Effects of wildfire and topography on soil nitrogen availability in a boreal larch forest of northeastern China

2015 ◽  
Vol 24 (3) ◽  
pp. 433 ◽  
Author(s):  
Jian-jian Kong ◽  
Jian Yang ◽  
Haiyan Chu ◽  
Xingjia Xiang
Keyword(s):  
Soil Nitrogen ◽  
Northeastern China ◽  
Larch Forest ◽  
N Availability ◽  
N Mineralisation ◽  
Soil N ◽  
Inorganic N ◽  
Soil N Availability ◽  
N Supply ◽  
Burned Site

Both topography and wildfire can strongly affect soil nitrogen (N) availability. Although many studies have examined the individual effects of fire and topography on N, few have investigated their combined influences and relative importance. In this study, we measured soil extractable inorganic N concentrations, N mineralisation rates, and in situ soil inorganic N supply rates at 36 plots in three topographic positions (north-facing, south-facing and flat valley bottom) of burned and unburned sites in a boreal larch forest of northeastern China. Our data showed that wildfire significantly increased soil N availability, with mean soil extractable inorganic N concentrations, N mineralisation rates and N supply rates being 63, 310 and 270% higher in the burned site 1 year following fire. Additionally, soil N availability in the unburned site was significantly greater on the north-facing slope than on the south-facing slope, though this pattern was reversed at the burned site. Wildfire and topography together explained ~50% of the variance in soil N availability, with wildfire explaining three times more than topography. Our results demonstrate that wildfire and topography jointly affected spatial variations of soil N availability, and that wildfire decreased the influence of topography in the early successional stage of this boreal larch ecosystem.

scholarly journals Eleven-year results on soft and durum wheat crops grown in an organic and in a conventional low input cropping system

2016 ◽  
Vol 11 (2) ◽  
pp. 77 ◽  
Author(s):  
Paolo Benincasa ◽  
Michela Farneselli ◽  
Giacomo Tosti ◽  
Umberto Bonciarelli ◽  
Maria Chiara Lorenzetti ◽  
...  
Keyword(s):  
Grain Yield ◽  
Durum Wheat ◽  
Dry Matter ◽  
N Availability ◽  
Soil N ◽  
Conventional System ◽  
Green Manures ◽  
Soil N Availability ◽  
Low Input ◽  
N Supply

Eleven-year results on yields and apparent balances of organic matter and nitrogen (N) are reported for soft and durum wheat crops grown in the BIOSYST long-term experiment for the comparison between an organic and a conventional low-input system in Central Italy. The N supply to organic wheat consisted of 40 kg N ha<sup>–1</sup> as poultry manure plus the supposed residual N left by green manures carried out before the preceding summer vegetable, while the N supply to conventional wheat consisted of 80 kg N ha<sup>–1</sup> as mineral fertilisers, split in two applications of 40 kg ha<sup>–1</sup> each, at tillering and pre-shooting. In every year, above ground biomass and N accumulation of each wheat species, including weeds, and the partitioning between grain yield and crop residues were determined. Apparent dry matter and N balances were calculated at the end of each crop cycle by taking into account the amounts of dry matter and N supplied to the system as fertilisers, and those removed with grain yield. Soft wheat yielded more than durum wheat. For both species, grain yield and protein content were more variable across years and generally lower in the organic than in the conventional system. In both systems, grain yield of both species resulted negatively correlated with fall-winter rainfall, likely for its effect on soil N availability. Both species caused a lower return of biomass and a higher soil N depletion in the organic than in the conventional system. Our experiment confirmed that winter wheat can help exploit the soil N availability and reduce N leaching in fall winter, especially after summer vegetables, but in stockless or stock-limited organic systems it needs to be included in rotations where soil fertility is restored by fall winter green manures to be carried out before summer crops.

scholarly journals Development of an Online Tool for Tracking Soil Nitrogen to Improve the Environmental Performance of Maize Production

2021 ◽  
Vol 13 (10) ◽  
pp. 5649
Author(s):  
Giovani Preza-Fontes ◽  
Junming Wang ◽  
Muhammad Umar ◽  
Meilan Qi ◽  
Kamaljit Banger ◽  
...  
Keyword(s):  
Real Time ◽  
N Uptake ◽  
Growing Season ◽  
Weather Data ◽  
N Availability ◽  
Soil N ◽  
N Losses ◽  
Online Tool ◽  
Support Tool ◽  
Soil N Availability

Freshwater nitrogen (N) pollution is a significant sustainability concern in agriculture. In the U.S. Midwest, large precipitation events during winter and spring are a major driver of N losses. Uncertainty about the fate of applied N early in the growing season can prompt farmers to make additional N applications, increasing the risk of environmental N losses. New tools are needed to provide real-time estimates of soil inorganic N status for corn (Zea mays L.) production, especially considering projected increases in precipitation and N losses due to climate change. In this study, we describe the initial stages of developing an online tool for tracking soil N, which included, (i) implementing a network of field trials to monitor changes in soil N concentration during the winter and early growing season, (ii) calibrating and validating a process-based model for soil and crop N cycling, and (iii) developing a user-friendly and publicly available online decision support tool that could potentially assist N fertilizer management. The online tool can estimate real-time soil N availability by simulating corn growth, crop N uptake, soil organic matter mineralization, and N losses from assimilated soil data (from USDA gSSURGO soil database), hourly weather data (from National Weather Service Real-Time Mesoscale Analysis), and user-entered crop management information that is readily available for farmers. The assimilated data have a resolution of 2.5 km. Given limitations in prediction accuracy, however, we acknowledge that further work is needed to improve model performance, which is also critical for enabling adoption by potential users, such as agricultural producers, fertilizer industry, and researchers. We discuss the strengths and limitations of attempting to provide rapid and cost-effective estimates of soil N availability to support in-season N management decisions, specifically related to the need for supplemental N application. If barriers to adoption are overcome to facilitate broader use by farmers, such tools could balance the need for ensuring sufficient soil N supply while decreasing the risk of N losses, and helping increase N use efficiency, reduce pollution, and increase profits.

Nitrous oxide emissions from red clover and winter wheat residues depend on interacting effects of distribution, soil N availability and moisture level

2021 ◽  
Author(s):  
Arezoo Taghizadeh-Toosi ◽  
Baldur Janz ◽  
Rodrigo Labouriau ◽  
Jørgen E. Olesen ◽  
Klaus Butterbach-Bahl ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Winter Wheat ◽  
Red Clover ◽  
Moisture Level ◽  
Nitrous Oxide Emissions ◽  
N Availability ◽  
Soil N ◽  
Soil N Availability

scholarly journals Atmospheric CO 2 , Soil-N Availability, and Allocation of Biomass and Nitrogen by Populus tremuloides

2000 ◽  
Vol 10 (1) ◽  
pp. 34 ◽  
Author(s):  
Donald R. Zak ◽  
Kurt S. Pregitzer ◽  
Peter S. Curtis ◽  
Christoph S. Vogel ◽  
William E. Holmes ◽  
...  
Keyword(s):  
Populus Tremuloides ◽  
N Availability ◽  
Soil N ◽  
Soil N Availability

scholarly journals Effect of Winter Cover Crops on Soil Nitrogen Availability, Corn Yield, and Nitrate Leaching

2001 ◽  
Vol 1 ◽  
pp. 22-29 ◽  
Author(s):  
S. Kuo ◽  
B. Huang ◽  
R. Bembenek
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
N Fertilizer ◽  
N Leaching ◽  
Corn Yield ◽  
N Availability ◽  
Soil N ◽  
Soil N Availability ◽  
N Concentration ◽  
Fertilizer Rates

Biculture of nonlegumes and legumes could serve as cover crops for increasing main crop yield, while reducing NO3leaching. This study, conducted from 1994 to 1999, determined the effect of monocultured cereal rye (Secale cereale L.), annual ryegrass (Lolium multiflorum), and hairy vetch (Vicia villosa), and bicultured rye/vetch and ryegrass/vetch on N availability in soil, corn (Zea mays L.) yield, and NO3-N leaching in a silt loam soil. The field had been in corn and cover crop rotation since 1987. In addition to the cover crop treatments, there were four N fertilizer rates (0, 67, 134, and 201 kg N ha-1, referred to as N0, N1, N2, and N3, respectively) applied to corn. The experiment was a randomized split-block design with three replications for each treatment. Lysimeters were installed in 1987 at 0.75 m below the soil surface for leachate collection for the N0, N2, and N3treatments. The result showed that vetch monoculture had the most influence on soil N availability and corn yield, followed by the bicultures. Rye or ryegrass monoculture had either no effect or an adverse effect on corn yield and soil N availability. Leachate NO3-N concentration was highest where vetch cover crop was planted regardless of N rates, which suggests that N mineralization of vetch N continued well into the fall and winter. Leachate NO3-N concentration increased with increasing N fertilizer rates and exceeded the U.S. Environmental Protection Agency’s drinking water standard of 10 mg N l�1 even at recommended N rate for corn in this region (coastal Pacific Northwest). In comparisons of the average NO3-N concentration during the period of high N leaching, monocultured rye and ryegrass or bicultured rye/vetch and ryegrass/vetch very effectively decreased N leaching in 1998 with dry fall weather. The amount of N available for leaching (determined based on the presidedress nitrate test, the amount of N fertilizer applied, and N uptake) correlated well with average NO3-N during the high N leaching period for vetch cover crop treatment and for the control without the cover crops. The correlation, however, failed for other cover crops largely because of variable effectiveness of the cover crops in reducing NO3leaching during the 5 years of this study. Further research is needed to determine if relay cover crops planted into standing summer crops is a more appropriate approach than fall seeding in this region to gain sufficient growth of the cover crop by fall. Testing with other main crops that have earlier harvest dates than corn is also needed to further validate the effectiveness of the bicultures to increase soil N availability while protecting the water quality.

scholarly journals INTERACTIVE EFFECTS OF ATMOSPHERIC CO2AND SOIL-N AVAILABILITY ON FINE ROOTS OFPOPULUS TREMULOIDES

2000 ◽  
Vol 10 (1) ◽  
pp. 18-33 ◽  
Author(s):  
Kurt S. Pregitzer ◽  
Donald R. Zak ◽  
Jennifer Maziasz ◽  
Jared DeForest ◽  
Peter S. Curtis ◽  
...  
Keyword(s):  
Fine Roots ◽  
Interactive Effects ◽  
N Availability ◽  
Soil N ◽  
Soil N Availability

scholarly journals Carbon Mineralization in a Soil Amended with Sewage Sludge-Derived Biochar

2019 ◽  
Vol 9 (21) ◽  
pp. 4481 ◽  
Author(s):  
Figueiredo ◽  
Coser ◽  
Moreira ◽  
Leão ◽  
Vale ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Co2 Emissions ◽  
Nitrogen Availability ◽  
Carbon Mineralization ◽  
Environmental Benefits ◽  
N Availability ◽  
Soil N ◽  
Total N ◽  
Soil N Availability ◽  
Organic Matter Stabilization

Biochar has been presented as a multifunctional material with short- and long-term agro-environmental benefits, including soil organic matter stabilization, improved nutrient cycling, and increased primary productivity. However, its turnover time, when applied to soil, varies greatly depending on feedstock and pyrolysis temperature. For sewage sludge-derived biochars, which have high N contents, there is still a major uncertainty regarding the influence of pyrolysis temperatures on soil carbon mineralization and its relationship to soil N availability. Sewage sludge and sewage sludge-derived biochars produced at 300 °C (BC300), 400 °C (BC400), and 500 °C (BC500) were added to an Oxisol in a short-term incubation experiment. Carbon mineralization and nitrogen availability (N-NH4+ and N-NO3−) were studied using a first-order model. BC300 and BC400 showed higher soil C mineralization rates and N-NH4+ contents, demonstrating their potential to be used for plant nutrition. Compared to the control, the cumulative C-CO2 emissions increased by 60–64% when biochars BC300 and BC400 were applied to soil. On the other hand, C-CO2 emissions decreased by 6% after the addition of BC500, indicating the predominance of recalcitrant compounds, which results in a lower supply of soil N-NH4+ (83.4 mg kg−1) in BC500, being 67% lower than BC300 (255.7 mg kg−1). Soil N availability was strongly influenced by total N, total C, C/N ratio, H, pore volume, and specific surface area in the biochars.

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