scholarly journals Use of the agricultural practice of pasture termination in reducing soil N2O emissions in high-rainfall cropping systems of south-eastern Australia

Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 585 ◽  
Author(s):  
Oxana N. Belyaeva ◽  
Sally J. Officer ◽  
Roger D. Armstrong ◽  
Rob H. Harris ◽  
Ashley Wallace ◽  
...  
Keyword(s):  
Cropping Systems ◽  
Pore Space ◽  
N2o Emission ◽  
First Year ◽  
N2o Emissions ◽  
Agricultural Practice ◽  
Fallow Period ◽  
High Rainfall ◽  
Eastern Australia ◽  
Second Year

Conversion of long-term pasture to cropping was investigated for its effects on nitrous oxide (N2O) emissions in a 2-year field experiment in the high-rainfall zone of south-western Victoria. Early termination (pasture terminated 6 months before sowing) followed by winter (ETw) and spring (ETs) crops and late termination (pasture terminated 1 month before sowing) followed by a winter crop (LTw) were compared with continuous, mown pasture (MP). Emissions of N2O were measured with an automated gas sampling and analysing system. Emissions from MP were the lowest throughout the study, resulting in annual losses of 0.13kg N2O-N ha–1 in the first and the second years of the experiment. N2O-N loss was 0.6kgha–1 from treatments without fallow in both years (LTw in 2013 and ETs in 2014). In the first year, annual losses from previous fallow in ETw and ETs plots were 7.1 and 3.6kg N2O-N ha–1, respectively. Higher annual N2O losses from treatments with fallow periods continued in the second year of the study and were 2.0 and 1.3kg N2O-N ha–1 from ETw and LTw treatments, respectively. High emissions were associated with N mineralisation and the accumulation of NO3-N in the soil during the extensive fallow period after early pasture termination or wheat harvest. Soil water content was a key factor influencing the temporal fluctuations in N2O emissions. Low emissions occurred when water-filled pore space was <30%, whereas high emissions occurred when it was >65%, suggesting that denitrification was the major source of N2O emission. Crop grain yield was not affected by the duration of fallow (and therefore timing of pasture termination) in the first year, but was lower (P<0.05) in the treatment without fallow in the second year. Terminating pasture late rather than early, thus reducing the length of the fallow period, is a practical way of reducing N2O emissions from mixed pasture–cropping systems.

Ecological segregation in a subterranean reptile assemblage in arid Australia

1989 ◽  
Vol 10 (3) ◽  
pp. 277-295 ◽  
Author(s):  
Klaus Henle
Keyword(s):  
National Park ◽  
Reproductive Effort ◽  
Arid Zone ◽  
Daily Maximum ◽  
First Year ◽  
Lizard Species ◽  
Eastern Australia ◽  
Food Size ◽  
Late Maturity ◽  
Second Year

AbstractThe organisation of the subterranean component of an arid zone reptile community was studies in Kinchega National Park (Eastern Australia) from September 1985 to May 1987. Three species of fossorial or semifossorial lizards and two species of snakes were found in Kinchega. All species were habitat generalists, but microhabitat, food size and food taxon clearly separated them. All species were primarily nocturnal although Lerista xanthura was occasionally active during the day. All three lizard species were active from September to May. Activity of Eremiascincus richardsonii and L. xanthura were significantly correlated with monthly mean daily maximum and minimum temperatures. The optimum temperature of L. punctatovittata was 28.8 °C in daytime retreats. Biomass ranged from 505-900 g/ha in E. richardsonii and from 968-1152 g/ha in L. punctatovittata. All three lizard species produced only one clutch per year. L. punctatovittata and E. richardsonii reached sexual maturity at the end of their second year, L. xanthura matured in its first year. The data show that subterranean lizard guilds have a different structure than diurnal and non-fossorial noctunal lizard assemblies. The data also indicate a correlation of late maturity and low reproductive effort in fossorial lizards.

scholarly journals Impacts of Nitrogen Addition on Nitrous Oxide Emission: Model-Data Comparison

2018 ◽  
Author(s):  
Yujin Zhang ◽  
Minna Ma ◽  
Huajun Fang ◽  
Dahe Qin ◽  
Shulan Cheng ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Global Climate ◽  
Pore Space ◽  
Terrestrial Ecosystem ◽  
N2o Emission ◽  
N Deposition ◽  
N2o Emissions ◽  
Emission Model ◽  
N Addition ◽  
N2o Production

Abstract. The contributions of long-lived nitrous oxide (N2O) to the global climate and environment have received increasing attention. Especially, atmospheric nitrogen (N) deposition has substantially increased in recent decades due to extensive use of fossil fuels in industry, which strongly stimulates the N2O emissions of the terrestrial ecosystem. Several models have been developed to simulate N2O emission, but there are still large differences in their N2O emission simulations and responses to atmospheric deposition over global or regional scales. Using observations from N addition experiments in a subtropical forest, this study compared six widely-used N2O models (i.e. DayCENT, DLEM, DNDC, DyN, NOE, and NGAS) to investigate their performances for reproducing N2O emission, and especially the impacts of two types of N additions (i.e. ammonium and nitrate: NH4+ and NO3−, respectively) and two levels (low and high) on N2O emission. In general, the six models reproduced the seasonal variations of N2O emission, but failed to reproduce relatively larger N2O emissions due to NH4+ compared to NO3− additions. Few models indicated larger N2O emission under high N addition levels for both NH4+ and NO3−. Moreover, there were substantial model differences for simulating the ratios of N2O emission from nitrification and denitrification processes due to disagreements in model structures and algorithms. This analysis highlights the need to improve representation of N2O production and diffusion, and the control of soil water-filled pore space on these processes in order to simulate the impacts of N deposition on N2O emission.

scholarly journals Modeling the emergence of North African knapweed (Centaurea diluta), an increasingly troublesome weed in Spain

Weed Science ◽  
2020 ◽  
Vol 68 (3) ◽  
pp. 268-277 ◽  
Author(s):  
Carlos Sousa-Ortega ◽  
Aritz Royo-Esnal ◽  
Antonio DiTommaso ◽  
Jordi Izquierdo ◽  
Iñigo Loureiro ◽  
...  
Keyword(s):  
Cropping Systems ◽  
Seedling Emergence ◽  
Management Strategies ◽  
First Year ◽  
Weibull Function ◽  
Limited Information ◽  
North African ◽  
High Predictability ◽  
Second Year ◽  
Base Water Potential

AbstractNorth African knapweed (Centaurea diluta Aiton) is an annual weed that is widespread in southern Spain and is of increasing concern in dryland cropping systems. Despite its expanding range in Spain, there is limited information on the emergence timing and pattern of this species, knowledge of which is critical for developing more timely and effective management strategies. Therefore, there is a need to develop simple and reliable models to predict the timing and emergence of this annual weed under dryland conditions. A multi-location field experiment was established across Spain in 2016 to 2017 to assess the emergence of C. diluta. At each of 11 locations, seeds were sown in the fall, and emergence was recorded. Overall emergence averaged 39% in the first year across all sites and 11% in the second year. In both years, the main emergence flush occurred at the beginning of the growing season. A three-parameter Weibull function best described seedling emergence of C. diluta. Emergence models were developed based on thermal time (TT) and hydrothermal time (HTT) and showed high predictability, as evidenced by root mean-square error prediction values of 10.8 and 10.7, respectively. Three cardinal points were established for TT and HHT at 0.5, 10, and 35 C for base, optimal, and ceiling temperatures, respectively, while base water potential was estimated at −0.5 MPa.

Seedbanks and seedling emergence of saffron thistle (Carthamus lanatus) in eastern Australian pastures

2002 ◽  
Vol 53 (12) ◽  
pp. 1327 ◽  
Author(s):  
B. S. Grace ◽  
A. W. Sheppard ◽  
R. D. B. Whalley ◽  
B. M. Sindel
Keyword(s):  
Weed Management ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
First Year ◽  
Seed Loss ◽  
Eastern Australia ◽  
Mesh Bags ◽  
Second Year ◽  
Number Of Seeds ◽  
Over Time

Weed management has often proved difficult because of persistent seedbanks that allow recruitment to occur for many years after the weed has otherwise been controlled. The number of seeds in seedbanks of Carthamus lanatus, a widespread and troublesome weed, has not been investigated. Little is known about longevity of its seedbanks in pastures of eastern Australia.The numbers of seeds in the soil and the rate of seed loss were investigated at 3 sites in eastern Australia. Seedbanks were found to be patchy, and they had mean densities between 815 and 2290 seeds/m2 after the main germination flush. These seedbanks decreased over time and between 11 and 15% of seeds remained in the soil after 2 years without further input. More seeds were lost in the first year than in the second year, and pasture cover did not affect the rate of seed loss.Seeds buried in mesh bags and exhumed regularly showed that dormancy was lost, induced, then lost again within the 2-year experiment. Maximum seed germinability coincided with peak germination times. The likelihood of a seed producing a seedling was reduced when seeds were sown at high density. C. lanatus seeds appear to be well adapted for persistence in eastern Australian pastures by maintaining a bank of seeds that generally germinate when conditions favour seedling survival.

scholarly journals Tillage does not increase nitrous oxide emissions under dryland canola (Brassica napus L.) in a semiarid environment of south-eastern Australia

Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 512 ◽  
Author(s):  
Guangdi D. Li ◽  
Mark K. Conyers ◽  
Graeme D. Schwenke ◽  
Richard C. Hayes ◽  
De Li Liu ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Brassica Napus ◽  
N2o Emission ◽  
Nitrous Oxide Emissions ◽  
Annual Rainfall ◽  
N2o Emissions ◽  
Brassica Napus L ◽  
South Eastern ◽  
Eastern Australia ◽  
South Eastern Australia

Dryland cereal production systems of south-eastern Australia require viable options for reducing nitrous oxide (N2O) emissions without compromising productivity and profitability. A 4-year rotational experiment with wheat (Triticum aestivum L.)–canola (Brassica napus L.)–grain legumes–wheat in sequence was established at Wagga Wagga, NSW, Australia, in a semiarid Mediterranean-type environment where long-term average annual rainfall is 541mm and the incidence of summer rainfall is episodic and unreliable. The objectives of the experiment were to investigate whether (i) tillage increases N2O emissions and (ii) nitrogen (N) application can improve productivity without increasing N2O emissions. The base experimental design for each crop phase was a split-plot design with tillage treatment (tilled versus no-till) as the whole plot, and N fertiliser rate (0, 25, 50 and 100kgN/ha) as the subplot, replicated three times. This paper reports high resolution N2O emission data under a canola crop. The daily N2O emission rate averaged 0.55g N2O-N/ha.day, ranging between –0.81 and 6.71g N2O-N/ha.day. The annual cumulative N2O-N emitted was 175.6 and 224.3g N2O-N/ha under 0 and 100kgN/ha treatments respectively. There was no evidence to support the first hypothesis that tillage increases N2O emissions, a result which may give farmers more confidence to use tillage strategically to manage weeds and diseases where necessary. However, increasing N fertiliser rate tended to increase N2O emissions, but did not increase crop production at this site.

Does 3,4-dimethylpyrazole phosphate or N-(n-butyl) thiophosphoric triamide reduce nitrous oxide emissions from a rain-fed cropping system?

Soil Research ◽  
2018 ◽  
Vol 56 (3) ◽  
pp. 296 ◽  
Author(s):  
Guangdi D. Li ◽  
Graeme D. Schwenke ◽  
Richard C. Hayes ◽  
Hongtao Xing ◽  
Adam J. Lowrie ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Grain Yield ◽  
Crop Yields ◽  
Cropping System ◽  
N2o Emission ◽  
Nitrous Oxide Emissions ◽  
Wheat Crop ◽  
N2o Emissions ◽  
Urease Inhibitors ◽  
Eastern Australia

Nitrification and urease inhibitors have been used to reduce nitrous oxide (N2O) emissions and increase nitrogen use efficiency in many agricultural systems. However, their agronomic benefits, such as the improvement of grain yield, is uncertain. A two-year field experiment was conducted to (1) investigate whether the use of 3,4-dimethylpyrazole phosphate (DMPP) or N-(n-butyl) thiophosphoric triamide (NBPT) can reduce N2O emissions and increase grain yield and (2) explore the financial benefit of using DMPP or NBPT in a rain-fed cropping system in south-eastern Australia. The experiment was conducted at Wagga Wagga, New South Wales, Australia with wheat (Triticum aestivum L.) in 2012 and canola (Brassica napus L.) in 2013. Results showed that urea coated with DMPP reduced the cumulative N2O emission by 34% for a wheat crop in 2012 (P < 0.05) and by 62% for a canola crop in 2013 (P < 0.05) compared with normal urea, but urea coated NBPT had no effect on N2O emission for the wheat crop in 2012. Neither nitrification nor urease inhibitors increased crop yields because the low rainfall experienced led to little potential for gross N loss through denitrification, leaching or volatilisation pathways. In such dry years, only government or other financial incentives for N2O mitigation would make the use of DMPP with applied N economically viable.

scholarly journals Effects of genetically modified herbicide-tolerant cropping systems on weed seedbanks in two years of following crops

2005 ◽  
Vol 2 (1) ◽  
pp. 140-143 ◽  
Author(s):  
L.G Firbank ◽  
P Rothery ◽  
M.J May ◽  
S.J Clark ◽  
R.J Scott ◽  
...  
Keyword(s):  
Oilseed Rape ◽  
Cropping Systems ◽  
Genetically Modified ◽  
First Year ◽  
Medium Term ◽  
Farmland Biodiversity ◽  
Winter Oilseed Rape ◽  
Herbicide Tolerant ◽  
Farm Scale ◽  
Second Year

The Farm Scale Evaluations (FSEs) showed that genetically modified herbicide-tolerant (GMHT) cropping systems could influence farmland biodiversity because of their effects on weed biomass and seed production. Recently published results for winter oilseed rape showed that a switch to GMHT crops significantly affected weed seedbanks for at least 2 years after the crops were sown, potentially causing longer-term effects on other taxa. Here, we seek evidence for similar medium-term effects on weed seedbanks following spring-sown GMHT crops, using newly available data from the FSEs. Weed seedbanks following GMHT maize were significantly higher than following conventional varieties for both the first and second years, while by contrast, seedbanks following GMHT spring oilseed rape were significantly lower over this period. Seedbanks following GMHT beet were smaller than following conventional crops in the first year after the crops had been sown, but this difference was much reduced by the second year for reasons that are not clear. These new data provide important empirical evidence for longer-term effects of GMHT cropping on farmland biodiversity.

Can nitrogen fertiliser and nitrification inhibitor management influence N2O losses from high rainfall cropping systems in South Eastern Australia?

2013 ◽  
Vol 95 (2) ◽  
pp. 269-285 ◽  
Author(s):  
Robert H. Harris ◽  
Sally J. Officer ◽  
Patricia A. Hill ◽  
Roger D. Armstrong ◽  
Kirsten M. Fogarty ◽  
...  
Keyword(s):  
Cropping Systems ◽  
Nitrification Inhibitor ◽  
Nitrogen Fertiliser ◽  
High Rainfall ◽  
South Eastern ◽  
Eastern Australia ◽  
South Eastern Australia

scholarly journals Effect of Biochar on Soil Greenhouse Gas Emissions at the Laboratory and Field Scales

Soil Systems ◽  
2019 ◽  
Vol 3 (1) ◽  
pp. 8 ◽  
Author(s):  
Rivka Fidel ◽  
David Laird ◽  
Timothy Parkin
Keyword(s):  
Field Study ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Cropping Systems ◽  
Cropping System ◽  
N2o Emission ◽  
N2o Emissions ◽  
Gas Emissions ◽  
Continuous Corn ◽  
The Impact

Biochar application to soil has been proposed as a means for reducing soil greenhouse gas emissions and mitigating climate change. The effects, however, of interactions between biochar, moisture and temperature on soil CO2 and N2O emissions, remain poorly understood. Furthermore, the applicability of lab-scale observations to field conditions in diverse agroecosystems remains uncertain. Here we investigate the impact of a mixed wood gasification biochar on CO2 and N2O emissions from loess-derived soils using: (1) controlled laboratory incubations at three moisture (27, 31 and 35%) and three temperature (10, 20 and 30 °C) levels and (2) a field study with four cropping systems (continuous corn, switchgrass, low diversity grass mix and high diversity grass-forb mix). Biochar reduced N2O emissions under specific temperatures and moistures in the laboratory and in the continuous corn cropping system in the field. However, the effect of biochar on N2O emissions was only significant in the field and no effect on cumulative CO2 emissions was observed. Cropping system also had a significant effect in the field study, with soils in grass and grass-forb cropping systems emitting more CO2 and less N2O than corn cropping systems. Observed biochar effects were consistent with previous studies showing that biochar amendments can reduce soil N2O emissions under specific but not all, conditions. The disparity in N2O emission responses at the lab and field scales suggests that laboratory incubation experiments may not reliably predict the impact of biochar at the field scale.

Survival and seasonal germination of seeds of Avena fatua and A. ludoviciana

1968 ◽  
Vol 19 (5) ◽  
pp. 721 ◽  
Author(s):  
PH Quail ◽  
OG Carter
Keyword(s):  
Soil Type ◽  
Dominant Species ◽  
First Year ◽  
Moisture Regime ◽  
Seed Type ◽  
Wild Oats ◽  
Eastern Australia ◽  
Buried Seed ◽  
Second Year ◽  
Better Than

The effects of soil type, temperature, and moisture on the survival and seasonal germination of seeds of A. fatua and A. ludoviciana, buried at five depths in the soil, were studied in a glasshouse experiment. Seeds of both species germinated only when mean weekly minimum temperatures were below 20°C and mean weekly maxima below 28°. A. fatua germinated better than A. ludoviciana in the 20–30° range and was therefore the dominant species in autumn germinations of wild oats. Both species germinated throughout winter. Only 30% of the seeds sown produced seedlings. Of these 90% emerged in the first year after seeding and the remainder in the second year. Only 2% of the seeds sown remained viable after 18 months. The depth at which the seeds were buried, seed type, soil type. and moisture regime all affected the survival of seeds and the percentage that produced seedlings. An explanation is offered for the dominance of A. ludoviciana in the northern wheat-belt of eastern Australia.

Sign in / Sign up

Export Citation Format

Share Document