Isotopic studies on the uptake of nitrogen by pasture plants. V. 15N balance experiments in field microplots

1973 ◽  
Vol 24 (5) ◽  
pp. 693 ◽  
Author(s):  
I Vallis ◽  
EF Henzell ◽  
AE Martin ◽  
PJ Ross
Keyword(s):  
Ammonium Sulphate ◽  
Potassium Nitrate ◽  
Standard Errors ◽  
15N Balance ◽  
Rhodes Grass ◽  
Advantages And Disadvantages ◽  
Isotopic Studies ◽  
Townsville Stylo ◽  
Pasture Plants ◽  
Area Of Application

Recovery of 15N from labelled fertilizers was measured in open microplots on pastures at three sites in southern Queensland. Very little 15N was recovered from plants growing further than 15-30 cm from the area of application. Most of the 'N found in soil and roots was in the top 15 cm of the profile. The following total recoveries of 15N (with their standard errors) were recorded: 83.0�2.7% from ammonium sulphate applied to Rhodes grass; 76.6 �3.7 % from potassium nitrate on a Townsville stylo-spear grass pasture; and 97.9�6.7% from urea applied to a Nandi setaria pasture. The weather during the three experiments was relatively dry, and it is unlikely that any ISN was leached below the depth of sampling. The advantages and disadvantages of open and enclosed microplots are discussed in some detail. It is suggested that while open microplots are satisfactory for some purposes, the use of plots enclosed by steel cylinders pressed into the soil is probably the most accurate technique available for 15N balance studies in the field.

Isotopic studies on the uptake of nitrogen by pasture plants. III. The uptake of small additions of 15N-labelled fertilizer by Rhodes grass and Townsville lucerne

1967 ◽  
Vol 18 (6) ◽  
pp. 865 ◽  
Author(s):  
I Vallis ◽  
KP Haydock ◽  
PJ Ross ◽  
EF Henzell
Keyword(s):  
Soil Nitrogen ◽  
Total Yield ◽  
Pure Stand ◽  
Tracer Technique ◽  
Rhodes Grass ◽  
Stylosanthes Humilis ◽  
Isotopic Studies ◽  
Chloris Gayana ◽  
Chloris Gayana Kunth ◽  
Pasture Plants

Small additions of (15NH4)2SO4 and K15NO3 were used to investigate the nitrogen economy of Townsville lucerne (Stylosanthes humilis H.B.K.) and Rhodes grass (Chloris gayana Kunth.) grown separately and together in pots. Rhodes grass reduced the total yield of nitrogen per plant in associated Townsville lucerne to about half that of Townsville lucerne in pure stand. It appears that the Rhodes grass seedlings competed strongly with Townsville lucerne for available soil nitrogen during the first 5 weeks of the experiment. When the two species were grown together, Rhodes grass took up about 20 times as much 15N as the Townsville lucerne during the first 9 weeks, and about 8 times as much between 9 and 13 weeks after sowing. This ratio was the same for (15NH4)2SO4 as for K15NO3. When the two species were grown separately they took up equal amounts of 15N between 9 and 13 weeks after sowing. Estimates of soil nitrogen uptake at 5 weeks showed that 47% of the nitrogen in the Townsville lucerne growing with Rhodes grass had come from the soil. At 9 weeks the cumulative uptake of soil nitrogen by this Townsville lucerne was only 6%, and at 13 weeks only 3%, of its total nitrogen yield. No significant transfer of unlabelled nitrogen from legume to grass was detected. Attention is drawn to the assumption used in calculating uptake of soil nitrogen by the legume. It is suggested that this tracer technique can be applied to 15N experiments in the field.

Isotopic studies on the uptake of nitrogen by pasture grasses. II. Uptake of fertilizer nitrogen by Rhodes grass in posts

1964 ◽  
Vol 15 (6) ◽  
pp. 876 ◽  
Author(s):  
EF Henzell ◽  
AE Martin ◽  
PJ Ross ◽  
KP Haydock
Keyword(s):  
Linear Function ◽  
Total Nitrogen ◽  
Nitrogen Uptake ◽  
Nitrogen Fertilizer ◽  
Rhodes Grass ◽  
Fertilizer Nitrogen ◽  
Pasture Grasses ◽  
Isotopic Studies ◽  
Pretreatment Phase

Nitrogen uptake by Rhodes grass was a linear function of the quantity of 15NH4N03 applied for rates up to the equivalent of 400 lb N/ac, but the proportion of fertilizer nitrogen recovered in the plants fell significantly when the rate was increased to 800 lb N/ac. A nitrogen pretreatment equivalent to 200 lb N/ac had relatively little effect on the uptake of 15NH4N03 by the grass, despite the fact that it almost doubled the weight of roots in the pots when the 15NH4N03 was first applied. Over the range 0–400 lb N/ac, 84.1%% of added total nitrogen and 75.5% of added 15N was taken up by plants that received no nitrogen fertilizer during the pretreatment phase, and 80.3% of added total nitrogen and 71.9% of added 15N was taken up by plants that received a pretreatment of 200 lb N/ac. Fertilizer nitrogen was distributed between tops and roots in the ratio (averaged for the two pretreatments) of 5.2 : 1 for total nitrogen and 4.5 : 1 for 15N; these ratios were constant over the range 0–400 lb N/ac and were not significantly different.

Isotopic studies on the uptake of nitrogen by pasture plants. IV. Uptake of nitrogen from labelled plant material by Rhodes grass and Siratro

1968 ◽  
Vol 19 (1) ◽  
pp. 65 ◽  
Author(s):  
EF Henzell ◽  
AE Martin ◽  
PJ Ross ◽  
KP Haydock
Keyword(s):  
Plant Material ◽  
Mineral Nitrogen ◽  
Rhodes Grass ◽  
Significant Difference ◽  
Isotopic Studies ◽  
Carbon Nitrogen Ratio ◽  
Nitrogen Ratio ◽  
Chloris Gayana ◽  
The Difference ◽  
Chloris Gayana Kunth

Rhodes grass (Chloris gayana Kunth.) and Siratro (Phaseolus atropurpureus D.C. var. Siratro) plants were grown separately and together in pots of soil containing 15N-labelled ground Rhodes grass plant material (carbon/nitrogen ratio 44). The added plant material immobilized nitrogen during the first 6 weeks of the experiment, and nitrogen uptake by Rhodes grass was still less than that of the control at 15 weeks. Both the grass and the nodulated legume took up 15N throughout the experiment, despite the reduction in availability of unlabelled soil nitrogen. Siratro grown alone took up as much 15N as Rhodes grass grown alone. When the plants were grown together about one-third of the 15N uptake went into the Siratro and two-thirds into the Rhodes grass. The Siratro roots had a higher 15N enrichment than the tops, indicating that relatively more of the unlabelled nitrogen fixed from the atmosphere went into the Siratro tops, compared with the labelled nitrogen taken up from the soil. With Rhodes grass the tops had a higher enrichment than the roots. The difference between the extractable mineral nitrogen in the pots of soil under grass and in the bare pots accounted for uptake by the grass at 3 weeks but underestimated it at 15 weeks. In addition, there was a significant difference in enrichment between the total extractable mineral nitrogen in the soil and the nitrogen taken up by the Rhodes grass. From the uptake and partition of 15N it was calculated that 43–50% of the nitrogen in the Siratro plants at 3 weeks was taken up from the soil (the rest was attributed to symbiotic fixation); at 15 weeks only 2–4% of the nitrogen in the Siratro was from the soil. Very little nitrogen was transferred from the Siratro to the associated Rhodes grass.

scholarly journals Public-Use vs. Restricted-Use: An Analysis Using the American Community Survey

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Saki Kinney ◽  
Alan F Karr
Keyword(s):  
Data Center ◽  
Community Survey ◽  
Standard Errors ◽  
American Community Survey ◽  
Statistical Research ◽  
The Public ◽  
Advantages And Disadvantages ◽  
Data Source ◽  
Statistical Agencies ◽  
Restricted Use

Statistical agencies frequently publish microdata that have been altered to protect condentiality. Such data retain utility for many types of broad analyses but can yield biased or insufficiently precise results in others. Research access to de-identied versions of the restricted-use data with little or no alteration is often possible, albeit costly and time-consuming. We investigate the advantages and disadvantages of public-use and restricted-use data from the American Community Survey (ACS) in constructing a wage index. The public-use data used were Public Use Microdata Samples, while the restricted-use data were accessed via a Federal Statistical Research Data Center. We discuss the advantages and disadvantages of each data source and compare estimated CWIs and standard errors at the state and labor market levels. We find the results from the publicly available data are generally good relative to the restricted-use data, with greater similarity for larger areas and less similarity for smaller areas. Standard errors are higher in the public-used data but may still be underestimated.

STUDIES WITH BACILLUS POLYMYXA: III. NUTRITIONAL REQUIREMENTS

1944 ◽  
Vol 22c (6) ◽  
pp. 273-279 ◽  
Author(s):  
H. Katznelson ◽  
A. G. Lochhead
Keyword(s):  
Growth Factor ◽  
Nicotinic Acid ◽  
Ammonium Sulphate ◽  
Pantothenic Acid ◽  
Casein Hydrolysate ◽  
Potassium Nitrate ◽  
Inorganic Salts ◽  
Nutritional Requirements ◽  
Bacillus Polymyxa ◽  
Other Substances

Eighty-two strains of Bacillus polymyxa grew in a medium consisting of inorganic salts, glucose, and casein hydrolysate only when biotin was added, hence this growth factor may be considered essential. Thiamin stimulated growth of some strains but inhibited others whereas pantothenic acid, nicotinic acid, riboflavin, pyridoxine, and inositol were without effect. Casein hydrolysate was replaceable by urea, ammonium sulphate, and a mixture of 18 amino hydrolysed acids, but with a few exceptions these substances were not as effective as the protein. Potassium nitrate and asparagine were poor sources of nitrogen. Yeast extract, in a medium containing only glucose and inorganic salts, was superior to all other substances tested in its stimulatory effect on B. polymyxa.

Nitrogen fertilizer responses of pasture grasses in south-eastern Queensland

1963 ◽  
Vol 3 (11) ◽  
pp. 290 ◽  
Author(s):  
EF Henzell
Keyword(s):  
Ammonium Sulphate ◽  
Field Experiments ◽  
Maximum Growth ◽  
Nitrogen Fertilizers ◽  
Nitrogen Recovery ◽  
Residual Effects ◽  
Rhodes Grass ◽  
South Eastern ◽  
Pasture Grasses ◽  
Chloris Gayana

The results are reported of field experiments with nitrogen-fertilized pasture grasses at Samford and D'Aguilar in south-eastern Queensland. The main findings were :- 1. Nitrogen applied as urea or ammonium sulphate increased the annual yield of dry matter under mowing from 1,000- 5,000 lb up to 10,000-20,000 lb an acre, and rates of fertilizer in excess of 400 lb of elemental nitrogen an acre a year were required ,for maximum grass yields during favourable seasons. 2. Ammonium sulphate, applied at rates up to 400 lb N/acre/year, had relatively little effect on the percentage of nitrogen in Rhodes grass (Chloris gayana Kunth.), Paspalum dilatatum Poir., and P. commersonii Lam., cut three times a year. Rates of urea above those required for maximum growth markedly increased the percentage nitrogen content of a Sorghum almum Parodi-blue couch (Digitaria didactyla Willd.) mixture. 3. In an experiment with Rhodes grass, P. dilatatum and P. commersonii, nitrogen recovery rose with increasing rates of ammonium sulphate. At 70 lb N/acre/year the average nitrogen recovery by Rhodes grass was 10 per cent; at 400 lb N/acre/year it was 47 per cent. 4. The residual effects of ammonium sulphate, measured on Rhodes grass during the growing season following two years of fertilization, were very small indeed. 5. Use of nitrogen fertilizers sometimes caused marked changes in the botanical composition of the sward.

Experiments measuring effects of ammonium and nitrate fertilizers, with and without sodium and potassium, on spring barley

1967 ◽  
Vol 69 (2) ◽  
pp. 197-207
Author(s):  
F. V. Widdowson ◽  
A. Penny ◽  
R. J. B. Williams
Keyword(s):  
Sodium Chloride ◽  
Sugar Beet ◽  
Ammonium Sulphate ◽  
Sodium Nitrate ◽  
Spring Barley ◽  
Calcium Nitrate ◽  
Potassium Nitrate ◽  
Grain Yields ◽  
Light Soil ◽  
Sodium And Potassium

1. Thirteen experiments were made with spring barley from 1963 to 1965 on soils overlying chalk. They compared yields at ear emergence and of ripe grain from ammonium sulphate and from calcium nitrate, from sodium nitrate or sodium chloride or both, and from potassium nitrate or potassium chloride. Two rates of seedbed N were tested, though they were different each year, and in 1964 and 1965 N top-dressings were also applied. The amounts of N, K, Na and Mg in the green barley, and of N in the grain, were measured.greatly increased grain yields in all but one experiment, where the barley followed sugar beet. Calcium nitrate gave larger grain yields than ammonium sulphate in three-quarters of the comparisons, but gave much smaller yields than ammonium sulphate on one light soil in 1964 when much rain fell after the fertilizers had been applied. Grain yields from calcium, potassium and sodium nitrates were nearly the same.3. Na slightly increased grain yields in three and K in two experiments, but combine-drilled P or PK fertilizers increased them in every experiment.

STUDIES ON THE BIONOMICS AND CONTROL OF THE BURSATE NEMATODES OF HORSES AND SHEEP: IV. ON THE LETHAL EFFECTS OF SOME NITROGENOUS FERTILIZERS ON THE FREE-LIVING STAGES OF SCLEROSTOMES

1937 ◽  
Vol 15d (7) ◽  
pp. 127-145 ◽  
Author(s):  
I. W. Parnell
Keyword(s):  
Strong Solution ◽  
Ammonium Sulphate ◽  
Sodium Nitrate ◽  
Calcium Nitrate ◽  
Potassium Nitrate ◽  
Diammonium Phosphate ◽  
Free Living ◽  
Lethal Effects ◽  
Medium Strength ◽  
And Control

The effect of ten of the commoner nitrogenous fertilizers on the free-living stages of Sclerostomes, is discussed. Urea is the most lethal. Under the conditions of the experiments, which are otherwise ideal for the survival of the larvae, one part of urea to 125 parts of fresh horse feces is necessary to sterilize them. The proportions of the others tested are: Calurea, 1:80; powdered cyanamide, 1:50, with granular cyanamide slightly lower; potassium nitrate, sodium nitrate and Calnitro, 1:20; calcium nitrate and diammonium phosphate (dry or in medium strength solution) 1:17; Nitro-chalk, about 1:16 (but should not be used in strong solution); ammonium sulphate, 1:14.

Isotopic studies on the uptake of sulphur by pasture plants

1977 ◽  
Vol 20 (2) ◽  
pp. 229-233 ◽  
Author(s):  
P. E. H. Gregg ◽  
K. M. Goh ◽  
D. W. Brash
Keyword(s):  
Isotopic Studies ◽  
Pasture Plants

STUDIES WITH BACILLUS POLYMYXA: IV NITROGEN REQUIREMENTS IN RELATION TO 2,3-BUTANEDIOL PRODUCTION FROM STARCH

1946 ◽  
Vol 24c (4) ◽  
pp. 99-108 ◽  
Author(s):  
H. Katznelson
Keyword(s):  
Amino Acids ◽  
Ammonium Sulphate ◽  
Yeast Extract ◽  
Casein Hydrolysate ◽  
Potassium Nitrate ◽  
Bacillus Polymyxa ◽  
Different Strains

Yeast extract, casein hydrolysate, and a mixture of 13 to 20 ammo acids were found to be superior to simpler substances such as ammonium sulphate, urea, potassium nitrate, or asparagine as sources of nitrogen for Bacillus polymyxa in relation to production of 2,3-butanediol from starch The complex sources of nitrogen were more or less interchangeable for most, but not all strains of this organism with regard to effectiveness for diol production, but the addition of yeast extract to either casein hydrolysate or amino acids resulted in a slightly higher yield of diol and an increase in the diol/ethanol ratio from 2 to 2.6 or higher.The requirements of different strains for specific ammo acids varied somewhat, but the need for isoleucine and asparagine was common to the tour strains studied. A fairly good fermentation was obtained with the most efficient of these strains in a medium containing isoleucine, tyrosine, glycine, methionine, and asparagine after three days' incubation. The fermentation went to completion after five days with certain concentrations of these five acids an effect that was achieved in three days by the addition to these of eight other acids but not by the addition of ammonium sulphate. Suppression of diol production by omission of certain of these amino acids was marked at three days but was largely overcome at five. Cystine (in concentrations above: 0.0125%; was inhibitory to the four strains studied and phenylalanine (0.02%) to one, after three but not after five days.

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