scholarly journals Differences in nitrogen uptake and marginal yield response between low and high yielding perennial ryegrass (Lolium perenne) genotypes

2017 ◽  
Vol 79 ◽  
pp. 245-249
Author(s):  
M. Harmer ◽  
C. Farlow ◽  
A.V. Stewart ◽  
D.R. Woodfield

Abstract Current nitrogen (N) use recommendations for perennial ryegrass (Lolium perenne) were derived from the response of historic genotypes certified or bred between 1930 and 1970. Despite significant increase in the yield of modern cultivars in seasons of lower forage growth (late spring through winter), no existing research considers the impact of this on N response functions or N uptake characteristics. In light of this a multi-year genotype by N rate trial was established. Data analysed confirms significant differences exist in the slope and intercept of genotype N response functions. Higher yielding modern cultivars had more than twice the marginal response to N of old genotypes in summer and autumn in addition they also yielded more when no N fertiliser was applied. Nitrogen uptake characteristics of higher yielding cultivars in the first winter were significantly greater than low yielding genotypes, thus they may present a different N leaching risk than older genotypes. Farm-scale implications of these preliminary findings warrants consideration once a larger dataset is available for analysis. Keywords: pasture, nitrogen fertiliser, genetic gain, N leaching, nitrogen economics

2010 ◽  
Vol 61 (3) ◽  
pp. 214 ◽  
Author(s):  
K. Dawar ◽  
M. Zaman ◽  
J. S. Rowarth ◽  
J. Blennerhassett ◽  
M. H. Turnbull

Improving nitrogen (N)-use efficiency of applied urea is critical to maximise its uptake and decrease environmental impact. Two glasshouse-based studies were conducted to investigate the potential of incorporating urea fertiliser with urease inhibitor (N-(n-butyl) thiophosphoric triamide (NBPT) or ‘Agrotain’) to enhance fertiliser N uptake efficiency. Topsoil (0–0.075 m, Typic Haplustepts silt loam) from a pasture site near Lincoln, Canterbury, New Zealand, was collected and ryegrass (Lolium perenne L.) was grown from seed in standard plant trays maintained at soil moisture contents of 75–80% field capacity. Urea, Agrotain-treated urea, ammonium nitrate, ammonium sulfate, or sodium nitrate, were applied in granular form at rates equivalent to 25 or 50 kg N/ha with 4 replicates. Herbage was harvested 21 and 42 days after application of treatments to assess dry matter (DM) production, N uptake, leaf amino acid, ammonium (NH4+) and nitrate (NO3–) concentrations, and nitrate reductase activity (NRA). In a separate pot experiment, granular 15N urea (10 atom%) with or without Agrotain was applied to ryegrass at 25 kg N/ha. At 0.5, 1, 2, 3, 5, 10, and 21 days after treatment application, 3 pots per treatment were destructively sampled to determine urea hydrolysis, herbage DM, and 15N uptake. In both experiments, Agrotain-treated urea improved bio-availability of added N and resulted in significantly higher herbage DM yield and N uptake than urea alone or other forms of N fertilisers. Agrotain-treated urea applied at 25 kg N/ha increased N response by 66% compared with urea alone (and by greater proportions compared with the other fertiliser forms). Agrotain-treated urea applied at 25 kg N/ha produced significantly higher uptake efficiency (13 g DM/g of applied N) than at 50 kg N/ha (5 g DM/g of applied N). Tissue amino acids, NH4+ and NO3– contents, and NRA were not significantly influenced by any type of fertiliser. Results from the 15N experiment support the suggestion that a delay in urea hydrolysis by Agrotain provided an opportunity for direct plant uptake of an increased proportion of the applied urea-N than in the case of urea alone. Treating urea with Agrotain thus has the potential to increase N-use efficiency and herbage production.


2018 ◽  
Vol 62 (1) ◽  
pp. 69-82 ◽  
Author(s):  
Thomas M. R. Maxwell ◽  
Roger D. McLenaghen ◽  
Grant R. Edwards ◽  
Hong J. Di ◽  
Keith C. Cameron

2017 ◽  
Vol 57 (7) ◽  
pp. 1336 ◽  
Author(s):  
Ronaldo Vibart ◽  
Alec Mackay ◽  
Andrew Wall ◽  
Iris Vogeler ◽  
Josef Beautrais ◽  
...  

Farm-scale models were integrated with spatially discrete estimates of pasture production to examine the potential farm and regional implications of removing palm-kernel expeller (PKE) as a supplementary feed from dairy farms in Southland, New Zealand. The following two farm-production systems representing the majority of dairy farms in the region were modelled: a System 3 farm (D3; mid-intensification, with 10–20% of imported feed) and a System 4 farm (D4; mid- to high intensification, with 20–30% of imported feed). Within each system, the impact of the following four PKE options was explored: (1) a control with PKE (Baseline); (2) no PKE, with fewer cows producing the same amount of milk per cow as in Baseline; (3) no PKE, with the same number of cows producing less milk per cow than in Baseline; and (4) PKE replaced with barley grain. Barley grain provides for similar flexibility (timing of purchase and feeding), and can be sourced locally. Faced with the need to remove PKE as a dietary ingredient, farmers would benefit from adopting the second PKE option (no PKE, with fewer cows producing the same amount of milk per cow as in Baseline); farm-operating profits were reduced by only 3% (compared with 30% of System 4 farms adopting the third PKE option, i.e. no PKE, with the same number of cows producing less milk per cow than in Baseline) relative to the Baseline farms. The narrow range of mean annual nitrate-nitrogen (nitrate-N) leaching losses (estimates ranged from 30 to 33 kg N/ha) reflects similar estimates of N intake and N excreted in urine across the modelled options. Substantial amounts of barley grain would need to be transported into the region or produced locally to replace PKE.


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.


2018 ◽  
Vol 45 (7) ◽  
pp. 696 ◽  
Author(s):  
Jingjing Wu ◽  
Herbert J. Kronzucker ◽  
Weiming Shi

Elevated CO2 concentrations ([CO2]) in the atmosphere often increase photosynthetic rates and crop yields. However, the degree of the CO2 enhancement varies substantially among cultivars and with growth stage. Here, we examined the responses of two rice cultivars, Wuyunjing23 (WYJ) and IIyou084 (IIY), to two [CO2] (~400 vs ~600) and two nitrogen (N) provision conditions at five growth stages. In general, both seed yield and aboveground biomass were more responsive to elevated [CO2] in IIY than WYJ. However, the responses significantly changed at different N levels and growth stages. At the low N input, yield response to elevated [CO2] was negligible in both cultivars while, at the normal input, yield in IIY was 18.8% higher under elevated [CO2] than ambient [CO2]. Also, responses to elevated [CO2] significantly differed among various growth stages. Elevated [CO2] tended to increase aboveground plant biomass in both cultivars at the panicle initiation (PI) and the heading stages, but this effect was significant only in IIY by the mid-ripening and the grain maturity stages. In contrast, CO2 enhancement of root biomass only occurred in IIY. Elevated [CO2] increased both total N uptake and seed N in IIY but only increased seed N in WYJ, indicating that it enhanced N translocation to seeds in both cultivars but promoted plant N acquisition only in IIY. Root C accumulation and N uptake also exhibited stronger responses in IIY than in WYJ, particularly at the heading stage, which may play a pivotal role in seed filling and seed yield. Our results showed that the more effective use of CO2 in IIY compared with WYJ results in a strong response in root growth, nitrogen uptake, and in yield. These findings suggest that selection of [CO2]-responsive rice cultivars may help optimise the rice yield under future [CO2] scenarios.


HortScience ◽  
2008 ◽  
Vol 43 (2) ◽  
pp. 575-579 ◽  
Author(s):  
Silvia Jiménez Becker ◽  
Maria Teresa Lao ◽  
Mari Luz Segura

Adjusting fertility programs according to peak demand periods will help prevent periodic nutrient disorders during crop growth, allowing enhanced use efficiency of water and fertilization. The objectives of this article were to investigate 1) the evolution of the changes in the concentration of nitrate and ammonium in the recycled solution with different N-NO3 –/N-NH4 + ratios; 2) the influence of the N form supply (N-NO3 – or N-NH4 +) on the nitrogen uptake, the nitrogen:water uptake ratio, and nitrogen use and uptake efficiency; and 3) the development of empirical models that would allow the prediction of nitrogen nutritional needs of Dieffenbachia amoena to increase the N use efficiency in a recycled system. To achieve these aims, N uptake has been correlated to climate parameters such as temperature, vapor pressure deficit and global radiation, and growth parameters such as leaf area index. The trial was carried out with Dieffenbachia amoena plants growing in a recycled system with expanded clay as substrate. The crop was placed in an INSOLE (Buried Solar Greenhouse), the plants being supplied with equal amounts of N, differing in the percentage of the N form applied (NO3 –:NH4 +): TA (100:0), TB (50:50), and TC (0:100). The nitrogen form generated important changes in the pH and nitrate and ammonium concentration in nutritive solution during the recirculating solution. In N-NO3 – treatment, pH increased and nitrate concentration showed a tendency to drop slightly. N-NH4 + treatment showed an abrupt N-NH4 + concentration decrease, and N-NO3 – concentration increased along with a pH drop. Also, the nitrogen form applied to the Dieffenbachia amoena crop affects nitrogen uptake. Nitrogen uptake rates and nitrogen uptake concentration were higher in the plants supplied with N-NH4 + or NO3 –+NH4 + than in the plants provided with N-NO3 – alone. The supply of a combination of 50:50 NO3 –+NH4 + improved the N use efficiency. The study also indicated the possibility of predicting the N uptake rate and N uptake concentration using the proposed models.


2002 ◽  
Vol 55 ◽  
pp. 111-115 ◽  
Author(s):  
J.P.J. Eerens ◽  
S.S. Seefeldt ◽  
G. Garry ◽  
M.L. Armstrong

The impact of grazing pasture to different heights on the development of Californian thistle (Cirsium arvense) was simulated over two years in container trials Californian thistle field densities were simulated by transplanting seedlings into perennial ryegrass (Lolium perenne) and white clover (Trifolium repens) that had been sown at 20 and 5 kg/ha respectively In a high fertility situation adding fertiliser did not influence Californian thistle development in the pasture sward Californian thistle grown without companion ryegrass and white clover grew the best reaching the highest levels of biomass (shoot and root material) and number of shoots (supra and subterranean) Californian thistle grown with the highest level of pasture competition fared the worst with the lowest level of biomass and number of shoots The results show that grazing to a higher residual severely reduces Californian thistle growth and is a useful tool to assist in the control of Californian thistle


1997 ◽  
Vol 37 (5) ◽  
pp. 537 ◽  
Author(s):  
D. J. Donaghy ◽  
J. M. Scott ◽  
W. J. Fulkerson

Summary. The present study investigated, in a subtropical environment, the timing of defoliation treatments in spring and summer irrigation management on the survival of perennial (Lolium perenne cv. Yatsyn) and biennial (L. multiflorum cv. Noble) ryegrass in a mixed ryegrass–white clover (Trifolium repens) pasture over the first summer, and seedling recruitment the following autumn. Defoliation options were related to various ryegrass plant development stages such as the number of leaves per tiller attained during regrowth, stem elongation and seed set. The criterion for timing of frequent defoliation was 1 leaf/tiller regrowth and infrequent defoliation 3 leaves/tiller. Both pasture types were defoliated either frequently or infrequently at specific times from sowing to mid summer. Half the plots were irrigated from 30 November to 6 April while the remaining plots were not irrigated over this period. There was no survival of biennial ryegrass plants into autumn of the second year and pasture production was entirely from seedling recruitment of seed set in the previous spring. The maximum seedling recruitment (plant population 89% of spring in establishment year) was achieved by infrequent defoliation in mid spring and then cessation of defoliation until mid summer to allow plants to set seed. However, this resulted in a production loss of 3094 kg dry matter/ha of ryegrass and clover. In contrast, production of perennial ryegrass in the second year was reliant almost exclusively on individual ryegrass plants surviving the summer, as there was little seed set and virtually no seedling recruitment. There would appear to be 2 contrasting defoliation requirements to optimise perennial ryegrass persistence. Infrequent defoliation from sowing to early spring (22 March–2 September) and frequent defoliation in early summer (19 November–3 February) resulted in maximum plant survival and minimum tropical grass incursion. Frequent, compared with infrequent, defoliation up to 2 September decreased root dry matter in February by 45% to 1.66 g dry matter/plant. However in early summer, frequent defoliation maximised survival, presumably by reducing shading by tropical grasses, and preventing a closed canopy which encourages ‘rust’ infestation of the ryegrass. Irrigation of ryegrass over summer, in situations likely to become waterlogged, will only be of benefit in dry years and if scheduling is frequent enough to benefit ryegrass rather than tropical grass. These results highlight the importance of maintaining an infrequent defoliation interval to maximise persistence of perennial ryegrass in the subtropics. More frequent defoliation may be necessary in late spring/early summer to reduce the impact of leaf rust.


HortScience ◽  
2019 ◽  
Vol 54 (11) ◽  
pp. 1907-1914 ◽  
Author(s):  
Desire Djidonou ◽  
Xin Zhao ◽  
Karen E. Koch ◽  
Lincoln Zotarelli

Growth and yield typically increase when tomato plants are grafted to selected interspecific hybrid rootstocks from which distinctive root system morphologies are envisioned to aid nutrient uptake. We assessed these relationships using a range of exogenous nitrogen (N) supplies under field production conditions. This study analyzed the impact of N on growth, root distribution, N uptake, and N use of determinate ‘Florida 47’ tomato plants grafted onto vigorous, interspecific, hybrid tomato rootstocks ‘Multifort’ and ‘Beaufort’. Six N rates, 56, 112, 168, 224, 280, and 336 kg·ha−1, were applied to sandy soil in Live Oak, FL, during Spring 2010 and 2011. During both years, the leaf area index, aboveground biomass, and N accumulation (leaf blade, petiole, stem, and fruit) responded quadratically to the increase in N fertilizer rates. Averaged over the two seasons, the aboveground biomass, N accumulation, N use efficiency (NUE), and N uptake efficiency (NUpE) were ≈29%, 31%, 30%, and 33% greater in grafted plants than in nongrafted controls, respectively. More prominent increases occurred in the root length density (RLD) in the uppermost 15 cm of soil; for grafted plants, RLD values in this upper 15-cm layer were significantly greater than those of nongrafted plants during both years with an average increase of 69% over the two seasons. Across all the grafted and nongrafted plants, the RLD decreased along the soil profile, with ≈60% of the total RLD concentrated in the uppermost 0 to 15 cm of the soil layer. These results demonstrated a clear association between enhanced RLD, especially in the upper 15 cm of soil, and improvements in tomato plant growth, N uptake, and N accumulation with grafting onto vigorous rootstocks.


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