The papers in this volume provide a balanced account of developments in soil organic matter research. It focuses on composition and structure, water quality, organic matter turnover, humus quality and fertility, and is essential reading for all those concerned with the environmental aspects of soil conservation and improvement.

Soil Organic Matter

Recognition of the importance of soil organic matter (SOM) in soil health and quality is a major part of fostering a holistic, preventive approach to agricultural management. Students in agronomy, horticulture, and soil science need a textbook that emphasizes strategies for using SOM management in the prevention of chemical, biological, and physical problems. Soil Organic Matter in Sustainable Agriculture gathers key scientific reviews concerning issues that are critical for successful SOM management. This textbook contains evaluations of the types of organic soil constituents—organisms, fresh residues, and well-decomposed substances. It explores the beneficial effects of organic matter on soil and the various practices that enhance SOM. Chapters include an examination of the results of crop management practices on soil organisms, organic matter gains and losses, the significance of various SOM fractions, and the contributions of fungi and earthworms to soil quality and crop growth. Emphasizing the prevention of imbalances that lead to soil and crop problems, the text also explores the development of soils suppressive to plant diseases and pests, and relates SOM management to the supply of nutrients to crops. This book provides the essential scientific background and poses the challenging questions that students need to better understand SOM and develop improved soil and crop management systems.

Soils comprise the largest pool of terrestrial carbon and therefore are an important component of carbon storage in the biosphere-atmosphere system. Structure and Organic Matter Storage in Agricultural Soils explores the mechanisms and processes involved in the storage and sequestration of carbon in soils. Focusing on agricultural soils - from tropical to semi-arid types - this new book provides an in-depth look at structure, aggregation, and organic matter retention in world soils. The first two sections of the book introduce readers to the basic issues and scientific concepts, including soil structure, underlying mechanisms and processes, and the importance of agroecosystems as carbon regulators. The third section provides detailed discussions of soil aggregation and organic matter storage under various climates, soil types, and soil management practices. The fourth section addresses current strategies for enhancing organic matter storage in soil, modelling techniques, and measurement methods. Throughout the book, the importance of the soil structure-organic matter storage relationship is emphasized. Anyone involved in soil science, agriculture, agronomy, plant science, or greenhouse gas and global change studies should understand this relationship. Structure and Organic Matter Storage in Agricultural Soils provides an ideal source of information not only on the soil structure-storage relationship itself, but also on key research efforts and direct applications related to the storage of organic matter in agricultural soils.

Advances in Agronomy continues to be recognized as a leading reference and a first-rate source for the latest research in agronomy. As always, the subjects covered are varied and exemplary of the myriad of subject matter dealt with by this long-running serial. - Maintains the highest impact factor among serial publications in agriculture - Presents timely reviews on important agronomy issues - Enjoys a long-standing reputation for excellence in the field

Soil organic matter (SOM) represents a major pool of carbon within the biosphere, roughly twice than in atmospheric CO2. SOM models embody our best understanding of soil carbon dynamics and are needed to predict how global environmental change will influence soil carbon stocks. These models are also required for evaluating the likely effectiveness of different mitigation options. The first important step towards systematically evaluating the suitability of SOM models for these purposes is to test their simulations against real data. Since changes in SOM occur slowly, long-term datasets are required. This volume brings together leading SOM model developers and experimentalists to test SOM models using long-term datasets from diverse ecosystems, land uses and climatic zones within the temperate region.

Soil organic matter (SOM) is the primary determinant of soil functionality. Soil organic carbon (SOC) accounts for 50% of the SOM content, accompanied by nitrogen, phosphorus, and a range of macro and micro elements. As a dynamic component, SOM is a source of numerous ecosystem services critical to human well-being and nature conservancy. Important among these goods and services generated by SOM include moderation of climate as a source or sink of atmospheric CO2 and other greenhouse gases, storage and purification of water, a source of energy and habitat for biota (macro, meso, and micro-organisms), a medium for plant growth, cycling of elements (N, P, S, etc.), and generation of net primary productivity (NPP). The quality and quantity of NPP has direct impacts on the food and nutritional security of the growing and increasingly affluent human population. Soils of agroecosystems are depleted of their SOC reserves in comparison with those of natural ecosystems. The magnitude of depletion depends on land use and the type and severity of degradation. Soils prone to accelerated erosion can be strongly depleted of their SOC reserves, especially those in the surface layer. Therefore, conservation through restorative land use and adoption of recommended management practices to create a positive soil-ecosystem carbon budget can increase carbon stock and soil health. This volume of Advances in Soil Sciences aims to accomplish the following: Present impacts of land use and soil management on SOC dynamics Discuss effects of SOC levels on agronomic productivity and use efficiency of inputs Detail potential of soil management on the rate and cumulative amount of carbon sequestration in relation to land use and soil/crop management Deliberate the cause-effect relationship between SOC content and provisioning of some ecosystem services Relate soil organic carbon stock to soil properties and processes Establish the relationship between soil organic carbon stock with land and climate Identify controls of making soil organic carbon stock as a source or sink of CO2 Connect soil organic carbon and carbon sequestration for climate mitigation and adaptation

Soil Carbon Storage: Modulators, Mechanisms and Modeling takes a novel approach to the issue of soil carbon storage by considering soil C sequestration as a function of the interaction between biotic (e.g. microbes and plants) and abiotic (climate, soil types, management practices) modulators as a key driver of soil C. These modulators are central to C balance through their processing of C from both plant inputs and native soil organic matter. This book considers this concept in the light of state-of-the-art methodologies that elucidate these interactions and increase our understanding of a vitally important, but poorly characterized component of the global C cycle. The book provides soil scientists with a comprehensive, mechanistic, quantitative and predictive understanding of soil carbon storage. It presents a new framework that can be included in predictive models and management practices for better prediction and enhanced C storage in soils. - Identifies management practices to enhance storage of soil C under different agro-ecosystems, soil types and climatic conditions - Provides novel conceptual frameworks of biotic (especially microbial) and abiotic data to improve prediction of simulation model at plot to global scale - Advances the conceptual framework needed to support robust predictive models and sustainable land management practices

It has long been recognized that soil organic matter is the key to soil fertility. As a nutrient store it gradually provides essential elements which the soil cannot retain for long in inorganic form. It buffers growing plants against sudden changes in their chemical environment and preserves moisture in times of drought. It keeps the soil in a friable, easily penetrated physical condition, well-aerated and free draining, providing young seedlings with an excellent medium for growth. But it has another property, the nature and extent of which have been the subject of argu ment and controversy ever since scientists began to study the soil, and that is its ability to affect growth directly, other than by providing nutrient elements. Any one wishing to learn about these effects has been faced with a daunting mass of literature, some confusing, often contradictory, and spread through a multitude of journals. Individual aspects have been covered from time to time in reviews but there has obviously been a need for a modern authoritative text book dealing with the many facets of this subject, so the publication of this volume is timely. The editors and authors are all specialists in their fields, fully familiar with the com plex nature of soil organic matter and with the particular difficulties arising in any study of its properties. Where controversies exist they have presented all sides of the argument and have highlighted areas where further work is badly needed.