Determination of nitrogen in agricultural materials by the nessler reagent. II.—Micro‐determinations in Plant Tissue and in Soil Extracts

Yuen, S. H.; Pollard, A. G.

doi:10.1002/jsfa.2740050803

Cited by 142 publications

(45 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This mixture was boiled at 350°C for 20 min, allowed to cool and 2 ml hydrogen peroxide added. The process was repeated 3 times until the samples became clear, after which a final heat treatment at 350°C for 30 min was applied (Yuen and Pollard 1954). Nitrogen was colorimetrically determined by indophenol blue (Searle 1984).…”

Section: Leaf Nitrogenmentioning

confidence: 99%

Herbivory, serotiny and seedling defence in Western Australian Proteaceae

Hanley

Lamont²

2001

Oecologia

View full text Add to dashboard Cite

We examined how acceptability characteristics displayed by 28-day-old seedlings of 12 species of Western Australian Proteaceae affect the likelihood of seedling herbivory in the field. The seedling attributes quantified were cotyledon phenolic, cyanide and nitrogen concentrations, and cotyledon area, thickness and specific leaf area. Only phenolic content was significantly correlated (negatively) with field rates of herbivore attack. This finding shows that the phenomenon of selective herbivore attack on seedlings may be influenced by a specific plant life-history trait, (in this case cotyledon phenolic concentration). In addition, we also studied the interaction between fire, serotiny and herbivory in matched burned and unburned plots. Although herbivore activity was greater in unburned plots, weakly serotinous species were as prone to defoliation as congeneric, strongly serotinous species, even though their seedlings recruit successfully in the absence of fire. This result suggests that seedlings of species able to establish between fires are not better defended against the higher levels of herbivory normally associated with unburned vegetation.

show abstract

Section: Leaf Nitrogenmentioning

confidence: 99%

Herbivory, serotiny and seedling defence in Western Australian Proteaceae

Hanley

Lamont²

2001

Oecologia

View full text Add to dashboard Cite

show abstract

“…loxophleba were used. Nitrogen was determined on a four-channel autoanalyser system, using modifications of the Technicon procedure (Anonymous, 1977), colorimetrically by the indophenol blue method after digestion with sulphuric acid and hydrogen peroxide (Yuen & Pollard, 1954). Phosphorus, K, Na, Ca, Mg, Cu, Fe, Mn and Zn were determined by inductively coupled plasma atomic emission spectroscopy on the same digest.…”

Section: Plant Materials and Soilsmentioning

confidence: 99%

Seed/cotyledon size and nutrient content play a major role in early performance of species on nutrient‐poor soils

1997

View full text Add to dashboard Cite

SUMMARYWe examined the importance of seed size in the early establishment of seedlings of four cotyledonous species restricted to nutrient-impoverished soils in south-western Australia. Experimentally removing cotyledons from seedlings increased mortality and reduced root-penetration, growth rate and final weight of plants after 12 wk, in proportion to seed size. The impact of removal of the cotyledons was least in the smallest-seeded, Eucalyptus loxophleba Benth., grown in the more fertile of two soils, and greatest in the largest-seeded, Hakea psilorrhyncha R. M. Barker, whose grow^th was otherwise unaffected by soil type. In the smallest-seeded species, cotyledon content of most mineral nutrients increased over time, especially in the more fertile soil, while chlorophyll content showed some decrease by the end of the experiment. In the other species, most nutrients (especially N, P, K and Cu in the less fertile soil) were translocated from the cotyledons to the growing plant, and chlorophyll content declined markedly. The translocated N, P, K, Mg and Cu in these species made up a substantial part of the total plant content by 12 wk after germination, while total Ca and Fe tended to increase in the cotyledons via substantial soil uptake. The results indicate, contrar^^ to reports for some other species, that the cotyledons have an important nutritional function in the early establishment of seedlings in these species. The results also show that, in the larger-seeded species, young seedlings rely to a greater extent on nutrient support from the cotyledons than from the soil. We propose that large seeds might be an adaptation for enhancing establishment in nutrient-poor soils.

show abstract

“…The dried samples were ground and sent to CSBP laboratories for analyses. Subsamples of the dried ground herbage were dissolved in a nitric acid and perchloric acid mixture (Yuen and Pollard 1954) and concentrations of elements in the digest were measured by inductively coupled plasma-atomic emission spectrometry (ICP-AES) (Zarcinas et al 1987). The concentration of the following elements were measured in dried herbage and reported: P, K, N, S, Cu, Zn, Mn, iron (Fe), calcium (Ca), magnesium (Mg) and boron (B).…”

Section: Soil Testingmentioning

confidence: 99%

Response of intensively grazed ryegrass dairy pastures to fertiliser phosphorus and potassium

Bolland¹,

Guthridge²,

Blincow³

2011

Nutr Cycl Agroecosyst

View full text Add to dashboard Cite

Intensively grazed, rain-fed dairy pastures on the predominantly sandy soils in the high rainfall ([800 mm annual average) Mediterranean-type climate of south-western Australia comprise [90% ryegrass (annual ryegrass, Lolium rigidum Gaud. and Italian ryegrass, L. multiflorum Lam.). To maximise pasture use for milk production, the pastures are rotationally grazed by starting grazing when ryegrass plants have 3 leaves per tiller, and fertiliser nitrogen (N) and sulfur (S), in the ratio of 3-4 N and 1S, need to be applied after each grazing for profitable pasture dry matter (DM) production. In addition, farmers usually also apply low levels of phosphorus (P) and potassium (K) fertiliser to these pastures after each grazing, despite Colwell soil test P usually being well above critical values for pasture production, and fertilizer K being only required for clover in the traditional clover (Trifolium subterraneum L.) ryegrass pastures of the region. In field experiments undertaken May 2006-June 2010 on intensively grazed ryegrass dairy pastures in the region, no significant ryegrass DM responses to applied fertiliser P or K were obtained, regardless of level or method of P or K application. When no P was applied, soil test P declined gradually, by between 4.4 and 7.1 mg/kg per year, and remained above the critical value for the soils at 2 sites, but declined below the critical value for soil at a third site. Critical soil test P is located near the maximum yield plateau in the flat part of the relationship between yield and soil test P, particularly when, as appropriate for dairy production, the critical value is for 95% of the maximum pasture DM yield. Consequently, when no P is applied and soil test P decreases, significant pasture DM yield decreases will only occur when soil test P approaches the steeper part of the relationship, which can take some time. In addition, as occurs on farms, faeces deposited by cows while grazing supplied P to pasture even when no fertiliser P was applied. Soil K testing proved unreliable for indicating the need for fertiliser K applications to pasture in the next growing season because many soil samples collected within and between urine patches contained elevated levels of K deposited by cows while grazing. We conclude fertiliser P should only be applied to intensively grazed ryegrass dairy pastures when soil testing indicates it is required. Further research is required to assess if plant K testing is an alternative, but urine patches may also pose a problem for plant testing.

show abstract

Determination of nitrogen in agricultural materials by the nessler reagent. II.—Micro‐determinations in Plant Tissue and in Soil Extracts

Cited by 142 publications

References 4 publications

Herbivory, serotiny and seedling defence in Western Australian Proteaceae

Herbivory, serotiny and seedling defence in Western Australian Proteaceae

Seed/cotyledon size and nutrient content play a major role in early performance of species on nutrient‐poor soils

Response of intensively grazed ryegrass dairy pastures to fertiliser phosphorus and potassium

Contact Info

Product

Resources

About