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  Subjects -> AGRICULTURE (Total: 660 journals)
    - AGRICULTURAL ECONOMICS (71 journals)
    - AGRICULTURE (443 journals)
    - CROP PRODUCTION AND SOIL (84 journals)
    - DAIRYING AND DAIRY PRODUCTS (25 journals)
    - POULTRY AND LIVESTOCK (37 journals)

AGRICULTURE (443 journals)                  1 2 3 4 5 | Last

Acta agriculturae Slovenica     Open Access   (Followers: 5)
Acta Agrobotanica     Open Access   (Followers: 3)
Acta Agronomica Hungarica     Full-text available via subscription   (Followers: 1)
Acta Agronomica Sinica     Full-text available via subscription   (Followers: 6)
Acta Scientiarum. Animal Sciences     Open Access   (Followers: 1)
Acta Scientiarum. Technology     Open Access   (Followers: 1)
Acta Technologica Agriculturae     Open Access   (Followers: 1)
Advances in Agriculture & Botanics     Open Access   (Followers: 10)
Advances in Agriculture, Sciences and Engineering Research     Open Access   (Followers: 10)
Advances in Agronomy     Full-text available via subscription   (Followers: 11)
Advances in Life Science and Technology     Open Access   (Followers: 5)
AFBM Journal     Open Access  
Africa Development     Open Access   (Followers: 6)
Africa Research Bulletin: Political, Social and Cultural Series     Hybrid Journal   (Followers: 6)
African Journal of Agricultural Research     Open Access   (Followers: 1)
African Journal of Food Science     Open Access   (Followers: 1)
African Journal of Food, Agriculture, Nutrition and Development     Open Access   (Followers: 1)
African Journal of Horticultural Science     Open Access   (Followers: 2)
African Journal of Range and Forage Science     Hybrid Journal   (Followers: 5)
African Journal of Sustainable Development     Full-text available via subscription   (Followers: 3)
Agribusiness : an International Journal     Hybrid Journal   (Followers: 5)
Agricultura Tecnica     Open Access   (Followers: 5)
Agricultura Tropica et Subtropica     Open Access   (Followers: 1)
Agricultural Advances     Open Access   (Followers: 3)
Agricultural and Food Science     Open Access   (Followers: 14)
Agricultural Economics     Hybrid Journal   (Followers: 44)
Agricultural History     Full-text available via subscription   (Followers: 150)
Agricultural Research     Hybrid Journal   (Followers: 2)
Agricultural Science     Full-text available via subscription   (Followers: 5)
Agricultural Sciences     Open Access   (Followers: 7)
Agricultural Sciences in China     Full-text available via subscription   (Followers: 3)
Agricultural Systems     Hybrid Journal   (Followers: 19)
Agricultural Water Management     Hybrid Journal   (Followers: 13)
Agriculture     Open Access   (Followers: 4)
Agriculture & Food Security     Open Access   (Followers: 9)
Agriculture (Poľnohospodárstvo)     Open Access   (Followers: 1)
Agriculture and Agricultural Science Procedia     Full-text available via subscription  
Agriculture and Human Values     Hybrid Journal   (Followers: 10)
Agriculture, Ecosystems & Environment     Hybrid Journal   (Followers: 29)
Agriprobe     Full-text available via subscription  
Agrivita : Journal of Agricultural Science     Open Access   (Followers: 4)
Agro-Science     Full-text available via subscription  
Agroalimentaria     Open Access   (Followers: 1)
Agrociencia     Open Access   (Followers: 2)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Agronomía Colombiana     Open Access   (Followers: 1)
Agronomía Costarricense     Open Access   (Followers: 2)
Agronomía Mesoamericana     Open Access   (Followers: 1)
Agronomie Africaine     Full-text available via subscription  
Agronomy     Open Access   (Followers: 8)
Agrosearch     Open Access  
AI & Society     Hybrid Journal   (Followers: 2)
Alinteri Zirai Bilimler Dergisi : Alinteri Journal of Agricultural Sciences     Open Access  
Ambiência     Open Access  
Ambiente & Agua : An Interdisciplinary Journal of Applied Science     Open Access   (Followers: 1)
American Journal of Agricultural and Biological Sciences     Open Access   (Followers: 9)
American Journal of Botany     Full-text available via subscription   (Followers: 13)
American Journal of Economics and Sociology     Hybrid Journal   (Followers: 19)
American Journal of Potato Research     Hybrid Journal   (Followers: 2)
Anais da Academia Brasileira de Ciências     Open Access   (Followers: 2)
Annales UMCS, Agricultura     Open Access  
Annales UMCS, Horticultura     Full-text available via subscription  
Annals of Agricultural and Environmental Medicine     Open Access   (Followers: 1)
Annals of Agricultural Sciences     Open Access   (Followers: 1)
Annual Review of Resource Economics     Full-text available via subscription   (Followers: 10)
APCBEE Procedia     Partially Free   (Followers: 2)
Applied Economics Letters     Hybrid Journal   (Followers: 18)
Applied Financial Economics Letters     Hybrid Journal   (Followers: 5)
Arboricultural Journal : The International Journal of Urban Forestry     Hybrid Journal   (Followers: 6)
Archivos de Zootecnia     Open Access  
Arquivos do Instituto Biológico     Open Access  
Arthropod-Plant Interactions     Hybrid Journal   (Followers: 1)
Asian Economic Papers     Hybrid Journal   (Followers: 3)
Asian Journal of Agricultural Research     Open Access   (Followers: 2)
Asian Journal of Plant Sciences     Open Access   (Followers: 1)
Australian Cottongrower, The     Full-text available via subscription   (Followers: 1)
Australian Economic Papers     Hybrid Journal   (Followers: 5)
Australian Forest Grower     Full-text available via subscription   (Followers: 2)
Australian Forestry     Full-text available via subscription   (Followers: 4)
Australian Grain     Full-text available via subscription   (Followers: 4)
Australian Holstein Journal     Full-text available via subscription  
Australian Journal of Agricultural and Resource Economics     Hybrid Journal   (Followers: 5)
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   (Followers: 1)
Bangladesh Journal of Scientific Research     Open Access  
Berkala Ilmiah Pertanian     Open Access   (Followers: 1)
Bioagro     Open Access   (Followers: 1)
Biocatalysis and Agricultural Biotechnology     Hybrid Journal   (Followers: 5)
Biocontrol Science and Technology     Hybrid Journal   (Followers: 5)
Biodiversity     Hybrid Journal   (Followers: 16)
Biodiversity : Research and Conservation     Open Access   (Followers: 17)
Biological Agriculture & Horticulture : An International Journal for Sustainable Production Systems     Partially Free   (Followers: 13)
Biosystems Engineering     Hybrid Journal   (Followers: 1)
Biotemas     Open Access  
Bragantia     Open Access   (Followers: 2)
Brazilian Archives of Biology and Technology     Open Access   (Followers: 1)
British Poultry Science     Hybrid Journal   (Followers: 5)
California Agriculture     Open Access   (Followers: 1)

        1 2 3 4 5 | Last

Journal Cover Advances in Agronomy
   [13 followers]  Follow    
   Full-text available via subscription Subscription journal
     ISSN (Print) 0065-2113
     Published by Elsevier Homepage  [2563 journals]   [SJR: 1.525]   [H-I: 59]
  • Index
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 126




      PubDate: 2014-06-18T20:42:54Z
       
  • Chapter Four Disease and Frost Damage of Woody Plants Caused by
           Pseudomonas syringae Seeing the Forest for the Trees
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 126
      Author(s): Jay Ram Lamichhane , Leonardo Varvaro , Luciana Parisi , Jean-Marc Audergon , Cindy E. Morris
      Pseudomonas syringae is a phytopathogenic bacterium that causes diseases of monocots, herbaceous dicots, and woody dicots, worldwide. On woody plants, reports of disease due to P. syringae have markedly increased in the last years and the diseases have been recognized as a major threat to the primary products of agroforestry practices. Detection in Italy of a new highly aggressive population of P. syringae in 2008 on kiwifruit, which caused severe epidemics in the following years throughout the kiwifruit-growing areas of Asia, Europe, Oceania, and South America, rendered the entire kiwifruit industry vulnerable to the disease. Similarly, occurrence of an aggressive population of P. syringae on horse chestnut in 2002 in the Netherlands has rapidly established itself as a major threat to horse chestnut throughout Northwest Europe. To better understand the origin of such disease epidemics, a thorough knowledge of the pathogen is needed in sensu lato. Here, we report the most important features of the pathogen and its hosts in an attempt to clarify some key aspects. In particular, the diseases and the economic losses they cause, disease epidemiology, pathogen diversity, and the possible means of disease control have been discussed throughout the manuscript. In addition to the ability to cause the disease, the damage caused to woody plants through the ice nucleation activity of this bacterium is discussed.


      PubDate: 2014-06-18T20:42:54Z
       
  • Chapter Three The Physiology of Potassium in Crop Production
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 126
      Author(s): Derrick M. Oosterhuis , Dimitra A. Loka , Eduardo M. Kawakami , William T. Pettigrew
      Potassium (K) plays a major role in the basic functions of plant growth and development. In addition, K is also involved in numerous physiological functions related to plant health and tolerance to biotic and abiotic stress. However, deficiencies occur widely resulting in poor growth, lost yield, and reduced fiber quality. This review describes the physiological functions of K and the role in stress relief and also provides some agronomic aspects of K requirements, diagnosis of soil and plant potassium status, and amelioration. The physiological processes described include enzymes and organic compound synthesis regulation, water relations and stomates, photosynthesis, transport, cell signaling, and plant response to drought stress, cold stress, salt stress, as well as biotic stresses.


      PubDate: 2014-06-18T20:42:54Z
       
  • Chapter Two Water-Saving Innovations in Chinese Agriculture
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 126
      Author(s): Qiang Chai , Yantai Gan , Neil C. Turner , Ren-Zhi Zhang , Chao Yang , Yining Niu , Kadambot H.M. Siddique
      Water scarcity, water pollution, and water-related waste threaten humanity globally, largely due to the limited supply of freshwater on the planet, the unbalanced distribution of water resources, and the excessive consumption of water from the growing population and its economic development. China is facing severe water shortages; the northern part of the country has an average freshwater availability of 760cubic meter per capita per year, 25% below the internationally accepted threshold for water scarcity. Agriculture in northwest China relies on annual precipitation of 50–500mm, 70% of which occurs from July to September, and annual evaporation from 1500 to 2600mm. In the Hexi Corridor regions where annual precipitation is below 150mm, farming largely depends on irrigation with water from Qilian Mountain snowmelt. However, permanent snow on the mountain has moved upwards at a rate of 0.2–1.0m annually, and groundwater in the valley has declined at a rate of 0.5–1.8myear−1. Consequently, some natural oases, along the old Silk Road, have shrunk or disappeared and wells have dried up. At the meantime, some farms use irrigation water at a rate as high as 11,000m3 ha−1, much greater than crop water requirements for high yield. In recent years, many innovative research projects have dealt with the water issue in arid and semiarid northwestern China. In this chapter, we summarize some key water-saving technologies developed from some of these recently completed research projects, and discuss integrated and innovative approaches for the development of water-saving agricultural systems. Our goal is to encourage the use of innovative water-saving technologies to reduce agricultural water use, increase crop water-use efficiency, and improve agricultural productivity.


      PubDate: 2014-06-18T20:42:54Z
       
  • Preface
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 126
      Author(s): Donald L. Sparks



      PubDate: 2014-06-18T20:42:54Z
       
  • Chapter One Soil Chemical Insights Provided through Vibrational
           Spectroscopy
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 126
      Author(s): Sanjai J. Parikh , Keith W. Goyne , Andrew J. Margenot , Fungai N.D. Mukome , Francisco J. Calderón
      Vibrational spectroscopy techniques provide a powerful approach to the study of environmental materials and processes. These multifunctional analytical tools can be used to probe molecular vibrations of solid, liquid, and gaseous samples for characterizing materials, elucidating reaction mechanisms, and examining kinetic processes. Although Fourier transform infrared (FTIR) spectroscopy is the most prominent type of vibrational spectroscopy used in the field of soil science, applications of Raman spectroscopy to study environmental samples continue to increase. The ability of FTIR and Raman spectroscopies to provide complementary information for organic and inorganic materials makes them ideal approaches for soil science research. In addition, the ability to conduct in situ, real time, vibrational spectroscopy experiments to probe biogeochemical processes at mineral interfaces offers unique and versatile methodologies for revealing a myriad of soil chemical phenomena. This review provides a comprehensive overview of vibrational spectroscopy techniques and highlights many of the applications of their use in soil chemistry research.


      PubDate: 2014-06-18T20:42:54Z
       
  • Contributors
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 126




      PubDate: 2014-06-18T20:42:54Z
       
  • Copyright
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 126




      PubDate: 2014-06-18T20:42:54Z
       
  • Front Matter
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 126




      PubDate: 2014-06-18T20:42:54Z
       
  • Advances in Agronomy
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 126




      PubDate: 2014-06-18T20:42:54Z
       
  • Chapter Four Fertilizer Intensification and Its Impacts in China's HHH
           Plains
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 125
      Author(s): Xiangbin Kong , Rattan Lal , Baoguo Li , Hongbin Liu , Kejiang Li , Guanglong Feng , Qingpu Zhang , Bangbang Zhang
      The accomplishment of China's food security by application of high rates of fertilizers has generated several controversies regarding the quality of soil and water resources. Thus, the objective of this chapter is to assess the effects and causes of the fertilizer intensification in the Huang Huai Hai (HHH) plains in China based on the data from five long-term experiments conducted over a period of 20 years, and those from the National Bureau of Statistics of China. The HHH region produces almost 60–80% of China's wheat and 35–40% of China's corn every year. The average increase in yield (kgha−1) between 1985 and 2009 ranged from 1582 to 5860 for wheat and 4492 to 5610 for corn. However, the average rates (kgha−1year−1) of fertilizer use are about 430 of N, 107 of P, and 17 of K. The results from five long-term experiments on sites representative the HHH indicated that fertilizer intensification resulted in an increasing trend of high input of nutrients→high SOM concentration→high yields of wheat (Triticum aestivum) and corn (Zea mays)→higher SOM concentration→higher rate of application of fertilizer in agroecosystems. These mechanisms motivated the farm households to apply higher rate of fertilizer to obtain higher and stable crop yields despite large uncertainties in crop production due to climate change and other risks. Important among future research needs are precision agriculture, soil test, micronutrients, and foliar applications, to enhance the use efficiency of fertilizers and reduce losses.


      PubDate: 2014-04-29T06:45:13Z
       
  • Chapter Three GlobalSoilMap Toward a Fine-Resolution Global Grid of Soil
           Properties
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 125
      Author(s): Dominique Arrouays , Michael G. Grundy , Alfred E. Hartemink , Jonathan W. Hempel , Gerard B.M. Heuvelink , S. Young Hong , Philippe Lagacherie , Glenn Lelyk , Alexander B. McBratney , Neil J. McKenzie , Maria d.L. Mendonca-Santos , Budiman Minasny , Luca Montanarella , Inakwu O.A. Odeh , Pedro A. Sanchez , James A. Thompson , Gan-Lin Zhang
      Soil scientists are being challenged to provide assessments of soil condition from local through to global scales. A particular issue is the need for estimates of the stores and fluxes in soils of water, carbon, nutrients, and solutes. This review outlines progress in the development and testing of GlobalSoilMap—a digital soil map that aims to provide a fine-resolution global grid of soil functional properties with estimates of their associated uncertainties. A range of methods can be used to generate the fine-resolution spatial estimates depending on the availability of existing soil surveys, environmental data, and point observations. The system has an explicit geometry for estimating point and block estimates of soil properties continuously down the soil profile. This geometry is necessary to ensure mass balance when stores and fluxes are computed. It also overcomes some limitations with existing systems for characterizing soil variation with depth. GlobalSoilMap has been designed to enable delivery of soil data via Web services. This review provides an overview of the system's technical specifications including the minimum data set. Examples from contrasting countries and environments are then presented to demonstrate the robustness of the technical specifications. GlobalSoilMap provides the means for supplying soil information in a format and resolution compatible with other fundamental data sets from remote sensing, terrain analysis, and other systems for mapping, monitoring, and forecasting biophysical processes. The initial research phase of the core project is nearing completion and attention is now shifting toward establishing the institutional and governance arrangements necessary to complete a full global coverage and maintaining the operational version of the GlobalSoilMap. This will be a grand and rewarding challenge for the soil science profession in the coming years.


      PubDate: 2014-04-29T06:45:13Z
       
  • Chapter Two Agronomic Biofortification of Cereal Grains with Iron and Zinc
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 125
      Author(s): Rajendra Prasad , Yashbir S. Shivay , Dinesh Kumar
      Iron and zinc deficiencies in human nutrition are widespread in developing Asian and African countries where cereal grains are the staple food. Effects are therefore underway to develop cereal genotypes with grains denser in Fe and Zn by traditional plant breeding or using genetic engineering techniques. This approach requires a long period and adequate funds. However, the products of genetic engineering are not well accepted in many countries. Also, there is a trade-off between yield and grain biofortification. Agronomic biofortification offers to achieve this without sacrificing on yield and with no problem of product acceptance. From the viewpoint of biofortification, foliar application has been reported to be better than the soil application of Fe and Zn, and for this purpose, chelated Fe and Zn fertilizers are better. When soil applied, water soluble sources of Zn are better. Soil application of Fe is not recommended. Agronomic biofortification depends upon management practices (tillage, water management, nutrient interactions), soil factors (amounts present, pH, mechanisms of Zn fixation other than pH), and plant factors (root characteristics, excretion of phytosiderophores and organic acids by roots, Zn utilization at the cellular level, translocation within plant and mechanisms of Zn accumulation in grain). Genetic and agronomic biofortification are complementary to each other. Once the genotypes having denser grains are developed, they will have to be adequately fertilized with Fe and Zn. However, much more research in agronomy, soil science, and plant physiology is needed to understand the complex soil–plant–management interaction under different agroecological conditions under which cereals are grown. The situation is more complex for rice, which is grown under flooded, upland, and intermediate water conditions.


      PubDate: 2014-04-29T06:45:13Z
       
  • Chapter One Advances in Using Oxygen Isotope Ratios of Phosphate to
           Understand Phosphorus Cycling in the Environment
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 125
      Author(s): Deb P. Jaisi , Ruth E. Blake
      Phosphorus (P) is universally recognized as an essential nutrient for all known forms of life and a key element in mediating between living and nonliving parts of the biosphere. Here, we provide a comprehensive review of the development of oxygen isotope methods of phosphate and application to understand the biogeochemical cycling of P. With the advent of robust analytical techniques able to accurately determine stable oxygen isotope ratios in phosphate (δ18OP) and the increased understanding of isotope effects from controlled process- or reaction-based studies, δ18OP values have been increasingly applied to identify sources and cycling of P in many natural environments. Because different sources have distinct isotopic compositions and various processes impart specific isotopic fractionation or produce distinct pathways of isotopic evolution, application of δ18OP values as a tracer for P in biogeochemical processes is expected to continue to expand as an exciting field of research in the future.


      PubDate: 2014-04-29T06:45:13Z
       
  • Preface
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 125
      Author(s): Donald L. Sparks



      PubDate: 2014-04-29T06:45:13Z
       
  • Contributors
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 125




      PubDate: 2014-04-29T06:45:13Z
       
  • Copyright
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 125




      PubDate: 2014-04-29T06:45:13Z
       
  • Index
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 125




      PubDate: 2014-04-29T06:45:13Z
       
  • Index
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 124




      PubDate: 2014-04-29T06:45:13Z
       
  • Index
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 123




      PubDate: 2014-04-29T06:45:13Z
       
  • Chapter Six Ammonia-Oxidizing Archaea Play a Predominant Role in Acid Soil
           Nitrification
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 125
      Author(s): Hang-Wei Hu , Zhi-Hong Xu , Ji-Zheng He
      Acid soils, extensively used for nitrogen-fertilized agriculture and agroforestry, have important roles in maintaining global biogeochemical cycling and ecosystem functions. Huge inputs of nitrogen-based fertilizers into terrestrial ecosystems accelerate soil acidification, concomitantly altering the nitrogen transformation processes. Nitrification, as a critical component of the nitrogen cycle, is a microbially mediated process from ammonia to nitrate via nitrite, contributing to enormous losses of fertilizers through atmospheric emissions of greenhouse gas N2O and nitrate leaching to groundwater. However, the functionally dominant nitrifiers and underlying mechanisms for the acid soil nitrification are a long-standing mystery, which have confused scientists for more than 100 years. This century-long paradox originated from the early observations of active nitrification activity in acid soils, intensified by the failure of ammonia-oxidizing bacteria (AOB) cultures to sustain the nitrification in liquid batch under acid conditions, might be resolved by the recent progress in metagenomic, isotopic probing studies, and isolation of acidophilic ammonia-oxidizing archaea (AOA). Emerging evidence led to the supposition of the predominant role of AOA in controlling the autotrophic ammonia oxidation of acid soils, which has radically revised the previous perception that this oxidative reaction was exclusively regulated by autotrophic AOB and occasionally by heterotrophic nitrifiers. In this chapter, we review the recent progress in our understanding of the pH-impacted distribution of ammonia oxidizers, the niche differentiation of AOA and AOB shaped by acid stress, and the possible mechanisms of autotrophic nitrification in acid soils. The unveiling of this key process in widely distributed acid soils would help to identify effective biological strategies for better management of terrestrial nitrogen turnover and balance.


      PubDate: 2014-04-29T06:45:13Z
       
  • Chapter Five Nutrient Management and Use Efficiency in Wheat Systems of
           South Asia
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 125
      Author(s): Mangi L. Jat , Bijay-Singh , Bruno Gerard
      With the advent of Green Revolution era in the mid-1960s, high-yielding wheat (Triticum aestivum L.) varieties and chemical fertilizers were introduced in South Asia. Fertilizer consumption is continuously increasing since then, but the productivity of wheat is relatively stagnant during the last decade. In South Asia, fertilizers have been applied to wheat as blanket recommendations for regions with similar climate and landform. There exists a large variation in nutrient use efficiencies in wheat because of following blanket recommendations for nitrogen, phosphorus, and potassium in fields differing greatly in nutrient-supplying capacity of the soil. Research carried out in South Asia suggests that further improvement in nutrient use efficiency will become possible by balanced use of nitrogen, phosphorus, and potassium fertilizers, and by rational use of organic manures in wheat systems. Long-term fertility experiments also confirm the need of balanced use of nutrients to produce high sustainable yield levels of wheat. In saline alkali soils, wheat needs to be supplied with higher amounts of nutrients, particularly N, than in normal soils. Band placement of fertilizers, particularly phosphorus, leads to improved fertilizer use efficiency, but appropriate machinery is lacking. Recently introduced site-specific nutrient management strategies for wheat take into account field-to-field variability and can help increase fertilizer use efficiency more than that achieved by following blanket fertilizer recommendations. Conservation agricultural practices consisting of reduced tillage and residue retention in wheat fields have already been introduced in South Asia. Nutrient management strategies for these wheat-growing environments are also being actively worked out. Yield gap analysis shows that productivity of wheat as well as nutrient use efficiencies can be further improved.


      PubDate: 2014-04-29T06:45:13Z
       
  • Series Page
    • Abstract: Publication date: 2014
      Source:Advances in Agronomy, Volume 125




      PubDate: 2014-04-29T06:45:13Z
       
  • 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
       
 
 
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