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  Subjects -> AGRICULTURE (Total: 653 journals)
    - AGRICULTURAL ECONOMICS (70 journals)
    - AGRICULTURE (438 journals)
    - CROP PRODUCTION AND SOIL (84 journals)
    - DAIRYING AND DAIRY PRODUCTS (24 journals)
    - POULTRY AND LIVESTOCK (37 journals)

AGRICULTURE (438 journals)                  1 2 3 4 5 | Last

Acta agriculturae Slovenica     Open Access   (4 followers)
Acta Agrobotanica     Open Access   (2 followers)
Acta Agronomica Hungarica     Full-text available via subscription   (1 follower)
Acta Agronomica Sinica     Full-text available via subscription   (6 followers)
Acta Scientiarum. Animal Sciences     Open Access  
Acta Scientiarum. Technology     Open Access  
Acta Technologica Agriculturae     Open Access  
Advances in Agriculture & Botanics     Open Access   (10 followers)
Advances in Agriculture, Sciences and Engineering Research     Open Access   (10 followers)
Advances in Agronomy     Full-text available via subscription   (12 followers)
Advances in Life Science and Technology     Open Access   (4 followers)
AFBM Journal     Open Access  
Africa Development     Open Access   (2 followers)
Africa Research Bulletin: Political, Social and Cultural Series     Hybrid Journal   (6 followers)
African Journal of Agricultural Research     Open Access  
African Journal of Food Science     Open Access   (1 follower)
African Journal of Food, Agriculture, Nutrition and Development     Open Access  
African Journal of Horticultural Science     Open Access   (2 followers)
African Journal of Range and Forage Science     Hybrid Journal   (5 followers)
African Journal of Sustainable Development     Full-text available via subscription   (2 followers)
Agribusiness : an International Journal     Hybrid Journal   (5 followers)
Agricultura Tecnica     Open Access   (5 followers)
Agricultura Tropica et Subtropica     Open Access   (1 follower)
Agricultural Advances     Open Access   (3 followers)
Agricultural and Food Science     Open Access   (14 followers)
Agricultural Economics     Hybrid Journal   (43 followers)
Agricultural History     Full-text available via subscription   (96 followers)
Agricultural Research     Hybrid Journal   (2 followers)
Agricultural Science     Full-text available via subscription   (5 followers)
Agricultural Sciences     Open Access   (7 followers)
Agricultural Sciences in China     Full-text available via subscription   (3 followers)
Agricultural Systems     Hybrid Journal   (19 followers)
Agricultural Water Management     Hybrid Journal   (13 followers)
Agriculture     Open Access   (4 followers)
Agriculture & Food Security     Open Access   (7 followers)
Agriculture (Poľnohospodárstvo)     Open Access   (1 follower)
Agriculture and Agricultural Science Procedia     Full-text available via subscription  
Agriculture and Human Values     Hybrid Journal   (10 followers)
Agriculture, Ecosystems & Environment     Hybrid Journal   (29 followers)
Agriprobe     Full-text available via subscription  
Agrivita : Journal of Agricultural Science     Open Access   (4 followers)
Agro-Science     Full-text available via subscription  
Agroalimentaria     Open Access   (1 follower)
Agrociencia     Open Access   (2 followers)
Agrokémia és Talajtan     Full-text available via subscription   (2 followers)
Agronomía Colombiana     Open Access   (1 follower)
Agronomía Costarricense     Open Access   (2 followers)
Agronomía Mesoamericana     Open Access   (1 follower)
Agronomie Africaine     Full-text available via subscription  
Agronomy     Open Access   (8 followers)
Agrosearch     Open Access  
AI & Society     Hybrid Journal   (2 followers)
Alinteri Zirai Bilimler Dergisi : Alinteri Journal of Agricultural Sciences     Open Access  
Ambiência     Open Access  
Ambiente & Agua : An Interdisciplinary Journal of Applied Science     Open Access   (1 follower)
American Journal of Agricultural and Biological Sciences     Open Access   (9 followers)
American Journal of Botany     Full-text available via subscription   (13 followers)
American Journal of Economics and Sociology     Hybrid Journal   (18 followers)
American Journal of Potato Research     Hybrid Journal   (2 followers)
Anais da Academia Brasileira de Ciências     Open Access   (2 followers)
Annales UMCS, Agricultura     Open Access  
Annales UMCS, Horticultura     Full-text available via subscription  
Annals of Agricultural and Environmental Medicine     Open Access   (1 follower)
Annals of Agricultural Sciences     Open Access   (1 follower)
Annual Review of Resource Economics     Full-text available via subscription   (10 followers)
APCBEE Procedia     Partially Free   (2 followers)
Applied Economics Letters     Hybrid Journal   (18 followers)
Applied Financial Economics Letters     Hybrid Journal   (4 followers)
Arboricultural Journal : The International Journal of Urban Forestry     Hybrid Journal   (5 followers)
Archivos de Zootecnia     Open Access  
Arquivos do Instituto Biológico     Open Access  
Arthropod-Plant Interactions     Hybrid Journal   (1 follower)
Asian Economic Papers     Hybrid Journal   (3 followers)
Asian Journal of Agricultural Research     Open Access   (2 followers)
Asian Journal of Plant Sciences     Open Access   (1 follower)
Australian Cottongrower, The     Full-text available via subscription   (1 follower)
Australian Economic Papers     Hybrid Journal   (5 followers)
Australian Forest Grower     Full-text available via subscription   (2 followers)
Australian Forestry     Full-text available via subscription   (4 followers)
Australian Grain     Full-text available via subscription   (4 followers)
Australian Holstein Journal     Full-text available via subscription  
Australian Journal of Agricultural and Resource Economics     Hybrid Journal   (5 followers)
Australian Journal of Agricultural Engineering     Open Access  
Australian Sugarcane     Full-text available via subscription  
Avances en Investigacion Agropecuaria     Open Access  
Bangladesh Journal of Agricultural Research     Open Access   (1 follower)
Bangladesh Journal of Scientific Research     Open Access  
Berkala Ilmiah Pertanian     Open Access   (1 follower)
Bioagro     Open Access   (1 follower)
Biocatalysis and Agricultural Biotechnology     Hybrid Journal   (5 followers)
Biocontrol Science and Technology     Hybrid Journal   (5 followers)
Biodiversity     Hybrid Journal   (16 followers)
Biodiversity : Research and Conservation     Open Access   (17 followers)
Biological Agriculture & Horticulture : An International Journal for Sustainable Production Systems     Partially Free   (12 followers)
Biosystems Engineering     Hybrid Journal   (1 follower)
Biotemas     Open Access  
Bragantia     Open Access   (2 followers)
Brazilian Archives of Biology and Technology     Open Access   (1 follower)
British Poultry Science     Hybrid Journal   (5 followers)
California Agriculture     Open Access   (1 follower)

        1 2 3 4 5 | Last

Advances in Agronomy    [14 followers]  Follow    
  Full-text available via subscription Subscription journal
     ISSN (Print) 0065-2113
     Published by Elsevier Homepage  [2556 journals]   [SJR: 1.525]   [H-I: 59]
  • Series Page
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 124




      PubDate: 2014-01-13T05:48:53Z
       
  • Copyright
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 124




      PubDate: 2014-01-13T05:48:53Z
       
  • Contributors
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 124




      PubDate: 2014-01-13T05:48:53Z
       
  • Preface
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 124
      Author(s): Donald L. Sparks



      PubDate: 2014-01-13T05:48:53Z
       
  • Chapter One Opportunities and Challenges of Soil Carbon Sequestration by
           Conservation Agriculture in China
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 124
      Author(s): Hai-Lin Zhang , Rattan Lal , Xin Zhao , Jian-Fu Xue , Fu Chen
      Conservation agriculture (CA), an emerging technology for sustainable agriculture, has been practiced in China for more than 30 years and is increasingly being adopted on cropland. CA system has four components: (i) no-till (NT), (ii) residue mulch, (iii) complex/diverse cropping system, and (iv) integrated nutrient management. Conservation tillage (CT, main technology of CA) methods, relevant to a range of cropping systems, are practiced on 6.67million hectare (Mha) in China. With growing concerns about global warming, soil organic carbon (SOC) sequestration is an important strategy to offset anthropogenic emissions. This chapter collates and synthesizes available research literature on SOC sequestration under different tillage systems in China. Specific focus is on the SOC dynamics, SOC stock, rate of SOC sequestration, and soil quality under different tillage systems in diverse agroeco regions. The research on CT effects on SOC sequestration has been conducted in China for more than 20 years since the 1990s. The review of the literature indicates that NT can increase SOC concentration in the surface layer under dryland farming and rice (Oryza sativa L.) paddy soils. The average rate of increase of SOC (gkg−1year−1) in 0–20cm depth under NT systems is 0.60–3.74, 0.14–4.15, 0.50–5.94, and 8.81–17.95 for the Northeast, North, Northwest, and paddy fields of Southern China, respectively. However, most research results indicate that SOC under NT is concentrated more in the surface soil (8.6–31.3gkg−1 in NT vs. 5.3–26.8gkg−1 in plow tillage (PT)) and is relatively less in the subsoil (6.9–17.6gkg−1 in NT vs. 10.2–24.5gkg−1 in PT). Residue management is the key factor in SOC sequestration, which also influences SOC dynamics. Cropping system and rotation also affect SOC sequestration. Further, NT can improve soil quality by enhancing and stabilizing aggregation. Because of relatively short duration, soil processes under CA management are not clearly understood and are confounded by the diverse cropping systems. There is a need to study pedospheric processes affecting SOC sequestration and soil quality under long-term use of CA in diverse cropping systems and complex agroeco regions of China. Potential and limitations of CA, and research priorities in China are discussed.


      PubDate: 2014-01-13T05:48:53Z
       
  • Chapter Two A Meta-Analysis and Review of Plant-Growth Response to Humic
           Substances Practical Implications for Agriculture
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 124
      Author(s): Michael T. Rose , Antonio F. Patti , Karen R. Little , Alicia L. Brown , W. Roy Jackson , Timothy R. Cavagnaro
      The breakdown products of plant and animal remains, extracted in an alkaline solution, are commonly referred to as humic substances (HS). They can be extracted from a wide variety of sources, including subbituminous coals, lignites (brown coals), peat, soil, composts, and raw organic wastes. The application of HS to plants has the potential to improve plant growth, but the extent of plant-growth promotion is inconsistent and relatively unpredictable when compared to inorganic fertilizers. The goal of this review was to determine the magnitude and likelihood of plant-growth response to HS and to rank the factors contributing to positive growth promotion. These factors included the source of the HS, the environmental growing conditions, the type of plant being treated, and the manner of HS application. Literature reports of exogenously applied HS–plant interactions were collated and quantitatively analyzed using meta-analytic and regression tree techniques. Overall, random-effects meta-analysis estimated shoot dry weight increases of 22±4% and root dry weight increases of 21±6% in response to HS application. Nevertheless, actual responses varied considerably and were mainly influenced by the source of the HS applied, the rate of HS application, and to a lesser extent, plant type and growing conditions. HS from compost sources significantly outperformed lignite and peat-derived HS in terms of growth promotion, while HS application rate nonlinearly moderated the growth response under different circumstances. Our results demonstrate the difficulty in generalizing recommendations for the use of HS in agriculture; however, some specific suggestions for maximizing the efficacy of HS under certain conditions are offered. We also outline some recent developments in the use of HS as synergists for improving fertilizer use efficiency and the activity of microbial inoculants. Finally, we identify a number of research gaps, which, when addressed, should clarify how, when, and where HS can be best applied for the greatest benefit.


      PubDate: 2014-01-13T05:48:53Z
       
  • Chapter Three Properties and Management of Acid Sulfate Soils in Southeast
           Asia for Sustainable Cultivation of Rice, Oil Palm, and Cocoa
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 124
      Author(s): J. Shamshuddin , A. Elisa Azura , M.A.R.S. Shazana , C.I. Fauziah , Q.A. Panhwar , U.A. Naher
      Acid sulfate soils occur sporadically in the coastal plains of countries throughout the globe. The soils are characterized by a low pH and the presence of sulfuric horizon, overlying sulfidic materials, mostly pyrite (FeS2). This pyrite is readily oxidized when the soils are drained to make way for development (e.g., agriculture). During the process of pyrite oxidation, a straw-yellow mineral called jarosite is formed and eventually high acidity and toxic aluminum are released into the environment, affecting crop growth. This chapter reviews the studies conducted in Southeast Asia on the management of soils for sustainable crop production. Some of the soils are utilized for the cultivation of rice, oil palm, and cocoa with mixed success because of their inherently low fertility, and Al and/or Fe toxicity. For rice cultivation, lime, basalt, or organic fertilizer can be used to alleviate the infertility of the soils. Application of lime or basalt increases soil pH, resulting in precipitation of inert Al hydroxides. Oil palm can be grown successfully on acid sulfate soils if the proper water management practice is carried out. The drains in the oil palm plantation should be designed in such a way that the excess water is removed from the area, while maintaining the water table level above the pyritic layer. Cocoa grows poorly on acid sulfate soils because of low pH and Al toxicity. However, with adequate liming, using ground magnesium limestone and organic matter, the soils can be utilized productively for cocoa production. In general, acid sulfate soils can be made productive for rice, oil palm, or cocoa cultivation by increasing soil pH with lime or basalt, applying organic matter, or adopting proper water management practices.


      PubDate: 2014-01-13T05:48:53Z
       
  • Chapter Four Plant Responses to Limited Moisture and Phosphorus
           Availability A Meta-Analysis
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 124
      Author(s): Lalith D.B. Suriyagoda , Megan H. Ryan , Michael Renton , Hans Lambers
      Phosphorus (P) is a scarce, nonrenewable resource; its acquisition by plants decreases when soil moisture declines, as anticipated under future climate-change scenarios. It is, therefore, important to understand plant responses and adaptations to dual moisture and P limitations, in order to maintain crop productivity and predict plant performance in natural ecosystems. We review current knowledge of the effect of simultaneous water and P shortage on plant function, and identify key knowledge gaps. Plants have developed a range of adaptations to ensure P uptake is adequate to maintain vital functions within a broad range, at least until a certain level of P and/or drought stress is exceeded. Differences in plant growth and amount of P taken up under dual moisture and P limitations greatly depend on the rate of soil drying and wetting, the severity and duration of drought cycles, plant uptake capacity, root system plasticity, presence and magnitude of hydraulic redistribution, P-resorption ability, and soil properties such as waterholding capacity, P diffusion rate, P mineralization and fixation rates, and the activity of arbuscular mycorrhizal (AM) symbioses. During the process of soil drying, both P fertilization and association with AM fungi may increase performance under drought, until a certain level of water stress is exceeded. A small number of previously reported contradictory results probably reflect differences/limitations in experimental approaches. When breeding crop varieties to increase the efficiency of P and water acquisition, and when examining performance of species in natural ecosystems, multiple and interacting processes, from the scale of cellular to whole plant, must be considered.


      PubDate: 2014-01-13T05:48:53Z
       
  • Chapter Five Elicitation An Underutilized Tool in the Development of
           Medicinal Plants as a Source of Therapeutic Secondary Metabolites
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 124
      Author(s): Jonathan Gorelick , Nirit Bernstein
      Although there is a plethora of traditional plants with great therapeutic potential, the majority of medicinal plants have yet to be utilized on a large scale. One of the main reasons for this is the chemical variability inherent in plant-derived therapeutics. Many of the medically useful secondary metabolites produced by plants are the result of the latter's response to stress. When medicinal plants taken from the wild are cultivated under “optimal” growing conditions, the natural stressors on the plant are removed and, therefore, the content of secondary metabolites and, consequently, the therapeutic activity of the plants are greatly reduced. A possible aid in overcoming these difficulties is elicitation, the use of biotic and abiotic elicitors to stimulate the stress response in plants and increase the content of biologically active compounds. Elicitation has already been utilized in the study of disease resistance in plants, as well as in metabolic studies in cell culture. Elicitation can also be a powerful aid in the characterization and development of many potentially beneficial medicinal plants. This review summarizes the current state of knowledge concerning the utilization of biotic and abiotic elicitors in plants.


      PubDate: 2014-01-13T05:48:53Z
       
  • Chapter Six Decision Support Systems to Manage Irrigation in
           Agriculture*Present address: Consiglio per la Ricerca e la Sperimentazione
           in Agricoltura, Cereal Research Centre, S.S. 673km 25,200, 71122 Foggia,
           Italy
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 123
      Author(s): Michele Rinaldi , Zhenli He
      A decision support system (DSS) is an interactive software-based system used to help decision-makers compile useful information from a combination of raw data, documents, and personal knowledge; to identify and solve problems; and to make an optimized decision. The DSS architecture consists of the database (or knowledge base), the model (i.e., the decision context and user criteria), and the user interface. The main advantages of using a DSS include examination of multiple alternatives, better understanding of the processes, identification of unpredicted situations, enhanced communication, cost effectiveness, and better use of data and resources. The application DSS in agriculture and environment has been rapidly increased in the past decade, which allows rapid assessment of agricultural production systems around the world and decision-making at both farm and district levels, though constraints exist for successful adoption of this technology in agriculture. One of the important applications of DSS in agriculture is water management at both field and district levels. Agriculture is facing more severe and growing competition with other sectors for freshwater. The water resources are becoming increasingly insufficient to meet the demand in developing countries and their quality is declining due to pollution and inadequate management. Irrigation is an effective means to enhance crop productions, but water needs to be supplied accurately, taking into account its availability, crop requirement and land size, irrigation systems, and crop productivity and feasibility. This chapter attempts to present the state-of-art principles, design, and application of DSS in agriculture, particularly irrigation practices, and to identify emerging approaches and future direction of research in this field.


      PubDate: 2013-12-20T04:13:58Z
       
  • Chapter Five Phosphorus Its Efficient Use in Agriculture
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 123
      Author(s): A. Edward Johnston , Paul R. Poulton , Paul E. Fixen , Denis Curtin
      Changes in understanding the behavior of soil and fertilizer phosphorus (P) during the last 150 years are presented and recent concepts have been linked with agronomic data to produce a model that considers four pools of inorganic soil P related to their plant availability and extractability by chemical extractants. The stronger the bonding of phosphate ions to soil components, the lower the plant availability. P-use efficiency in agriculture is related to soils reaching and being maintained at a critical level of readily plant-available P, and factors affecting the critical level are discussed. Efficiency can be assessed by the direct, difference, and balance methods. The latter, calculated as the P output/input ratio, shows that P-use efficiency can exceed 80–90%. Combined data from controlled experiments in England and derived “statewide” aggregate information in the United States relating output/input ratios to changes in plant-available P could best be described by a single, simple function, making a powerful and convincing statement suggesting that there is an underlying “simple rule” for the behavior of plant-available inorganic soil P that is related to the four-pool concept discussed.


      PubDate: 2013-12-20T04:13:58Z
       
  • Chapter Four Major Issues of Diffuse Reflectance NIR Spectroscopy in the
           Specific Context of Soil Carbon Content Estimation A Review
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 123
      Author(s): Alexia Gobrecht , Jean-Michel Roger , Véronique Bellon-Maurel
      Soil carbon sequestration is one possible way of reducing greenhouse gas emissions in the atmosphere. However, to evaluate the real benefits offered by these methods (new agricultural practices, reforestation, etc.), there is a need in rapid, precise, and low-cost analytical tools. Near-infrared spectroscopy (NIRS) is now commonly used to measure different physical and chemical parameters of soils, including carbon content. However, prediction model accuracy is insufficient for NIRS to replace routine laboratory analysis and/or to make in situ measurements, whatever the type of soil. One of the biggest issues that need to be addressed concerns the calibration process: how does the mathematical method or the sample selection influence the model quality? In most cases, there are not a lot of thoughts put into the choice of the mathematical method, which is often made empirically (test and try). It is therefore essential to return to fundamental laws governing spectrum formation in order to optimize calibration. Indeed, the light/matter interactions are at the basis of the resulting linear modeling. This chapter reviews and discusses the basic theoretical concepts underpinning NIRS and linear chemometric modeling in the specific context of soil: (i) light scattering due to soil particles causes departure in the assumed linear relationship between the spectrum and the carbon content, and (ii) the other classical linear regression assumptions (constant residual variance, normal error distribution, etc.) are also put into question. Regarding these specific issues, the different chemometric methods presented as possible solutions to perform better calibration model are discussed, from linear methods associated with various preprocessing, local methods, or nonlinear methods.


      PubDate: 2013-12-20T04:13:58Z
       
  • Chapter Three Today's Use of Haploids in Corn Plant Breeding
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 123
      Author(s): David F. Weber
      Haploids have become one of the most effective tools in maize breeding. This chapter discusses two approaches utilizing maize haploids that have assumed great importance in commercial corn breeding. They are (1) producing and doubling the chromosomes in maternal haploids to generate double haploids (instant inbreds) and (2) utilizing paternal haploids produced utilizing the indeterminate gametophyte1 mutation to convert male-fertile lines into cytoplasmic male-sterile lines. Both approaches require only two generations, while traditional procedures require about seven to eight generations. These procedures have helped to make the breeding of corn more efficient and economical. The characteristics of maize haploids, methods to produce and select them and double their chromosomes, and the advantages of utilizing maize haploids are discussed.


      PubDate: 2013-12-20T04:13:58Z
       
  • Chapter Two Global Warming and Its Possible Impact on Agriculture in India
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 123
      Author(s): Bhagirath Singh Chauhan , Prabhjyot-Kaur , Gulshan Mahajan , Ramanjit Kaur Randhawa , Harpreet Singh , Manjit S. Kang
      Progress has been significant in climate science and the direct and indirect influences of climate on agricultural productivity. With the likely growth of the world's population toward 10 billion by 2050, demand for food crops will grow faster than demand for other crops. The prospective climate change is global warming (with associated changes in hydrologic regimes and other climatic variables) induced by the increasing concentration of radiatively active greenhouse gases. Climate models project that global surface air temperatures may increase by 4.0–5.8°C in the next few decades. These increases in temperature will probably offset the likely benefits of increasing atmospheric concentrations of carbon dioxide on crop plants. Climate change would create new environmental conditions over space and time and in the intensity and frequency of weather and climate processes. Therefore, climate change has the potential to influence the productivity of agriculture significantly. Climate variability has also become a reality in India. The increase in mean temperature by 0.3–0.6°C per decade since the 1860s across India indicates significant warming due to climate change. This warming trend is comparable to global mean increases in temperature in the past 100 years. It is projected that rainfall patterns in India would change with the western and central areas witnessing as many as 15 more dry days each year, whereas the northern and northwestern areas could have 5 to 10 more days of rainfall annually. Thus, dry areas are expected to get drier and wet areas wetter. It is projected that India's population could reach 1.4 billion by 2025 and may exceed China's in the 2040s. If agricultural production is adversely affected by climate change, livelihood and food security in India would be at risk. Because the livelihood system in India is based on agriculture, climate change could cause increased crop failure and more frequent incidences of pests. Therefore, future challenges will be more complex and demanding. This chapter focuses on the variability of climate change and its probabilistic effects on agricultural productivity and adaptation and mitigation strategies that can help in managing the adverse effect of climate change on agricultural productivity, in particular for India.


      PubDate: 2013-12-20T04:13:58Z
       
  • Preface
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 123
      Author(s): Donald L. Sparks



      PubDate: 2013-12-20T04:13:58Z
       
  • Chapter One Bioavailability, Toxicity, and Fate of Manufactured
           Nanomaterials in Terrestrial Ecosystems
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 123
      Author(s): Jonathan D. Judy , Paul M. Bertsch
      The use of manufactured nanomaterials (MNMs) in consumer products has increased steadily over the past decade. MNMs from these consumer products are being discharged into waste streams and subsequently entering terrestrial ecosystems, primarily via land application of biosolids. As a result, the concentrations of MNMs in terrestrial ecosystems are increasing exponentially. Despite this, the majority of research investigating the bioavailability, fate, and effects of MNMs has focused on aquatic ecosystems. We review the current state of the knowledge on the fate of MNMs in terrestrial ecosystems as well as their effects on critical terrestrial ecoreceptors, including plants, bacteria, fungi, and soil invertebrates. While research on the bioavailability, toxicity, and ultimate fate of MNMs in terrestrial ecosystems is in its infancy, we conclude that there are critical knowledge gaps and an incomplete picture is emerging, with many studies reporting contradictory results. We also conclude that major discrepancies in the literature are primarily related to methodological and experimental shortcomings, such as inadequate MNM characterization, lack of consideration of MNM aggregation or dissolution, lack of proper controls, or the use of environmentally irrelevant MNM concentrations and/or exposure conditions. However, it is now evident that, under certain circumstances, MNMs are bioavailable and toxic to several key terrestrial ecoreceptors. It is also evident that additional systematic research focusing on the most environmentally relevant MNMs, including MNM transformation products and exposure conditions, is required to assess the risks posed to terrestrial ecosystems by nanotechnology.


      PubDate: 2013-12-20T04:13:58Z
       
  • Contributors
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 123




      PubDate: 2013-12-20T04:13:58Z
       
  • Copyright
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 123




      PubDate: 2013-12-20T04:13:58Z
       
  • Sereis Page
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 123




      PubDate: 2013-12-20T04:13:58Z
       
  • Chapter Four Genetic Diversity for Wheat Improvement as a Conduit to Food
           Security
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 122
      Author(s): A. Mujeeb-Kazi , Alvina Gul Kazi , Ian Dundas , Awais Rasheed , Francis Ogbonnaya , Masahiro Kishii , David Bonnett , Richard R.-C. Wang , Steven Xu , Peidu Chen , Tariq Mahmood , Hadi Bux , Sumaira Farrakh
      Genetic diversity is paramount for cultivated crops genetic improvement, and for wheat this resides in three gene pools of the Triticeae. In wheat, access to this diversity and its exploitation is based upon the genetic distance of the wild species relatives from the wheat genomes. For several decades, these wide crosses have been a reservoir of novel variation for wheat improvement. Among these, close relatives of the primary gene pool have been preferred since this ensures successful gene transfer as they permit homologous genetic exchanges to occur between related genomes, as exemplified by the A and D genome diploid progenitors. One strategy has been based upon first producing genetic stocks that capture the potential of the diploids via bridge crossing where the D genome synthetic hexaploid wheats (2n =6x =42, AABBDD) are exploited. The synthetics are products of crosses between elite durum wheat cultivars (Triticum turgidum) and various Aegilops tauschii accessions. Similarly, the diversity of the A and B genomes has also been assembled as AABBAA (T. turgidum/A genome diploids Triticum boeoticum, Triticum monococcum, Triticum urartu) and AABBBB (SS) (T. turgidum/Aegilops speltoides). The utilization of these useful diversity for various biotic/abiotic stresses including in the development of molecular tools for enhancing breeding efficiency has been in the forefront of wheat improvement over the past two decades. Additional strategy employed includes the direct crosses between parental diploids and recipient wheat cultivars extended to give even swifter products by top- or backcrossing the F1 combinations with either durum or bread wheats. Relatively less progress has been made in the use of genes from tertiary gene pool often involving “intergeneric crosses.” The potency of potentially useful diversity in tertiary gene pool warrants further exploitation of this resource. Presented here are major facets of intergeneric hybridization embracing a taxonomic consideration of genetic diversity within the Triticeae, the exploitation protocols, prebreeding strategies, and some of the outputs from distant hybridization with a major focus on wheat/alien chromosomal exchanges classed as “translocations” such as T1BL.1RS and to a lesser degree the T1AL.1RS Robertsonian translocations. This chapter also attempts to relate the exploitation of the Triticeae genetic diversity with wheat productivity as a means of addressing diverse stress constraints that if pursued will provide yield enhancing outputs necessary for overriding environmental limitations of climate change, unpredictable incidences of biotic stresses, and catalyzing gains for food security with wheat.


      PubDate: 2013-09-17T04:35:07Z
       
  • Chapter Three Wien Effect in Suspensions and Its Application in Soil
           Science A Review
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 122
      Author(s): Yu-Jun Wang , Cheng-Bao Li , Dong-Mei Zhou , Shmulik P. Friedman
      The exchange and adsorption of ions in soils depend on their interactions with the charged mineral and organic soil particles. In the last several decades, these interactions were quantified in terms of adsorption energies, but the few reported attempts to evaluate adsorption energies between ions and soil particles were based on indirect deduction, rather than on direct measurement, because of lack of reliable and practical experimental methods. This chapter presents and reviews a recently suggested Wien Effect method; it offers an opportunity for more reliable and direct characterization and quantification of interactions between soil particles and ions, in terms of several quantifiers that range in nature from phenomenological to mechanistic to thermodynamic. The term “Wien Effect” refers to the increase of electrical conductivity (EC) with increasing applied electrical field (E). After introducing the subject of ion adsorption on charged soil particles, we describe our first experimental findings and discuss the mechanisms of the Wien Effect in simple electrolyte solutions and in suspensions. We then review a few methods of interpreting Wien Effect measurements in suspensions, along with demonstrating their application to quantifying the particle–ion interactions for several systems of soil, clay, and oxide particles interacting with various cations and anions. The examples of EC(E) measurements of various soil particle–ion systems and their interpretations by several quantifiers presented in this chapter demonstrate the merits of the Wien Effect method for quantifying particle–ion interactions and adsorption energies. Obviously, the Wien Effect method can also be used to characterize the adsorption of ions on other charged, nonsoil colloidal particles.


      PubDate: 2013-09-17T04:35:07Z
       
  • Chapter Two Assessment and Modeling of Soil Available Phosphorus in
           Sustainable Cropping Systems
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 122
      Author(s): Noura Ziadi , Joann K. Whalen , Aimé J. Messiga , Christian Morel
      Phosphorus (P) is one of the most limiting essential nutrients for agricultural crop production. Diminishing global reserves of rock phosphate are expected to reduce supply and increase the cost of mineral P fertilizers, a major concern in regions where low soil available P levels constrain crop production. In other parts of the world, intensive livestock production and agricultural management have resulted in high soil available P concentrations, which contribute to environmental pollution and threaten water quality. The objective of this review was to examine the factors affecting soil available P in agroecosystems. Physicochemical and biological controls on the soil available P, in the context of P biogeochemical cycling, are presented. Agricultural management practices such as crop rotations, tillage, and P fertilizer sources influence the size of the soil available P pool, while environmental conditions such as freezing–thawing and wetting–drying cycles control the temporal dynamics of this pool. Methods to evaluate soil available P in the laboratory and in situ are reviewed. Attention is given to the isotopic dilution method that quantifies fluxes of P ions between soil solid phase and soil solution, which can be combined with the Freundlich kinetic equation to describe diffusive soil P transfer, leading to the development of a process-based mass-balance model to assess soil available P. This model has potential to advance scientific understanding about soil available P dynamics for better decision making about P fertilization and agroenvironmental management in sustainable cropping systems.


      PubDate: 2013-09-17T04:35:07Z
       
  • Preface
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 122
      Author(s): Donald L. Sparks



      PubDate: 2013-09-17T04:35:07Z
       
  • Chapter One Micronutrient Constraints to Crop Production in the Middle
           East–West Asia Region Significance, Research, and Management
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 122
      Author(s): John Ryan , Abdul Rashid , José Torrent , Sui Kwong Yau , Hayriye Ibrikci , Rolf Sommer , Emin Bulent Erenoglu
      In addition to nine major nutrients, eight micronutrients [i.e., boron (B), chlorine (Cl), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), and zinc (Zn)] are also essential for healthy growth and reproduction of higher plants. Globally, crop production is largely dependent on chemical fertilizer use, especially in developed countries. While fertilizer use, particularly nitrogen (N) and phosphorus (P), has increased substantially in the past four decades in developing countries, such as Pakistan and India, fertilizer use is limited in many areas of the world where agriculture is constrained by harsh climatic conditions, especially low rainfall. The disparity between developed and developing countries is particularly acute with respect to micronutrient awareness and use. One area of the world that is characterized by major climatic and soil constraints, often exacerbated by unfavorable socioeconomic conditions, is the Middle East–West Asia region. This review provides a current perspective on that region of the world where crop yields are invariably low due to drought, with limited inputs and inherent soil nutrient deficiencies. With a high population, there is an urgent need to sustainably expand output. However, there is generally limited awareness of the potential significance of micronutrients in agriculture as factors in crop production, as well as limited research on micronutrients in most countries of the region. The long history of cultivated agriculture in the Middle East–West Asia region and the peculiar characteristics of its soils and climate predispose it toward problems of micronutrient deficiencies. Over three decades ago, a global study on micronutrients indicated widespread deficiencies of iron (Fe) and zinc (Zn), in contrast to copper (Cu) and manganese (Mn), but suggested the likelihood of excess levels of boron (B) in some countries of the region. This overview primarily addresses three focal points in the region, Pakistan in the east, Syria/Lebanon/Turkey in the center, and Spain on the western fringes, reflecting the zones of activity of the respective authors; the latter focal point is a developed region, where, because of soil and climatic similarities, the research is relevant to the whole Middle East–West Asia region. While providing some international context, this article brings together and summarizes published work in the areas of crop and soil micronutrient availability, their behavior in soils in relation to crop growth, and strategies to deal with either deficiency or toxicity, including crop selection for tolerance and subsequent genetic manipulation. Considerable strides have been made in elucidating the significance of both Zn and Fe in the region's mainly calcareous soils, through soil and plant analysis, with the resulting knowledge providing a sound basis for management interventions through validated field research. While B deficiency is common in some countries such as Pakistan, the problem of B toxicity (BT), where it exists, is only handled by crop adaptation. The review also highlights the implications of micronutrient constraints in the soil–plant–human–animal continuum. Intensification of agricultural production as a result of overall macronutrient use, expansion of irrigation, and introduction of new or “niche” crops is likely to accentuate micronutrient deficiencies in the region, but developments such as conservation agriculture may counteract this trend. As the trend for land-use intensification increases because of higher yields due to fertilizer use and irrigation and the introduction of new crops, and as other nutrient constraints are eliminated, micronutrients will inevitably assume greater significance in the future agriculture of the Middle East–West Asia region together with improvements in plant breeding and crop management.


      PubDate: 2013-09-17T04:35:07Z
       
  • Contributors
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 122




      PubDate: 2013-09-17T04:35:07Z
       
  • Copyright
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 122




      PubDate: 2013-09-17T04:35:07Z
       
  • Series Page
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 122




      PubDate: 2013-09-17T04:35:07Z
       
  • Chapter Three Characterization of Organic Matter Composition of Soil and
           Flow Path Surfaces Based on Physicochemical Principles—A Review
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 121
      Author(s): Ruth H. Ellerbrock , Horst H. Gerke
      Surfaces of macropores in structured soils can made of clay-organic coatings on soil aggregates or linings on worm burrow or root channel walls. The outermost layer of such surfaces is mostly covered by organic matter (OM), which finally controls sorption properties that are relevant for preferential flow and transport. However, the OM properties and local distributions along flow path surfaces are largely unknown, and methods for analyzing intact surfaces are limited. This chapter reviews the principles and applications of Fourier Transform infrared (FTIR) spectroscopy in comparison with complementary nuclear magnetic resonance technique; it describes FTIR techniques for analyzing the composition of bulk soil OM and of OM fractions and of the millimeter-scale spatial distribution at intact surfaces in structured soils for comparing OM composition with cation exchange capacity of OM and soil wettability. Maps of the millimeter-scale heterogeneous spatial distribution of OM composition at aggregate and burrow surfaces could be obtained with diffuse reflectance FTIR (DRIFT) mapping technique. The distribution of OM composition suggests that sorption properties of the OM and wettability of macropore surfaces are also spatially variable at this local scale. DRIFT mapping technique requires relatively smooth and fine-textured intact sample surfaces; further developments need to account for effects of microtopography on the scattering of infrared light. The results indicate yet unknown implications for preferential flow and transport in structured soil, especially for reactive solutes.


      PubDate: 2013-06-20T23:14:14Z
       
  • Chapter Two Conservation Practices for Climate Change Adaptation
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 121
      Author(s): Jorge A. Delgado , Mark A. Nearing , Charles W. Rice
      The threat of climate change is a great challenge to sustainable land management (USDA-NRCS, 2010a). Several publications have reported that over the last few decades, rainfall intensities have increased in many parts of the world, including in the United States. Without good, productive soils and the ecosystem services provided by them, the survival of our species will be in jeopardy. The future changes in climate that will drive erosion processes will significantly impact soil erosion rates, with higher projected erosion rates for the United States. These higher erosion rates will significantly contribute to lower soil productivity, lower soil organic matter content, lower soil quality, and higher rates of nutrient loss that will contribute to a reduction in the inherent soil fertility that is so important for maintaining viable economic systems and sustainability. These same hydrological changes will also include the occurrence of occasional droughts, and for some regions, such as the southwestern United States, projections suggest that there will be a decrease in precipitation and a drier region, which will have negative effects on plant productivity and increase the potential for wind erosion. Farmer management adaptations and use of conservation practices to adapt to a changing climate (e.g., no-till practices, crop rotations, precision conservation, crop selection and dates of planting, harvest, and tillage) have the potential to greatly reduce soil erosion rates. Conservation practices will be key and must be used as strategies for adaptation to climate change impacts on the soil resource. Examples of key strategies are the use of conservation tillage, management of crop rotations and crop residue (including use of cover crops where viable), management of livestock grazing intensities, improved management of irrigation systems, use of technologies, and precision conservation. Many other conservation practices also have the potential to reduce much or all of the potential acceleration of soil erosion rates that may occur under a change in climate that will bring more total rainfall with higher intensity rainfall events, or a change to a drier climate that will potentially bring higher wind erosion rates. One important adaptation practice will be to consider projected spatial changes in the hydrological cycle, such as wetter and drier regions, and periods of drought. This could help in the development and/or implementation of soil and water conservation policies that consider temporal and spatial effects from climate change at the regional level. These policies should also consider conservation practices that contribute to increased water-holding capacity in the soil profile, improved drainage practices, and the development of new crop varieties and cropping systems that are more resistant to drought.


      PubDate: 2013-06-20T23:14:14Z
       
  • Preface
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 121
      Author(s): Donald L. Sparks



      PubDate: 2013-06-20T23:14:14Z
       
  • Chapter One Advances in the Analysis of Biogeochemical Interfaces NanoSIMS
           to Investigate Soil Microenvironments
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 121
      Author(s): Carsten W. Mueller , Peter K. Weber , Matt R. Kilburn , Carmen Hoeschen , Markus Kleber , Jennifer Pett-Ridge
      Since a NanoSIMS high-resolution secondary ion mass spectrometry (SIMS) instrument was first used for cosmochemistry investigations over a decade ago, both interest in NanoSIMS and the number of instruments available have significantly increased. However, SIMS comes with a set of challenges that are of both technical and conceptual nature, particularly for complex samples such as soils. Here, we synthesize existing research and provide conceptual and technical guidance to those who wish to investigate soil processes at the submicron scale using SIMS, specifically with NanoSIMS. Our review not only offers advice resulting from our own operational experience but also intends to promote synergistic research on yet unresolved methodological issues. We identify and describe the basic setup of a NanoSIMS instrument, and important issues that may arise as a soil sample specimen are prepared for NanoSIMS analysis. This is complemented by discussions of experimental design, data analysis, and data representation. Next to experimental design, sample preparation is the most crucial prerequisite for successful NanoSIMS analyses. We discuss the requirements and limitations for sample preparation over the size range from individual soil particles to intact soil structures such as macroaggregates or intact soil cores. For robust interpretation of data obtained by NanoSIMS, parallel spatial, textural (scanning electron microscopy, atomic force microscopy), or compositional analyses (scanning transmission X-ray microscopy) are often necessary to provide necessary context. We suggest that NanoSIMS analysis is most valuable when applied in concert with other analytical procedures and can provide powerful inference about small-scale processes that can be traced via isotopic labeling or elemental mapping.


      PubDate: 2013-06-20T23:14:14Z
       
  • Copyright
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 121




      PubDate: 2013-06-20T23:14:14Z
       
  • Contributors
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 121




      PubDate: 2013-06-20T23:14:14Z
       
  • Series Page
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 121




      PubDate: 2013-06-20T23:14:14Z
       
  • Chapter Four The Chemistry and Biochemistry of Organic Components in the
           Soil Solutions of Wheat Rhizospheres
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 121
      Author(s): Carlos M. Monreal , Morris Schnitzer
      As very little is known about the chemical identities of organic compounds present in soil solutions, the purpose of this research was to chemically characterize soil solutions obtained from a Brunisol on which wheat (Triticum aestivum) was grown to maturity. Soil solutions were obtained by high-speed centrifugation from the rhizospheres at four growth stages of wheat: four leaves unfolded, flag leaf, grain—early milk, and grain—dry seed. Pyrolysis-field ionization mass spectrometry (Py-FIMS) was used to chemically characterize the soil solutions. We identified 346 organic components in each soil solution, which we grouped into the following 11 compound classes: carbohydrates, amino acids, phenols+lignin monomers, lignin dimers, n-alkyl benzenes, flavonoids, alkyl radicals, fatty acids+alkanes, N-heterocyclics+other N-compounds, sterols and steroids, and esters of suberin. The most abundant classes were lipids (fatty acids and alkanes), N-heterocyclics, and phenols+lignin monomers and dimers. The highest content of most organic components (except carbohydrates) in soil solutions occurred at the flag leaf stage of wheat growth. Many of the identified organics in soil solutions are secondary plant metabolites which represent key weapons in the continuous struggle of plant and soil microorganisms for ensuring vital space and access to nutrients and energy resources. Some of the identified compounds are also chemical signals for the interactions between plants and soil microorganisms. The chemical components of the four soil solutions from wheat rhizosphere resembled that of humic substances (HSs). Organic components in soil solutions are substrates for the microbial and chemical synthesis of HS.


      PubDate: 2013-06-20T23:14:14Z
       
  • Chapter Five Sustainable Management of Soils of Dryland Ecosystems of
           India for Enhancing Agronomic Productivity and Sequestering Carbon
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 121
      Author(s): Ch. Srinivasarao , B. Venkateswarlu , Rattan Lal , A.K. Singh , Sumanta Kundu
      Soil organic carbon (SOC) is a strong determinant of soil quality and crop productivity, especially in the arid and semiarid environments of the tropics. Drought stress, high temperatures reaching up to 45°C for 8–10 weeks in a year, coupled with low biomass productivity are common features of dry agroecosystems. India, with only 2.5% of the world’s geographical area, is a home to 17% of the global population. Population increased from 361 million in 1951 to 1140 million in 2011, more than threefold increase over 50 years. Productivity levels of rainfed dryland crops are far below those of global average. Thus, increasing productivity of rainfed cropping systems is an urgent task to meet the food demand of an ever-increasing population because 57% of the total arable land area of 141Mha is under rainfed farming. Yields of important rainfed production systems in long-term manurial experiments under different climate and soil types show declining trends even with adoption of some recommended management practices (RMPs). Some RMPs include diverse crop rotations with legumes, and integrated nutrient management (INM) involving addition of farmyard manure (FYM), use of groundnut shells (GNS) and other crop residues (CRs), green leaf manuring (GLM), etc. These RMPs have been tested in seven long-term experiments of 13–27 years duration established in diverse soils and agroecoregions. These studies, under the auspices of the All India Coordinated Research Project on Dryland Agriculture (AICRPDA), were conducted under diverse soil and climatic conditions, viz., Anantapur and Bengaluru (Alfisol), Solapur and Indore (Vertisol), Sardar Krushinagar (Entisol), and Varanasi (Inceptisol). Seven rainfed cropping system experiments involved major crops of the region including groundnut (Arachis hypogaea), finger millet (Eleusine coracana), winter sorghum (Sorghum bicolor), pearl millet (Pennisetum glaucum), cluster bean (Cyamopsis tetragonoloba), castor (Ricinus communis), soybean (Glycine max), safflower (Carthamus tinctorius), lentil (Lens esculenta), and upland rice (Oryza sativa). Diverse nutrient management treatments assessed included cattle manure, green leaf manure, crop residues, and chemical fertilizers. Common soil fertility management treatments across seven experiments were control (no fertilizer or organics), 100% recommended dose of fertilizers (RDFs), 50% RDF+50% organics, and 100% organics. Maintaining or improving SOC concentration in rainfed dryland agroecosystems is a major agronomic challenge. Yet, the data from long-term experiments show that increasing SOC concentration by C sequestration and stabilization positively affects yields of several crops. Agronomic efficiency of added nutrients and partial factor productivity of crops are maintained or enhanced with INM practices including application of organics in conjunction with chemical fertilizers, but decline with application of only chemical fertilizers because of declining SOC concentration and soil quality with continuous cropping. In comparison with the control, grain yield of all crops are increased significantly with the adoption of INM practices using locally available organic resources. The magnitude of increase in yield (Mgha−1) in respect to control is from: (1)0.78 to 1.03 in groundnut with 50% RDF+FYM4Mgha−1, (2) 0.40 to 1.34 and 0.82 to 3.96 in groundnut and finger millet, respectively, through FYM10Mgha−1 +100% NPK in groundnut–finger millet rotation, (3) 0.84 to 3.28 in finger millet through FYM10Mgha−1 +100% NPK, (4) 0.61 to 1.19 in winter sorghum through 25kgNha−1 (Leucaena clippings)+25kgNha−1 (urea), (5) 0.43 to 0.81, 0.32 to 0.58 and 0.44 to 0.83 in pear millet, cluster bean, and castor, respectively, through 50% RDN (fertilizer)+50% RDN (FYM), (6) 1.04 to 2.10 and 0.63 to 1.49 in soybean and safflower, respectively, through FYM6Mgha−1 +20kgN+13kgPha−1, and (7) 1.08 to 1.95 and 0.48 to 1.04 in rice and lentil, respectively, through 50% N (FYM)+50% RDF treatment.
      PubDate: 2013-06-20T23:14:14Z
       
  • Chapter Six The Influence of Volcanic Tephra (Ash) on Ecosystems
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 121
      Author(s): Olafur Arnalds
      Volcanic eruptions affect a large proportion of Earth’s ecosystems, ranging from subtle dust inputs to thick deposits near the volcanoes. In this chapter, multiple influences of tephra deposition on land are investigated, using examples of recent volcanic eruptions. “Tephra” is the collective term for airborne volcanic materials, while ash is restricted to materials <2mm in grain size. Impacts of tephra is depended on the nature of the tephra, including crystallinity, chemical composition, and grain size. The interaction between vegetation height and the deposition depth has a major influence on impacts, while surface roughness and other factors are also important. Low growing Arctic, alpine, and desert ecosystems are much more sensitive than higher vegetation and forests. Recovery time ranges from few to >1000 years. Alien species can severely interfere with ecosystem recovery. Erosion processes contribute to volcanic impacts by redistributing tephra, thus reducing tephra thicknesses in some places, but can also cause erosion rates exceeding 100,000tkm−2 year−1. Wind erosion of tephra affects ecosystems, agriculture, and health but can provide beneficial dust inputs afar. Thick tephra deposits have pronounced impacts on agriculture, and F toxicity is common in volcanic areas. Soils that form in parent materials dominated by volcanic ash are mostly Andisols with the colloidal fraction dominated by short range order minerals and metal–humus complexes. Andisols are often fertile soils with a high capacity to accumulate carbon. There is a need for multidisciplinary long-term research on impacts and responses to volcanic eruptions.


      PubDate: 2013-06-20T23:14:14Z
       
  • Chapter Seven Advances in Elucidating Beneficial Interactions Between
           Plants, Soil, and Bacteria
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 121
      Author(s): Birgit Mitter , Günter Brader , Muhammad Afzal , Stephane Compant , Muhammad Naveed , Friederike Trognitz , Angela Sessitsch
      Survival of every organism on earth depends on its interactions with other organisms. For example, animals form associations with the intestinal microflora, while plants develop symbiotic associations with neighboring plants, microflora, and microfauna. Most of the associations between plants and microorganisms are mediated by organic compounds released by the plant. The plant root system acts as a factory and exudes enormous amount of chemicals to effectively communicate with the surrounding soil organisms. Bacteria on roots and in the rhizosphere can also utilize these organic compounds as a source of nutrients and enhance their population size and metabolic activities. In return, plant-associated bacteria improve plant growth and development by different mechanisms including nitrogen fixation, provision of nutrients, and mediating resistance against pathogens. Although plant–bacterial partnerships have been found effective to enhance biomass production, their importance and relevance in agricultural systems are still underestimated. A better understanding of beneficial interactions between plant, soil, and bacteria could be exploited to improve growth and health of food and feed crops. Plant growth-promoting mechanisms of bacteria might enhance biomass production in a more sustainable manner, even on marginal land. Furthermore, plant growth-promoting and/or pollutant-degrading activities of bacteria could be exploited to improve the efficiency of phytoremediation of organic and inorganic pollutants from the soil and water or to protect the food chain by decreasing the concentrations of pollutants in food crops.


      PubDate: 2013-06-20T23:14:14Z
       
  • Chapter Eight The Buffer Power Concept and Its Relevance in African and
           Asian Soils
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 121
      Author(s): K.P. Prabhakaran Nair
      “The Nutrient Buffer Power Concept,” a revolutionary soil testing procedure developed and tested over more than three decades after laboratory and field experimentation in European, African, and Asian soils, looks at soil testing to devise appropriate and accurate fertilizer recommendations for many field crops such as rye, wheat, and maize among cereals, red gram among pulses, white clover among fodder crops, and black pepper and cardamom among perennial spice crops, with a totally new perspective, as compared to routine “text book” methods of soil testing. The center piece of the concept is the accurate quantification of a soil nutrient's buffer power, which is then integrated into routine soil test data to derive appropriate and accurate fertilizer recommendations. Results showed that plant uptake of phosphorus, potassium, and zinc, the principal test elements, were closely related to their buffer power, with a coefficient of determination of as much as 98%, rather than their routine soil test data. The author makes out a strong case to propagate the new idea on a global basis. The concept has received global scientific attention and was recently short listed (the only one from Asia) for the very prestigious U.S. $1 million Rolex Awards for Enterprise of the Rolex Foundation, Geneva, from among more than 3500 nominations.


      PubDate: 2013-06-20T23:14:14Z
       
  • Chapter Two Chromium Contamination and Its Risk Management in Complex
           Environmental Settings
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 120
      Author(s): Girish Choppala , Nanthi Bolan , Jin Hee Park
      Chromium reaches the soil environment through waste disposal emanating from a number of industrial activities, including coal-fired power production, electroplating, leather tanning, timber treatment, pulp production, and mineral ore and petroleum refining. Of the heavy metals, chromium (Cr) is a major pollutant, poses a great threat to flora and fauna and persists for long time. The most abundant species of Cr—Cr(III) and Cr(VI)—have very different properties. The toxicity, mobility, and bioavailability of Cr mainly depend on its speciation. In the natural environment, Cr(III) is most immobile, less soluble and stable, whereas Cr(VI) is highly mobile, soluble and bioavailable. Redox reactions play an important role in the interconversion of Cr(VI) and Cr(III). As our awareness of the rising toxicity of Cr increases, it is necessary to develop new and advanced strategies to mitigate this toxicity in the environment. Several physicochemical methods have been developed but these techniques are expensive and are not readily applicable to large contaminated zones. This chapter provides an overview of the concepts of Cr biogeochemistry, bioavailability and integrated risk management. The physicochemical factors, speciation and toxicity have been discussed with special emphasis on the remediation methods due to the complex reactions associated with Cr toxicity mitigation. Furthermore, this study identified systematically the future needs for understanding Cr biogeochemistry and low-cost remediation methods.


      PubDate: 2013-04-29T19:46:31Z
       
  • Front Matter
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 120




      PubDate: 2013-04-29T19:46:31Z
       
  • Advances in Agronomy
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 120




      PubDate: 2013-04-29T19:46:31Z
       
  • Copyright
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 120




      PubDate: 2013-04-29T19:46:31Z
       
  • Contributors
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 120




      PubDate: 2013-04-29T19:46:31Z
       
  • Preface
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 120
      Author(s): Donald L. Sparks



      PubDate: 2013-04-29T19:46:31Z
       
  • Chapter One Food, Nutrition and Agrobiodiversity Under Global Climate
           Change
    • Abstract: Publication date: 2013
      Source:Advances in Agronomy, Volume 120
      Author(s): Sangam Dwivedi , Kanwar Sahrawat , Hari Upadhyaya , Rodomiro Ortiz
      Available evidence and predictions suggest overall negative effects on agricultural production as a result of climate change, especially when more food is required by a growing population. Information on the effects of global warming on pests and pathogens affecting agricultural crops is limited, though crop–pest models could offer means to predict changes in pest dynamics, and help design sound plant health management practices. Host-plant resistance should continue to receive high priority as global warming may favor emergence of new pest epidemics. There is increased risk, due to climate change, to food and feed contaminated by mycotoxin-producing fungi. Mycotoxin biosynthesis gene-specific microarray is being used to identify food-born fungi and associated mycotoxins, and investigate the influence of environmental parameters and their interactions for control of mycotoxin in food crops. Some crop wild relatives are threatened plant species and efforts should be made for their in situ conservation to ensure evolution of new variants, which may contribute to addressing new challenges to agricultural production. There should be more emphasis on germplasm enhancement to develop intermediate products with specific characteristics to support plant breeding. Abiotic stress response is routinely dissected to component physiological traits. Use of transgene(s) has led to the development of transgenic events, which could provide enhanced adaptation to abiotic stresses that are exacerbated by climate change. Global warming is also associated with declining nutritional quality of food crops. Micronutrient-dense cultivars have been released in selected areas of the developing world, while various nutritionally enhanced lines are in the release pipeline. The high-throughput phenomic platforms are allowing researchers to accurately measure plant growth and development, analyze nutritional traits, and assess response to stresses on large sets of individuals. Analogs for tomorrow’s agriculture offer a virtual natural laboratory to innovate and test technological options to develop climate resilience production systems. Increased use of agrobiodiversity is crucial to coping with adverse impacts of global warming on food and feed production and quality. No one solution will suffice to adapt to climate change and its variability. Suits of technological innovations, including climate-resilient crop cultivars, will be needed to feed 9 billion people who will be living in the Earth by the middle of the twenty-first century.


      PubDate: 2013-04-29T19:46:31Z
       
 
 
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