Archive for the category: Display Poster

Hoang Thi Thai Hoa¹, Tran Thi Anh Tuyet¹, Do Dinh Thuc¹, Surender Mann², Richard Bell²

¹ Hue University- Hue College of Agriculture and Forestry, 102 Phung Hung street, Hue city, Thua Thien Hue province, Vietnam, 530000, http://www.huaf.edu.vn, hoangthithaihoa@huaf.edu.vn

² School of Veterinary and Life Sciences, Murdoch University, Murdoch WA 6150 Australia

Abstract

Sandy soils of Central Vietnam represent an important soil order that increasingly contributes to regional economic growth. However these soils have generally low productivity because of chemical and physical constraints associated with low pH values and sand contents exceeding 70%, are common for those soils. Obviously, organic matter management represents a key factor for crop productivity improvement on these soils. However, before considering the possible contributions of various organic amendments, it is important to evaluate the actual contribution of the initial soil organic matter through its N-mineralization, considered as a prime source of N for plants. Therefore, soil samples (0-20 cm) representing peanut growing sandy soils were collected before the spring season to incubate with 4 types of organic materials which added to the same sandy soil amount under anaerobic conditions for 0, 5, 10, 20, 30 and 40 days to determine their N-mineralization capacity. The release of NH₄⁺, NO₃^– was on average higher in treatments with added organic fertilizers. Significant amounts of NH₄⁺ and NO₃^– were found with different types of organic materials added to the soil and increased with the time of incubation from 5 to 40 days after incubation. Fitting the results with a first order kinetic equation led to the calculation of potentially mineralizable nitrogen. The N-pool identified in this study can be considered as very labile N which might be available to crops within few weeks. Therefore, the total N-content of soils cannot be considered as a reliable indicator of short term N-availability.

Kuroda Hisao¹, Lin Xiaolan², Kitamura Tatsumi³, Oouchi Takao³ and Sugaya Kazuhisa³

¹ College of Agriculture, Ibaraki University, 3-21-1, Chuuo, Ami-town, Inashiki, Ibaraki, 300-0393, Japan, http://www.agr.ibaraki.ac.jp/, hisao.kuroda.agr@vc.ibaraki.ac.jp

² United Graduate School of Agricultural Science Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-city, Tokyo 183-8509, Japan

³ Ibaraki Kasumigaura Environmental Science Center, 1853 Okijyuku Tsuchiura-city Ibaraki 300-0023, Japan.

Abstract

Lake Kasumigaura is the second largest lake in Japan and it is eutrophic. Nutrient loads from agriculture and livestock waste have been identified as a possible cause. Of particular concern are increasing nitrogen concentrations in the Hokota River, where pig farming is a major enterprise. The Japanese government has been advocating conservation measures such as a reduction in the use of chemical fertilizers and synthetic pesticides. As a result, organic forms of nutrients were believed to be good for the environment and less harmful than chemical fertilizers.  However, incorrect application of nutrients in any form may contribute to nitrogen pollution. We propose that increasing nitrogen concentrations in Hokota River results from excessive application of swine manure to upland fields, as there has not been an increase in the amount of mineral fertiliser applied. Similarly, increases in nitrogen concentration were observed in spring water (from ground water to surface water) below an upland field that received a large application of horse manure.

In addition, soil core results from an upland field receiving nitrogen inputs for 30 years and subsequently drained in 2011 showed slow movement of residual soil nitrogen from the profile.  As a result, residues of nitrogen remain in the soil from historical nitrogen inputs. Nitrogen leaching from the upper portion from rainfall during the last few years was evident, but slow. These results suggest that there was long-term nitrogen leaching potential due to the influence of the accumulated nitrogen. As a result, it was concluded: 1)  Livestock waste or organic fertilizer is a likely significant contributor to nitrogen pollution. 2) Nitrogen water quality signatures lag behind the application of organic nitrogen (manure). 3) the infiltration of nitrogen from the soil in upland fields is driven by rainfall.

Keryn Roberts¹, Md Moklesur Rahman², Wei Wen Wong², Perran Cook², Michael Grace²

¹ Water Studies Centre, Monash University, Wellington, Clayton, Victoria, 3800, Australia, roberts.keryn@gmail.com

² Water Studies Centre, Monash University, Wellington, Clayton, Victoria, 3800, Australia

Abstract

The increased pressure of anthropogenic nitrogen inputs on our waterways has increased the importance of nitrogen management strategies such as constructed wetlands. Several studies have assessed the effectiveness of wetland operation by examining wetland components in the design process, however, long term management of operational wetlands is often reliant on monitoring only nutrient concentrations. Stable isotopes of nitrogen can be a useful tool in investigating nitrogen processing and are often applied to detailed mechanistic studies but rarely utilised in ongoing monitoring strategies. Here we present a conceptual model for two stable isotope approaches, one quantitative and one qualitative, to assess their feasibility as management tools to improve our current understanding of nitrogen removal over the lifetime of a constructed wetland system. The first approach is the direct measurement of NO₃^– reduction pathways (denitrification) to assess nitrogen removal whilst the second approach uses the dual isotopic composition (δ¹⁵N and δ¹⁸O) of NO₃^– at the natural abundance level in the surface water to qualitatively assess denitrification and assimilation. We propose the natural abundance stable isotope approach, with further research, would complement current monitoring programs providing further information on the behaviour of nitrogen in wetlands.

Tetsuto Sugai*, Kazuhito Kita***, Toshihiro Watanabe** and Takayoshi Koike*

* Silviculture and Forest Ecological Studies, Hokkaido University, Sapporo 060-8589, Japan

** Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan

***Hokkaido Forestry Research Institute, Bibai 079-0198, Japan

Wenxu Dong¹, Yuying Wang¹, Xiaoxin Li¹, Chunsheng Hu¹

¹ Key Laboratory of Agricultural Water Resources, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021, China.  E-mail: dongwx@sjziam.ac.cn

Abstract

Soil inorganic carbon (SIC) exerts a strong influence on the carbon (C) sequestered in response to nitrogen (N) additions in arid and semi-arid ecosystems, but limited information is available on in situ SIC storage at the field level. This study determined the soil organic/inorganic carbon storage in the soil profile at 0–100 cm depths in 4 N application treatments (0, 200, 400, and 600 kg N ha^-1 y^-1) for 15 years in the North China Plain. Results showed that after 15 years of N fertilizer application the SOC contents at depths of 0-100 cm significantly increased, whereas the SIC contents significantly decreased at depths of 0-60 cm. However, the actual measured loss of carbonate was far higher than the theoretical maximum values of dissolution via protons from nitrification. Furthermore, the amount of HCO₃^– and the HCO₃^–/ (Ca²⁺ + Mg²⁺) ratio in soil leachate were higher in the N application treatments than no fertilizer input (CK) for the 0-80 cm depth. The result suggested that the dissolution of carbonate was mainly enhanced by soil carbonic acid, a process which can absorb soil or atmosphere CO₂ and less influenced by protons through the nitrification which would release CO₂.

Jason Lynch, Clara Funk and Richard Haeuber

U.S. Environmental Protection Agency, 1200 Pennsylvania Ave. NW, Washington, DC, 20006, www.epa.gov/airmarkets, Haeuber.richard@epa.gov

Abstract

Data from several monitoring programs are examined to assess the effectiveness and environmental benefit of air pollution reduction programs in the United States (U.S.).  Integrated assessment of monitoring data demonstrates that reductions of nitrogen compound emissions, such as NO_x, and byproducts like ozone lead to improved air quality and forest ecosystem health.  Three important environmental monitoring programs were used to evaluate the impact of emission reductions and improved ozone concentrations on forest health.  Assessing the impact of ground-level ozone on forests in the eastern U.S. involves understanding the risk to tree species from ambient ozone concentrations and accounting for the prevalence of those species within the forest. As a way to quantify the risk to particular trees, scientists have developed concentration-response (C-R) functions that relate ozone exposure to tree response.  In 2014, regulated pollution sources reduced NO_x emissions by 4.7 million tons (73%) from 1990 levels.  Based on regional data from CASTNET from 2000 through 2014, annual mean ambient nitrate concentration (an ambient pollutant resulting from NO_X emissions) declined 48% from 3.1 ppb to 1.6 ppb in the eastern U.S. Rural ozone concentrations, calculated as DM8A, were found to decrease from 84 ppb to 66 ppb (22%) from 2000-2002 and 2012-14 in the eastern U.S.  Comparing data from the start of the NO_X Budget Trading Program (2000-2002) to 2007-2009, we found that the total land area in the Eastern U.S. with significant biomass loss decreased substantially for all sensitive tree species as NO_x emissions and concentrations of ambient nitrogen compounds have declined over this time period.

Atsushi Hayakawa, Yu Funaki, Tatsuya Sudo, Ryoki Asano, Shintaro Watanabe, Yuichi Ishikawa, Shin Hidaka

Department of Biological Environment, Faculty of Bioresource Science, Akita Prefectural University, Akita, 010-0195, Japan, hayakawa@akita-pu.ac.jp

Abstract

We examined the linkages between topography and electron donors for denitrification in headwater streams in the Lake Hachiro watershed that has marine sedimentary rocks. In 33 headwater streams, we sampled water at the catchment nine times in 2 years. Stream sediment was sampled once for measurement of denitrification potential (DP), water-extractable soil organic carbon (WESOC), and easily oxidizable sulfide (EOS), which are considered the principal potential electron donors for denitrification. The topographical features of each catchment were calculated using a digital elevation model with 10-m grid cells. Stream NO₃^– concentrations displayed large spatial variation among catchments, ranging from 0.06 to 0.52 mg N L^–1, and were significantly positively correlated with slope in the catchments (r = 0.663, P < 0.01, n = 33), indicating that NO₃^– was removed to a greater extent in gentle slope catchments. Generalized linear model showed slope, slope aspect, sediment DP, and EOS significantly affected in-stream NO₃^– concentration. Stream SO₄^2– concentrations tended to increase as NO₃^– concentrations decreased and EOS contents increased, indirectly indicating sulfur-mediated denitrification. NO₃^– reduction with SO₄^2– production, and sulfur-oxidizing bacteria was detected in the stream bank soil with high EOS content. We conclude that catchment topography and the distribution of electron donors in riverbed sediment explain the spatial variation in in-stream NO₃^– concentration and, by inference, catchment denitrification. These results indicate that more NO₃^– may be denitrified by sulfur-mediated denitrification owing to the abundance of sulfides in the catchment from marine sedimentary rocks.

Cathryn O’Sullivan¹, Jairo Palta ¹, Mark Farrell², Karen Treble¹.

¹ CSIRO Agriculture, 147 Underwood Ave, Floreat, WA, 6014, http://www.csiro.au/en/Research/AF, c.osullivan@csiro.au

² CSIRO Agriculture, Waite Road, Urrbrae SA 5064, http://www.csiro.au/en/Research/AF, m.farrell@csiro.au

Abstract

Improving the nitrogen (N) uptake efficiency (NUpE) of wheat has the potential to offer significant economic gains to growers and improvement in environmental quality. One way to improve NUpE may be by matching wheat genotypes which have greater uptake efficiency for NH₄⁺ or NO₃^– to soil types that favour the production of one of these N forms over the other. Surprisingly there has been little previous research investigating the genotypic variation in wheat for preference of different forms of N. The aim of this study was to screen a range of wheat cultivars and landraces for their ability to uptake N and produce biomass on NH₄⁺, NO₃^– and a mixture of NH₄NO₃. To date, 21 wheat genotypes have been grown hydroponically on three different nutrient solutions providing N as NH₄⁺, NO₃^– or NH₄NO₃. The nutrient solutions were all supplemented with a nitrification inhibitor, well aerated and pH controlled. At 8 weeks after sowing (post-tillering for all lines) the shoots were harvested and leaf area, shoot biomass and N content measured.

There is significant variation among the genotypes tested in their ability to uptake N and produce biomass on different N sources. Several cultivars, including Frame and Gamenya, produced more biomass with higher N content on NO₃-. Others, including Yitpi and Wyalkatchem performed best on NH₄⁺ while others, including Halberd and Condor, performed better on NH₄NO₃ than on either NO₃^– or NH₄⁺. This information is critical for further research to determine whether it is possible to improve NUpE by targeting genotypes with differing N preferences to soil types where a particular N form is likely to occur.

Zisheng Xing^1,2, Bernie. J. Zebarth¹, Sheng Li^1,2*, Fanrui Meng², Herb. W. Rees¹, Noura Ziadi³, and Lien Chow¹

¹ Fredericton Research and Development Centre, Agriculture and Agri-Food Canada, PO Box 20280, 850 Lincoln Road, Fredericton, New Brunswick, Canada E3B 4Z7,*Corresponding Author: Sheng.Li@agr.gc.ca

² Faculty of Forestry & Environmental Management, University of New Brunswick, Fredericton, New Brunswick, Canada E3B

³ Quebec Research and Development Centre, Agriculture and Agri-Food Canada,  2560 Blvd. Hochelaga, Québec QC G1V 2J3, Canada, presenter: Noura.Ziadi@agr.gc.ca / Tel: 418-210-5052 / TTY:  613-773-2600

Abstract

A 2-year field trial with a randomized complete block design with four replications was conducted in New Brunswick, Canada to evaluate N fertilization effects on potato (Solanum tuberosum L.) tuber yields and quality as well as soil nitrate leaching. Eight N fertilizer treatments were examined, including three N sources (i.e. conventional, controlled-release and organic fertilizers) at two application rates (100 and 200 kg N ha^-1),  a split application of conventional fertilizer at the high rate and a zero N fertilizer input as control. Application of N-fertilizer significantly increased tuber yield (by 76% maximum) and quality over the unfertilized treatments whereas differences between the two N fertilizer application rates were non-significant. Fertilizer use efficiency varied from 16% to 56% over treatments and years. Low application rates resulted in lower seasonal soil and soil solution NO₃^– concentrations than high application rates. The controlled-release and organic form of fertilizer both reduced seasonal mean soil and soil solution N concentrations than conventional fertilizer, with low leaching potential.

Moses Ogbaji

Department of Crop Production, University of Agriculture, Makurdi, Nigeria.

Abstract

Food security and sustainability are serious challenges in Africa. Legumes are the main source of protein since most people cannot afford animal protein. Many indigenous legumes of Africa with potentials to ameliorate nutritional food securities are presently neglected and underutilized. African Yam Bean (Spenostylis stenocerpa) (AYB) is one of such crop with tremendous nutritional value with poor awareness especially its nutritive value, the precise knowledge of factors affecting its growth and yield particularly the use of Nitrogen fertilizers. The nutritive value of AYB including Nitrogen content was therefore compared with cowpea (Vigna unguiculta(L.) Walp) in the laboratory using the methods of AOAC (1995). Kjeldehl method was used to determine the Nitrogen content. Secondly, a field experiment using a 3×3 factorial arrangement in a Randomized Complete Block Design was carried out in 2014 to test the growth and yield response of five varieties of AYB to different Nitrogen and Lime rates.

Results of the study indicated that AYB was as nutritious as cowpea when all the nutrients including Nitrogen were compared. AYB gave a Nitrogen content of 0.096 compared with that of cowpea (0.093). Similarly, 90kgN/ha combined with 90kg Lime/ha better enhanced the growth and yield of different AYB varieties better than all other treatment combinations. The interactive effects between fertilizers and the different accessions of AYB were also significant as far as growth and yield of the crop were concerned. Favourable intensified research findings to encourage the production, wide consumption and general acceptability of AYB are hereby strongly advocated.