Soil is a critical  natural resource for sustaining ecosystems and meeting production needs of humankind. World population is projected to grow from approximately 6.2 billion in 1999 to between 8 and 11 billion by 2025. This growth will place an ever increasing demand on the thin layer of soil that is critical for sustaining life on earth=s land surfaces. This living and dynamic resource influences surface runoff and groundwater flow, sustains essential plant nutrients, and purifies natural and human-created wastes. Sustainable management of soil to meet these enormous demands will require careful, science-based principles. Adequate public investment in research for sustainable soil resource management is essential to prevent future failures of agriculture and to ensure environmental resiliency.

Human management of soils and soil properties strongly affects the economic farm balance through its impact on plant and animal production. Soil also provides the primary interface between humankind and the environment, influencing the quality of air we breathe and water we drink. It is imperative that soil management practices be developed and practiced in a manner that promotes sustainable use of this critical resource while meeting humanity's production needs. The emphasis of this Soil Resource Management National Program is research aimed at meeting the food, feed, and fiber needs of humanity while protecting, preserving, restoring, and enhancing the soil resource.

Soil management programs are challenged by the complex variability of the resource itself. Soil geographical variability is further complicated by differences in crops and cropping systems as well as financial, logistical, and management resources and technologies available to the farmers and land managers who strive to balance productivity with overall environmental quality. Because soil is a dynamic and living entity, soil management research and the practices developed must account for soil biological, chemical, and physical components and interactions that can produce soil property changes in seconds to centuries. To illustrate the diverse and unique characteristics influencing the soil management projects being coordinated through this National Program, 24 Land Resource Regions (LRR) in the U.S. are listed in table 1. For brevity, only a few of the predominant crops grown in each LRR are included, and LRRs in the U.S. Territories are not listed. The most important concept for the reader is to recognize is the diversity of soil resources being addressed through the research outlined in this National Program.

Table 1. Land resource regions (LRR) in the United States (adapted from USDA-Natural Resource Conservation Service (NRCS) Handbook No. 296).

Providing economically viable and environmentally sustainable solutions to the various soil management constraints, while meeting the increased world demand for food, feed, and fiber from these diverse soil resources will not be easy, especially since current 1-1.1% annual rates of increase in productivity are less than the 2.0-2.5% annual rates generally associated with the AGreen Revolution.@ To balance production demands with environmental needs, soil resource management programs will be required to meet new challenges associated with natural and human resources. Among the challenges are development of improved systems for production of food free from harmful levels of chemical and biological contamination. This must be balanced with a global desire to seek new technologies that permit continued production increases while minimizing dependencies on nonrenewable resources. New science-based soil management practices need to be developed and promoted that will overcome current limitations to productivity while protecting the environment and preserving the soil resource.

To accomplish these objectives, the Soil Resource Management National Program will have five science-based program components. These components will address (1) Soil Conservation and Restoration, (2) Nutrient Management, (3) Soil Water, (4) Soil Biology, and (5) Productive and Sustainable Soil Management Systems. Among the critical problems being addressed by these components are (1) reducing soil erosion and compaction; (2) understanding pesticide interactions with soil properties and processes and resultant effects on efficacy; (3) improving precipitation- and irrigation-use efficiencies and efficacy; (4) preventing salinity and other chemical problems; (5) improving drainage while preventing unwanted leaching; (6) optimizing soil management in grazed systems to minimize compaction, erosion, and other forms of degradation; (7) balancing nutrient supply and demand, considering both organic and inorganic nutrient sources (i.e., derived from living and nonliving sources), processes, and cycling; (8) developing optimum site-specific soil management practices, (9) understanding and managing soil biological processes; and (10) restoring degraded and disturbed soils. In addition, tools and techniques to assess inherent and dynamic physical, chemical, and biological properties and processes of soil are needed to determine the effectiveness and sustain ability of soil and land management practices. Providing the new information and guidance to address the various challenges will require creative, science-based solutions that are both economically viable and socially acceptable. Some key aspects of each program component are listed below.

Soil Conservation and Restoration.  Soil degradation, through human activities and natural forces, has reduced the productivity of our soils and damaged adjacent ecosystems. Soil degradation can result from accelerated soil erosion, loss of vegetative cover, oxidation of soil organic matter, and impairment of other soil physical, chemical, and biological properties. Worldwide, erosion by water, wind, tillage, and irrigation remains a major cause of soil degradation and a primary environmental concern. Equipment traffic, grazing, and natural consolidation can cause soil compaction, thereby restricting root growth and movement of water, air, and chemicals. Poor land management can cause accelerated soil acidification and buildup of sodium and other soluble salts. Mining and industrial activities and improper use of municipal and industrial byproducts and animal manures can cause buildup of excess nutrients and toxic trace elements in soils. Despite the many advances in technology to reduce the environmental and economic risks associated with intensification of agriculture and other land uses, economically feasible methods are needed to control soil erosion, prevent soil compaction, and remediate soils degraded by erosion, compaction, or contamination.

Nutrient Management.  Since the 1950s, philosophy and practices governing nutrient management have changed significantlyBfrom on-farm recycling of nutrients such as animal or green manure to the use of concentrated chemical fertilizers. This shift continues to be a significant factor facilitating conversion to intensified agricultural systems. However, fertilizer use efficiency is commonly less than 50% in many agricultural systems. Application of excessive amounts of fertilizer or manure is one reason agriculture is the largest nonpoint source of surface and groundwater pollution. Overuse of either type of nutrient source can result in depletion of oxygen in bodies of water, which causes fish and other aquatic life to die, thus limiting the use of these bodies of water for fisheries, recreation, industry, and water supply. Economic use of renewable nutrient sources and improved nutrient use efficiency in agricultural systems are problems that must be addressed to reduce input costs and protect the environment. Research is needed to understand nutrient fate and transformations in soil so that management practices can be developed for sustainable production while protecting soil, water, and air.

Soil Water.  Water is the most limiting soil factor for crop growth and yield in most agricultural soils, accounting for approximately 80% of crop yield variability. Soil water, directly of indirectly, affects most soil physical, chemical, and biological properties and processes. It also functions as a transport medium for chemicals and microorganisms into, through, and below the soil profile. Most crop production problems associated with soil water relate to its supply and availability; infiltration adequacy and timing; and prevention, elimination, or mitigation of soil water excesses. Some soil water management considerations are similar regardless of cropping systems. Others vary considerably, especially between rainfed and irrigated agriculture. Characterization of soil properties affecting soil water remains difficult, slowing progress on other fronts, especially development and validation of new soil water concepts, theories and models. Research in this component area will address these and other issues associated with soil water management.

Soil Biology. The living portion of the soil consists of plant roots and great numbers of remarkably diverse living organisms that are partially to totally invisible to the naked eye. Soil microorganisms can account for 10% or more of the weight of soil organic matter, and over 10,000 species of microorganisms can exist in a single gram (.035 ounce) of soil. Although the importance of these organisms is generally accepted, a greater understanding of their role in soil physical, chemical, and biological properties and processes will be needed to manage this resource for the benefit of agricultural and other land uses. Research also will be needed to understand the basic ecology of communities of soil organisms in bulk as well as in close proximity to plant roots and seeds. Other areas that will require investigation include interactions between soil management practices and soil organisms; the role of soil organisms in controlling plant diseases, plant pests, and weeds; and the role of soil organisms in degradation of pesticides and other synthetic and natural toxins.

Productive and Sustainable Soil Management Systems. Major advances in agriculture have been made through improvements in plant genetics; nutrient and water management; tillage practices; weed, insect and pathogen control; and planting and harvesting equipment. These advances have not come without environmental and economic costs. Our focus in this component area will be to develop more sustainable soil management practices by using a systems approach to integrate principles of soil biology, chemistry, and physics into management practices that will optimize land use and be readily adoptable by producers. This systems approach will be characterized by a coordinated effort to balance all inputs and outputs to optimize productivity, profitability, and sustainability, while minimizing adverse environmental impacts. Recommended practices must not be at odds with each other. Research in this area will include developing environmentally sound, economically viable, and innovative crop rotation, cover crop, and residue management strategies; providing site-specific soil management practices to optimize soil biological, chemical, and physical properties and processes; and determining how soil management affects the soil resource. Greater emphasis will be placed on delivering research results and technology in a timely, efficient manner and in appropriate forms. New avenues of information delivery will be explored including electronic formats that can be easily captured by technology transfer groups, and the coordination and integration of information from multiple ARS laboratories and research programs will be encouraged.

Beneficiaries of this Research Program

The primary beneficiaries of the information developed and transferred through this National Program will be the producers and other land managers who will implement site- and time-specific practices needed to develop sustainable and environmentally benign land management systems. This program will benefit action agencies such as NRCS, Cooperative Extension, Environmental Protection Agency, U. S. Bureau of Land Management, and U. S. Geological Survey; and agribusiness persons who advise land managers on crop production, water management, and pest control for a variety of soil resource conditions; as well as resource managers, policy makers, and land stewards who need information and techniques for evaluating the status and trends in our soil resource base . More indirectly, the public at large will benefit through improved water, air, and soil, recreational areas, and a sustainable, nutritious, and safe food, feed, and fiber supply. Finally, although several specific potential cooperators within and outside the Federal Government have been identified here and within the various components, this list is not meant to be exclusive or prevent any interested entity from contacting ARS researchers should they care to be involved and contribute to these research goals.

Sustaining Soils and Society

To develop and transfer science-based knowledge needed to ensure abundant and affordable food, feed and fiber for the Nation without compromising our soil, water, air, or human resources.

A program planning workshop for the Soil Resource Management National Program was held in Denver, Colorado, from February 23-26, 1999. Approximately 150 participants attended the workshop including producers, commodity group representatives, agricultural industry representatives, representatives of non-governmental organizations, university scientists, and scientists and administrators from ARS and other federal and state agencies. At the workshop our customers, stakeholders, and partners provided input concerning their problems and needs relative to soil resource management. Five component areas were identified for the Soil Resource Management National Program: (1) Soil Conservation and Restoration, (2) Nutrient Management, (3) Soil Water, (4) Soil Biology, and (5) Productive and Sustainable Soil Management Systems.

Writing teams composed of ARS scientists and members of the National Program Staff (NPS) were formed for each program component to develop planning documents that will provide an overall framework for the direction of ARS research in this area. The writing teams used input from the workshop, their own knowledge of the subject matter area, and input from ARS scientists and cooperators to identify researchable problems that need to be addressed. This information was incorporated into a Strategic Plan for each component that provides background information about the overall component and explains why a particular research area is important, how it could be addressed, and the benefits of conducting the research. The Vision Statement, Mission Statement, and a brief description of the five Program Components are given in the preceding sections.

Table 3. Milestones and expected outcomes, such as those listed below, will be developed for each program component during the implementation phase, evaluated for scientific quality during the peer review phase, and assessed for impact during the assessment phase of the Soil Resource Management National Program.