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Pasley HR, Camberato JJ, Cairns JE, Zaman-Allah M, Das B, Vyn TJ. Nitrogen rate impacts on tropical maize nitrogen use efficiency and soil nitrogen depletion in eastern and southern Africa. Nutr Cycl Agroecosyst 2020; 116:397-408. [PMID: 32765186 PMCID: PMC7380447 DOI: 10.1007/s10705-020-10049-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 01/18/2020] [Indexed: 06/11/2023]
Abstract
Sub-Saharan Africa is facing food security challenges due, in part, to decades of soil nitrogen (N) depletion. Applying N fertilizer could increase crop yields and replenish soil N pools. From 2010 to 2015, field experiments conducted in Embu and Kiboko, Kenya and Harare, Zimbabwe investigated yield and N uptake response of six maize (Zea mays L.) hybrids to four N fertilizer rates (0 to 160 kg N ha-1) in continuous maize production systems. The N recovery efficiency (NRE), cumulative N balance, and soil N content in the upper 0.9 m of soil following the final harvest were determined at each N rate. Plant and soil responses to N fertilizer applications did not differ amongst hybrids. Across locations and N rates, NRE ranged from 0.4 to 1.8 kg kg-1. Higher NRE values in Kiboko and Harare occurred at lower post-harvest soil inorganic N levels. The excessively high NRE value of 1.8 kg kg-1 at 40 kg N ha-1 in Harare suggested that maize hybrids deplete soil inorganic N most at low N rates. Still, negative cumulative N balances indicated that inorganic soil N depletion occurred at all N rates in Embu and Harare (up to - 193 and - 167 kg N ha-1, respectively) and at the 40 kg N ha-1 rate in Kiboko (- 72 kg N ha-1). Overall, maize N uptake exceeded fertilizer N applied and so, while yields increased, soil N pools were not replenished, especially at low total soil N levels (< 10,000 kg N ha-1 in top 0.9 m).
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Affiliation(s)
- Heather R. Pasley
- Agronomy Department, Purdue University, 915 W. State Street, West Lafayette, IN 47907 USA
| | - James J. Camberato
- Agronomy Department, Purdue University, 915 W. State Street, West Lafayette, IN 47907 USA
| | - Jill E. Cairns
- International Maize and Wheat Improvement Centre (CIMMYT), Harare, Zimbabwe
| | | | - Biswanath Das
- International Maize and Wheat Improvement Centre (CIMMYT), Nairobi, Kenya
| | - Tony J. Vyn
- Agronomy Department, Purdue University, 915 W. State Street, West Lafayette, IN 47907 USA
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Lee MS, Anderson EK, Stojšin D, McPherson MA, Baltazar B, Horak MJ, de la Fuente JM, Wu K, Crowley JH, Rayburn AL, Lee DK. Assessment of the potential for gene flow from transgenic maize (Zea mays L.) to eastern gamagrass (Tripsacum dactyloides L.). Transgenic Res 2017; 26:501-514. [PMID: 28466411 PMCID: PMC5504203 DOI: 10.1007/s11248-017-0020-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 04/24/2017] [Indexed: 10/24/2022]
Abstract
Eastern gamagrass (Tripsacum dactyloides L.) belongs to the same tribe of the Poaceae family as maize (Zea mays L.) and grows naturally in the same region where maize is commercially produced in the USA. Although no evidence exists of gene flow from maize to eastern gamagrass in nature, experimental crosses between the two species were produced using specific techniques. As part of environmental risk assessment, the possibility of transgene flow from maize to eastern gamagrass populations in nature was evaluated with the objectives: (1) to assess the seeds of eastern gamagrass populations naturally growing near commercial maize fields for the presence of a transgenic glyphosate-tolerance gene (cp4 epsps) that would indicate cross-pollination between the two species, and (2) to evaluate the possibility of interspecific hybridization between transgenic maize used as male parent and eastern gamagrass used as female parent. A total of 46,643 seeds from 54 eastern gamagrass populations collected in proximity of maize fields in Illinois, USA were planted in a field in 2014 and 2015. Emerged seedlings were treated with glyphosate herbicide and assessed for survival. An additional 48,000 seeds from the same 54 eastern gamagrass populations were tested for the presence of the cp4 epsps transgene markers using TaqMan® PCR method. The results from these trials showed that no seedlings survived the herbicide treatment and no seed indicated presence of the herbicide tolerant cp4 epsps transgene, even though these eastern gamagrass populations were exposed to glyphosate-tolerant maize pollen for years. Furthermore, no interspecific hybrid seeds were produced from 135 hand-pollination attempts involving 1529 eastern gamagrass spikelets exposed to maize pollen. Together, these results indicate that there is no evidence of gene flow from maize to eastern gamagrass in natural habitats. The outcome of this study should be taken in consideration when assessing for environmental risks regarding the consequence of gene flow from transgenic maize to its wild relatives.
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Affiliation(s)
- Moon-Sub Lee
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, 1102 S. Goodwin Ave., Urbana, IL, 61801, USA
| | - Eric K Anderson
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, 1102 S. Goodwin Ave., Urbana, IL, 61801, USA
| | - Duška Stojšin
- Monsanto Company, 800 North Lindbergh Blvd., St. Louis, MO, 63167, USA
| | - Marc A McPherson
- Monsanto Company, 800 North Lindbergh Blvd., St. Louis, MO, 63167, USA
| | - Baltazar Baltazar
- Monsanto Company, 800 North Lindbergh Blvd., St. Louis, MO, 63167, USA
| | - Michael J Horak
- Monsanto Company, 800 North Lindbergh Blvd., St. Louis, MO, 63167, USA
| | - Juan Manuel de la Fuente
- Monsanto Company, Park Plaza Torre II, 504 Javier Barros Sierra Ave., Col. Santa Fe, Del. Alvaro Obregon, CP 01210, Mexico, DF, Mexico
| | - Kunsheng Wu
- Monsanto Company, 700 Chesterfield Parkway W., St. Louis, MO, 63017, USA
| | - James H Crowley
- Monsanto Company, 700 Chesterfield Parkway W., St. Louis, MO, 63017, USA
| | - A Lane Rayburn
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, 1102 S. Goodwin Ave., Urbana, IL, 61801, USA
| | - D K Lee
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, 1102 S. Goodwin Ave., Urbana, IL, 61801, USA.
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Schirrmann M, Joschko M, Gebbers R, Kramer E, Zörner M, Barkusky D, Timmer J. Proximal Soil Sensing - A Contribution for Species Habitat Distribution Modelling of Earthworms in Agricultural Soils? PLoS One 2016; 11:e0158271. [PMID: 27355340 PMCID: PMC4927140 DOI: 10.1371/journal.pone.0158271] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 06/13/2016] [Indexed: 11/19/2022] Open
Abstract
Background Earthworms are important for maintaining soil ecosystem functioning and serve as indicators of soil fertility. However, detection of earthworms is time-consuming, which hinders the assessment of earthworm abundances with high sampling density over entire fields. Recent developments of mobile terrestrial sensor platforms for proximal soil sensing (PSS) provided new tools for collecting dense spatial information of soils using various sensing principles. Yet, the potential of PSS for assessing earthworm habitats is largely unexplored. This study investigates whether PSS data contribute to the spatial prediction of earthworm abundances in species distribution models of agricultural soils. Methodology/Principal Findings Proximal soil sensing data, e.g., soil electrical conductivity (EC), pH, and near infrared absorbance (NIR), were collected in real-time in a field with two management strategies (reduced tillage / conventional tillage) and sandy to loam soils. PSS was related to observations from a long-term (11 years) earthworm observation study conducted at 42 plots. Earthworms were sampled from 0.5 x 0.5 x 0.2 m³ soil blocks and identified to species level. Sensor data were highly correlated with earthworm abundances observed in reduced tillage but less correlated with earthworm abundances observed in conventional tillage. This may indicate that management influences the sensor-earthworm relationship. Generalized additive models and state-space models showed that modelling based on data fusion from EC, pH, and NIR sensors produced better results than modelling without sensor data or data from just a single sensor. Regarding the individual earthworm species, particular sensor combinations were more appropriate than others due to the different habitat requirements of the earthworms. Earthworm species with soil-specific habitat preferences were spatially predicted with higher accuracy by PSS than more ubiquitous species. Conclusions/Significance Our findings suggest that PSS contributes to the spatial modelling of earthworm abundances at field scale and that it will support species distribution modelling in the attempt to understand the soil-earthworm relationships in agroecosystems.
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Affiliation(s)
- Michael Schirrmann
- Leibniz Institute for Agricultural Engineering Potsdam-Bornim, Max-Eyth-Allee 100, 14469, Potsdam, Germany
- * E-mail:
| | - Monika Joschko
- Leibniz Centre for Agricultural Landscape Research (ZALF), Institute for Landscape Biogeochemistry, Eberswalder Str. 84, 15374, Muencheberg, Germany
| | - Robin Gebbers
- Leibniz Institute for Agricultural Engineering Potsdam-Bornim, Max-Eyth-Allee 100, 14469, Potsdam, Germany
| | - Eckart Kramer
- Eberswalde University for Sustainable Development, Schicklerstraße 5, 16225, Eberswalde, Germany
| | - Mirjam Zörner
- Forschungszentrum Juelich GmbH, Institute of Bio- and Geosciences, IBG-3, Wilhelm-Johnen-Straße, 52428, Juelich, Germany
| | - Dietmar Barkusky
- Leibniz Centre for Agricultural Landscape Research (ZALF), Research Station Muencheberg, Eberswalder Str. 84, 15374, Muencheberg, Germany
| | - Jens Timmer
- University of Freiburg, BIOSS Centre for Biological Signalling Studies, Schänzlestr. 18, 79104, Freiburg, Germany
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