Stable Isotope Biogeochemistry of Seabird Guano Fertilization: Results from Growth Chamber Studies with Maize (Zea mays)
by Paul Szpak
Szpak P., F. J. Longstaffe, J.-F. Millaire, C. D. White. 2012. Stable Isotope Biogeochemistry of Seabird Guano Fertilization: Results from Growth Chamber Studies with Maize (Zea mays). PLoS One 7: e33741.
Background
Stable isotope analysis is being utilized with increasing regularity to examine a wide range of issues... more
Background
Stable isotope analysis is being utilized with increasing regularity to examine a wide range of issues (diet, habitat use, migration) in ecology, geology, archaeology, and related disciplines. A crucial component to these studies is a thorough understanding of the range and causes of baseline isotopic variation, which is relatively poorly understood for nitrogen (δ15N). Animal excrement is known to impact plant δ15N values, but the effects of seabird guano have not been systematically studied from an agricultural or horticultural standpoint.
Methodology/Principal Findings
This paper presents isotopic (δ13C and δ15N) and vital data for maize (Zea mays) fertilized with Peruvian seabird guano under controlled conditions. The level of 15N enrichment in fertilized plants is very large, with δ15N values ranging between 25.5 and 44.7‰ depending on the tissue and amount of fertilizer applied; comparatively, control plant δ15N values ranged between −0.3 and 5.7‰. Intraplant and temporal variability in δ15N values were large, particularly for the guano-fertilized plants, which can be attributed to changes in the availability of guano-derived N over time, and the reliance of stored vs. absorbed N. Plant δ13C values were not significantly impacted by guano fertilization. High concentrations of seabird guano inhibited maize germination and maize growth. Moreover, high levels of seabird guano greatly impacted the N metabolism of the plants, resulting in significantly higher tissue N content, particularly in the stalk.
Conclusions/Significance
The results presented in this study demonstrate the very large impact of seabird guano on maize δ15N values. The use of seabird guano as a fertilizer can thus be traced using stable isotope analysis in food chemistry applications (certification of organic inputs). Furthermore, the fertilization of maize with seabird guano creates an isotopic signature very similar to a high-trophic level marine resource, which must be considered when interpreting isotopic data from archaeological material.
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Download (.pdf) Recycling pulp mill sludge to improve soil fertility using GIS tools
P. Ribeiro, A. Albuquerque, L. Quinta-Nova, V. Cavaleiro
Resources, Conservation & Recycling, 2010, V. 54, 12, 1303–1311.
Pulp mill sludge produced in the Cova da Beira region (Portugal) contains organic matter (11–47%), nitrogen (38–2560mg... more
Pulp mill sludge produced in the Cova da Beira region (Portugal) contains organic matter (11–47%), nitrogen (38–2560mg N/kg) and phosphorus (167–370mg P/kg), which may be valuable for increasing soil productivity. The levels of heavy metals are below the limits recommended by legislation and the
amount of nitrogen and phosphorous to be introduced in soils does not present a risk for nutrient leaching.
After identifying the environmental and technical restrictions on its application, an area of 1650 ha was identified where the sludge can be applied in forage crops, fruit trees, olive groves and vineyards. A suitable area was also found for a biosolids storage centre. The use of GIS allowed to define a sludge
application index and to produce land-use suitability maps, which can be useful for sludge management.
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The major biotinyl protein from Pisum sativum seeds covalently binds biotin at a novel site
by Manuel Duval
Manuel Duval, Richard T. DeRose, Claudette Job, Didier Faucher, Roland Douce and Dominique Job
Plant Molecular Biology
Volume 26, Number 1, 265-273, DOI: 10.1007/BF00039537
Seeds of Pisum sativum contain a biotinyl polypeptide called SBP65 that behaves as a putative sink for the free... more Seeds of Pisum sativum contain a biotinyl polypeptide called SBP65 that behaves as a putative sink for the free vitamin, representing more than 90% of the total protein-bound biotin in mature seeds. A cDNA encoding SBP65 was cloned and sequenced. The deduced primary structure of the protein was confirmed by protein sequencing. Peptide sequencing also indicated binding of the biotin to lysine 103. The biotinylation domain of SBP65 differs markedly from that of presently known biotin enzymes. Molecular analysis of the protein sequence reveals an extremely hydrophilic protein containing several repeated motifs. These properties, as well as the temporal and spatial patterns of expression of this protein, suggest that SBP65 belongs to the LEA (late embryogenesis-abundant) group of proteins.
Aspects of phosphorus transfer from soils in Europe
Imbalanced nutrient management has caused soil phosphorus (P) to become an environmental rather an agronomic problem... more Imbalanced nutrient management has caused soil phosphorus (P) to become an environmental rather an agronomic problem in more economically developed countries. This subject has been the topic of numerous journal special issues, conferences, and reviews but we consider yet another review of this subject is necessary with the main target of providing a point of view on nonpoint transfer from soils and control strategies for an improved environmental management of P. This review considers the causes of the excessive P transfer from soil to surface water in Europe and the scientific knowledge necessary to develop control strategies.
Onset of the rainy season and crop yield in sub-Saharan Africa – tools and perspectives for Cameroon
by Patrick Laux
Ecohydrology of Surface and Groundwater Dependent Systems: Concepts, Methods and Recent Developments
In dry sub-humid and semi-arid regions, where rainfall is limited to only a few months per year, rainfall is the most... more
In dry sub-humid and semi-arid regions, where rainfall is limited to only a few months per year, rainfall is the most important factor affecting crop growth and yield. Every year, farmers are faced with the crucial question of when to start planting. Do the first rainfalls after the dry season resemble the onset of the rainy season (ORS) or not? A fuzzy logic-based algorithm for estimating the ORS and the optimal planting date was developed. It is based on rainfall data and accounts for agriculturally meaningful aspects. The ORS algorithm, which calculates the planting date for each year, was coupled to the physically-based crop model CropSyst. A Monte Carlo approach was applied to generate annual planting dates from 1979 to 2003. Therefore, the definition constraints, which are allowed to vary within reasonable parameter ranges, are generated randomly. The averaged crop yield served as a performance measure for each realization. The parameter range of the best realizations is retained. Various iterations are necessary to obtain a robust set of “optimal” definition parameters. The coupled ORS definition-crop modelling system was applied for two different crop species and five different observation stations across Cameroon for the period 1979–2003. It is shown that the derived “optimal” planting dates would allow for significantly increased crop yields compared to the existing planting rules in Cameroon.
Key words crop modelling; CropSyst; Monte Carlo approach; onset of the rainy season; planting date
Impact of climate change on agricultural productivity under rainfed conditions in Cameroon—A method to improve attainable crop yields by planting date adaptations
by Patrick Laux
Agricultural and Forest Meteorology, doi:10.1016/j.agrformet.2010.05.008
Rainfed farming systems in sub-Saharan Africa are suffering from low productivity. Prolonged dry spells and droughts... more
Rainfed farming systems in sub-Saharan Africa are suffering from low productivity. Prolonged dry spells and droughts often lead to significant crop losses, a situation that is expected to be exacerbated by climate change. In this study, the impact of climate change on attainable yields of maize and groundnut, as major alimentary crops in sub-Saharan Africa, is evaluated at five stations in Cameroon under rainfed conditions. It is focussed on the contribution of future climate change in terms of the direct fertilisation effect of the expected CO2 alteration and the indirect effects of the expected temperature and precipitation change. As improved agricultural management practices in rainfed systems are crucial to increase agricultural productivity, the impact of the planting date is analysed in detail. For this purpose, a fuzzy logic-based algorithm is developed to estimate the agriculturally relevant onset of the rainy season (ORS) and, thus, the optimal planting date. This algorithm is then connected to the physically based crop model CropSyst, hereinafter referred to as optimal planting date following crop modelling system. A Monte Carlo approach is used to optimise the ORS algorithm in terms of maximising the mean annual crop yields (1979–2003). The optimal planting date following crop modelling system is applied to past and future periods, mainly for two reasons: (i) to derive optimal fuzzy rules and increase mean attainable crop yields; and (ii) to reliably estimate the impact of climate change to crop productivity with (‘optimal planting date scenario’) and without planting date adaptations (‘traditional planting date scenario’).
It is shown that the fuzzy rules derived for assessing the optimal planting dates may allow for significantly increased crop yields compared to the existing planting rules in Cameroon under current climatic conditions, especially for the drier northern regions. A change in the climatic conditions due to global warming will reduce the growing cycle and, thus, the crop yields. However, the positive effect of CO2 fertilisation is likely to outweigh the negative effects of precipitation and temperature change for the 2020s and partly for the 2080s. When additionally considering planting date adaptations, groundnut yield is expected to increase for the 2020s and the 2080s, with maximum yield surpluses of about 30% for the 2020s compared to the extended baseline period. For maize, crop yield is likely to increase (decrease) for the 2020s (2080s) by approximately 15%. For the driest stations analysed, the negative impacts of temperature and precipitation change could be mitigated significantly by planting date adaptations.
Keywords: Crop modelling; CropSyst; Monte Carlo approach; Onset of the rainy season; Planting date; Climate change; Attainable crop yield
L'experimentació sobre sitges tradicionals. Aportacions de l'arqueologia i de l'agronomia
by Josep Miret
Published in 'Revista d'Arqueologia de Ponent' 18, 2008, 217-240.
Results of some thirty series of experiments on traditional silos
made by archaeologists and agronomists in... more
Results of some thirty series of experiments on traditional silos
made by archaeologists and agronomists in several places in the
world are presented in this article.
The various factors influencing preservation of cereal grains in
silos are analysed: lack of oxygen associated to a high rate of carbon dioxide; low temperatures; low humidity; association to repellent or toxic products for pests. It is difficult to draw conclusions from these experiments due to a difference in climates and kind of silos but, generally speaking, some conclusions can be pointed out: while in traditional silos, moisture content of the cereal grains increases, as well as temperature, fungi growth and losses caused by weevil (in
unsealed silos); germination rate decreases and, finally, nutritional qualities in grains attacked by fungi deteriorate.
Key words: experimental archaeology, experimentation, agronomy, ethnoarchaeology, silos, preservation of cereals, traditional techniques.
How good is the turbid medium-based approach for accounting for light partitioning in contrasted grass-legume intercropping systems?
Romain Barillot, Gaëtan Louarn, Abraham J. Escobar Gutiérrez, Pierre Huynh and Didier Combes
Annals of Botany, 2011, 108 (6): 1013-1024. doi: 10.1093/aob/mcr199.
Background and aims: Most studies dealing with light partitioning in intercropping systems used statistical models... more
Background and aims: Most studies dealing with light partitioning in intercropping systems used statistical models based on the turbid medium approach, thus assuming homogeneous canopies. However, these models could not be directly validated although spatial heterogeneities could arise in such canopies. The aim of the present study was to assess the ability of the turbid medium approach to accurately estimate light sharing within grass-legume mixed canopies. The benchmarks for light interception efficiency (LIE) estimates were provided by the combination of a light projective model and 3-dimensional virtual plant mock-ups that explicitly account for plant architecture.
Methods:
Mixtures were sown according to various pattern and densities. 3D plant mock-ups were derived from magnetic digitizations carried out at different stages of development. Reconstructed virtual plants then provided: i) reference LIE estimations by using VEGESTAR software; and ii) SIRASCA inputs such as leaf area index and leaf inclination. SIRASCA was then set to account for vertical heterogeneity of the foliage i.e. the canopy was either described as one, two or ten horizontal layers of leaves.
Key results:
Mixtures exhibited various and heterogeneous profiles of foliar distribution, leaf inclination and component species height. Despites these heterogeneities most of LIE were satisfactorily predicted by SIRASCA. Biased estimations were however observed for i) grass species and ii) FA swards grown at high density. Most of discrepancies were due to vertical heterogeneities and were corrected by increasing the vertical description of canopies although, in practice, this would require tedious and time-consuming measurements.
Conclusions:
The turbid medium analogy could be successfully used in a wide range of canopies. However, a more detailed description of the canopy is required for mixtures exhibiting vertical stratifications and inter/intra-species foliage overlapping. Architectural models remain a relevant tool for studying light partitioning in intercropping systems that exhibit strong vertical heterogeneities. Such models are also able to integrate the effects of microclimate variations on plant growth.
Keywords: Turbid medium-based models, functional structural plant models, light interception efficiency, light partitioning, intercropping systems, grass – legume mixtures, canopy structure, Festuca arundinacea, Medicago sativa, Pisum sativum, Trifolium repens, Triticum aestivum
Le rôle de l'ingénieur agronome dans la situation politique de l'agriculture vénézuélienne: 1936-1948
Arvanitis, Rigas & Thierry Bardini (1990) 'Le rôle de l'ingénieur agronome dans la situation politique de l'agriculture vénézuélienne: 1936-1948', Cahiers des Sciences Humaines 26(3):429-46.
http://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_texte