RELATIVE EFFICIENCY OF FERTILIZER N AND SOIL NITRATE AT VARIOUS DEPTHS FOR THE PRODUCTION OF SOFT WHITE WHEAT

1989 ◽  
Vol 69 (4) ◽  
pp. 867-874 ◽  
Author(s):  
J. M. CAREFOOT ◽  
T. ENTZ ◽  
J. B. BOLE
Keyword(s):  
Interactive Effect ◽  
Soil Layer ◽  
Yield Response ◽  
Soil Nitrate ◽  
Fertilizer N ◽  
Marginal Rate ◽  
Fertilizer Nitrogen ◽  
White Wheat ◽  
Wide Range ◽  
Low Levels

Soft white wheat was grown on a clay loam soil for 2 yr with a wide range of soil nitrate (SN) (70–280 kg ha−1) and fertilizer nitrogen (FN) (0–400 kg ha−1) treatments The field experiment was designed to determine the slopes of the yield response curves to FN (δy/δFN) and to SN (δy/δSN), to determine how the ratio of (δy/δSN)/(δy/δFN), or marginal rate of substitution, is affected by FN, SN, and depth of SN and to determine if refinements to the current FN recommendations for irrigated soft white wheat are required. The δy/δFN values in both years were high at low levels of FN and SN but declined as FN and SN increased. The δy/δSN in 1985 when most SN was situated in the 0- to 30-cm soil layer was initially high (26.0) at low levels of SN but rapidly declined as SN increased. The δy/δSN in 1986, when most SN was situated in the 30- to 120-cm soil layer, was intially low (6.0) but increased as SN increased. Since the δy/δFN and δy/δSN values were sensitive to changes in FN and SN as well as the depth of SN the MRS values were variable in both years. The δy/δSN increased as SN increased when SN was situated in the 30- to 120-cm soil layer so there was only a small effect of depth of SN on FN recommendations. The FN at maximum profit occurred at a greater combined amount of SN and FN for the higher SN levels in both years. This preliminary field study suggested that fertilizer N recommendations could be improved by using an equation for predicting FN that considers a variable yield response to FN and SN, an interactive effect of FN and SN on yield, and an effect of depth of SN on yield. Key words: Soil nitrate, fertilizer nitrogen, soft white wheat, soil test N

Nitrogen needs of wheat. 2. Grain yield response to nitrogenous fertilizer

1978 ◽  
Vol 18 (90) ◽  
pp. 118 ◽  
Author(s):  
AC Taylor ◽  
RR Storrier ◽  
AR Gilmour
Keyword(s):  
Wheat Yield ◽  
Growing Season ◽  
Annual Rainfall ◽  
Yield Response ◽  
Soil Nitrate ◽  
Soil Tests ◽  
Available Nitrogen ◽  
Nitrogenous Fertilizer ◽  
Wide Range ◽  
Average Annual Rainfall

In southern New South Wales, the increase in wheat yield due to nitrogenous fertilizer (34 kg N ha-1) was examined against a wide range of controlled and uncontrolled factors over three years in which rainfall was generally above average. The controlled factors included paddock history, cultural aspects and a range of nitrogen soil tests. Multivariate regression procedures were used in the examination. Average annual rainfall was a major determinant of fertilizer response patterns. Overall, soil nitrate (0-30 cm) was superior to paddock history and to other soil tests in predicting responses to added nitrogen. In the west (average annual rainfall 400 to 550 mm), nitrogen applications were profitable when soil nitrate levels were low, but only if growing season rain was at least average. At each soil nitrate level, responses to applied nitrogen declined as average annual rainfall increased. In the east (average annual rainfall greater than 550 mm), responses to added nitrogen were profitable at all nitrate levels, provided growing season rain was not limiting. The magnitude of the responses was related to the level of potentially available nitrogen in the soil (0-10 cm) rather than to nitrate.

The effect of farmyard manure on the fertilizer requirement of sugar beet

1969 ◽  
Vol 73 (1) ◽  
pp. 119-124 ◽  
Author(s):  
A. P. Draycott
Keyword(s):  
Sugar Beet ◽  
Soil Analysis ◽  
Farmyard Manure ◽  
Sugar Yield ◽  
Yield Response ◽  
Chemical Analyses ◽  
Fertilizer N ◽  
Fertilizer Nitrogen ◽  
Fertilizer Requirement ◽  
Commercial Farms

SUMMARYThirty-eight experiments were made on commercial farms to determine the fertilizer requirement of sugar beet grown with farmyard manure (F.Y.M.). They were in two groups; the first (1961–3), with uniformly applied F.Y.M., tested the value of additional fertilizer—nitrogen, phosphate and potash, with and without agricultural salt (crude sodium chloride). The second (1964–7) tested the value of fertilizer N and agricultural salt with and without F.Y.M.The average economic optimum dressings of fertilizers with F.Y.M. were 0·6 cwt/acre N, 0·3 cwt/acre P2O5, 0·5 cwt/acre K2O, with agricultural salt which largely replaced the need for potash. Chemical analyses of samples of F.Y.M. used in the second group of experiments gave no reliable guide to the requirement of additional nitrogen or sodium. With adequate P2O5 and K2O, the F.Y.M. increased sugar yield at all except one site, on average equivalent to the increase from 0·3 cwt/acre N. Agricultural salt increased yield economically at most sites except on the silts round the Humber and the Wash. No clear relationship was found between soil analysis for sodium and sugar yield response to agricultural salt, but where the exchangeable soil sodium was less than 25 ppm Na, a response was likely.

Yield response of rice to root inoculation withAzospirillum

1983 ◽  
Vol 100 (3) ◽  
pp. 689-691 ◽  
Author(s):  
V. Rajaramamohan Rao ◽  
D. N. Nayak ◽  
P. B. B. N. Charyulu ◽  
T. K. Adhya
Keyword(s):  
N Fertilizer ◽  
Yield Response ◽  
Fertilizer N ◽  
Tropical Conditions ◽  
Low Levels ◽  
N Fertility

SUMMARYResponse of rice to root inoculation withAzospirillumunder different N fertility levels was studied over three consecutive seasons under tropical conditions. The response toAzospirillumwas more pronounced at lower levels (30 and 45 kg N/ha) of fertilizer N than at a higher level (60 kg N/ha). Although the root inoculation withAzospirillumresulted in a significant increase in mean yields of both grain and straw especially at low levels of N (30 and 45 kg N/ha), the interaction between the N fertilizer and inoculation was not statistically significant.

Yield response of forage grasses to N fertilizer as related to spring soil nitrate sorbed on anionic exchange membranes

2000 ◽  
Vol 80 (1) ◽  
pp. 203-212 ◽  
Author(s):  
N. Ziadi ◽  
R. R. Simard ◽  
G. Allard ◽  
G. Parent
Keyword(s):  
N Uptake ◽  
N Fertilizer ◽  
Forage Yield ◽  
Yield Response ◽  
Soil Nitrate ◽  
Forage Grasses ◽  
Fertilizer N ◽  
Fertilizer Rate ◽  
Anionic Exchange ◽  
N Fertilizer Rate

Soil N availability is an important factor in forage grass production. Maximising N fertilizer efficiency is essential to improve profitability and to reduce the environmental risk associated with residual excess soil N. The objectives of this study were (i): to determine the effects of N fertilizer on yield, N uptake and NO3–N concentration of forage grasses produced in Western Quebec; and (ii) to compare spring soil NO3−measured by anionic exchange membranes (NO3AEMs) and by water extraction (NO3w) as a criterion to predict fertilizer N requirements of forage grasses. The yield response of grasses, especially timothy (Phleum pratense L.), to different rates of NH4NO3 (0 to 240 kg N ha−1) on heavy clay soils (Humic Gleysols) was studied from 1994 to 1996 at four sites in the Abitibi-Temiscamingue area, Quebec (Canada). Nitrogen significantly (P < 0.001) increased forage yield, N uptake, and NO3–N concentration. The economically optimum N fertilizer rate (Nop) for forage yield varied from 25 to 240 kg N ha−1 depending on sites and years, and averaged 125 kg N ha−1. The Nop can be predicted more adequately by NO3AEMs (R2 = 0.45) than by NO3w (R2 = 0.09). Based only on the relationship between the relative yield and spring soil nitrate, NO3AEMs could be used as a criterion for fertilizer N recommendation of forage grasses in this cool continental climate. Key words: N fertilizer, nitrate, grass, economically optimum N fertilizer rate

Response of grass swards to fertilizer N under cutting or grazing

1979 ◽  
Vol 92 (3) ◽  
pp. 549-562 ◽  
Author(s):  
M. V. Jackson ◽  
T. E. Williams
Keyword(s):  
Dry Matter ◽  
Management Systems ◽  
Significant Response ◽  
Yield Response ◽  
First Year ◽  
Fertilizer N ◽  
Fertilizer Nitrogen ◽  
Cutting Management ◽  
Cutting Experiments ◽  
Applied Nitrogen

SUMMARYAn experiment was conducted at six widely separated centres in England and Wales for 4 years to compare the response of a perennial ryegrass (cv. S. 23) sward to fertilizer N at input rates of 200, 400 and 600 kg N/ha under cutting-only or grazing-only management systems. Under both managements the yield response to N varied substantially and was always greater under cutting than grazing and the response was greater in the first than in subsequent years. Under cutting, significant responses were obtained from 200 to 400 kg N/ha at all sites and in all years but very few sites responded significantly from 400 to 600 kg N/ha after the first year. Under grazing there was on average of all sites (but not at every site) a significant response from 200 to 400 kg N/ha only in the first year. In subsequent years no single site gave a worthwhile response in each year. Under grazing no site showed a significant response from 400 to 600 kg N/ha.At the lowest application of nitrogen, 200 kg N/ha, dry-matter yields under grazing were greater than those under cutting on eight of the possible 24 centre-year occasions. At the two higher rates of applied nitrogen dry-matter yields under cutting were consistently greater than those under grazing.With smaller responses to applied nitrogen on grazed than on cut swards maximum yields were achieved under grazing with an input of about 200 kg N/ha less than under cutting management. The results suggest that cutting experiments cannot be used to predict herbage yields and responses to fertilizer nitrogen under grazing conditions.

Grain protein responses to nitrogen applied to wheat growing on a red earth

1991 ◽  
Vol 42 (5) ◽  
pp. 735 ◽  
Author(s):  
JF Angus ◽  
RA Fischer
Keyword(s):  
Ammonium Nitrate ◽  
Theoretical Background ◽  
Yield Response ◽  
Grain Protein ◽  
Fertilizer N ◽  
South Wales ◽  
Eastern Australia ◽  
Red Earth ◽  
Subsequent Crop ◽  
Urea Ammonium Nitrate

Dryland wheat was fertilized with ammonium nitrate or liquid urea-ammonium nitrate at the time of sowing or about 3 months later (generally at the terminal-spikelet stage) on a well-drained site near Harden on the south-west slopes of New South Wales. The experiments continued from the second to the fifth year (1981-1984) of the cropping phase of a crop-pasture rotation. The maximum agronomic efficiencies for yield in the four consecutive years were 19, 4, 23 and 25 kg grain per kg of applied nitrogen (N). The three large responses were obtained in wetter than average seasons and the small response was obtained during drought. In the last three years of the study the yield response to nitrogen at the terminal-spikelet stage was found to be close to but slightly less than that for N applied at sowing. In those years the agronomic efficiencies for the late-applied N were 0, 22 and 22. The apparent recovery of fertilizer N in the above-ground parts of the crop at maturity was up to 70% of the fertilizer applied in the year of sowing, and, after the drought during which there was little uptake of fertilizer N, up to 62% by the subsequent crop. The fertilizer efficiencies in the non-drought years were higher than generally reported in south-eastern Australia, and indicate potential for profitable delayed application of N fertilizer to wheat. Grain-protein responses were variable from year to year and are discussed against a simple theoretical background of the amount of N applied and grain-yield response.

scholarly journals Acceptance threshold theory can explain occurrence of homosexual behaviour

2015 ◽  
Vol 11 (1) ◽  
pp. 20140603 ◽  
Author(s):  
Katharina C. Engel ◽  
Lisa Männer ◽  
Manfred Ayasse ◽  
Sandra Steiger
Keyword(s):  
Animal Species ◽  
Reproductive Potential ◽  
Search Time ◽  
Same Sex ◽  
Burying Beetles ◽  
Acceptance Threshold ◽  
Threshold Theory ◽  
Wide Range ◽  
Low Levels ◽  
Perceived Costs

Same-sex sexual behaviour (SSB) has been documented in a wide range of animals, but its evolutionary causes are not well understood. Here, we investigated SSB in the light of Reeve's acceptance threshold theory. When recognition is not error-proof, the acceptance threshold used by males to recognize potential mating partners should be flexibly adjusted to maximize the fitness pay-off between the costs of erroneously accepting males and the benefits of accepting females. By manipulating male burying beetles' search time for females and their reproductive potential, we influenced their perceived costs of making an acceptance or rejection error. As predicted, when the costs of rejecting females increased, males exhibited more permissive discrimination decisions and showed high levels of SSB; when the costs of accepting males increased, males were more restrictive and showed low levels of SSB. Our results support the idea that in animal species, in which the recognition cues of females and males overlap to a certain degree, SSB is a consequence of an adaptive discrimination strategy to avoid the costs of making rejection errors.

Post-anthesis sink size in a high-yielding dwarf wheat: yield response to grain number

1977 ◽  
Vol 28 (2) ◽  
pp. 165 ◽  
Author(s):  
RA Fischer ◽  
I Aguilar ◽  
DR Laing
Keyword(s):  
Grain Yield ◽  
Wheat Yield ◽  
Kernel Weight ◽  
Yield Response ◽  
High Fertility ◽  
Grain Number ◽  
Wide Range ◽  
Carbon Dioxide Fertilization ◽  
Sink Size ◽  
The One

Experiments to study the effect of grain number per sq metre on kernel weight and grain yield in a high-yielding dwarf spring wheat (Triticum aestivum cv. Yecora 70) were conducted in three seasons (1971–1973) under high-fertility irrigated conditions in north-western Mexico. Crop thinning, shading and carbon dioxide fertilization (reported elsewhere), and crowding treatments, all carried out at or before anthesis, led to a wide range in grain numbers (4000 to 34,000/m2). Results indicated the response of grain yield to changing sink size (grains per sq metre), with the post-anthesis environment identical for all crops each year, and with all but the thinner crops intercepting most of the post-anthesis solar radiation. Kernel weight fell linearly with increase in grain number over the whole range of grain numbers studied, but the rate of fall varied with the season. Grain yield, however, increased, reaching a maximum at grain numbers well above those of crops grown with optimal agronomic management but without manipulation. It was concluded that the grain yield in normal crops was limited by both sink and post-anthesis source. There was some doubt, however, as to the interpretation of results from crowded crops, because of likely artificial increases in crop respiration on the one hand, and on the other, in labile carbohydrate reserves in the crops at anthesis. Also deterioration in grain plumpness (hectolitre weight) complicates the simple inference that further gains in yield can come from increased grain numbers alone.

Inhibitory effects of catecholamines in canine cardiac Purkinje fibers

1976 ◽  
Vol 231 (5) ◽  
pp. 1415-1420 ◽  
Author(s):  
P Posner ◽  
EL Farrar ◽  
CR Lambert
Keyword(s):  
Negative Response ◽  
Chronotropic Effect ◽  
Inhibitory Effects ◽  
Purkinje Fibers ◽  
Spontaneous Rate ◽  
Negative Chronotropic Effect ◽  
Cardiac Purkinje Fibers ◽  
Wide Range ◽  
Low Levels

The effect of catecholamines over a wide range of concentrations was studied on 42K uptake and efflux, as well as on spontaneous rate in canine cardiac Purkinje fibers. Low levels of catecholamines (less than 10(-10) M epinephrine; less than 10(-9) M norepinephrine) decreased automaticity. This negative chronotropic effect was blocked by phentolamine and mimicked by phenylephrine. These low levels of epinephrine and norepinephrine also inhibited 42K uptake by Purkinje fibers but had no effect on 42K efflux. The inhibition of 42K uptake was blocked by phentolamine and verapamil and mimicked by phenylephrine. The data indicate an alpha-receptor-mediated negative response of rate and 42K uptake to low levels of catecholamine. The end result is discussed in terms of a competitive increase in the influx of Ca2+ rather than Na+ and an indirect inhibition of the Na+-K+ pump.

Breeding and Mating Systems of Australian Proteaceae

1998 ◽  
Vol 46 (4) ◽  
pp. 421 ◽  
Author(s):  
Ross L. Goldingay ◽  
Susan M. Carthew
Keyword(s):  
Fruit Development ◽  
Mating Systems ◽  
Pollen Deposition ◽  
Genetic Studies ◽  
The Past ◽  
Wide Range ◽  
The Family ◽  
Self Compatibility ◽  
Low Levels ◽  
Key Events

There has been a significant increase in the number of studies investigating plant breeding and mating systems over the past 10 years. The family Proteaceae, in particular, has dominated such research conducted in Australia. Thus it is now timely to present a critical review of the breeding and mating systems of the Australian Proteaceae. It is hoped that this will stimulate further research. The review covers key events between pollen deposition on stigmas through to fruit set. The genus Banksia, although not the most diverse of the family, has received a disproportionate amount of attention. It has featured in nine published studies of self-compatibility compared to 13 studies spanning the other 45 genera and has featured in eight genetic studies of the mating system compared to just two on other genera. Few studies have assessed the timing of stigma receptivity despite the intriguing situation in most Proteaceae of auto-deposition of self-pollen on or near stigmas at anthesis. Studies suggest that stigmas are not receptive until 0.5–4 days after anthesis. Banksia species appear to show low levels of self-compatibility although one subspecies shows high levels of selfing and evidence of selective fruit development. Self-compatibility may be more common in other genera, although a dearth of studies precludes generalisation. Assessment of mating systems indicates almost complete outcrossing for most species, lending support to the idea of selective fruit development. It is clear that many further studies of all topics are required but particularly across a wide range of genera because many have not been studied at all.

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