Conservation Tillage in U.S. Agriculture

Environmental, Economic, and Policy Issues

Noel Uri

• Verlag: CRC Press
• Jahr: 2021
• ISBN:
  9781000447910
• Auflage: 1
• Thema: Volkswirtschaftslehre
• Thema: Handelspolitik

Discover farming techniques that will decrease soil erosion and costs! Soil erosion from U.S. croplands has long been recognized as a national problem. Conservation Tillage in U.S. Agriculture: Environmental, Economic, and Policy Issues is the first ever complete study of the costs and benefits of using conservation tillage to prevent soil erosion. Designed for professionals working in the areas of soil science, agronomy, economics, environmental studies, and agriculture, this complete study covers everything from machinery and trends in conservation tillage to its adoption to use in regions of the United States. With this in-depth manual, you will examine different types of tillage and the many benefits this practice can ensure, such as improving water quality, increasing organic matter in your soil, sequestering carbon, and providing habitat and food for wildlife. Covering the economic, environmental, and policy issues of this practice, Conservation Tillage in U.S. Agriculture features:

• the history of conservation tillage
• case studies on costs and benefits of differing conservation tillage practices with various crops
• tables and graphs of trends, and case studies concerning the use of different farming methods
• U.S. Department of Agriculture soil conservation policies
• how to prevent soil erosion without harming the environment
• factors affecting conservation tillage, adoption, and use for crops such as peanuts, potatoes, beets, tobacco, and vegetables. With the help of this book, you will measure the benefits and costs of conservation tillage based on profitability and environmental impact and explore the positive and negative environmental consequences that may involve air, land, water, and/or the health and ecological status of wildlife. Conservation Tillage in U.S. Agriculture is a timely and informative look at conservation tillage practices that will help you improve residue management and create better conditions for wildlife and the environment.

Chapter 1

Introduction

Soil erosion from cropland in the United States has been recognized as an important problem for over sixty years. Concern initially was centered on the loss of fertile topsoil and the fear that agricultural productivity would decline. Recently, however, there has been a growing understanding of the off-farm impacts of sediment and chemical transport (U.S. Environmental Protection Agency, 1995). Therefore, both private (on-farm) and public (off-farm) benefits can be gained from reducing erosion from the nation’s agricultural lands.

Conservation tillage is one of many conservation practices developed to reduce soil erosion. In its broadest sense, conservation tillage is defined as a tillage system that leaves enough crop residue on the field after harvest to protect the soil from erosion. In general, tillage that leaves a residue cover of at least 30 percent after planting is deemed conservation tillage; residue cover will vary, however, according to soil type, slope, crop rotation, winter crop cover, and other factors.

Additional benefits are associated with the use of conservation tillage beyond keeping the soil on the field. After several years under the practice, the soil’s organic matter and structure may improve, thus increasing the quality of the agricultural soil. The change in organic content and the lack of soil disturbance also serve to sequester carbon, which may have long-term environmental benefits. Cropland on which conservation tillage is used also can serve as important habitat for wildlife. The residue left on the field offers food for some species and shelter for others.

Conservation tillage is not used on most U.S. cropland. The decision to change production technologies is based on many factors. Farmers will adopt conservation tillage if they perceive a gain in net benefits from switching technologies. These benefits can represent more than just the direct monetary factors reflected on a business balance sheet. Farmers also include nonmonetary adjustment costs, such as having to learn new skills or deal with new suppliers, when they assess whether to change production practices. What is not typically included in farmers’ private decisions are the benefits or costs to society associated with the use of a new practice.

The purpose of this book is to identify and quantify, as much as possible, the likely benefits and costs associated with the use of conservation tillage that would accrue to farmers and to the public.

The current status of conservation tillage adoption is described in Chapter 2. The use of the technology varies widely by crop and by region, and factors affecting the adoption decision are discussed.

In Chapter 3, the on-farm and off-farm benefits and costs of conservation tillage adoption are identified. Conservation tillage and conventional tillage are compared with respect to yields and costs of production. Differences in input use are also described. As with many resource-conserving technologies, the relative advantage of conservation tillage depends on farm and regional characteristics (Caswell, Zilberman, and Casterline, 1993). The off-site or off-farm impacts of soil erosion, particularly with respect to water quality, are identified, and the benefits of tillage adoption on wildlife habitat and the reduction of carbon emissions are discussed.

An analysis is conducted to estimate the reduction of soil erosion that would result from the adoption of conservation tillage on lands for which the technology is considered suitable. Using figures developed by Ribaudo (1989) and Huzsar and Piper (1986), estimates are made of the public benefits that would be realized from the adoption-induced reductions in off-site erosion impacts. The results of this analysis are presented in Chapter 3.

If the off-site and on-site benefits of increasing the use of conservation tillage are greater than the costs to farmers of adopting the technology, several public policies can help influence farmers to adopt conservation tillage. A lexicon of these policy options is provided in Chapter 4. The U.S. government, primarily through the U.S. Department of Agriculture (USDA), has developed a suite of policies to promote the use of preferred agricultural practices. These policies and their effect on the adoption of conservation tillage are also described.

Before the discussion of current conditions and policies, let us first consider a brief history of conservation tillage in the United States.

CONSERVATION TILLAGE IN HISTORICAL CONTEXT

The use of crop residue in the United States to sustain soil productivity dates to the early eighteenth century. Colonists from Europe, observing the more severe storms in the New World than in the Old, realized the need to use cover crops and crop residue to mitigate soil erosion (Moldenhauer, Kemper, and Langdale, 1994). Throughout the nineteenth century, farmers experimented with alternative production practices to produce food and fiber without degrading the soil resources in the process. It was only in the 1920s, however, that field experiments were initiated to assess objectively the effects of sheet and rill erosion¹ and wind erosion on soil productivity. These early efforts were disparate and tended to focus on issues of concern to a specific geographic area, for example, corn in Illinois (Odell et al., 1984). Unfortunately, no objective measures are available that describe how these efforts affected farmer behavior and net farm income (private benefits) or the extent to which soil erosion was reduced (public benefits) and soil productivity enhanced.

With the establishment of the Soil Conservation Service in 1935, a more organized and comprehensive assessment of conservation tillage began. A large number of conservation tillage practices, such as mulch tillage, were evaluated at land grant university experiment stations throughout the United States (Moldenhauer, Kemper, and Langdale, 1994). It was quickly realized that due to spatial variation in soil characteristics and weather patterns, farming with conservation tillage required a different approach to soil preparation, fertilizer application, and weed and insect control, as well as an awareness of the topography of the land farmed in relation to water sources. Therefore, conservation tillage technology was difficult to transfer unilaterally across major soil resource areas. Thus, conservation tillage diversity would be the norm, meaning that conservation tillage practices would have to be tailored to the specific crops grown and to the climatic conditions in a geographic region. A characteristic that all such practices would possess, however, was a need for the farmer to understand and use appropriate management practices.

Following World War II, plow planting methods were refined by the U.S. Department of Agriculture and land grant university researchers. It was shown that the best soil conservation contribution of these methods was surface roughness to control runoff. Although cool season crop residues were managed near the soil surface, some secondary cultivation was required for weed control, even though selective herbicides were available.

Many other forms of conservation tillage emerged during the 1960s and 1970s, including ridge tillage for cold wet soils of the Corn Belt and strip till for restrictive horizon Ultisols of the Southeast. It was during this time period that the use of conservation tillage became widespread.

The following chapters will place in perspective the role that conservation tillage can play in sustaining agricultural productivity and improving the environment.

Chapter 2

Current Status of Conservation Tillage

• Conservation tillage was used on nearly 36 percent of planted acreage in 1996. This level has remained relatively unchanged over the past few years.

• The use of conservation tillage varies by crop and is dependent on site-specific factors, including soil type, topsoil depth, and local climatic conditions.

• A number of economic, demographic, geographic, and policy factors have affected the adoption of conservation tillage. It is not possible to quantify exactly the impact of these factors on conservation tillage use.

• Management complexities and profitability are key factors impeding the adoption of conservation tillage.

The adoption of conservation tillage and the current extent of its use depend on a variety of economic, demographic, geographic, and policy factors. This chapter describes the evolution of the use of conservation tillage and provides some insights into the importance of economic and environmental considerations in a farmer’s decision to adopt its practices.

DEFINITION OF CONSERVATION TILLAGE

Conservation tillage has evolved from tillage practices that range from reducing the number of trips over the field to raising crops without primary or secondary tillage. Emphasis tod...