scholarly journals Nitrogen use efficiency of 15N urea applied to wheat based on fertiliser timing and use of inhibitors

2019 ◽  
Vol 116 (1) ◽  
pp. 41-56 ◽  
Author(s):  
Ashley J. Wallace ◽  
Roger D. Armstrong ◽  
Peter R. Grace ◽  
Clemens Scheer ◽  
Debra L. Partington

Abstract Improving fertiliser nitrogen (N) use efficiency is essential to increase productivity and avoid environmental damage. Using a 15N mass balance approach, we investigated the effects of five N fertiliser management strategies to test the hypothesis that increasing uptake of applied N by wheat improves productivity and reduces loss of N in a semi-arid environment. Three experiments were conducted between 2012 and 2014. Treatments included urea application (50 kg N/ha) at sowing with and without nitrification inhibitor (3,4-dimethylpyrazole phosphate, DMPP) and surface broadcast with and without urease inhibitor (n-butyl thiophosphoric triamide, NBPT) at the end of tillering plus an unfertilised control. It was found that deferring fertiliser application until the end of tillering decreased losses of fertiliser N (35–52%) through increasing uptake by the crop and or recovery in the soil at harvest, while maintaining yield except when rainfall following application was low. In this case, deferring application reduced fertiliser uptake (− 71%) and grain yield (− 18%) and increased recovery of N in the soil (+ 121%). Use of DMPP or NBPT reduced N loss where seasonal conditions were conducive to denitrification during winter (DMPP) and volatilisation or denitrification later in the season (NBPT). Their effect on grain yield was less significant; DMPP increased yield (+ 3–31%) in all years and NBPT increased yield (+ 7–11%) in 2 of 3 years compared to unamended urea. The majority of crop N uptake was supplied from soil reserves and as a result, crop recovery of applied N was not strongly related to grain yield response.

Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 619 ◽  
Author(s):  
Robert H. Harris ◽  
Roger D. Armstrong ◽  
Ashley J. Wallace ◽  
Oxana N. Belyaeva

Some of the highest nitrous oxide (N2O) emissions arising from Australian agriculture have been recorded in the high-rainfall zone (>650mm) of south-western Victoria. Understanding the association between nitrogen (N) management, crop N uptake and gaseous losses is needed to reduce N2O losses. Field experiments studied the effect of N-fertiliser management on N2O emissions, crop N uptake and crop productivity at Hamilton and Tarrington in south-western Victoria. Management included five rates of urea-N fertiliser (0, 25, 50, 100 and 200kgN/ha) topdressed at either mid-tillering or first-node growth stages of wheat development; urea-N deep-banded 10cm below the seed at sowing; and urea coated with the nitrification inhibitor DMPP (3,4-dimethylpyrazole phosphate) was either topdressed or deep-banded. Pre-sowing soil profile chemical properties were determined before static chambers were installed to measure N2O losses, accompanied by wheat dry matter, crop N uptake and grain yield and quality, to measure treatment differences. N2O losses increased significantly (P≤0.10) where urea-N was deep-banded, resulting in a 2–2.5-fold increase in losses, compared with the nil N control. The high N2O losses from deep-banding N appeared to result from winter waterlogging triggering gaseous or drainage losses before wheat reached peak growth and demand for N in spring. Despite the high losses from deep-banding urea-N, grain yields were largely unaffected by N management, except at Hamilton in 2012, where topdressed wheat growing in a soil with large reserves of NO3–-N, and later experiencing post-anthesis water deficit resulted in a negative grain yield response. All sites had high concentrations of soil organic carbon (>2.8%) and the potential for large amounts of N mineralisation throughout the growing season to supplement low N fertiliser recovery. However, topdressed urea-N resulted in significant enrichment of crop tissue (P≤0.004) and associated positive response in grain protein compared with the deep banded and nil N treatments. 3,4-Dimethylpyrazole phosphate (DMPP)-coated urea provided no additional benefit to crop yield over conventional urea N. Our study highlighted the importance of synchronising N supply with peak crop N demand to encourage greater synthetic N uptake and mitigation of N2O losses.


2015 ◽  
Vol 154 (6) ◽  
pp. 978-988 ◽  
Author(s):  
P. YAN ◽  
Q. ZHANG ◽  
X. F. SHUAI ◽  
J. X. PAN ◽  
W. J. ZHANG ◽  
...  

SUMMARYUnderstanding the physiological mechanisms of biomass accumulation and partitioning in the grain, and the nitrogen (N) uptake associated with different plant densities and N management strategies, is essential for achieving both high yield and N use efficiency (NUE) in maize plants. A field experiment was conducted in 2013 and 2014, using five rates of N application and three plant densities (6·0, 7·5 and 9·0 plants/m2) in Quzhou County on the North China Plain (NCP). The objective was to evaluate whether higher plant density can produce more biomass allocated to the grain to achieve higher grain yield and to determine the optimal N management strategies for different plant densities. The highest grain yield and NUE were achieved in the 7·5 plants/m2 treatment; both the sub-optimal (6·0 plants/m2) and supra-optimal (9·0 plants/m2) plant densities resulted in diminished yield and NUE. Compared to 6·0 plants/m2, the 7·5 plants/m2 treatment displayed higher biomass accumulation during the grain-filling period and also exhibited more biomass allocated to kernels with similar total biomass accumulation compared with the 9·0 plants/m2 treatment, which contributed to its higher grain yield. The N uptake in the 7·5 plants/m2 treatment was similar to that in the 9·0 plants/m2 treatment up to pre-silking. However, the post-silking N uptake of the 7·5 plants/m2 treatment was 66·4 kg/ha, which was 29·1% higher than that of the 9·0 plants/m2 treatment. Furthermore, the highest maize grain yield was achieved in the 0·7 × optimal N rate (ONR × 0·7), ONR and ONR × 1·3 treatments for 6·0, 7·5 and 9·0 plants/m2, respectively, which suggests that different N management strategies are needed for different plant densities. In conclusion, selecting a planting density of 7·5 plants/m2 with an in-season root zone N management is a potentially effective strategy for achieving high grain yield and high NUE for maize production on the NCP.


Soil Research ◽  
2019 ◽  
Vol 57 (8) ◽  
pp. 859 ◽  
Author(s):  
G. D. Schwenke ◽  
B. M. Haigh

Most soil nitrous oxide (N2O) emissions from rain-fed grain sorghum grown on sub-tropical Vertosols in north-west New South Wales, Australia, occur between fertiliser nitrogen (N) application at sowing and booting growth stage. At three experiments, we investigated the potential for deferring some (split-N) or all (delayed) fertiliser N until booting to mitigate N2O produced without compromising optimum crop yields. N products included urea, 3,4-dimethyl pyrazole phosphate (DMPP)-urea, polymer-coated urea (PCU) and N-(n-butyl)thiophosphoric triamide (NBPT)-urea. For a fourth experiment, the N fertiliser rate was varied according to pre-sowing soil mineral N stocks left by different previous crops. All experiments incorporated 15N mini-plots to determine whether delayed or split-N affected crop N uptake or residual soil N. Compared to urea applied at-sowing, delayed applications of urea, DMPP-urea or NBPT-urea at booting reduced the N2O emission factor (EF, percentage of applied N emitted) by 67–81%. Crop N uptake, grain yield and protein tended to be lower with delayed N than N at-sowing due to dry mid-season conditions. Much of the unused N remained in the soil at harvest. Split-N (33% sowing:67% booting) using urea, reduced EF by 59% compared to at-sowing urea, but maintained crop N uptake, grain yield and protein. Using DMPP-urea or PCU for the at-sowing portion of the split reduced EF by 84–86%. Grain yield was maintained using PCU, but was lower with DMPP-urea, which had more N in vegetative biomass. Using NBPT-urea for the in-crop portion of the split did not affect N2O emissions or crop productivity. Nitrogen budgeting to account for high pre-sowing soil mineral N nullified urea-induced N2O emissions. An N-budgeted, split-N strategy using urea offers the best balance between N2O mitigation, grain productivity and provision of a soil mineral N buffer against dry mid-season conditions. Split-N using DMPP-urea or PCU further enhanced N2O mitigation but there was no yield response to justify the extra expense.


Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 817
Author(s):  
Kirsten Paff ◽  
Senthold Asseng

Tef is an Ethiopian staple grain that provides both food security and income for smallholders. As tef is nutritious and gluten free, it is also gaining popularity as a health food. A tef model was calibrated based on the Decision Support System for Agrotechnology Transfer’s (DSSAT) NWheat model and included parameter changes in phenology, photoperiod response, radiation use efficiency, and transpiration efficiency for both standard and elevated atmospheric CO2, based on published literature for tef and other C4 species. The new DSSAT-Tef model was compared with tef field experiments. DSSAT-Tef accurately simulated phenology and responded to changes in N supply and irrigation, but overestimated growth and occasionally yields. Simulation-observation comparisons resulted in an RMSE of 2.5 days for anthesis, 4.4 days for maturity, 2624 kg/ha (49.6%) for biomass, and 475 kg/ha (41.0%) for grain yield. Less data were available for N uptake, and the model simulated crop N uptake with an RMSE of 45 kg N/ha (46.2%) and 15 kg N/ha (37.3%) for grain N. While more data from contrasting environments are needed for further model testing, DSSAT-Tef can be used to assess the performance of crop management strategies, the suitability of tef for cultivation across growing environments, and food security.


2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Temesgen Godebo ◽  
Fanuel Laekemariam ◽  
Gobeze Loha

AbstractBread wheat (Triticum aestivum L.) is one of the most important cereal crops in Ethiopia. The productivity of wheat is markedly constrained by nutrient depletion and inadequate fertilizer application. The experiment was conducted to study the effect of nitrogen (N) and potassium (K) fertilizer rates on growth, yield, nutrient uptake and use efficiency during 2019 cropping season on Kedida Gamela Woreda, Kembata Tembaro Zone Southern Ethiopia. Factorial combinations of four rates of N (0, 23, 46 and 69 kg Nha−1) and three rates of K2O (0, 30 and 60 kg Nha−1) in the form of urea (46–0-0) and murate of potash (KCl) (0-0-60) respectively, were laid out in a randomized complete block design with three replications. The results showed that most parameters viz yield, yield components, N uptake and use efficiency revealed significant differences (P < 0.05) due to interaction effects of N and K. Fertilizer application at the rate of 46 N and 30 kg K ha−1 resulted in high grain yield of 4392 kg ha− 1 and the lowest 1041 from control. The highest agronomic efficiency of N (52.5) obtained from the application of 46 kg N ha−1. Maximum physiological efficiency of N (86.6 kg kg−1) and use efficiency of K (58.6%) was recorded from the interaction of 46 and 30 kg K ha−1. Hence, it could be concluded that applying 46 and 30 kg K ha−1was resulted in high grain yield and economic return to wheat growing farmers of the area. Yet, in order to draw sound conclusion, repeating the experiment in over seasons and locations is recommended.


2018 ◽  
Vol 98 (3) ◽  
pp. 683-702 ◽  
Author(s):  
B.L. Beres ◽  
R.J. Graf ◽  
R.B. Irvine ◽  
J.T. O’Donovan ◽  
K.N. Harker ◽  
...  

To address knowledge gaps around enhanced efficiency urea fertilizer efficacy for nitrogen (N) management, a study was designed to improve integrated nutrient management systems for western Canadian winter wheat producers. Three factors were included in Experiment 1: (i) urea type [urea, urea + urease inhibitor—Agrotain®; urea + urease and nitrification inhibitor—SuperU®, polymer-coated urea—Environmentally Smart Nitrogen® (ESN®), and urea ammonium nitrate (UAN)], (ii) application method (side-band vs. spring-broadcast vs. 50% side-band: 50% spring-broadcast), and (iii) cultivar (AC Radiant hard red winter wheat vs. CDC Ptarmigan soft white winter wheat). The Agrotain® and CDC Ptarmigan treatments were removed in Experiment 2 to allow for additional application methods: (i) fall side-band, (ii) 50% side-band — 50% late fall broadcast, (iii) 50% side-band — 50% early spring broadcast, (iv) 50% side-band — 50% mid-spring broadcast, and (v) 50% side-band — 50% late spring broadcast. CDC Ptarmigan produced superior grain yield and N utilization over AC Radiant. Grain yield and protein content were influenced by N form and application method. Split applications of N usually provided the maximum yield and protein, particularly with Agrotain® or SuperU®. An exception to the poor fall-application results was the SuperU® treatments, which produced similar yield to the highest-yielding treatments. The results suggest that split applications of N might be most efficient for yield and protein optimization when combined with an enhanced efficiency urea product, particularly with urease or urease + nitrification inhibitors, and if the majority of N is applied in spring.


Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1505
Author(s):  
Amritbir Riar ◽  
Gurjeet Gill ◽  
Glenn K. McDonald

Canola has a high nitrogen requirement and optimal nitrogen (N) management in environments with variable rainfall is a challenge. This study investigated the impact of timing of N as a single or split application at different growth stages on seed yield, N uptake and water-use efficiency in canola. Nitrogen rates of 100 and 200 kg ha−1 were applied after sowing when two leaves were unfolded or equally split between the rosette, green bud and first flower stages. The experiments were conducted at two sites with contrasting rainfall and a supplementary irrigation treatment at the low rainfall site, generating a third environment. Nitrogen application increased seed yield by up to 20% at a high rainfall site and by up to 77% at a medium rainfall site, but the timing of N did not significantly affect the yield response to N. Seed yield was closely associated with total dry matter production and seed m−2. N-use efficiency was influenced more by N recovery and uptake efficiency, rather than physiological efficiency, which highlights the importance of soil moisture availability and the ability of the crop to exploit soil water and N reserves. The results suggest that better use of subsoil moisture by overcoming some of the subsoil constraints may be an avenue for further improvements in yield and nitrogen-use efficiency (NUE) of canola in this environment.


Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1241
Author(s):  
Peter Omara ◽  
Lawrence Aula ◽  
Fikayo B. Oyebiyi ◽  
Elizabeth M. Eickhoff ◽  
Jonathan Carpenter ◽  
...  

Biochar (B) has shown promise in improving crop productivity. However, its interaction with inorganic nitrogen (N) in temperate soils is not well-studied. The objective of this paper was to compare the effect of fertilizer N-biochar-combinations (NBC) and N fertilizer (NF) on maize (Zea mays L.) grain yield, N uptake, and N use efficiency (NUE). Trials were conducted in 2018 and 2019 at Efaw and Lake Carl Blackwell (LCB) in Oklahoma, USA. A randomized complete block design with three replications and ten treatments consisting of 50, 100, and 150 kg N ha−1 and 5, 10, and 15 Mg B ha−1 was used. At LCB, yield, N uptake, and NUE under NBC increased by 25%, 28%, and 46%, respectively compared to NF. At Efaw, yield, N uptake, and NUE decreased under NBC by 5%, 7%, and 19%, respectively, compared to NF. Generally, results showed a significant response to NBC at ≥10 Mg B ha−1. While results were inconsistent across locations, the significant response to NBC was evident at LCB with sandy loam soil but not Efaw with silty clay loam. Biochar application with inorganic N could improve N use and the yield of maize cultivated on sandy soils with poor physical and chemical properties.


Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 634 ◽  
Author(s):  
Graeme D. Schwenke ◽  
David F. Herridge ◽  
Clemens Scheer ◽  
David W. Rowlings ◽  
Bruce M. Haigh ◽  
...  

The northern Australian grains industry relies on nitrogen (N) fertiliser to optimise yield and protein, but N fertiliser can increase soil fluxes of nitrous oxide (N2O) and methane (CH4). We measured soil N2O and CH4 fluxes associated with wheat (Triticum aestivum) and barley (Hordeum vulgare) using automated (Expts 1, 3) and manual chambers (Expts 2, 4, 5). Experiments were conducted on subtropical Vertosol soils fertilised with N rates of 0–160kgNha–1. In Expt 1 (2010), intense rainfall for a month before and after sowing elevated N2O emissions from N-fertilised (80kgNha–1) wheat, with 417gN2O-Nha–1 emitted compared with 80g N2O-Nha–1 for non-fertilised wheat. Once crop N uptake reduced soil mineral N, there was no further treatment difference in N2O. Expt 2 (2010) showed similar results, however, the reduced sampling frequency using manual chambers gave a lower cumulative N2O. By contrast, very low rainfall before and for several months after sowing Expt 3 (2011) resulted in no difference in N2O emissions between N-fertilised and non-fertilised barley. N2O emission factors were 0.42, 0.20 and –0.02 for Expts 1, 2 and 3, respectively. In Expts 4 and 5 (2011), N2O emissions increased with increasing rate of N fertiliser. Emissions were reduced by 45% when the N fertiliser was applied in a 50:50 split between sowing and mid-tillering, or by 70% when urea was applied with the nitrification inhibitor 3,4-dimethylpyrazole-phosphate. Methane fluxes were typically small and mostly negative in all experiments, especially in dry soils. Cumulative CH4 uptake ranged from 242 to 435g CH4-Cha–1year–1, with no effect of N fertiliser treatment. Considered in terms of CO2 equivalents, soil CH4 uptake offset 8–56% of soil N2O emissions, with larger offsets occurring in non-N-fertilised soils. The first few months from N fertiliser application to the period of rapid crop N uptake pose the main risk for N2O losses from rainfed cereal cropping on subtropical Vertosols, but the realisation of this risk is dependent on rainfall. Strategies that reduce the soil mineral N pool during this time can reduce the risk of N2O loss.


2015 ◽  
Vol 52 (2) ◽  
pp. 314-329 ◽  
Author(s):  
ANITA IERNA ◽  
GRAZIA MARIA LOMBARDO ◽  
GIOVANNI MAUROMICALE

SUMMARYLimited information is available concerning the influence of nitrogen fertilization jointly on yield response, nitrogen use efficiency (NUE) and grain quality of durum wheat under semi-arid Mediterranean conditions. The study focused on evaluating, through a systematic study, over three seasons in southern Italy the effects of three nitrogen fertilization rates (0, 80 and 160 kg N ha−1– N0, N80and N160), on grain yield, yield components, nitrogen efficiency indices and grain quality characteristics of three durum wheat genotypes (‘Creso’, ‘Trinakria’ and ‘Line 25’) from different breeding eras to achieve a more sustainable fertilization management of the durum wheat crop. We found that nitrogen fertilization at 80 kg N ha−1was able to maximize the yield performances (2.1 t ha−1year–1) of the crop and keep NUE index at an acceptable level (16.3 kg kg−1). On the other hand, nitrogen fertilization at 160 kg N ha−1improved grain quality measured through protein (up to 14.3%) and dry gluten concentration (up to 12.8%), but had a detrimental effect on grain yield and nitrogen efficiency. Among the genotypes studied, ‘Trinakria’ showed the greatest potential to utilize nitrogen fertilization to improve grain yield and NUE (at N80) and quality (at N160), ‘Line 25’ made good use of N80both for yield and quality, whereas ‘Creso’ proved wholly unresponsive to nitrogen. The effect of N fertilization on grain yield and N use efficiency depends on rainfall distribution, giving the best results when about 80% of total rainfall occurred from sowing to heading. Overall, our data show that in seasons with regular rainfall in quantity and distribution, combining no more than 80 kg ha−1of nitrogen fertilization with genotypes characterized by a more efficient response to nitrogen, is a useful tool to improve the agronomic and quality performance of the crop, ensuring, at the same time, a more environment-friendly nitrogen fertilization.


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