Nitrogen Dynamics Following Incorporation of 3-Year Old Grassland Set-Asides in the Fraser River Delta of British Columbia

Short-term grassland set-asides (GLSA) have been incorporated into intensive annual crop rotations to improve soil quality. The legacy of the GLSA to subsequent annual crops, however, is not well understood. The objective of this study was to determine the impacts of 3-year-old GLSA on nitrogen (N) dynamics and the yield of the subsequent cash crop. A regional analysis was conducted over two years, utilizing eight production fields transitioning from GLSA, paired with fields in continuous annual crop rotation (ACR) with matching management. A controlled plot-scale experiment was also conducted on a single 3-year-old GLSA, comparing fertilizer types, rates, and timing of incorporation. In each experiment, soils were sampled every 10–14 days for ammonium (NH4+-N) and nitrate (NO3−-N), along with ion probes, installed near the rooting zone to track plant available nitrogen (PAN) throughout the season. The results from the regional analysis are confounding, in 2015 showing that GLSA supplied an additional 18 kg PAN ha−1 compared to ACR but showed no PAN benefits in 2016. The controlled plot-scale experiment highlighted the importance of fertilizer type to subsequent PAN, showing synthetic treatments consistently supplied more PAN than organic. The results from this study suggest that 3-year-old GLSAs can potentially improve PAN to subsequent crops depending on how they are managed.

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A Regional Analysis of the Dependency between Registered Unemployment and the Stocks and Flows of Notified Vacancies

Environment and Planning A Economy and Space ◽

10.1068/a100853 ◽

1978 ◽

Vol 10 (7) ◽

pp. 853-866 ◽

Cited By ~ 4

Author(s):

G Hyman ◽

D J Palmer

Keyword(s):

Time Series ◽

Regional Analysis ◽

Leading Indicators ◽

Labour Demand ◽

Short Term ◽

Quarterly Data ◽

Rapid Changes ◽

Duration Of Unemployment ◽

Stocks And Flows ◽

Regional Labour Markets

This paper presents the results of a time-series analysis of short-term changes in the conditions prevailing in regional labour markets. A set of alternative indicators of changes in these conditions are evaluated for each of the standard regions by use of quarterly data for a period that includes the rapid changes in the economy associated with the ‘Barber Boom’. Leading indicators of changes in labour demand are contrasted with lagging indicators and the findings for different regions compared. The results of the analysis show that in general the numbers of vacant jobs and the rates at which the jobs are being filled provide leading indicators of changes in the region's level of unemployment and of changes in the duration of unemployment in the region, and that there is no feedback from unemployment to change the demand for labour in the region. In consequence it would be justified to claim that changes in regional unemployment and its duration are caused by changes in the demand for labour in the region.

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The Reduction of Plant-Available Nitrogen by Cover Crop Mulches and Subsequent Effects on Soybean Performance and Weed Interference

Agronomy Journal ◽

10.2134/agronj2012.0396 ◽

2013 ◽

Vol 105 (2) ◽

pp. 539-545 ◽

Cited By ~ 37

Author(s):

M. S. Wells ◽

S. C. Reberg-Horton ◽

A. N. Smith ◽

J. M. Grossman

Keyword(s):

Cover Crop ◽

Available Nitrogen ◽

Weed Interference ◽

Plant Available Nitrogen

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Potential of Phototrophic Purple Nonsulfur Bacteria to Fix Nitrogen in Rice Fields

Microorganisms ◽

10.3390/microorganisms10010028 ◽

2021 ◽

Vol 10 (1) ◽

pp. 28

Author(s):

Isamu Maeda

Keyword(s):

Nitrogen Fixation ◽

Regulatory Networks ◽

Nitrogenase Activity ◽

Field Studies ◽

Rice Fields ◽

Purple Nonsulfur Bacteria ◽

Available Nitrogen ◽

Nitrogenase Activities ◽

Plant Available Nitrogen ◽

Biological Nitrogen

Biological nitrogen fixation catalyzed by Mo-nitrogenase of symbiotic diazotrophs has attracted interest because its potential to supply plant-available nitrogen offers an alternative way of using chemical fertilizers for sustainable agriculture. Phototrophic purple nonsulfur bacteria (PNSB) diazotrophically grow under light anaerobic conditions and can be isolated from photic and microaerobic zones of rice fields. Therefore, PNSB as asymbiotic diazotrophs contribute to nitrogen fixation in rice fields. An attempt to measure nitrogen in the oxidized surface layer of paddy soil estimates that approximately 6–8 kg N/ha/year might be accumulated by phototrophic microorganisms. Species of PNSB possess one of or both alternative nitrogenases, V-nitrogenase and Fe-nitrogenase, which are found in asymbiotic diazotrophs, in addition to Mo-nitrogenase. The regulatory networks control nitrogenase activity in response to ammonium, molecular oxygen, and light irradiation. Laboratory and field studies have revealed effectiveness of PNSB inoculation to rice cultures on increases of nitrogen gain, plant growth, and/or grain yield. In this review, properties of the nitrogenase isozymes and regulation of nitrogenase activities in PNSB are described, and research challenges and potential of PNSB inoculation to rice cultures are discussed from a viewpoint of their applications as nitrogen biofertilizer.

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Influences of different organic fertilizers on nutrients of humic sandy soil and on the growth of Spinach (Spinacia oleracea L.)

Acta Agraria Debreceniensis ◽

10.34101/actaagrar/70/1812 ◽

2016 ◽

pp. 23-28

Author(s):

Andrea Balláné Kovács ◽

Rita Kremper ◽

Ida Kincses ◽

Ágnes Leviczky

Keyword(s):

Plant Growth ◽

Sandy Soil ◽

Food Waste ◽

Spinacia Oleracea ◽

Cattle Manure ◽

Available Nitrogen ◽

Horse Manure ◽

Spinacia Oleracea L ◽

Plant Available Nitrogen ◽

Food Waste Compost

A greenhouse pot experiment was conducted to compare the effects of manure with different origin (horse, cattle), various bedding materials (straw, sawdust) and diverse doses (30 t ha-1, 60 t ha-1) and the impact of food waste compost on the plant growth and the available plant nutrient content of soil. The study was conducted on humic sandy soil and consisted of 9 treatments in a randomized complete block design with four replications. Spinach (Spinacia oleracea L.) was grown as the test crop. The treatments were: 1. unfertilized control; 2. horse manure with straw (30 t ha-1); 3. horse manure with sawdust (30 t ha-1); 4. cattle manure (30 t ha-1); 5 food waste compost (30 t ha-1); 6. horse manure with straw (60 t ha-1); 7. horse manure with sawdust (60 t ha-1); 8. cattle manure (60 t ha-1); 9. food waste compost (60 t ha-1). Plant growth was monitored for 4 weeks. Shoot and root weights per pot were measured, total biomass weight per pot were counted. On the basis of the results it can be concluded, that among treatments the application of horse manure with straw enhanced spinach growth most significantly compared to other treatments and to the non-treated control, resulted the highest weights of leaves and roots of spinach. At the same time even small dose (30 t ha-1) of this fertilizer caused increased plant available nitrogen and phosphorus of soil and the higher dosage further increased these values. The horse manure with sawdust applied in lower dose did not alter the leaves and roots weights, but higher portion (60 t ha-1) caused significantly decreased plant biomass. The results proved that the bedding material may significantly alter the composition of manure and may change the plant nutrition effect of organic fertilizer. Cattle manure and food waste compost in both applied doses enhanced plant growth. Both fertilizers increased the plant available nitrogen forms and phosphorus content of soil, but cattle manure caused higher increase.

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Vertisols and Cambisols had contrasting short term greenhouse gas responses to crop residue management

Plant Soil and Environment ◽

10.17221/599/2019-pse ◽

2020 ◽

Vol 66 (No. 5) ◽

pp. 222-233 ◽

Cited By ~ 1

Author(s):

Giuseppe Badagliacca ◽

Robert Martin Rees ◽

Dario Giambalvo ◽

Sergio Saia

Keyword(s):

Faba Bean ◽

Crop Residues ◽

Residue Management ◽

Short Term ◽

N Dynamics ◽

Total N ◽

Soil C ◽

Residue Decomposition ◽

Soil C And N ◽

C And N

In sustainable agriculture crop residues management should consider the interactions between soil and residue properties, which can affect the decomposition and global greenhouse gases (GHGs) emission. Through a laboratory experiment, we investigated the effect of the management (incorporation and surface placement) of wheat and faba bean residues on their decomposition and CO2, CH4 and N2O emissions from two soils, a Chromic Vertisol and an Eutric Cambisol. In the Vertisol, wheat residues increased the CO2 emission more than faba bean when left on the surface whereas no differences among residues were observed when incorporated. In the Cambisol, faba bean emitted more than wheat when left in the surface and less when incorporated. Total CH4 emissions were higher in faba bean in Cambisol for both management and only when applied in the surface in Vertisol. Total N2O emission in the Vertisol was higher when faba bean was incorporated, and wheat was left on the surface. In the Cambisol, wheat addition increased total N2O emissions by 20% compared to faba bean, with no differences between managements. Our study confirmed that contrasting properties among tested soils resulted in significant interactions with residues own degradability and their placement affecting residue decomposition, soil C and N dynamics, and GHGs emission.

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Nitrogen release and plant available nitrogen of composted and un‐composted biosolids

Water Environment Research ◽

10.1002/wer.1260 ◽

2020 ◽

Vol 92 (4) ◽

pp. 631-640 ◽

Cited By ~ 1

Author(s):

Olawale Oladeji ◽

Guanglong Tian ◽

Pauline Lindo ◽

Kuldip Kumar ◽

Albert Cox ◽

...

Keyword(s):

Nitrogen Release ◽

Available Nitrogen ◽

Plant Available Nitrogen

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Water use, competition, and crop production in low rainfall, alley farming systems of south-eastern Australia

Australian Journal of Agricultural Research ◽

10.1071/ar03049 ◽

2003 ◽

Vol 54 (8) ◽

pp. 751 ◽

Cited By ~ 17

Author(s):

Murray Unkovich ◽

Kerrin Blott ◽

Alex Knight ◽

Ivan Mock ◽

Abdur Rab ◽

...

Keyword(s):

Soil Water ◽

Water Use ◽

Crop Yield ◽

Farming Systems ◽

Alley Farming ◽

Annual Crop ◽

South Eastern ◽

Annual Crops ◽

Eastern Australia ◽

Perennial Shrubs

Annual crops were grown in alleys between belts of perennial shrubs or trees over 3–4 years at 3 sites across low rainfall (<450 mm) south-eastern Australia. At the two lower rainfall sites (Pallamana and Walpeup), crop grain yields within 2–5 m of shrub belts declined significantly with time, with a reduction equivalent to 45% over 9 m in the final year of cropping. At the third, wetter site (Bridgewater), the reduction in crop grain yields adjacent to tree belts was not significant until the final year of the study (12% over 11 m) when the tree growth rates had increased. The reductions in crop yield were associated with increased competition for water between the shrub or tree belts and the crops once the soil profile immediately below the perennials had dried. At all 3 sites during the establishment year, estimates of water use under the woody perennials were less than under annual crops, but after this, trends in estimates of water use of alley farming systems varied between sites. At Pallamana the perennial shrubs used a large amount of stored soil water in the second summer after establishment, and subsequently were predominantly dependent on rainfall plus what they could scavenge from beneath the adjacent crop. After the establishment year at the Walpeup site, water use under the perennial shrubs was initially 67 mm greater than under the annual crop, declining to be only 24 mm greater in the final year. Under the trees at Bridgewater, water use consistently increased to be 243 mm greater than under the adjacent annual crop by the final year. Although the shrub belts used more water than adjacent crop systems at Walpeup and Pallamana, this was mostly due to the use of stored soil water, and since the belts occupied only 7–18% of the land area, increases in total water use of these alley farming systems compared with conventional crop monocultures were quite small, and in terms of the extent of recharge control this was less than the area of crop yield loss. At the wetter, Bridgewater site, alley farming appeared to be using an increasing amount of water compared with conventional annual cropping systems. Overall, the data support previous work that indicates that in lower rainfall environments (<350 mm), alley farming is likely to be dogged by competition for water between crops and perennials.

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Soil nitrous oxide emissions associated with conversion of forage grass to annual crop receiving annual application of pig manure

Canadian Journal of Soil Science ◽

10.1139/cjss-2018-0134 ◽

2019 ◽

Vol 99 (4) ◽

pp. 420-433

Author(s):

Mayowa Adelekun ◽

Olalekan Akinremi ◽

Mario Tenuta ◽

Paligwendé Nikièma

Keyword(s):

Nitrous Oxide ◽

Perennial Grass ◽

Perennial Grasses ◽

Nitrous Oxide Emissions ◽

Environmental Drivers ◽

Pig Manure ◽

Forage Grass ◽

Annual Crop ◽

Annual Crops ◽

Change Mitigation

The disruptive land-use change during forage grass conversion to annual crop can be critical for determining nitrous oxide (N2O) emissions, but this is an understudied period. We measured soil N2O fluxes (using closed static vented chambers) together with potential environmental drivers of these fluxes from liquid pig manure (LPM) and solid pig manure (SPM) applied to an annual crop (ANN) and perennial forages (FPP) that was converted to annual crop. Unamended plots were used as a control (CON). The results showed that in 2013, average soil nitrate-N was significantly higher on the recently converted FPP (ranging from 19 to 83 mg N kg−1) than the continuous ANN plots (from 16 to 35 mg N kg−1). The recently converted perennial forage system produced three times greater N2O than the continuous annual system, which is likely a result of accelerated N mineralization from the accumulated soil organic matter (over 4 yr) and grass residues of the recently killed forage grasses. However, during the second year of the study when the FPP plots were reseeded to perennial grasses, the system emitted 30% less N2O than the ANN system. These results suggest that including perennial forage grass in rotation with annual crops can provide N-saving and climate change mitigation benefits; however, some of the N stored in the soil would be lost when the perennial grass plots are cultivated to grow annual crops.

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