2 years. Almost all remaining mulched material had been immobilised into the soil organic N.In all treatments, about 20% of the added ~SN remained in soil at the first harvest. This was almost entirely in organic fractions (<0.4% in inorganic N) and mostly in the surface 150-mm layer. The 15N content in soil changed little over time (from 20 to 17% between the first and third harvests respectively) and indicated that most of the N had been immobilised into stable humus forms.

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“…N-losses under urine patches via nitrogen leaching are of great concern, whereas under dung patches N mineralization-immobilization processes dominate (Thompson and Fillery 1997). The total amount of N leached under urine patches varies between 18 and 58% of the applied N, depending on the soil texture (Clough et al 1998), application time (Cuttle and Bourne 1993;Ledgard et al 1988;Di and Cameron 2002;Stout 2003), the amount of urine (Thompson and Fillery 1997;Stout 2003), and the botanical composition of the pasture (Loiseau et al 2001). An estimation of the contribution of dung to N-losses under pasture is difficult as the results from incubation experiments (Barrow 1961;Takahashi et al 2004) are not translatable to field conditions.…”

Section: Introductionmentioning

confidence: 98%

Nitrogen Leaching from 15N Labelled Cow Urine and Dung Applied to Grassland on a Sandy Soil

Wachendorf

Taube²,

Wachendorf³

2005

Nutr Cycl Agroecosyst

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Nitrogen (N) leaching under grazed pastures can be very high directly under urine spots. The amount of N which is returned by one excretion of urine or dung can locally exceed 1000 kg ha À1 a À1 which is far more than the uptake by surrounding plants during one grazing period. We therefore quantified the contribution of N deriving from urine and dung to the total N leaching under urine and dung patches. Dung N and urine N was separately sampled from a cow feed with 15 N labelled grassilage, and were amended on lysimeters in October 2000 and October 2001. Lysimeters (350 mm diameter and 800 mm length) were filled with sand, and an intact grass sod from a pasture, 4 lysimeter each were amended with the 15 N labelled dung and urine; 4 lysimeters without an application of dung or urine served as control. During 11 months after dung and urine amendment the amount of leachate was monitored and leachate was analysed for nitrate, ammonium and total N. 15 N in these fractions was measured. Dung and urine applications of 1052 and 1030 kg N ha À1 in autumn increased N leaching. Leaching loss of nitrate and dissolved organic N deriving from dung was only 37 kg N ha À1 in both years, whereas under urine patches 447 kg nitrate-N ha À1 , 108 kg N ha À1 ammonia-N and 53 kg ha À1 dissolved organic N leached on average of both experimental years. N not deriving from dung and urine exceeded the leached N under the control by about 36 and 136 kg ha À1 on average of both years, suggesting the contribution of different priming processes.

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Influence of time of application on the fate of¹⁵N-labelled urea applied to dairy pasture

Abstract: Urea eSN-enriched) was applied at 50 kg

Cited by 36 publications

References 7 publications

Within-season grass yield and nitrogen uptake, and soil nitrogen as affected by nitrogen applied at various rates and distributions in a high rainfall environment

Within-season grass yield and nitrogen uptake, and soil nitrogen as affected by nitrogen applied at various rates and distributions in a high rainfall environment

Fate of 15N-labelled nitrogen fertilizer applied to kiwifruit (Actinidia deliciosa) vines

Nitrogen Leaching from 15N Labelled Cow Urine and Dung Applied to Grassland on a Sandy Soil

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Influence of time of application on the fate of15N-labelled urea applied to dairy pasture

Abstract: Urea eSN-enriched) was applied at 50 kg

Cited by 36 publications

References 7 publications

Within-season grass yield and nitrogen uptake, and soil nitrogen as affected by nitrogen applied at various rates and distributions in a high rainfall environment

Within-season grass yield and nitrogen uptake, and soil nitrogen as affected by nitrogen applied at various rates and distributions in a high rainfall environment

Fate of 15N-labelled nitrogen fertilizer applied to kiwifruit (Actinidia deliciosa) vines

Nitrogen Leaching from 15N Labelled Cow Urine and Dung Applied to Grassland on a Sandy Soil

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Influence of time of application on the fate of¹⁵N-labelled urea applied to dairy pasture