The nitrogen economy of broadacre lupin in southwest Australia

1994 ◽  
Vol 45 (1) ◽  
pp. 149 ◽  
Author(s):  
MJ Unkovich ◽  
JS Pate ◽  
J Hamblin

The time courses of above- and below-ground accumulation of biomass and N were followed in a crop of narrowleaf lupin (Lupinus angustifolius L. cv. Illyarrie) at Geraldton, W.A., and concurrent N2 fixation assessed using the 15N natural abundance technique. Crop biomass peaked at 10 t DM and 231 kg N ha-1 with 13% of this N below ground. The crop accumulated the bulk (90%) of its N through symbiotic N2 fixation. Of the 164 kg total plant N ha-1 remaining in recoverable biomass at maturity 44% was recovered as grain, 49% as other above-ground residues and 7% as roots. Despite a decrease in recoverable N of 67 kg ha-1 between peak biomass and maturity, 96 kg N ha-1 was returned as crop residues after grain harvest. Investigation of six farm crops in the study region gave values for nitrogen accumulation at peak biomass ranging from 199 to 372 kg ha-1 of which, on average, 86% (222 kg ha-1) was fixed from the atmosphere. Predicted N returns to the soil from fixation averaged 65 kg ha-1, though the range (32-96 kg ha-1) indicated that south-west Australian lupin crops provide somewhat variably sized pools of mineralizeable crop residues for following cereal growth.

2003 ◽  
Vol 54 (4) ◽  
pp. 333 ◽  
Author(s):  
Dil F. Khan ◽  
Mark B. Peoples ◽  
Graeme D. Schwenke ◽  
Warwick L. Felton ◽  
Deli Chen ◽  
...  

The objectives of this study were to quantify below-ground nitrogen (BGN) of rainfed fababean (Vicia faba), chickpea (Cicer arietinum), and barley (Hordeum vulgare) and to use the values to determine N balances for the 3 crops. The BGN fraction of legumes in particular represents a potentially important pool of N that has often been grossly underestimated or ignored in calculating such balances. A field experiment was conducted at Breeza on the Liverpool Plains, New South Wales, in which BGN of fababean, chickpea, and barley was estimated using 15N methodologies. Plants were grown in 0.32-m2 microplots and labelled with 15N on 5 occasions during vegetative growth with a total of 1.0 mL of 0.5% 15N urea (98 atom% 15N) using leaf-flap (fababean), leaf-tip (barley), or cut petiole (chickpea) shoot-labelling procedures. At peak biomass (146–170 days after sowing), all plant material and soil to 45 cm depth was sampled from one microplot in each replicate plot and analysed for dry matter (DM), %N, and 15N. At plant maturity, the remaining 3 microplots in each replicate plot were harvested for shoot and grain DM and N. With fababean, 15N enrichments of intact roots and shoots were reasonably uniform at 537‰ and 674‰, respectively. Microplot soil at 0–25 cm depth had a 15N enrichment of 18‰ (natural abundance of 6.1‰). The 25–45 cm soil enrichment was 8.7‰ (natural abundance of 6.3‰). In contrast, 15N enrichment of chickpea shoots was about twice that of recovered roots (685‰ v. 331‰), and the soil enrichment was relatively high (30‰ and 8.8‰ for the 0–25 and 25–45 cm depths, respectively). The 15N enrichments of barley shoots and recovered roots were 2272‰ and 1632‰, respectively, with soil enrichments of 34‰ and 10.7‰ for the 0–25 and 25–45 cm depths, respectively. Estimates of BGN as a percentage of total plant N, after adjusting the 15N shoot-labelling values of fababean and chickpea for uneven distribution of 15N-depleted nodules, were 24% for fababean, 68% for chickpea, and 36% for barley. The BGN values were combined with N2 fixation (fababean and chickpea only) and shoot and grain yield data (all 3 species) to construct N budgets. The inclusion of BGN in the budgets increased N balances by 38 kg N/ha to +36 kg N/ha for fababean and by 93 kg N/ha to +94 kg N/ha for chickpea. As there was no external (N2 fixation) input of N to barley, the inclusion of BGN made no difference to the N balance of the crop of –74 kg N/ha. Such values confirm the importance of BGN of N2-fixing legumes in the N economies of cropping systems.


1994 ◽  
Vol 45 (3) ◽  
pp. 613 ◽  
Author(s):  
JM Carter ◽  
WK Gardner ◽  
AH Gibson

The response of faba beans (Vicia faba L. cv. Fiord) to seed inoculation with eight strains of Rhizobium leguminosarum biovar. viciae was examined in field experiments at six sites on acid soils in south-west Victoria. At two of the sites, two additional strains were examined, and in 1988, 14 strains were examined at one site. Very low natural populations of R. leguminosarum bv. viciae were found at the experimental sites. Most strains resulted in improved early nodulation and increased grain yield at all sites, when compared to inoculation with the commercial strain of rhizobia (SU391). Plant dry matter production and nitrogen accumulation in the plant shoot tissue was also increased at one site during the flowering period by some strains. Large visual differences between plots inoculated with SU391 and other strains were evident at most sites. Most uninoculated treatments were not nodulated and yielded very poorly. Treatments inoculated with the strain SU391 performed similarly to the uninoculated treatments.


2016 ◽  
Author(s):  
Sophie Bonnet ◽  
Melika Baklouti ◽  
Audrey Gimenez ◽  
Hugo Berthelot ◽  
Ilana Berman-Frank

Abstract. In marine ecosystems, N2 fixation provides the predominant external source of nitrogen (N) (140 ± 50 Tg N yr−1), contributing more than atmospheric and riverine inputs to the N supply. Yet the fate and magnitude of the newly-fixed N, or diazotroph-derived N (hereafter named DDN) in marine ecosystems is poorly understood. Moreover, it remains unclear whether the DDN is preferentially directly exported out of the photic zone, recycled by the microbial loop, and/or transferred into larger organisms, subsequently enhancing indirect particle export. These questions were investigated in the framework of the VAHINE (VAriability of vertical and tropHIc transfer of diazotroph derived N in the south wEst Pacific) project. Triplicate large volume (~50 m3) mesocosms were deployed in the tropical South West Pacific coastal ocean (New Caledonia) to maintain a stable water-mass without disturbing ambient light and temperature conditions. The mesocosms were intentionally fertilized with ~0.8 μM dissolved inorganic phosphorus (DIP) at the start of the experiment to stimulate diazotrophy. A total of 47 stocks, fluxes, enzymatic activities and diversity parameters were measured daily inside and outside the mesocosms by the 40 scientists involved in the project. The experiment lasted for 23 days and was characterized by two distinct and successive diazotroph blooms: a dominance of diatom-diazotroph associations (DDAs) during the first half of the experiment (days 2–14) followed by a bloom of UCYN-C during the second half of the experiment (days 15–23). These conditions provided a unique opportunity to compare the DDN transfer and export efficiency associated with different diazotrophs. Here we summarize the major experimental and modelling results obtained during the project and described in the VAHINE Special issue, in particular those regarding the evolution of the main standing stocks, fluxes and biological characteristics over the 23-days experiment, the contribution of N2 fixation to export fluxes, the DDN released to dissolved pool and its transfer to the planktonic food web (bacteria, phytoplankton, zooplankton). We then apply our Eco3M modelling platform further to infer the fate of DDN in the ecosystem and role of N2 fixation on productivity, food web structure and carbon export. Recommendations for future work are finally provided in the conclusion section.


2015 ◽  
Vol 81 ◽  
pp. 149-177 ◽  
Author(s):  
Christopher D. Standish ◽  
Bruno Dhuime ◽  
Chris J. Hawkesworth ◽  
Alistair W. G. Pike

Lead isotope analyses of 50 Irish Chalcolithic and Early Bronze Age gold artefacts favour a gold source in southern Ireland. However when combined with major element analysis, the artefacts are not consistent with any Irish gold deposit analysed to date. Understanding the lead isotope signatures of ore deposits within a study region allows informed inferences to be drawn regarding the likelihood that an unanalysed ore deposit was exploited in the past. If an Irish gold source is assumed, then the gold is most likely to have originated from deposits hosted by Old Red Sandstone in the Variscan ore field of south-west Ireland. However, based on our current understanding of mineralisation in the region, this scenario is considered unlikely. A non-Irish source for the gold is therefore preferred – a scenario that may favour cosmologically-driven acquisition, ie, the deliberate procurement of a material from distant or esoteric sources. Available geochemical data, combined with current archaeological evidence, favour the alluvial deposits of south-west Britain as the most likely source of the gold.


2020 ◽  
Vol 94 (5) ◽  
pp. 1625-1638
Author(s):  
Andrew L. Thomas ◽  
Robert Kallenbach ◽  
Thomas J. Sauer ◽  
David K. Brauer ◽  
David M. Burner ◽  
...  

Abstract Agroforestry systems that integrate useful long-lived trees have been recognized for their potential in mitigating the accumulation of atmospheric fossil fuel-derived carbon (C). Black walnut (Juglans nigra) is frequently planted and cultivated in North America for its valuable lumber and edible nuts, and is highly amenable to the integration of understory crops or livestock in agroforestry systems. However, little is known about C content in black walnut trees, including the amounts of C assimilated into lignocellulosic tissues within different tree compartments. Therefore, allometric equations for above- and below-ground compartments of 10-year-old black walnut trees across diverse locations were developed. Ten grafted black walnut trees from each of four sites across the midwestern USA were destructively harvested for above- and below-ground biomass, and dry biomass weight (DWw), C (Cw) and nitrogen (N; Nw) stocks were quantified. Soils surrounding the harvested trees were sampled and analyzed for soil organic C (SOC) and total N (TN). Total DWw ranged from 27 to 54 kg tree−1, with woody tissues containing an average of 467 g kg−1 C and 3.5 g kg−1 N. Woody tissues differed in Cw and Nw across location, and above-ground sections contained more C and less N compared with most root tissues. The slopes of the allometric equations did not differ significantly among locations, while intercepts did, indicating that trees only differed in initial size across locations. SOC and TN did not vary in distance from the trees, likely because the trees were not yet old enough to have impacted the surrounding soils. Our results establish a foundation for quantifying C and N stocks in newly established black walnut alley cropping systems across diverse environments.


1997 ◽  
Vol 48 (1) ◽  
pp. 39 ◽  
Author(s):  
E. L. Armstrong ◽  
D. P. Heenan ◽  
J. S. Pate ◽  
M. J. Unkovich

Nitrogen balances of narrow leaf lupin (Lupinus angustifolius L.), albus lupin (L. albus L.), field pea (Pisum sativum L.), chickpea (Cicer arietinum L.), and barley (Hordeum vulgare L.) sown over a range of dates were examined in 1992 in a rotation study at Wagga Wagga, NSW. Each N budget included assessment of dependence on fixed as opposed to soil N, peak aboveground biomass N, and N removed as grain or returned as unharvested aboveground crop residues. N balances of wheat sown across the plots in 1993 were assessed similarly in terms of biomass and grain yield. Yields, N2 fixation, and crop residue N balances of the legumes were markedly influenced by sowing time, and superior performance of lupins over other species was related to higher biomass production and proportional dependence on N2 fixation, together with a poorer harvest index. Residual N balances in aboveground biomass after harvest of the 1992 crops were significantly correlated with soil mineral N at 1993 sowing and with biomass and grain N yields of the resulting wheat crop. Best mean fixation and grain N yield came from albus lupin. Wheat grain N yields following the 2 lupins were some 20% greater than after fiield pea and chickpea and 3 times greater than after barley. Net soil N balance based solely on aboveground returns of N of legumes in 1992 through to harvest of wheat in 1993 was least for narrow leaf lupin-wheat ( –20 kg N/ha), followed by albus lupin-wheat ( –44), chickpea-wheat ( –74), and field pea-wheat ( –96). Corresponding combined grain N yields (legume+wheat) from the 4 rotations were 269, 361, 178, and 229 kg N/ha, respectively. The barley-wheat rotation yielded a similarly computed soil N deficit of 67 kg/ha. Data are discussed in relation to other studies on legume-based rotations.


1996 ◽  
Vol 36 (6) ◽  
pp. 701 ◽  
Author(s):  
CP Horn ◽  
RC Dalal ◽  
CJ Birch ◽  
JA Doughton

Following long-term studies at Warra, on the western Darling Downs, chckpea (Cicer anetinum) was selected as a useful grain legume cash crop with potential for improvement of its nitrogen (N) fixing ability through management. This 2-year study examined the effect of sowing time and tillage practice on dry matter yield, grain yield (Horn et al. 1996), N accumulation, N2 fixation, and the subsequent soil N balance. Generally, greater N accumulation resulted from sowing in late autumn-early winter (89-117 kg N/ha) than sowing in late winter (76-90 kg N/ha). The amount of N2 fixed was low in both years (15-32 kg N/ha), and was not significantly affected by sowing time or tillage. The potential for N2 fixation was reduced in both years due to high initial soil nitrate levels and low total biomass of chickpea because of low rainfall. Nitrogen accumulation by grain was higher under zero tillage (ZT) than conventional tillage (CT) for all sowing times, and this affected the level of grain N export. The consequence of low N2 fixation and high N export in chickpea grain was a net loss of total soil N, (2-48 kg N/ha under CT and 22-59 kg N/ha under ZT). Management practices to ensure larger biomass production and lower soil nitrate-N levels may result in increased N2 fixation by chickpea and thus a positive soil N balance.


2020 ◽  
Vol 12 (6) ◽  
pp. 2402
Author(s):  
Zaharaddeen Ali Hussaini ◽  
Peter King ◽  
Chris Sansom

In power tower systems, the heliostat field is one of the essential subsystems in the plant due to its significant contribution to the plant’s overall power losses and total plant investment cost. The design and optimization of the heliostat field is hence an active area of research, with new field improvement processes and configurations being actively investigated. In this paper, a different configuration of a multi-tower field is explored. This involves adding an auxiliary tower to the field of a conventional power tower Concentrated Solar Power (CSP) system. The choice of the position of the auxiliary tower was based on the region in the field which has the least effective reflecting heliostats. The multi-tower configuration was initially applied to a 50 MWth conventional field in the case study region of Nigeria. The results from an optimized field show a marked increase in the annual thermal energy output and mean annual efficiency of the field. The biggest improvement in the optical efficiency loss factors be seen from the cosine, which records an improvement of 6.63%. Due to the size of the field, a minimal increment of 3020 MWht in the Levelized Cost of Heat (LCOH) was, however, recorded. In much larger fields, though, a higher number of weaker heliostats were witnessed in the field. The auxiliary tower in the field provides an alternate aim point for the weaker heliostat, thereby considerably cutting down on some optical losses, which in turn gives rise to higher energy output. At 400 MWth, the multi-tower field configuration provides a lower LCOH than the single conventional power tower field.


1992 ◽  
Vol 22 (1-2) ◽  
pp. 73-93 ◽  
Author(s):  
B.J. Radford ◽  
G. Gibson ◽  
R.G.H. Nielsen ◽  
D.G. Butler ◽  
G.D. Smith ◽  
...  

2015 ◽  
Vol 95 (2) ◽  
pp. 87-93 ◽  
Author(s):  
Martin A. Bolinder ◽  
Thomas Kätterer ◽  
Christopher Poeplau ◽  
Gunnar Börjesson ◽  
Leon E. Parent

Bolinder, M. A., Kätterer, T., Poeplau, C., Börjesson, G. and Parent, L. E. 2015. Net primary productivity and below-ground crop residue inputs for root crops: Potato (Solanum tuberosum L.) and sugar beet (Beta vulgaris L.). Can. J. Soil Sci. 95: 87–93. Root crops are significant in agro-ecosystems of temperate climates. However, the amounts of crop residues for these crop types are not well documented and they need to be accounted for in the modeling of soil organic carbon dynamics. Our objective was to review field measurements of root biomass left in the soil as crop residues at harvest for potato and sugar beet. We considered estimates for crop residue inputs as root biomass presented in the literature and some unpublished results. Our analysis showed that compared to, for example, cereals, the contribution of below-ground net primary productivity (NPP) to crop residues is at least two to three times lower for root crops. Indeed, the field measurements indicated that root biomass for topsoils only represents on average 25 to 30 g dry matter (DM) m−2 yr−1. Other estimates, albeit variable and region-specific, tended to be higher. We suggest relative plant DM allocation coefficients for agronomic yield (RP), above-ground biomass (RS) and root biomass (RR) components, expressed as a proportion of total NPP. These coefficients, representative for temperate climates (0.739:0.236:0.025 for potato and 0.626:0.357:0.017 for sugar beet), should be useful in the modeling of agro-ecosystems that include root crops.


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