Nitrogen management to optimise canola production in Australia

2016 ◽  
Vol 67 (4) ◽  
pp. 419 ◽  
Author(s):  
R. M. Norton
Keyword(s):  
Seed Oil ◽  
Stem Elongation ◽  
N Uptake ◽  
Oil Quality ◽  
Growth Period ◽  
Yield Potential ◽  
N Budget ◽  
N Supply ◽  
Oil Concentration ◽  
N Management

The expansion of canola production in Australia coincided with an increase in cropping intensity and a reduction in pastures and tillage. These changes mean that nitrogen (N) is often recognised as the most limiting nutrient in canola production, and is the largest single input cost for many growers. Canola responds to added N by producing larger plants that results in a longer leaf area duration, building a larger photosynthetic canopy for seed filling. Although the crop can compensate for poor early growth, a larger canopy is able to compete more effectively against weeds and helps reserve water for crop transpiration rather than soil evaporation. Nitrogen uptake is most rapid during stem elongation, and the N acquired can be remobilised to developing pods and then to seeds. Unlike wheat, N uptake can continue until drought or high temperatures prevent further assimilate supply to the reproductive apex. Data from Australian experiments that measured N uptake over the whole growth period showed that each tonne of seed required ~80 kg N to be taken up, and this forms the basis of a budgeting approach for determining N supply. Typically, added N reduces seed oil concentration at a rate of between –0.03 and –0.13%/kg N. Despite this decline due to added N, oil yield usually increases and the overall value of the crop also increases. Nitrogen has little impact on oil quality or seed glucosinate concentration. The efficiency and effectiveness of N management depends first on selecting a rate appropriate to the water-limited yield potential. Most growers estimate the N rate required using an N budget based on supplying 80 kg N/t less indigenous N supply. The budgeted N can be split over two, three or even more applications with little loss in agronomic efficiency. Splitting application enables growers to make decisions about N when there is more certainty about seasonal conditions. Urea is the most common N source used, and unless there are particular loss processes that are likely to occur, it is cheap and effective. Suggested areas for future N research on canola are to develop tools that can assess in-crop N status, an evaluation of late season N product rate and timing particularly on seed oil concentration, N management for grazed canola, and the development of guidelines to identify, and then address, particular N loss pathways using enhanced efficiency fertilisers.

Recovery of field-grown canola from sulfur deficiency

1996 ◽  
Vol 36 (1) ◽  
pp. 79 ◽  
Author(s):  
PJ Hocking ◽  
A Pinkerton ◽  
A Good
Keyword(s):  
Seed Yield ◽  
Seed Oil ◽  
No Reduction ◽  
Stem Elongation ◽  
Potassium Sulfate ◽  
Growth Stages ◽  
Flower Buds ◽  
S Deficiency ◽  
Oil Concentration ◽  
Seed Yields

Sulfate-sulfur was applied to sulfur (S)-deficient canola at several growth stages in a field experiment at Cargo near Orange, New South Wales. Applications of 0, 10 or 40 kg S/ha (S0, S10 and S40) as mixtures of potassium sulfate and potassium chloride were made at sowing, the 5-6 leaf rosette stage, flower buds visible, stem elongation and first flowering. The plots received either 80 or 160 kg nitrogen (N)/ha at sowing. Plants from the S0 plots showed symptoms of severe S deficiency during rapid stem elongation, and had a 52% reduction in seed yield and a 21% reduction in seed oil concentration compared with the S40 plants. Application of S10 at sowing, or topdressing S-deficient plants with this rate of S, was inadequate because, although seed oil concentrations were normal (39-42%), seed yields were 25% lower than those from plots that received S40. Topdressing S-deficient plants with S40 at either the 5-6 leaf rosette stage, flower buds visible or stem elongation resulted in the same seed yields and seed oil concentrations as obtained when S40 was applied at sowing. However, there was a 15% reduction in seed yield but no reduction in seed oil concentration when the S40 topdressing was delayed until flowering. Although S10 was inadequate to correct the S deficiency, there was no reduction in either seed yield or seed oil concentration when S10 was topdressed as late as flowering, when compared with this rate of S applied at sowing. Seed meal protein levels were increased by the S40 topdressings. Concentrations of S in seed from the S0 and S10 plants were below the critical value of 0.36% for canola. Seed N:S concentration ratios of S-deficient plants were greater than 10, but 7.5 for plants which received adequate S. Total glucosinolates in seed were increased by the application of S, but the levels were still well below the limit set for the canola standard.

An Evaluation of the Oil Concentration in Sesame Seeds in Relation to Developmental Stage, Node Position and Capsule Age

1984 ◽  
Vol 20 (2) ◽  
pp. 129-134
Author(s):  
S. N. Saha ◽  
S. C. Bhargava
Keyword(s):  
Seed Oil ◽  
Dry Weight ◽  
Yield Potential ◽  
Main Shoot ◽  
Oil Accumulation ◽  
Sesame Seeds ◽  
Oil Concentration ◽  
Sesame Genotypes ◽  
Node Position ◽  
Oil Formation

SUMMARYWeekly measurements were made of the seed oil concentration (% dry weight) in five sesame genotypes (Sesamum indicum) from flowering to maturity. During early but not late development the oil concentration of main shoot capsules was less variable than that in capsules taken from branches. The oil concentration of seeds from capsules at different nodes decreased from 67 to 22% between the lowest (oldest) capsule at node 8 and the youngest one at the uppermost node (25) in 1976, and from 65 to 19% for the same nodes in 1977. Variations in oil accumulation in relation to capsule age revealed that oil formation begins within 5 days after fertilization and maximum accumulation (52% oil) was achieved after 30 days. The implications of these findings for the assessment of oil yield potential are discussed.

Critical phosphorus concentrations in oilseed rape (Brassica napus) and Indian mustard (Brassica juncea) as affected by nitrogen and plant age

1991 ◽  
Vol 31 (1) ◽  
pp. 107 ◽  
Author(s):  
A Pinkerton
Keyword(s):  
Oilseed Rape ◽  
Stem Elongation ◽  
Indian Mustard ◽  
Critical Values ◽  
Plant Age ◽  
Sand Culture ◽  
Mustard Seed ◽  
P Deficiency ◽  
N Supply ◽  
Oil Concentration

Oilseed rape and Indian mustard were grown in sand culture experiments in a glasshouse to derive values for a tissue test for the diagnosis of phosphorus (P) deficiency. Seven rates of P, combined factorially with 3 rates of nitrogen (N), were used to determine critical P concentrations. Suitable tissues to sample for a diagnostic test were the whole shoot of both species at any stage, or the youngest fully expanded leaf of rape and leaves 4-6 of mustard at the rosette stage. Critical P concentrations depended on both plant age and N supply. The critical values reported here for rape agreed closely with critical values found previously in tissues of field-grown crops of similar phenological age. Critical P levels in whole rape shoots adequately supplied with N decreased from 0.29% at the early rosette stage to 0.21% at the late rosette or yellow bud stage, while critical values in mustard fell from 0.25% at the early rosette stage to 0.18% at stem elongation to full flower. Critical P concentrations for prediction of seed yield were slightly higher (0.05% higher at the rosette stage). A nutrient supply with high P and high N reduced the seed oil concentration of both species; a low P and high N supply reduced the oil concentration in rape seed but increased it in mustard seed.

Soil tests for predicting nitrogen supply for grassland under controlled environmental conditions

2014 ◽  
Vol 152 (S1) ◽  
pp. 82-95 ◽  
Author(s):  
N. T. MCDONALD ◽  
C. J. WATSON ◽  
R. J. LAUGHLIN ◽  
S. T. J. LALOR ◽  
J. GRANT ◽  
...  
Keyword(s):  
N Uptake ◽  
Soil Types ◽  
Soil N ◽  
Soil Tests ◽  
Mineral N ◽  
N Supply ◽  
Supply Potential ◽  
Growing Conditions ◽  
N Management ◽  
Over Time

SUMMARYMineralized soil nitrogen (N) is an important source of N for grassland production. Some soils can supply large quantities of plant-available N through mineralization of soil organic matter. Grass grown on such soils require less fertilizer N applications per unit yield. A reliable, accurate and user-friendly method to account for soil N supply potential across a large diversity of soils and growing conditions is needed to improve N management and N recommendations over time. In the current study, the effectiveness of chemical N tests and soil properties to predict soil N supply for grass uptake across 30 Irish soil types varying in N supply potential was investigated under controlled environmental conditions. The Illinois soil N test (ISNT) combined with soil C : N ratio provided a good estimate of soil N supply in soils with low residual mineral N. Total oxidized N (TON) had the largest impact on grass dry matter (DM) yield and N uptake across the 30 soil types, declining in its influence in later growth periods. This reflected the high initial mineral N levels in these soils, which declined over time. In the current study, a model with ISNT-N, C : N and TON (log TON) best explained variability in grass DM yield and N uptake. All three rapid chemical soil tests could be performed routinely on field samples to provide an estimate of soil N supply prior to making N fertilizer application decisions. It can be concluded that these soil tests, through their assessment of soil N supply potential, can be effective tools for N management on grassland; however, field studies are needed to evaluate this under more diverse growing conditions.

An Evaluation of the Oil Concentration in Sesame Seeds in Relation to Developmental Stage, Node Position and Capsule Age

1984 ◽  
Vol 20 (2) ◽  
pp. 129-134
Author(s):  
S. N. Saha ◽  
S. C. Bhargava
Keyword(s):  
Seed Oil ◽  
Dry Weight ◽  
Yield Potential ◽  
Main Shoot ◽  
Oil Accumulation ◽  
Sesame Seeds ◽  
Oil Concentration ◽  
Sesame Genotypes ◽  
Node Position ◽  
Oil Formation

SUMMARYWeekly measurements were made of the seed oil concentration (% dry weight) in five sesame genotypes (Sesamum indicum) from flowering to maturity. During early but not late development the oil concentration of main shoot capsules was less variable than that in capsules taken from branches. The oil concentration of seeds from capsules at different nodes decreased from 67 to 22% between the lowest (oldest) capsule at node 8 and the youngest one at the uppermost node (25) in 1976, and from 65 to 19% for the same nodes in 1977. Variations in oil accumulation in relation to capsule age revealed that oil formation begins within 5 days after fertilization and maximum accumulation (52% oil) was achieved after 30 days. The implications of these findings for the assessment of oil yield potential are discussed.

Management of nitrogen and phosphorus fertilizer in no-till flax

2003 ◽  
Vol 83 (4) ◽  
pp. 681-688 ◽  
Author(s):  
G. Lafond ◽  
C. Grant ◽  
A. Johnston ◽  
D. McAndrew ◽  
W. May
Keyword(s):  
Seed Yield ◽  
Seed Oil ◽  
Seed Quality ◽  
N Uptake ◽  
P Uptake ◽  
Fertilizer Placement ◽  
Management Options ◽  
Crop Establishment ◽  
Oil Concentration ◽  
P Placement

The major flax-growing areas of Canada coincide with areas where large shifts towards conservation tillage have occurred. These shifts have also brought about major changes in the way fertilizer is applied. The objective of this study was to determine the combination of nitrogen fertilizer form and N and P fertilizer placement methods that can increase N and P uptake, seed yield and seed oil concentration and composition in flax. The study was conducted at four locations covering the flax-growing areas over a 3-yr period. Three fertilizer forms, ammonium nitrate (AN), ammonium sulphate (AS) and urea were compared using different placement methods, pre-plant band (Pp) or side-band (Sb) in combination with monoammonium phosphate in either a Pp, Sb or seed-placed (Sp) position. Plant uptake of N and P was measured at 7, 14, 21 and 28 d after crop emergence and at the start of flowering. Other variables collected included crop establishment, crop yield and seed oil concentration and composition. AS resulted in the highest N uptake followed by AN then urea. As well, AS in the Sb showed higher N uptake than when applied Pp. The largest uptake of P was observed on days 7, 14 and 21 when AS and P were placed together in an Sb position. Crop establishment was adversely affected by urea and least by AN and AS, indicating that adequate seed-fertilizer separation between urea and flax seed is critical to minimizing reductions in plant stands. N form and placement, and P placement had no effect on seed oil concentration and composition in this study. Seed yield was improved marginally, overall, with the addition of P, while changes in N and P placement had no overall yield benefits. Treatments that resulted in improved N and P uptake in the first 21 d after crop emergence did not result in improved seed yields. When site × year interactions were investigated, 2 of 12 site years showed better yields when N and P were placed together in the Sb position. Based on the results of this study, we conclude that flax growers have many agronomically acceptable N and P management options available. Key words: Linum usitatissimum L., fertilizer placement, fertilizer form, nutrient uptake, seed yield, seed quality, oil quantity, urease inhibitor, Agrotain™

Short-term nitrogen dynamics in soil amended with poultry litter containing woodchip bedding

2016 ◽  
Vol 96 (4) ◽  
pp. 427-434 ◽  
Author(s):  
Ben W. Thomas ◽  
Joann K. Whalen ◽  
Mehdi Sharifi
Keyword(s):  
N Mineralization ◽  
N Uptake ◽  
Poultry Litter ◽  
Growth Period ◽  
Application Rate ◽  
Net N Mineralization ◽  
Short Term ◽  
Wheat Growth ◽  
Total N ◽  
N Supply

Concurrent N mineralization and immobilization in soils receiving poultry litter containing woodchip bedding may reduce synchrony between the short-term N supply and crop N demand. Therefore, we used soil chemical tests, ion exchange membranes, and wheat N uptake to assess N dynamics in a poultry-litter-amended soil. Air-dried soil was thoroughly mixed with five poultry litter rates (50, 100, 150, 200, or 250 mg total N kg−1) and preincubated for 7 d in a controlled environment chamber. After preincubating, soil was placed in 10-cm-diameter pots and planted with spring wheat (Triticum aestivum ‘Wilkin’), or left unplanted and monitored with anion and cation exchange membranes for 45 d. Soil nitrate (NO3-N) concentration increased with poultry litter application rate at the end of the preincubation period, but subsequent wheat N uptake did not, suggesting that little net N mineralization occurred during the 45 d of wheat growth. The membrane data indicated a shift from net N immobilization during the early part of the wheat growth period to net mineralization during the latter portion of the wheat growth period. We conclude that alternating N mineralization and immobilization in soils receiving poultry litter containing woodchip bedding limited the short-term N supply to wheat.

scholarly journals Supplying nitrate before bud break induces pronounced changes in nitrogen nutrition and growth of young poplars

2012 ◽  
Vol 39 (9) ◽  
pp. 795 ◽  
Author(s):  
Suraphon Thitithanakul ◽  
Gilles Pétel ◽  
Michel Chalot ◽  
François Beaujard
Keyword(s):  
Leaf Area ◽  
Nitrogen Nutrition ◽  
N Uptake ◽  
Experimental Studies ◽  
Growth Period ◽  
Bud Break ◽  
Total N ◽  
N Supply ◽  
C And N ◽  
N Remobilisation

Tree nutrient research concentrated on endogenous C and N remobilisation in spring has neglected to acknowledge the possibilities of significant effects of N uptake before bud break, especially on the quality of regrowth and N reserve remobilisation. To investigate this subject, experimental studies were performed on young poplars (Populus tremula × Populus alba, clone INRA 717–1B4) grown with a controlled nutrient supply: (i) without N, ‘control’; (ii) N supplied throughout the course of the experiment, ‘N-supply’; and (iii) N supplied only before bud break, ‘N-pulse’. Results confirm the hypothesis that poplar scions can significantly take up nitrate before bud break, amounting to ~34% of the total N stored the previous year. After bud break, emerging leaves restart the sap flow, which increased nitrate uptake to support the regrowth. N-pulse and N-supply treatments were found to have significant effects shortly after a growth period, i.e. by increasing N content of all tissues (e.g. 37 and 81% in new shoots respectively), leaf area (18 and 29%) and specific leaf area (20 and 35%). Therefore, results confirm the hypothesis that early N supply plays a significant role in the N status and N remobilisation involved in the spring regrowth of young trees.

Nitrogen budget of wheat growing on a Riverine clay soil

2000 ◽  
Vol 51 (7) ◽  
pp. 867 ◽  
Author(s):  
C. J. Smith ◽  
F. X. Dunin ◽  
R. Poss ◽  
J. F. Angus
Keyword(s):  
Stem Elongation ◽  
N Uptake ◽  
15N Tracer ◽  
Wagga Wagga ◽  
Water Retention Capacity ◽  
Mineral N ◽  
Total N ◽  
Leaching Losses ◽  
N Supply ◽  
Net Mineralisation

The fate of nitrogen in wheat grown on a Mesotrophic, Red Kandosol near Wagga Wagga was studied in the 1993 growing season, which had above-average rainfall: 417 mm (31 May–30 November 1993) compared with an average (June–November) of 289 mm. Nitrogen supply (fertiliser and mineralisation) was partitioned between crop uptake, gaseous and leaching losses, and residual mineral N in the soil profile. The study plots were 2 adjacent 5-ha areas. At stem elongation (Zadock’s decimal code 31), one area was topdressed with urea at 14 g N/m2 (fertilised crop). The total N supply to the fertilised crop was 29 g N/m2—8 g N/m2 of mineral N in the soil at sowing, net mineralisation of 5.3 g N/m2, and fertiliser inputs of 1.7 and 14 g N/m2. The corresponding value for the non-fertilised crop was 15 g N/m2. The urea application produced a 50% increase in above-ground biomass (1521 and 1008 g/m2 dry matter at harvest) and a 1.8-fold increase in grain yield (692 and 384 g/m2). The proportion of the total N supply recovered in the crops was similar (55% and 60% for the non-fertilised and fertilised treatments, respectively). Leaching losses were low (0.4 and 0.5 g N/m2), even though ≈100 mm drained beyond the root-zone (equivalent to 24% of the seasonal rainfall). The periods of saturated soil required to generate drainage also caused denitrification losses of 1.7 and 3.4 g N/m2 for the non-fertilised and fertilised treatments, respectively. Increased net mineralisation and reduced crop N uptake that began a month prior to anthesis were responsible for the substantial amounts of mineral N remaining in the soil after harvest (4.7 and 4.3 g N/m2, respectively). The low NO3 leaching loss associated with high drainage was explained by displacement flow mechanics operating in soil that has a high water retention capacity, which is confirmed by Br and 15N tracer analysis. The N balance was closed for the non-fertilised crop, but a discrepancy of 2.8 g N/m2 remains for the fertilised crop. The uncertainty of ≈10% of the fertilised treatment may possibly be due to ammonia volatilisation following topdressing with urea.

Development of an algorithm for optimizing nitrogen fertilization in wheat using GreenSeeker proximal optical sensor

2020 ◽  
Vol 56 (5) ◽  
pp. 688-698
Author(s):  
Ali M. Ali
Keyword(s):  
Vegetation Index ◽  
Field Experiments ◽  
N Uptake ◽  
Yield Potential ◽  
N Recovery ◽  
Spatial And Temporal Variability ◽  
Fertilizer N ◽  
Total N ◽  
General Recommendation ◽  
N Management

AbstractProximal plant sensing with active canopy sensors offers a leap in the non-destructive assessment of crop agronomic information. For managing fertilizer nitrogen (N), sensor readings must be translated using functional models or algorithms to fertilizer amounts. Six field experiments were conducted in three wheat seasons in the West Nile Delta in Egypt to develop and validate an algorithm based on GreenSeeker canopy reflectance sensor for field-specific fertilizer N management in wheat, which takes into account both spatial and temporal variability of N during the crop growth season. The proposed algorithm is based on the prediction of total N uptake and response index of N uptake determined from normalized difference vegetation index measured by the sensor from plots differing in yield potential as established by applying a range of fertilizer N levels in the four experiments conducted in the first two wheat seasons. The treatments in the two experiments conducted in the third wheat season were designed to define appropriate fertilizer N management prior to applying a sensor-based dose at Feekes 6 stage (jointing stage). The application of 40 and 60 kg N ha−1 at 10 and 30 days after sowing of wheat and a sensor-guided dose of N estimated by using the algorithm developed in this study resulted in yields similar to those obtained by following the general recommendation, but with an average of 66 kg N ha−1 less fertilizer N. These results were also reflected in a substantial increase in N recovery (21.9%) and agronomic (7.7 kg grain kg−1 N) efficiencies compared with the general recommendation, thereby proving the usefulness of the sensor-based algorithm in optimizing fertilizer N management in wheat.

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