Beschreibung
In an effort to implement conservation measures farmers have used a variety of production methods, including the use of reduced or zero tillage and cover crops. One benefit of these production methods has been early season weed control. The literature suggests that a variety of mechanisms may be involved, among them the allelopathic effects of phenolic acids. This retrospective analysis addresses the following: How likely are phenolic acid concentrations and environmental conditions in wheat no-till cropping systems for the inhibition of annual broadleaf weed emergence? and Do phenolic acids have a dominant role or are they just one component of a larger promoter/modifier/inhibitor complex? The book covers allelopathic plant-plant interactions, laboratory and field experiments, and future research. It uses a journal format, provides justifications for procedures used, if-then hypotheses, and cons and pros so that readers can reach their own conclusions.
Inhaltsverzeichnis
List of Illustrations; List of Tables; Abbreviations; Dedication; Preface; References; Acknowledgements Chapter 1. Plant-plant Allelopathic Interactions; 1.1 References Chapter 2. Plant-plant Allelopathic Interactions. Phase I: The Laboratory; 2.1. Criteria for Model Systems; 2.2 Materials, Methods, and Commentary; 2.2.1 General Bioassay Procedures; 2.2.2 Bioassay Species; 2.2.3 Soil Substrates; 2.2.4 Seedling Containers; 2.2.5 Sorption and Microbial Utilization Studies; 2.2.6 Phenolic Acids; 2.2.7 Phenolic Acid Solutions; 2.2.8 Solution Additions to Seedling Systems; 2.2.9 Phenolic Acid Extraction Procedures; 2.2.10 Quantification of Individual Phenolic Acids; 2.2.11 Rhizosphere and Soil Microbial Populations; 2.2.12 Measurements; 2.2.13 Data Analyses; 2.3 Research Objectives; 2.4 Results and Discussion; 2.4.1 Effects and Duration of Effects of Phenolic Acids on Seedlings in Nutrient Culture; 2.4.2 Effects of Seedlings, Mixtures of Phenolic Acids, and Microbes on Phenolic Acid Concentrations in Nutrient Culture; 2.4.3 Interactions of Phenolic Acids with Sterile and Non-sterile Soils; 2.4.4 Effects of Phenolic Acids on Bulk-soil and Rhizosphere Microbial Populations; 2.4.5 Effects and Duration of Effects of Phenolic Acids on Seedlings in Soil Culture; 2.4.6 Relationships Between Phenolic Acid-utilizing Microbes and Phenolic Acid Inhibition; 2.4.7 Effects of Seedling-microbe-soil Systems on Available Concentrations of Phenolic Acids in Soil Solutions; 2.4.8 Comparison of the Effects of Phenolic Acids on Seedlings in Nutrient and Soil Culture; 2.4.9 Effects of Phenolic Acids at Various Life Stages; 2.5 Summary of Major Points for Model Systems; 2.5.1 Seedlings; 2.5.2 Microbes; 2.5.3 Phenolic Acids; 2.6 Relevance of Model Systems to Field Studies; 2.6.1 Promoters, Modifiers, and Inhibitors; 2.7References Chapter 3: Plant-plant Allelopathic Interactions. Phase II: Field/Laboratory Experiments; 3.1 Annual Broadleaf Weed Control in No-till Systems; 3.2 Material, Methods, and Commentary; 3.2.1 Soil and Plant Tissue/Residue Analyses; 3.2.2 Laboratory Bioassays; 3.2.3 Field Studies; 3.2.4 Data Analyses; 3.3 Research Objectives; 3.4 Results and Discussion; 3.4.1 Characterize the Phenolic Acids in Soils of No-till and Conventional-till Systems and to Establish Correlations Between Easily Obtained Soil Characteristics and Phenolic Acids in Soils; 3.4.2 Determine if Soil Extracts could be Used Directly in Laboratory Bioassays for the Detection of Allelopathic Activity; 3.4.3 Characterize How Cover Crop Residues in No-till Systems Affect Early Emergence of Broadleaf Weeds and to Establish and Characterize Potential Relationships Between Early Broadleaf Weed Seedling Emergence and the Physical and Chemical Environments Resulting from the Presence of Cover Crop Residues; 3.4.4 Characterize Cover Crops and Cover Crop Residues and How These May Potentially Modify the Soil Environment; 3.4.5 Determine Under Controlled Conditions How Effects of Shoot Cover Crop Residues Taken from the Field Change with Time After Desiccation and How Such Effects are Modified by Temperature, Moisture, and Nitrogen Levels; 3.4.6 Determine the Respective Importance of Shoot and Root Residues in Regulating Early Broadleaf Weed Seedling Emergence; 3.4.7 Determine Under Controlled Conditions How Phenolic Acids-Containing Plant Tissues/Residues Mixed into Soil Modify Phenolic Acid-utilizing Bulk-Soil and Rhizosphere Microbial Populations; 3.5 Summary of Major Points; 3.5.1 Effects of Cover Crop Residues on Physicochemical and Biotic Environments of the Soil; 3.5.2 Phenolic Acids in Cecil Soils; 3.5.3 Bioassays of Soil Extracts; 3.5.4 Field Residue Bioassays: Seedling Emergence; 3.5.5 Laboratory Bioassays: Seedlings and Microbes; 3.6 References Chapter 4: Phase III: Summing Up; 4.1 Hypotheses; 4.1.1 Plant-plant Allelopathic Interactions. Phase I: The Laboratory; 4.1.2 Plant-plant Allelopathic Interactions. Phase II: Field/Laboratory; 4.2 Final ...
Autorenporträt
InhaltsangabeList of Illustrations; List of Tables; Abbreviations; Dedication; Preface; References; Acknowledgements Chapter 1. Plant-plant Allelopathic Interactions; 1.1 References Chapter 2. Plant-plant Allelopathic Interactions. Phase I: The Laboratory; 2.1. Criteria for Model Systems; 2.2 Materials, Methods, and Commentary; 2.2.1 General Bioassay Procedures; 2.2.2 Bioassay Species; 2.2.3 Soil Substrates; 2.2.4 Seedling Containers; 2.2.5 Sorption and Microbial Utilization Studies; 2.2.6 Phenolic Acids; 2.2.7 Phenolic Acid Solutions; 2.2.8 Solution Additions to Seedling Systems; 2.2.9 Phenolic Acid Extraction Procedures; 2.2.10 Quantification of Individual Phenolic Acids; 2.2.11 Rhizosphere and Soil Microbial Populations; 2.2.12 Measurements; 2.2.13 Data Analyses; 2.3 Research Objectives; 2.4 Results and Discussion; 2.4.1 Effects and Duration of Effects of Phenolic Acids on Seedlings in Nutrient Culture; 2.4.2 Effects of Seedlings, Mixtures of Phenolic Acids, and Microbes on Phenolic Acid Concentrations in Nutrient Culture; 2.4.3 Interactions of Phenolic Acids with Sterile and Non-sterile Soils; 2.4.4 Effects of Phenolic Acids on Bulk-soil and Rhizosphere Microbial Populations; 2.4.5 Effects and Duration of Effects of Phenolic Acids on Seedlings in Soil Culture; 2.4.6 Relationships Between Phenolic Acid-utilizing Microbes and Phenolic Acid Inhibition; 2.4.7 Effects of Seedling-microbe-soil Systems on Available Concentrations of Phenolic Acids in Soil Solutions; 2.4.8 Comparison of the Effects of Phenolic Acids on Seedlings in Nutrient and Soil Culture; 2.4.9 Effects of Phenolic Acids at Various Life Stages; 2.5 Summary of Major Points for Model Systems; 2.5.1 Seedlings; 2.5.2 Microbes; 2.5.3 Phenolic Acids; 2.6 Relevance of Model Systems to Field Studies; 2.6.1 Promoters, Modifiers, and Inhibitors; 2.7References Chapter 3: Plant-plant Allelopathic Interactions. Phase II: Field/Laboratory Experiments; 3.1 Annual Broadleaf Weed Control in No-till Systems; 3.2 Material, Methods, and Commentary; 3.2.1 Soil and Plant Tissue/Residue Analyses; 3.2.2 Laboratory Bioassays; 3.2.3 Field Studies; 3.2.4 Data Analyses; 3.3 Research Objectives; 3.4 Results and Discussion; 3.4.1 Characterize the Phenolic Acids in Soils of No-till and Conventional-till Systems and to Establish Correlations Between Easily Obtained Soil Characteristics and Phenolic Acids in Soils; 3.4.2 Determine if Soil Extracts could be Used Directly in Laboratory Bioassays for the Detection of Allelopathic Activity; 3.4.3 Characterize How Cover Crop Residues in No-till Systems Affect Early Emergence of Broadleaf Weeds and to Establish and Characterize Potential Relationships Between Early Broadleaf Weed Seedling Emergence and the Physical and Chemical Environments Resulting from the Presence of Cover Crop Residues; 3.4.4 Characterize Cover Crops and Cover Crop Residues and How These May Potentially Modify the Soil Environment; 3.4.5 Determine Under Controlled Conditions How Effects of Shoot Cover Crop Residues Taken from the Field Change with Time After Desiccation and How Such Effects are Modified by Temperature, Moisture, and Nitrogen Levels; 3.4.6 Determine the Respective Importance of Shoot and Root Residues in Regulating Early Broadleaf Weed Seedling Emergence; 3.4.7 Determine Under Controlled Conditions How Phenolic Acids-Containing Plant Tissues/Residues Mixed into Soil Modify Phenolic Acid-utilizing Bulk-Soil and Rhizosphere Microbial Populations; 3.5 Summary of Major Points; 3.5.1 Effects of Cover Crop Residues on Physicochemical and Biotic Environments of the Soil; 3.5.2 Phenolic Acids in Cecil Soils; 3.5.3 Bioassays of Soil Extracts; 3.5.4 Field Residue Bioassays: Seedling Emergence; 3.5.5 Laboratory Bioassays: Seedlings and Microbes; 3.6 References Chapter 4: Phase III: Summing Up; 4.1 Hypotheses; 4.1.1 Plant-plant Allelopathic Interactions. Phase I: The Laboratory; 4.1.2 Plant-plant Allelopathic Interactions. Phase II: Field
