Nitrogen and phosphorus nutrition of dryland grain sorghum at Katherine, Northern Territory. 1. Effect of rate of nitrogen fertilizer

1978 ◽  
Vol 18 (93) ◽  
pp. 554 ◽  
Author(s):  
RJK Myers
Keyword(s):  
Nitrogen Fertilizer ◽  
Field Experiments ◽  
Nitrogen Concentration ◽  
Balance Sheet ◽  
Grain Sorghum ◽  
Northern Territory ◽  
Grain Weight ◽  
Nitrogen And Phosphorus ◽  
Nitrogen Response ◽  
Applied Nitrogen

Responses of dryland grain sorghum to applied nitrogen were examined in three field experiments at Katherine, Northern Territory, in 1969-70, 1970-71 and 1971-72. Rates of nitrogen up to 89 kg ha-1 in the first season and up to 200 kg ha-1 in subsequent seasons were used. The crops were sampled at floral initiation, mid-elongation, anthesis, and maturity. The three growing seasons were rated as below average, above average and average, respectively, for grain sorghum production. Nitrogen response was strongly season-dependent, Maximum yields (adjusted to 14 per cent moisture) were: 1969-70, 2280 kg ha-1, with 22.4 kg N ha-1 applied (with lower yields at higher rates of nitrogen) ; 1970-71,7730 kg ha-1 with 150 kg N ha-1 applied; and 1971-72,4440 kg ha-1 with 200 kg N ha-1 applied. These represented increases of 6, 50, and 62 per cent, respectively, over the zero nitrogen treatments. Applied nitrogen increased grain numbers per head and individual grain weight, but had no significant effect on head numbers. Applied nitrogen increased yields of nitrogen and phosphorus in plant material, and increased nitrogen concentration in plant parts. Apparent recoveries of nitrogen fertilizer ranged from 0 to 40 per cent, depending on year and rate applied. An approximate balance sheet suggested substantial losses from the mineral nitrogen pool in 1970- 71, a year of above average rainfall. Significant interactions between nitrogen and phosphorus fertilizer occurred only with grains per head and thousand grain weight.

Nitrogen and phosphorus nutrition of dryland grain sorghum at Katherine, Northern Territory. 2. Effect of rate and source of phosphorus fertilizer

1978 ◽  
Vol 18 (93) ◽  
pp. 564 ◽  
Author(s):  
RJK Myers
Keyword(s):  
Field Experiments ◽  
Grain Sorghum ◽  
Northern Territory ◽  
Diammonium Phosphate ◽  
Yield Response ◽  
Growth Stages ◽  
Growth Responses ◽  
Triple Superphosphate ◽  
Monoammonium Phosphate ◽  
Nitrogen And Phosphorus

Field experiments were conducted at Katherine, Northern Territory, in 1970-71 and 1971 -72 to examine responses of dryland grain sorghum to applied phosphorus at different growth stages. In the first, the effect of rate of application up to 100 kg P ha-1 as triple superphosphate was investigated. Growth responses to phosphorus were noted from mid-elongation onwards, but the magnitude of response varied between seasons, being greater in the higher rainfall season 1970-71. Maximum yields of grain were 7730 kg ha-1 with 50 kg P ha-1 in 1970-71, and 4440 kg ha-1 with 100 kg P ha-1 in 1971-72, which were increases of 49 and 37 per cent respectively over the appropriate zero phosphorus treatment. These suggested an increased requirement for phosphorus over previous recommendations. Phosphorus reduced the time from emergence to anthesis from 68 to 60 and from 70 to 63 days respectively in the two seasons. About half of the plant phosphorus was taken up after anthesis. It was concluded from soil analysis that phosphate-treated plots had an enhanced supply of phosphorus throughout the period of crop growth. In the second study, four phosphorus sources (superphosphate, triple superphosphate, monoammonium phosphate, and diammonium phosphate) were compared. With 25 kg P ha-1 and with constant nitrogen, grain yield response followed the order superphosphate > monoammonium phosphate > diammonium phosphate > triple superphosphate in both years. Triple superphosphate tended to give lower dry matter yields and nitrogen and phosphorus concentrations than the other three sources.

Nitrogen and phosphorus nutrition of dryland grain sorghum at Katherine, Northern Territory. 3. Effect of nitrogen carrier, time and placement

1978 ◽  
Vol 18 (95) ◽  
pp. 834 ◽  
Author(s):  
RJK Myers
Keyword(s):  
Ammonium Nitrate ◽  
Ammonium Sulphate ◽  
Field Experiments ◽  
Grain Sorghum ◽  
Northern Territory ◽  
Nitrogen And Phosphorus ◽  
Rooting Zone ◽  
Loam Soil ◽  
Dry Soil ◽  
Moisture Conditions

Different nitrogen carriers, and placements and strategies of application to dryland grain sorghum growing in a clay loam soil were compared in field experiments at Katherine, Northern Territory. The nitrogen carriers were ammonium sulphate, ammonium nitrate, urea and anhydrous ammonia ; placements were banding, mixing into the topsoil, and broadcasting; and strategies consisted of split application, and varying time of broadcasting. The rate used throughout was 50 kg N ha-1.Responses to the various treatments varied between the two seasons (1970-71, 1971-72) due to differing soil moisture conditions. There was a response to broadcasting nitrogen after emergence, giving higher grain yield and nitrogen yield than earlier broadcasting or application with the seed. Banded nitrogen (both seasons) and split nitrogen (one season) were superior to other methods of applying nitrogen with the seed. The only yield differences between sources of nitrogen were with broadcast application, where ammonium sulphate proved superior in one season, and with respect to apparent recovery of nitrogen by the crop, when the order ammonium nitrate > ammonium sulphate > urea was observed in both seasons. It is suggested that in this environment and on this soil, nitrogen is not particularly susceptible to volatilization, and broadcasting urea and ammonium fertilizer onto dry soil may retain nitrogen within the rooting zone, in comparison with nitrate, which is more susceptible to leaching. Incorporated fertilizer is more susceptible to nitrification and subsequent leaching, while banded nitrogen appears to resist nitrification and leaching.

Effects of nitrogen fertilizer, plant population and irrigation on sugar beet: II. Nutrient concentration and uptake

1971 ◽  
Vol 76 (2) ◽  
pp. 269-275 ◽  
Author(s):  
A. P. Draycott ◽  
M. J. Durrant
Keyword(s):  
Sugar Beet ◽  
Nitrogen Fertilizer ◽  
Nutrient Concentration ◽  
Field Experiments ◽  
Nitrogen Concentration ◽  
Plant Size ◽  
Plant Population ◽  
Sugar Yield ◽  
Phosphorus Concentration ◽  
Wide Range

SUMMARYThe concentration of nitrogen, phosphorus, potassium, sodium, calcium and magnesium was measured in the dry matter of sugar beet from four field experiments (1966–9). All combinations of four amounts of nitrogen fertilizer (0–1·8 cwt/acre), four plant populations (8800–54000 plants/acre) and irrigation were tested, which gave a wide range of plant size and yield. Nutrient concentration and uptake by the crop were also greatly affected by the treatments.Nitrogen fertilizer and irrigation increased uptake of nitrogen by the crop but increasing the plant population had little effect on uptake and decreased the concentration of nitrogen. Sugar yield was related to the total nitrogen concentration in tops and roots and to uptake. There were optimal values of nitrogen concentration for maximal sugar yield, but the optima were greatly affected by plant population. Leaf colour was a good guide to nitrogen concentration.Phosphorus concentration was affected little by the treatments but cation concentrations were greatly affected. In general, uptake of all the elements was increased by all treatments – the exception was sodium, which decreased as the plant population increased but this was balanced to somo extent by increased potassium uptake.

Nitrogen and phosphorus fertilizer sources and placement methods in maize (Zea mays L.) using labelled fertilizers

1983 ◽  
Vol 101 (3) ◽  
pp. 687-690 ◽  
Author(s):  
E. P. Papanicolaou ◽  
V. D. Skarlou ◽  
C. Nobeli ◽  
N. S. Katranis
Keyword(s):  
Crop Yield ◽  
Nitrogen Fertilizer ◽  
Field Experiments ◽  
Alluvial Soil ◽  
Ammonium Phosphate ◽  
Maize Yield ◽  
Phosphate Fertilizer ◽  
Pot Experiment ◽  
Phosphorus Fertilizer ◽  
Nitrogen And Phosphorus

SUMMARYThe influence of various nitrogen and phosphorus sources, applied at the preseeding stage with two placement methods, on maize yield and fertilizer utilization, was studied in two field experiments and a pot experiment with a calcareous, heavy to medium heavy textured recent alluvial soil.Phosphorus alone had no effect on crop yield. Nitrogen alone or nitrogen (various forms) and phosphorus had a clear positive effect on crop yield. As to the various sources the observed differences in the crop yield of the field experiments were not significant, while in the pot experiment ammonium sulphate gave the highest yields.The data on the phosphate concentrations in the tops derived from phosphate fertilizer (Pf) indicate that the presence of nitrogen increased the utilization of phosphorus fertilizer. From the tested placement methods the incorporation method appears clearly superior in the pot experiment with a similar trend in the field experiment for all sources except ammonium phosphate-sulphate.The utilization coefficients of the nitrogen fertilizer sources suggest that ammonium and urea were better utilized than nitrates, that the higher nitrogen utilization reflected higher yields and that phosphorus fertilizer exerted a beneficial effect on nitrogen fertilizer utilization. Finally they suggest that the addition of 120 kg N/ha enhanced the amount of soil nitrogen taken up in the maize grain by 53%.

Effect of nitrogen and phosphorus fertilizers on the seed yield and oil concentration of oilseed rape (Brassica napus L.) and the prediction of responses by soil tests and past paddock use

1987 ◽  
Vol 27 (5) ◽  
pp. 713 ◽  
Author(s):  
DC Lewis ◽  
TD Potter ◽  
SE Weckert ◽  
IL Grant
Keyword(s):  
Oilseed Rape ◽  
Seed Oil ◽  
Sandy Loam ◽  
Seed Oil Content ◽  
Nitrogen And Phosphorus ◽  
Peat Soils ◽  
Nitrogen Response ◽  
Black Clay ◽  
Highly Correlated ◽  
Applied Nitrogen

The response of oilseed rape to applied nitrogen and phosphorus was investigated in 2 areas of the South East of South Australia. The nitrogen rates applied varied from 0 to 50 kg/ha, while phosphorus rates applied in the Mundulla area ranged from 0 to 20 kg/ha and 0 to 34 kg/ha in the Millicent area. At 9 sites in the Mundulla area, where soils were primarily sandy loam over clay, oilseed rape yields were increased significantly by applied nitrogen at 7 sites and by applied phosphorus at 2 sites. On heavy black clay and peat soils in the Millicent area, oilseed rape yields were increased significantly by applied nitrogen at 5 of the 12 sites and by applied phosphorus at 6 sites. Of the measured soil variables, anaerobic ammonium nitrogen measured in the top 10 cm best predicted responses in seed yield to applied nitrogen. The critical nutrient range was 45-65 mg/kg. The response of oilseed rape to applied nitrogen was highly correlated with past paddock use but varied between the 2 areas. From the prediction equations developed, it was concluded that, in the Mundulla area, a significant (P< 0.05) nitrogen response was likely if the oilseed rape followed 2 or more crops, the last a non-legume, but was unlikely if the oilseed rape followed 1 or more years of pasture. At Millicent, a nitrogen response was likely if the oilseed rape was grown as the sixth crop in a continuous cropping program, and was unlikely if it was the first or second crop in the rotation, provided the preceding crop was a non-legume. The response of oilseed rape to applied phosphorus was highly correlated to extractable soil phosphorus measured in the top 10 cm (Colwell). The critical nutrient range was 20-25 mg/kg for the sandy loam soils at Mundulla and 40-50 mg/kg for the black clay and peat soils at Millicent. Nitrogen applications significantly increased seed oil content at 6 sites, significantly decreased it at 2 sites and had no effect at 13 sites. Phosphorus significantly increased seed oil content at only 1 site, significantly decreased it at 3 sites, and had no effect at the other 17 sites.

Nitrogen requirements of sugar beet in relation to harvesting date

1976 ◽  
Vol 86 (2) ◽  
pp. 373-377 ◽  
Author(s):  
M. R. J. Holmes ◽  
J. R. Devine ◽  
F. W. Dunnett
Keyword(s):  
Sugar Beet ◽  
Nitrogen Fertilizer ◽  
Field Experiments ◽  
Sugar Content ◽  
Sugar Yield ◽  
Yield Response ◽  
Nitrogen Rate ◽  
Nitrogen Response ◽  
Oolitic Limestone ◽  
Early Harvest

SummarySeven field experiments were made on the effect of two harvesting dates on the nitrogen requirements of sugar beet. All were on Rauceby series soils overlying oolitic limestone in Lincolnshire.Nitrogen fertilizer increased sugar yield in all experiments, and yield was considerably higher at the mid-December harvest than in early October. On average, the sugar-yield response to nitrogen was greater at the late harvest, and the requirement for nitrogen was about 45 kg/ha higher then than at the early harvest. Sugar content was depressed less at the late harvest than at the early by increasing nitrogen rate.These results suggest that farmers should apply more nitrogen to fields that they plan to harvest late than to early-harvested fields; they also have implications for the conduct and interpretation of nitrogen response experiments on sugar beet.

Nitrogen and phosphorus nutrition of dryland grain sorghum at Katherine, Northern Territory. 4. 15-nitrogen studies on nitrogen carrier and method of application

1979 ◽  
Vol 19 (99) ◽  
pp. 481 ◽  
Author(s):  
RJK Myers
Keyword(s):  
Ammonium Nitrate ◽  
Ammonium Sulphate ◽  
Field Experiments ◽  
N Uptake ◽  
Poor Performance ◽  
Nitrogen Sources ◽  
Grain Sorghum ◽  
Nitrogen And Phosphorus ◽  
Significant Treatment ◽  
Effective Source

The effect of nitrogen source and method of application on yield and N uptake of dryland grain sorghum was studied, using 15-nitrogen labelled fertilizers. The nitrogen sources were ammonium sulphate, ammonium nitrate and urea, and the methods were banded, mixed and split application, using a rate of 50 kg N ha-1 throughout. The experiment was conducted over two wet seasons, 1970-71 and 1971-72. Method of application increased yield and nitrogen uptake in the order banded > mixed > split. Source of nitrogen resulted in the order ammonium sulphate = ammonium nitrate > urea. In the drier season, urea behaved somewhat differently, i.e. banded urea > banded ammonium nitrate= banded ammonium sulphate. Calculation of percentage recovery in general confirmed these results. It was concluded that nitrogenous fertilizer is more effective when banded, and that urea was a less effective source of nitrogen than the two ammonium salts. The results obtained with 15-nitrogen revealed a significant treatment effect that was not apparent in non-tracer experiments namely, the poor performance of urea in the second year. Because of its greater sensitivity, and because it identifies the nitrogen derived from fertilizer, the 15-nitrogen technique has scope for use in field experiments comparing fertilizers and cultural techniques.

scholarly journals Comparison of Root Characteristics of Conventionally Grown Cowpeas and Cowpeas Grown without Added Nitrogen Fertilizer

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 687b-687
Author(s):  
Brian A. Kahn ◽  
Judith L. Schroeder
Keyword(s):  
Vigna Unguiculata ◽  
Nitrogen Fertilizer ◽  
Field Experiments ◽  
Lateral Roots ◽  
Nitrogen Concentration ◽  
Dry Weight ◽  
Fresh Weight ◽  
Root Characteristics ◽  
Cultural Systems ◽  
Input Sample

Field experiments were conducted in Oklahoma in 1993 and 1994. Cowpeas [Vigna unguiculata (L.) Walp.] were grown using either non-inoculated seed and 23 kg·ha–1 of preplant nitrogen fertilizer (conventional) or inoculated seed and no preplant nitrogen fertilizer (reduced input). Sample plants were excavated at first pod set and analyzed for nodulation and root morphology. Additional plants were excavated at the green-shell stage and were analyzed for nitrogen concentration. Conventional and reduced input cowpeas did not differ in nodule distribution among root morphological components, total nodule fresh weight, total root dry weight, or nitrogen concentration. Most nodules generally were located on the basal and lateral roots. Results indicate that cowpea root characteristics are not necessarily altered by differing cultural systems at a given location.

Nitrogen fertilizer and wheat in a semi-arid environment. 4. Empirical yield response models and economic factors

1968 ◽  
Vol 8 (35) ◽  
pp. 736 ◽  
Author(s):  
JS Russell
Keyword(s):  
Grain Yield ◽  
Nitrogen Fertilizer ◽  
Field Experiments ◽  
Response Surfaces ◽  
Maximum Temperature ◽  
Yield Response ◽  
Nitrate Content ◽  
Economic Factors ◽  
Late Application ◽  
Applied Nitrogen

The difficulties in predicting grain yield response to applied nitrogen under conditions of low and variable rainfall are discussed. Three models of grain yield response to applied nitrogen fertilizer for each of two strategies are proposed, based on data from field experiments carried out in the wheat growing areas of South Australia. In the first strategy (nitrogen applied at sowing) the parameters are May-August rainfall, October mean maximum temperature and one of three alternative site criteria, initial soil nitrate content (0-6 inches sampled shortly before sowing), 15-atmospheres soil moisture percentage (0-6 inches), or estimated nitrogen status. In the second strategy (nitrogen applied in late winter) the parameters are similar, except that May-July rainfall replaced May-August rainfall and a statistical relationship between yield response due to late application as compared with application at sowing was used. The response surfaces were examined using a calculated most profitable rate of application with a range of grain : fertilizer price ratios from 2 to 8. These calculations emphasize the importance of economic factors in affecting fertilizer use in areas where responses are small and variable. The limitations of the models and problems associated with the use of predicted climatic criteria are discussed. There is a need for further studies to iteratively test and modify these empirical models and ultimately to develop mechanistic models. Further study is also suggested on field aspects of late application and the possible role of both plant analysis and the single ion nitrate electrode for site characterization.

Effect of green manures on yield and nitrogen requirement of sugar beet

1981 ◽  
Vol 97 (1) ◽  
pp. 159-170 ◽  
Author(s):  
P. J. Last ◽  
A. P. Draycott ◽  
D. J. Webb
Keyword(s):  
Sugar Beet ◽  
Nitrogen Fertilizer ◽  
Field Experiments ◽  
Nitrogen Fertilizers ◽  
Late Winter ◽  
Soil Mineral Nitrogen ◽  
Green Manures ◽  
Nitrogen Requirement ◽  
Isobutylidene Diurea ◽  
Applied Nitrogen

SUMMARYFour field experiments in 1972–6 investigated the effect of undersowing trefoil or ryegrass in barley, and of fodder radish sown after barley, on yield and nitrogen requirement of following sugar beet. Autumn applications of isobutylidene diurea or glycoluril (slow-release nitrogen fertilizers) were also included for comparison with green manures. The plots were split in the following spring and dressings of 0, 50, 100 and 150 kg N/ha as ‘Nitro-Chalk’ tested on the sugar-beet crop.The undersown green manure crops slightly decreased the yield of barley but, at the time of ploughing, returned up to 3·7 t dry matter/ha and 50 kg N/ha. In the absence of spring-applied nitrogen fertilizer for the sugar beet, green manures increased root and sugar yield, but when more than 50 kg N/ha was applied for the sugar beet they had no effect on yield. Autumn applications of nitrogen fertilizers such as isobutylidene diurea decreased the requirement for nitrogen in spring, but yields were no greater than from spring-applied nitrogen alone. Top and subsoils sampled in late winter and early summer from plots where green manures had been grown showed no detectable increase in soil organic carbon or total nitrogen, but soil mineral-nitrogen concentrations were increased slightly by green manures as was the potentially available mineralnitrogen released in an incubation test. It is concluded that, on loamy soils, green manures decrease the nitrogen requirement of sugar beet but give no benefits in yield which cannot be obtained from nitrogen fertilizer in spring before sowing the crop. assistance and Miss G. Smith for statistical analyses.

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