29 Result(s)

Chapter

Symbiotic N₂ Fixation by Faba Bean (Vicia faba L.) in a Gyspum-Treated Sodic Soil

A. P. Smith, D. Chen, P. M. Chalk in Nitrogen Fixation: From Molecules to Crop Productivity (2000)

Chapter

Nitrogen Fixation and N Balance in Subterranean Clover Pasture Associated with Annual and Perennial Grasses

D. Chen, J. Evans, P. M. Chalk, R. E. White in Nitrogen Fixation: From Molecules to Crop … (2000)

Article

Nitrogen transformations in a flooded soil in the presence and absence of rice plants: 1. Nitrification

Nitrification rates (n) in the floodwater of an alkaline clay were measured in the absence or presence of rice plants by inhibition of ammonium oxidation and ¹⁵N-dilution techniques. Floodwater nitrate concentrat...

D.L. Chen, P.M. Chalk, J.R. Freney, Q.X. Luo in Nutrient Cycling in Agroecosystems (1998)

Article

Nitrogen transformations in a flooded soil in the presence and absence of rice plants: 2. Denitrification

Denitrification rates (d) in a flooded alkaline clay were measured following addition of either \(^{15} NO_3^ - or^{15} NH_4^ + \)

D.L. Chen, P.M. Chalk, J.R. Freney in Nutrient Cycling in Agroecosystems (1998)

Article

Effect of soil treatment with cereal straw and method of crop establishment on field pea (Pisum sativum L.) N₂ fixation

The effects of soil incorporation with cereal straw (nil, 2.5, 5 and 10 t straw ha⁻¹) and direct drilling on the proportion and amount of pea N derived from biological N fixation were investigated in three field ...

J. Evans, N. A. Fettell, G. E. O'Connor, D. J. Carpenter… in Biology and Fertility of Soils (1997)

Article

Estimating nitrogen transfer by foliar 15N-labelling in legume – non-legume associations

We examined the basis for estimating the transfer of legume N to companion cereals or grasses in intercrop** or pature systems using the foliar ¹⁵N-labelling technique. Published data from three pot experiment...

P. M. Chalk, C. J. Smith in Biology and Fertility of Soils (1997)

Article

A yield-independent, ¹⁵N-isotope dilution method to estimate legume symbiotic dependence without a non-N₂-fixing reference plant

The proportional contribution of atmospheric N₂ to the N nutrition of lupin (P _atm) was estimated in a field experiment following addition of NH₄Cl of KNO₃ to unconfined microplots (1.5 m²) at 2.5 g N m^-2 (10 ato...

P. M. Chalk, C. J. Smith, P. Hopmans, S. D. Hamilton in Biology and Fertility of Soils (1996)

Article

Mineralization of soil organic nitrogen solubilized by aqua ammonia fertilizer

Organic N solubilized by NH_3(aq) was extracted from ¹⁵N-labelled or unlabelled soil, concentrated and added to non-extracted soil, which was incubated under aerobic conditions at 27±1°C. Gross N mineralization, g...

S. Sen, P. M. Chalk in Biology and Fertility of Soils (1996)

Article

Estimation of nitrification rates in flooded soils

Three techniques for estimating nitrification rates in flooded soils were evaluated in short-term incubation experiments using three soils. The techniques were based on inhibition of either ammonium or nitrite...

D.L. Chen, P. M. Chalk, J.R. Freney, C. J. Smith, Q. X. Luo in Microbial Ecology (1995)

Article

Biological interactions between soil nitrogen and alkaline-hydrolysing nitrogen fertilizers

Added N interactions were measured in four soil incubated with ¹⁵N-labelled urea or diammonium phosphate. The use of biologically active, γ-irradiated, or reinoculated γ-irradiated samples allowed us to separate ...

S. Sen, P. M. Chalk in Biology and Fertility of Soils (1995)

Article

Solubilization of soil organic N by alkaline-hydrolysing N fertilizers

Interactions between¹⁵N-labelled fertilizers applied at concentrations representative of the fertilizer microsite and the solubility of the nitrogenous component of soil organic matter were investigated in labora...

S. Sen, P. M. Chalk in Fertilizer research (1994)

Article

¹⁵N isotope dilution methodology for evaluating the dynamics of biologically fixed N in legume-non-legume associations

We examined the theoretical basis for estimating the transfer of N₂ fixed by legumes to companion cereals or grasses in intercrop** or pasture systems using ¹⁵N isotope dilution methodology. A method was develo...

P. M. Chalk, C. J. Smith in Biology and Fertility of Soils (1994)

Article

Nitrogen fixation in a white clover-grass pasture irrigated with saline groundwater

Nitrogen (N₂) fixation in an irrigated white clover-grass sward was estimated using the ¹⁵N isotope dilution technique following the addition of K¹⁵NO₃ at 0.5 gN m⁻² and 80 atom % ¹⁵N in a field study during the ...

C. J. Smith, P. M. Chalk, C. L. Noble, J. B. Prendergast… in Irrigation Science (1993)

Article

Sources of N uptake by wheat (Triticum aestivum L.) and N transformations in soil treated with a nitrification inhibitor (nitrapyrin)

Rates of N uptake by spring wheat as ammonium and as nitrate, and rates of nitrification, gross N immobilization and gross N mineralization were measured in a pot experiment during 84 days of growth in a clay ...

D. M. Crawford, P. M. Chalk in Plant and Soil (1993)

Article

Use of nitrification inhibitors to increase fertilizer nitrogen recovery and lint yield in irrigated cotton

This paper describes field experiments designed to evaluate the effectiveness of several nitrification inhibitors to prevent loss of fertilizer nitrogen (N) applied to cotton. The usefulness of nitrapyrin, ace...

J. R. Freney, D. L. Chen, A. R. Mosier, I. J. Rochester… in Fertilizer research (1993)

Article

Characterization of the N benefit of a grain legume (Lupinus angustifolius L.) to a cereal (Hordeum vulgare L.) by an in situ ¹⁵N isotope dilution technique

A crop of barley was grown on plots which had previously supported pure stands of lupins, canola, ryegrass, and wheat. The plots were labelled with ¹⁵N-enriched fertilizers at the time of sowing of the antecedent...

P. M. Chalk, C. J. Smith, S. D. Hamilton, P. Hopmans in Biology and Fertility of Soils (1993)

Article

Chemical interactions between soil N and alkaline-hydrolysing N fertilizers

Chemical interactions between soil N and alkaline-hydrolysing N fertilizers labelled with¹⁵N were studied in the laboratory using twelveγ-irradiated soils. Fertilizer was recovered in the soil organic N fraction ...

S. Sen, P. M. Chalk in Fertilizer research (1993)

Article

Evaluation of reference plants by labelling with ³⁵S in the estimation of N₂ fixation by ¹⁵N isotope dilution

Lupins, canola, ryegrass and wheat fertilized with Na₂ ³⁵SO₄ and either ¹⁵NH₄Cl or K¹⁵NO₃(N:S=10:1), were grown in the field in unconfined microplots, and the sources of N and S (fertilize...

S. D. Hamilton, P. M. Chalk, C. J. Smith, P. Hopmans in Plant and Soil (1992)

Article

Estimating N₂ fixation by field-grown lupins (Lupinus angustifolius L.) using soil and plant ¹⁵N enrichment

Biological N₂ fixation was estimated in a field experiment following the addition of NH₄Cl or KNO₃ to unconfined microplots (1.5 m²) at 2.5 g N m^-2 (10 atom% ¹⁵N). A model of total N and ¹⁵N accumulation in lupin...

C. J. Smith, P. M. Chalk, S. D. Hamilton, P. Hopmans in Biology and Fertility of Soils (1992)

Article

Nitrogen fertilization of dry-seeded rice in south-east Australia

Dry-seeded rice is often fertilized by broadcasting prilled urea on the soil surface shortly before permanent flood commences. Although this method is more efficient than nitrogen application at other stages, ...

E. Humphreys, P. M. Chalk, W. A. Muirhead, R. J. G. White in Fertilizer research (1992)