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Suggested Citation:"Contents." National Research Council. 1993. Soil and Water Quality: An Agenda for Agriculture. Washington, DC: The National Academies Press. doi: 10.17226/2132.
×
   

Advantages of the Farming Systems Approach

 

110

   

Farming System as Unit of Analysis and Management

 

113

   

Targeting Problem Areas and Farms

 

127

   

Implementing a Systems Approach

 

137

4.

 

POLICIES TO PROTECT SOIL AND WATER QUALITY

 

145

   

Environmental and Agricultural Policy

 

146

   

Factors Affecting Producers' Decisions

 

160

   

Continuum of Policies

 

162

PART TWO

 

 

INTRODUCTION:

 

SOIL, WATER, AND FARMING SYSTEMS

 

187

5.

 

MONITORING AND MANAGING SOIL QUALITY

 

189

   

Defining Soil Quality

 

190

   

Importance of Soil Quality

 

191

   

Importance of Monitoring Changes in Soil Quality

 

204

   

Extent of Degradation of U.S. Soils

 

218

6.

 

NITROGEN IN THE SOIL-CROP SYSTEM

 

237

   

The Nitrogen Cycle

 

237

   

Nitrogen Mass Balance

 

240

   

Opportunities to Reduce Nitrogen Losses

 

266

7.

 

PHOSPHORUS IN THE SOIL-CROP SYSTEM

 

283

   

The Problem of Phosphorus Delivery to Surface Waters

 

283

   

Sources of Phosphorus

 

284

   

Phosphorus in the Soil-Crop System

 

289

   

Transport Processes

 

299

   

Possible Management Methods for Phosphorus Loss Reduction

 

302

8.

 

FATE AND TRANSPORT OF PESTICIDES

 

313

   

Fate and Transport Processes

 

314

   

Reduction of Pesticide Pollution

 

329

   

Assessments of the Knowledge Base

 

333

   

Proper Use of Pesticides

 

334

9.

 

FATE AND TRANSPORT OF SEDIMENTS

 

337

   

Effects of Erosion and Sedimentation

 

337

   

Sedimentation Processes

 

338

Suggested Citation:"Contents." National Research Council. 1993. Soil and Water Quality: An Agenda for Agriculture. Washington, DC: The National Academies Press. doi: 10.17226/2132.
×

Tables and Figures

TABLES

1-1

 

U.S. Department of Agriculture and U.S. Environmental Protection Agency Soil and Water Quality Programs

 

23

1-2

 

Cropland and Pastureland Soils Affected by Saline or Sodic Conditions

 

26

1-3

 

New Initiatives in the 1990 Food, Agriculture, Conservation and Trade Act

 

28

2-1

 

Regional and National Estimates of Nitrogen Inputs, Outputs, and Balance on Croplands

 

61

2-2

 

Nitrogen Budgets for Four Farms (A, B, C, and D) in Southeastern Minnesota

 

62

2-3

 

Crops Receiving Fertilizer Nitrogen Before, During, and After Seeding

 

67

2-4

 

Regional and National Estimates of Phosphorus Inputs, Outputs, and Balances on Croplands

 

72

2-5

 

Percentage of Soil Tests Reporting High to Very High Levels of Soil Phosphorus

 

74

2-6

 

Proportion of Cropland Soils Tested for Nutrient Levels, Major Field Crops, 1989

 

76

2-7

 

Use of Integrated Pest Management for 12 Major Crops in the United States, 1986

 

85

2-8

 

Highly Erodible, Not Highly Erodible, and Nondesignated Lands on which Conservation or Conventional Tillage Systems Are Used for Various Crops, 1990

 

100

Page xvii Cite
Suggested Citation:"Contents." National Research Council. 1993. Soil and Water Quality: An Agenda for Agriculture. Washington, DC: The National Academies Press. doi: 10.17226/2132.
×

3-1

 

Application of Farming System Approach at Different Geographic Scales

 

114

3-2

 

Ranking of Information Sources by Surveyed Farmers

 

126

3-3

 

Expenditures for Soil and Water Quality Programs as a Percentage of Expenditures on Pesticides, Synthetic Fertilizers, and Commodity Programs

 

143

4-1

 

Constraints to Adopting New Technologies and Program Responses to Nonadoption

 

147

5-1

 

Reference and Measured Values of Minimum Data Set for a Hypothetical Typic Hapludoll from North-Central United States

 

202

5-2

 

Indicators of Change in Soil Quality and Their Relationship to Components of Soil Quality

 

208

5-3

 

Some Pedotransfer Functions

 

212

5-4

 

Organic Carbon Additions Necessary to Maintain Soil Organic Carbon at Present Levels at Several Locations

 

225

5-5

 

Amounts of Organic Carbon Needed Annually in Residue to Maintain Soil Organic Carbon on Lands with Different Slopes and Erosion Levels

 

226

5-6

 

Extent of Salinity and Associated Problems by Land Use in California

 

231

5-7

 

Salinity and Drainage Problems by Major Irrigated Areas

 

232

6-1

 

Nitrogen (N) Inputs, Outputs, and Balances in the United States under the Low, Medium, and High Scenarios

 

241

6-2

 

Nitrogen Accumulation and Nitrogen Replacement Value Estimated for Alfalfa and Soybeans

 

243

6-3

 

State and National Nitrogen Inputs and Outputs (metric tons)

 

244

6-4

 

State and National Nitrogen Contributions to Total Inputs and Outputs

 

250

6-5

 

Nitrogen and Phosphorus Fertilizer Use: Top Ten States

 

256

6-6

 

Estimated Nitrogen Balance for Crop Production in the United States, 1977

 

262

6-7

 

Potential Reductions in Nitrogen Fertilizer Applied to Corn

 

268

7-1

 

Phosphorus Inputs and Outputs in the United States, 1987

 

291

7-2

 

State and National Phosphorus Inputs and Outputs (metric tons)

 

294

7-3

 

State and National Phosphorus Inputs and Outputs as Percentage of Total Mass of Phosphorus Inputs

 

296

7-4

 

Soils Testing Very Low to Medium or High to Very High for Soil-P (percent)

 

305

8-1

 

Partition Coefficients and Half-Lives of Pesticides Used in Florida

 

318

Page xviii Cite
Suggested Citation:"Contents." National Research Council. 1993. Soil and Water Quality: An Agenda for Agriculture. Washington, DC: The National Academies Press. doi: 10.17226/2132.
×

9-1

 

Conservation Tillage Systems in the United States

 

353

9-2

 

Surface Soil Cover, Soil erosion, and Runoff from Different Wheat Tillage Systems

 

354

9-3

 

Runoff and Soil Loss from Watersheds under Conventionally and Conservation Tilled Systems

 

354

9-4

 

Cropland Area under Various Forms of Conservation Tillage, 1985

 

355

10-1

 

Concentration of Trace Elements Commonly Observed in Forage Crops

 

385

10-2

 

Recommended Maximum Concentration of 15 Trace Elements in Irrigation Waters for Long-Term Protection of Plants and Animals

 

386

10-3

 

Total Removal by Crops of Cadmium and Zinc from Sludge-Treated Greenfield Sandy Loam Soils, 1976–1981

 

389

11-1

 

Manure and Its Associated Nutrient Content

 

401

11-2

 

Economic Value of Nitrogen, Phosphorus, and Potassium in Manures

 

401

11-3

 

Quantity of Livestock or Poultry Manure Needed to Supply 100 kg of Nitrogen over the Cropping Year with Repeated Applications of Manure

 

405

A-1

 

Factors Used to Estimate Total Nitrogen and Phosphorus Voided in Manures

 

435

A-2

 

Nitrogen Voided in Recoverable Manures

 

436

A-3

 

Phosphorus Voided in Recoverable Manures

 

437

A-4

 

Estimates of Nitrogen Fixation by Legumes

 

438

A-5

 

Estimated Rates of Nitrogen Accumulation and Nitrogen Replacement Value for Alfalfa and Soybeans in Low-, Medium-, and High-Fixation Scenarios

 

440

A-6

 

Factors Used to Estimate Nitrogen and Phosphorus in Crop Residues

 

442

A-7

 

Nitrogen and Phosphorus Content of Harvested Crops

 

443

A-8

 

Inputs and Outputs of Nitrogen and Phosphorus on Croplands in the United States, 1987

 

445

FIGURES

1-1

 

Percentage of land eroding by sheet and rill erosion at greater than the soil loss tolerance level

 

25

1-2

 

Farm production regions used in this report

 

27

1-3

 

Sources and types of nonpoint source pollution in affected U.S. rivers and lakes

 

29

1-4

 

Interactions of factors that influence producer's decisions

 

31

Suggested Citation:"Contents." National Research Council. 1993. Soil and Water Quality: An Agenda for Agriculture. Washington, DC: The National Academies Press. doi: 10.17226/2132.
×

2-1

 

Changes in soil quality affect water quality

 

46

2-2

 

Nutrient cycle and pathways in agroecosystems

 

56

2-3

 

Pesticide pathways in agroecosystems

 

56

2-4

 

Irrigation pathways of water in agroecosystems

 

57

2-5

 

Economic return from insurance nitrogen (N) and deficit N applications

 

92

2-6

 

Distribution of erosion events over 38 years on a field in Missouri

 

102

3-1

 

Proportion of national nitrogen and phosphorus inputs and balances contributed by each farm production region

 

111

3-2

 

Conceptual diagram of three-dimensional targeting

 

129

3-3

 

Use of a geographic information system to target and direct soil and water quality programs

 

136

3-4

 

Conservation expenditures by the U.S. Department of Agriculture (USDA) and related state and local programs, 1983 to 1990

 

140

4-1

 

History of land set-aside programs in the United States as cropland area reductions by type of program (1933–1991) and net farm income (1945–1990)

 

173

4-2

 

States with water quality laws that affect agriculture

 

178

5-1

 

Processes of soil degradation

 

218

5-2

 

Interactions of factors that cause soil degradation

 

219

5-3

 

U.S. pH soil test summary as percentage of soils testing 6.0 or less in 1989

 

235

6-1

 

The nitrogen cycle

 

238

6-2

 

Amount of fertilizer-N and manure-N applied in relation to annual average nitrate concentration in groundwater in Big Spring Basin, Iowa

 

265

6-3

 

Yield response of corn to nitrogen applied to three soils

 

276

6-4

 

Yield response of corn to fertilizer for three crop rotations

 

277

6-5

 

Nitrogen recovery related to fertilization rate

 

278

7-1

 

The phosphorus cycle

 

290

7-2

 

Relationship between broadcast phosphorus (PB) and extractable soil phosphorus (Ps)

 

298

7-3

 

Economic returns on investments of annual applications of phosphorus (P) fertilizers

 

306

7-4

 

Decrease of soil-P over time, measured as Mehlich 1-extractable phosphorus, on Portsmouth soil during the residual phase

 

308

8-1

 

Interactions and loss pathways of organic chemicals (OCs) in soils

 

315

8-2

 

Pesticide transport and transformation in the soil-plant environment and the vadose zone

 

316

8-3

 

Mass balance of a hypothetical aerial foliar-spray application of an insecticide

 

324

Suggested Citation:"Contents." National Research Council. 1993. Soil and Water Quality: An Agenda for Agriculture. Washington, DC: The National Academies Press. doi: 10.17226/2132.
×

9-1

 

Crop residue levels on planted acreage by region in 1992

 

356

10-1

 

Typical salt accumulation patterns in surface soils for various methods of water application

 

373

10-2

 

Detrimental effects of salinity on plant growth

 

374

10-3

 

Relative salt tolerance of agricultural crops

 

376

10-4

 

Possible abiotic and biotic processes affecting the reactivities and mobilities of trace elements

 

379

10-5

 

Total selenium concentrations in the top 30.5 cm (12 inches) of soil (A) and in shallow groundwater from 1984 to 1989 (B) in the San Joaquin Valley

 

382

10-6

 

Heavy metal contents in Greenfield sandy loam treated with composted sludge from 1976 to 1981

 

384

10-7

 

Concentrations of selenium in tissues of various edible crops

 

388

11-1

 

Schematic of livestock-crop system showing gap in traditional manure recycling system because of use of relatively inexpensive fertilizers

 

403

11-2

 

Ratio of amount of manure produced to amount of cropland available for manure application

 

408

11-3

 

Average amount of manure nitrogen produced by animals per unit area in relation to animal spacing

 

409

12-1

 

Conceptual diagram of a landscape showing potential for grass vegetative filter strips and riparian buffer zones to intercept nonpoint source pollutants transported by surface water runoff and groundwater flow

 

419

12-2

 

Conceptual diagram comparing (A) cropland enrolled by field in the Conservation Reserve Program (CRP) with (B) the same area of land set aside in riparian buffer zones

 

428

Suggested Citation:"Contents." National Research Council. 1993. Soil and Water Quality: An Agenda for Agriculture. Washington, DC: The National Academies Press. doi: 10.17226/2132.
×

SOIL AND WATER QUALITY

An Agenda for Agriculture

Page xxii Cite
Suggested Citation:"Contents." National Research Council. 1993. Soil and Water Quality: An Agenda for Agriculture. Washington, DC: The National Academies Press. doi: 10.17226/2132.
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Suggested Citation:"Contents." National Research Council. 1993. Soil and Water Quality: An Agenda for Agriculture. Washington, DC: The National Academies Press. doi: 10.17226/2132.
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Suggested Citation:"Contents." National Research Council. 1993. Soil and Water Quality: An Agenda for Agriculture. Washington, DC: The National Academies Press. doi: 10.17226/2132.
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Suggested Citation:"Contents." National Research Council. 1993. Soil and Water Quality: An Agenda for Agriculture. Washington, DC: The National Academies Press. doi: 10.17226/2132.
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Page xxii Cite
Suggested Citation:"Contents." National Research Council. 1993. Soil and Water Quality: An Agenda for Agriculture. Washington, DC: The National Academies Press. doi: 10.17226/2132.
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Soil and Water Quality: An Agenda for Agriculture Get This Book
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How can the United States meet demands for agricultural production while solving the broader range of environmental problems attributed to farming practices? National policymakers who try to answer this question confront difficult trade-offs.

This book offers four specific strategies that can serve as the basis for a national policy to protect soil and water quality while maintaining U.S. agricultural productivity and competitiveness. Timely and comprehensive, the volume has important implications for the Clean Air Act and the 1995 farm bill.

Advocating a systems approach, the committee recommends specific farm practices and new approaches to prevention of soil degradation and water pollution for environmental agencies.

The volume details methods of evaluating soil management systems and offers a wealth of information on improved management of nitrogen, phosphorus, manure, pesticides, sediments, salt, and trace elements. Landscape analysis of nonpoint source pollution is also detailed.

Drawing together research findings, survey results, and case examples, the volume will be of interest to federal, state, and local policymakers; state and local environmental and agricultural officials and other environmental and agricultural specialists; scientists involved in soil and water issues; researchers; and agricultural producers.

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