PROFITABLE AND SUSTAINABLE SOIL TEST-BASED NUTRIENT MANAGEMENT

REFERENCES

• Halvorson , A.D. and Murphy , L.S. 1987 . “ Interaction of Soil Fertility with Other Inputs in Crop Production for Maximum Economic Return ” . In Future Developments in Soil Science Research Edited by: Boersma , L.L. 181 – 191 . Madison, WI : Soil Sci. Soc. Am. .
   Google Scholar
• Lal , R. , ed. 1994 . Best Management Practices for Irrigated Agriculture Fort Collins, CO : Colorado Water Research Institute. Colorado State University .
   Google Scholar
• Bock , B.R. 1984 . “ Efficient Use of Nitrogen in Cropping Systems ” . In Nitrogen in Crop Production Edited by: Hauck , R.D. 273 – 294 . Madison, WI : Am. Soc. Agron./Crop Sci. Soc. Am./Soil Sci. Soc. Am. .
   Google Scholar
• Baligar , V.C. , Fageria , N.K. and He , Z.L. 2001 . Nutrient Use Efficiency in Plants . Commun. Soil Sci. Plant Anal. , 32 : 921 – 950 .
   Web of Science ®Google Scholar
• Newbould , P. 1989 . The Use of Nitrogen Fertilizer in Agriculture. Where Do We Go Practically and Ecologically? . Plant Soil , 115 : 297 – 311 .
   Web of Science ®Google Scholar
• Baligar , V.C. and Bennett , O.L. 1986 . Outlook on Fertilizer Use Efficiency in the Tropics . Fert. Res. , 10 : 83 – 96 .
   Web of Science ®Google Scholar
• Baligar , V.C. and Bennett , O.L. 1986 . NPK-Fertilizer Efficiency. A Situation Analysis for the Tropics . Fert. Res. , 10 : 147 – 164 .
   Web of Science ®Google Scholar
• Raun , W.R. and Johnson , G.V. 1999 . Improving Nitrogen Use Efficiency for Cereal Production . Agron. J. , 91 : 357 – 363 .
   Web of Science ®Google Scholar
• Lynch , J. 1998 . “ The Role of Nutrient-Efficient Crops in Modern Agriculture ” . In Nutrient Use in Crop Production Edited by: Rengel , Z. 241 – 264 . New York : Food Products Press, an Imprint of the Haworth Press, Inc. .
   Google Scholar
• Bausch , W.C. and Diker , K. 2001 . Innovative Remote Sensing Techniques to Increase Nitrogen Use Efficiency of Corn . Commun. Soil Sci. Plant Anal. , 32 : 1371 – 1390 .
   Web of Science ®Google Scholar
• Van Erp , P.J. and Van Beusichem , M.L. 1998 . “ Soil and Plant Testing Programs as a Tool for Optimizing Fertilizer Strategies ” . In Nutrient Use in Crop Production Edited by: Rengel , Z. 53 – 80 . New York : Food Products Press, an Imprint of the Haworth Press, Inc. .
   Google Scholar
• Waskom , R.M. , Westfall , D.G. , Spellman , D.E. and Soltanpour , P.N. 1996 . Monitoring Nitrogen Status of Corn with a Portable Chlorophyll Meter . Commun. Soil Sci. Plant. Anal. , 27 : 545 – 560 .
   Web of Science ®Google Scholar
• Soltanpour , P.N. , Malakouti , M.J. and Ronaghi , A. 1995 . Comparison of Diagnosis and Recommendation Integrated System and Nutrient Sufficiency Range for Corn . Soil Sci. Soc. Am. J. , 59 : 133 – 139 .
   Web of Science ®Google Scholar
• Peck , T.R. and Soltanpour , P.N. 1990 . “ The Principles of Soil Testing ” . In Soil Testing and Plant Analysis , 3rd Ed. Edited by: Westermann , R.L. 1 – 9 . Madison, WI : Soil Sci. Soc. Am. .
   Google Scholar
• Soltanpour , P.N. , Khan , A. and Schwab , A.P. 1979 . Effects of Grinding Variables on the NH4HCO3-DTPA Soil Test Values for Fe, Zn, Mn, Cu, P, and K . Commun. Soil Sci. Plant Anal. , 10 : 903 – 909 .
   Web of Science ®Google Scholar
• Soltanpour , P.N. , Khan , A. and Lindsay , W.L. 1976 . Factors Affecting DTPA-Extractable Zn, Fe, Mn, and Cu from the Soils . Commun. Soil Sci. Plant Anal. , 7 : 797 – 821 .
   Web of Science ®Google Scholar
• Houba , V.J.G. , Novozamsky , I. and Van der Lee , J.J. 1989 . Some Aspects of Determinations of Nitrogen Fractions in Soil Extracts . VDLUFA-Schriftenreihe , 30 : 305 – 312 .
   Google Scholar
• Westfall , D.G. , Henson , M.A. and Evans , E.P. 1978 . The Effect of Soil Sample Handling Between Collection and Drying on Nitrate Concentration . Commun. Soil Sci. Plant Anal. , 9 : 169 – 185 .
   Web of Science ®Google Scholar
• Khan , A. and Soltanpour , P.N. 1978 . Effect of Wetting and Drying on DTPA-Extractable Fe, Zn, Mn, and Cu in Soils . Commun. Soil Sci. Plant Anal. , 9 : 193 – 202 .
   Web of Science ®Google Scholar
• Kitchen , N.R. , Havlin , J.L. and Westfall , D.G. 1990 . Soil Sampling Under No-Till Banded Phosphorus . Soil Sci. Soc. Am. J. , 54 : 1661 – 1665 .
   Web of Science ®Google Scholar
• Self , J.R. and Soltanpour , P.N. 1995 . Soil Sampling Fort Collins, CO : Colorado State University .
   Google Scholar
• James , D.W. and Wells , K.L. 1990 . “ Soil Sample Collection and Handling: Technique Based on Source and Degree of Field Variability ” . In Soil Testing and Plant Analysis , 3rd Ed. Edited by: Westermann , R.L. 25 – 44 . Madison, WI : Soil Sci. Soc. Am. .
   Google Scholar
• Reuss , J.O. , Soltanpour , P.N. and Ludwick , A.E. 1977 . Sampling Distribution of Nitrates in Irrigated Fields . Agron. J. , 69 : 588 – 592 .
   Web of Science ®Google Scholar
• Petersen , R.G. and Calvin , L.D. 1996 . “ Sampling ” . In Methods of Soil Analysis, Part 3 Edited by: Sparks , D.L. 1 – 9 . Madison, WI : Soil Sci. Soc. Am. .
   Google Scholar
• Bhatti , A.U. , Bakhsh , A. , Afzal , M. and Gurmani , A.H. 1999 . Spacial Variability of Soil Properties and Wheat Yields in an Irrigated Field . Commun. Soil Sci. Plant Anal. , 30 : 1279 – 1290 .
   Web of Science ®Google Scholar
• Hooker , M.L. Sampling Intensities Required to Estimate Available N and P in Five Nebraska Soil Types Lincoln, NE : University of Nebraska . 1976
   Google Scholar
• Uehara , G. and Yost , R.S. 1987 . “ Spatial and Temporal Agroecosystem Variability ” . In Future Developments in Soil Science Research Edited by: Boersma , L.L. 43 – 57 . Madison, WI : Soil Sci. Soc. Am. .
   Google Scholar
• Schloeder , C.A. , Zimmerman , N.E. and Jacobs , M.J. 2001 . Comparison of Methods for Interpolating Soil Properties Using Limited Data . Soil Sci. Soc. Am. J. , 65 : 470 – 479 .
   Web of Science ®Google Scholar
• Mulla , D.J. 1993 . “ Mapping and Managing Spacial Patterns in Soil Fertility and Crop Yield: Soil-Specific Crop Management ” . In Proceedings of Soil-Specific Crop Management, Minneapolis, MN, April 14–16, 1992 Edited by: Robert , P.C. 15 – 26 . Madison, WI : ASA .
   Google Scholar
• Soltanpour , P.N. and Schwab , A.P. 1977 . A New Soil Test for Simultaneous Extraction of Macro- and Micro-Nutrients in Alkaline Soils . Commun. Soil Sci. Plant Anal. , 8 : 195 – 207 .
   Web of Science ®Google Scholar
• Soltanpour , P.N. and Workman , S.M. 1979 . Modification of the NH4HCO3–DTPA Soil Test to Omit Carbon Black . Commun. Soil Sci. Plant Anal. , 10 : 1411 – 1420 .
   Web of Science ®Google Scholar
• Soltanpour , P.N. 1991 . Determination of Nutrient Availability and Elemental Toxicity by AB-DTPA Soil Test and ICPS . Adv. Soil Sci. , 16 : 165 – 190 .
   Google Scholar
• in press .
   Google Scholar
• Rodriguez , J.B. , Peterson , G.A. and Westfall , D.G. 1989 . Calibration of Nitrogen and Phosphorus Soil Tests with Yield of Proso Millet . Soil Sci. Soc. Am. J. , 53 : 1737 – 1741 .
   Web of Science ®Google Scholar
• Labhsetwar , V.K. “ Evaluation of NH4HCO3–DTPA Soil Test for Phosphorus ” . Fort Collins, CO : Colorado State University .
   Google Scholar
• Rashid , A. 1992 . “ Internal P Requirement of Crops and Use of Universal Soil Tests for Evaluating P Fertility of Pakistan Soils ” . In Role of Phosphorus in Crop Production Edited by: Ahmed , N. , Saleem , M.T. and Twyford , I.T. 147 – 173 . Pakistan : Government of Pakistan Planning and Development Div., National Fert. Development Center .
   Google Scholar
• Rashid , A. , Din , J. and Bashhir , M. 1999 . Phosphorus Deficiency Diagnosis and Fertilization in Mungbean Grown in Rainfed Calcareous Soils of Pakistan . Commun. Soil Sci. Plant Anal. , 30 : 2054 – 2056 .
   Web of Science ®Google Scholar
• Jones , B.A. Jr. 1990 . Universal Soil Extractants: Their Composition and Use . Commun. Soil Sci. Plant Anal. , 21 : 1091 – 1102 .
   Web of Science ®Google Scholar
• Mehlich , A. 1984 . Mehlich 3 Soil Test Extractant: A Modification of Mehlich2 Extractant . Commun. Soil Sci. Plant Anal. , 15 : 1409 – 1416 .
   Web of Science ®Google Scholar
• Rodriguez , J.B. , Self , J.R. and Soltanpour , P.N. 1994 . Optimal Conditions for Phosphorus Analysis by the Ascorbic Acid–Molybdenum Blue Method . Soil Sci. Soc. Am. J. , 58 : 866 – 870 .
   Web of Science ®Google Scholar
• Nesse , P. , Grava , J. and Bloom , P.R. 1988 . Correlation of Several Tests for Phosphorus with Resin-Extracted Phosphorus for 30 Alkaline Soils . Commun. Soil Sci. Plant Anal. , 19 : 675 – 689 .
   Web of Science ®Google Scholar
• Skogley , E.O. 1994 . “ Reinventing Soil Testing for the Future ” . In Soil Testing: Prospects for Improving Nutrient Recommendations Edited by: Havlin , J.J. and Jacobsen , J.S. 187 – 201 . Madison, WI : Soil Sci. Soc. Am. .
   Google Scholar
• Ryan , J. , Garabet , S. , Rashid , A. and El Gharous , M. 1999 . Assessment of Soil and Plant Analysis Laboratories in the West Asia–North Africa Region . Commun. Soil Sci. Plant Anal. , 30 : 885 – 894 .
   Web of Science ®Google Scholar
• Miller , R.O. and Kotuby-Amacher , J. 2001 . “ North American Proficiency Testing (NAPT) Program for Soil, Plant, and Water Analysis Laboratories ” . In Program and Abstracts. 7th International Symposium on Soil and Plant Analysis. 21–27 July, 2001 3 Alberta, Canada : Edmonton .
   Google Scholar
• Van Dijk , D. 2001 . “ World Wide Proficiency Programmes: WEPAL ” . In Program and Abstracts. 7th International Symposium on Soil and Plant Analysis. 21–27 July, 2001 4 Alberta, Canada : Edmonton .
   Google Scholar
• Stanford , G. and Smith , S.J. 1972 . Nitrogen Mineralization Potential of Soils . Soil Sci. Soc. Am. Proc. , 36 : 465 – 472 .
   Web of Science ®Google Scholar
• El Gharous , M. , Westerman , R.L. and Soltanpour , P.N. 1990 . Nitrogen Mineralization Potential of Arid and Semiarid Soils of Morocco . Soil Sci. Soc. Am. J. , 54 : 438 – 443 .
   Web of Science ®Google Scholar
• Vigil , M.F. , Kissel , D.E. and Smith , S.J. 1991 . Field Crop Recovery and Modeling of Nitrogen Mineralization from Labeled Sorghum Residues . Soil Sci. Soc. Am. J. , 55 : 1031 – 1037 .
   Web of Science ®Google Scholar
• in press .
   Google Scholar
• Lal , R. , ed. 1994 . Soil Testing: Prospects for Improving Nutrient Recommendations Madison, WI : Soil Sci. Soc. Am. .
   Google Scholar
• in press .
   Google Scholar
• Moraghan , J.T. , Sims , A. and Smith , L. 2000 . Remote Sensing of Sugarbeet Canopies for Improved Nitrogen Fertilizer Recommendations for a Subsequent Wheat Crop . Commun. Soil Sci. Plant Anal. , 31 : 827 – 836 .
   Web of Science ®Google Scholar
• Dahnke , W.C. and Olson , R.A. 1990 . “ Soil Test Correlation, Calibration, and Recommendation ” . In Soil Testing and Plant Analysis , 3rd Ed. Edited by: Westermann , R.L. 45 – 71 . Madison, WI : Soil Sci. Soc. Am. .
   Google Scholar
• Patel , S. “ Predicting Corn Yield for Midseason Fertilizer Management ” . Fort Collins, CO : Colorado State University . 1996
   Google Scholar
• in press .
   Google Scholar
• Westerman , R.L. and Tucker , T.C. 1987 . “ Soil Fertility Concepts: Past, Present and Future ” . In Future Developments in Soil Science Research Edited by: Boersma , L.L. 171 – 179 . Madison, WI : Soil Sci. Soc. Am. .
   Google Scholar
• Mobiela , F. , Nicholaides , J.J. III and Nelson , L.A. 1981 . A Method to Determine the Appropriate Mathematical Form for Incorporating Soil Test Levels in Fertilizer Response Models for Recommendation Purposes . Agron. J. , 73 : 937 – 941 .
   Web of Science ®Google Scholar
• Soltanpour , P.N. , Schlegel , A. , Cardon , G. , Waskom , R. and Halvorson , A. 2000 . “ Regional N Fertilizer Recommendations for Dryland Wheat ” . In Great Plains Soil Fertility Conference Proceedings. Denver, Co., March 7–8, 2000 Edited by: Schlegel , A. 335 – 341 . Manhattan, KS : Kansas State University .
   Google Scholar
• Soltanpour , P.N. , El Gharous , M. , Azzaoui , A. and Abdelmonem , M. 1989 . A Soil Test Based N Recommendation Model for Dryland Wheat . Commun. Soil Sci. Plant Anal. , 20 : 1053 – 1068 .
   Web of Science ®Google Scholar
• Bates , T.E. 1971 . Factors Affecting Critical Nutrient Concentration in Plants and Their Evaluations: A Review . Soil Sci. , 112 : 116 – 130 .
   Web of Science ®Google Scholar
• Munson , R.D. and Nelson , W.L. 1990 . “ Principles and Practices in Plant Analysis ” . In Soil Testing and Plant Analysis , 3rd Ed. Edited by: Westerman , R.L. 357 – 387 . Madison, WI : Soil Sci. Soc. Am. .
   Google Scholar
• Walworth , J.L. and Sumner , M.E. 1987 . “ The Diagnosis and Recommendation Integrated System Dris ” . In Advances in Soil Science Edited by: Stewart , B.A. Vol. 6 , 149 – 188 . New York : Springer-Verlag .
   Google Scholar
• Kelling , K.A. and Shulte , E.E. 1986 . DRIS as a Part of Routine Plant Analysis Program . J. Fert. Issues. , 3 : 107 – 112 .
   Google Scholar
• Baldock , J.O. and Schulte , E.E. 1996 . Plant Analysis with Standardized Scores Combines DRIS and Sufficiency Range Approaches for Corn . Agron. J. , 88 : 448 – 455 .
   Web of Science ®Google Scholar
• Lal , R. , ed. 1990 . Soil Testing and Plant Analysis Madison, WI : Soil Sci. Soc. Am. .
   Google Scholar
• Khiari , L. , Parent , L.E. and Tremblay , N. 2001 . Selecting the High-yield Subpopulation for Diagnosing Nutrient Imbalance in Crops . Agron. J. , 93 : 802 – 808 .
   Web of Science ®Google Scholar
• Zhang , H. , Redmon , L. , Fuhrman , J.K. and Springer , T. 1999 . Quick Nitrate Test for Hybrid Sudangrass and Pearlmillet Hays . Commun. Soil Sci. Plant Anal. , 30 : 1573 – 1582 .
   Web of Science ®Google Scholar
• Schepers , J.S. , Francis , D.D. , Vigil , M. and Below , F.E. 1992 . Comparison of Corn Leaf Nitrogen Concentration and Chlorophyll Meter Readings . Commun. Soil Sci. Plant Anal. , 23 : 2173 – 2187 .
   Web of Science ®Google Scholar
• Wood , C.W. , Reeves , D.W. and Himelrick , D.G. 1993 . Relationships Between Chlorophyll Meter Readings and Leaf Chlorophyll Concentration N Status, and Crop Yield: A Review . Proc. Agron. Soc. NZ , 23 : 1 – 9 .
   Google Scholar
• Yadava , U.L. 1986 . A Rapid Nondestructive Method to Determine Chlorophyll in Intact Leaves . HortSci. , 21 : 1449 – 1450 .
   Web of Science ®Google Scholar
• Blackmer , T.M. , Schepers , J.S. , Varvel , G.E. and Walter-Shea , E.A. 1996 . Nitrogen Deficiency Detection Using Reflected Shortwave Radiation from Irrigated Corn Canopies . Agron. J. , 88 : 1 – 5 .
   Web of Science ®Google Scholar
• Bausch , W.C. , Duke , H.R. and Iremonger , C.J. 1996 . “ Assessment of Plant Nitrogen in Irrigated Corn ” . In Proc. 3rd Int. Conf. on Precision Agriculture Edited by: Robert , P.C. , Rust , R.H. and Larson , W.E. 23 – 32 . Madison, WI : Am. Soc. Agron. .
   Google Scholar
• McMurtrey , J.E. III , Chappelle , E.W. , Kim , M.S. , Meisinger , J.J. and Corp , L.A. 1994 . Distinguishing Nitrogen Fertilization Levels in Field Corn (Zea mays L.) with Actively Induced Fluorescence and Passive Reflectance Measurements . Remote Sens. Environ. , 47 : 36 – 44 .
   Web of Science ®Google Scholar
• Thomas , J.R. and Gausman , H.W. 1977 . Leaf Reflectance vs Leaf Chlorophyll and Carotenoid Concentrations for Eight Crops . Agron. J. , 69 : 799 – 802 .
   Web of Science ®Google Scholar
• Al-Abbas , A.H. , Barr , R. , Hall , J.D. , Crane , F.L. and Baumgardner , M.F. 1974 . Spectra of Normal and Nutrient-Deficient Maize Leaves . Agron J. , 66 : 16 – 20 .
   Web of Science ®Google Scholar
• Stanhill , G. , Kalkofi , V. , Fuchs , M. and Kagan , Y. 1972 . The Effects of Fertilizer Applications on Solar Reflectance from a Wheat Crop . Israel J. Agric. Res. , 22 : 109 – 118 .
   Google Scholar
• Bausch , W.C. and Duke , H.R. 1996 . Remote Sensing of Plant Nitrogen Status in Corn . Trans. Am. Soc. Agric. Engineers , 39 ( 5 ) : 1869 – 1875 .
   Google Scholar
• Wood , G.A. , Thomas , G. and Taylor , J.C. 1999 . “ Calibration Techniques to Map Crop Variation and Yield Potential Using Remote Sensing ” . In Proc. 4th Int. Conf. on Precision Agriculture Edited by: Robert , P.C. , Rust , R.H. and Larson , W.E. 1367 – 1378 . Madison, WI : Am. Soc. Agron. .
   Google Scholar
• Tucker , C.J. 1979 . Red and Photographic Infrared Linear Combinations for Monitoring Vegetation . Remote Sens. Environ. , 8 : 127 – 150 .
   Web of Science ®Google Scholar
• Khosla , R. and Alley , M.M. 1999 . Soil-Specific Nitrogen Management on Mid-Atlantic Coastal Plain Soils . Better Crops , 3 : 6 – 7 .
   Google Scholar
• Hergert , G.W. , Ferguson , R.B. , Gotway , C.A. and Peterson , T.A. 1996 . “ The Impact of Variable Rate N Application on N Use Efficiency of Furrow Irrigated Corn ” . In Proceedings of the Third International Conference on Precision Agriculture Edited by: Robert , P.C. , Rust , R.H. and Larson , W.E. 389 – 398 . Madison, WI : Am. Soc. Agron. .
   Google Scholar
• Redulla , C.A. , Havlin , J.L. , Kluitenberg , G.L. , Zhang , N. and Schrock , M.D. 1996 . “ Variable Nitrogen Management for Improving Groundwater Quality ” . In Proceedings of the Third International Conference on Precision Agriculture Edited by: Robert , P.C. , Rust , R.H. and Larson , W.E. 1101 – 1110 . Madison, WI : Am. Soc. Agron. .
   Google Scholar
• Ortega , R.A. , Westfall , D.G. and Peterson , G.A. 1997 . Variability of Phosphorus over Landscapes and Dryland Winter Wheat Yields . Better Crops , 81 : 24 – 27 .
   Google Scholar
• Khan , A. and Soltanpour , P.N. 1978 . Factors Associated with Zn Chlorosis in Dryland Beans . Agron. J. , 70 : 1022 – 1026 .
   Web of Science ®Google Scholar
• Ells , J.E. , McSay , A.E. , Soltanpour , P.N. , Schweissing , F.C. , Bartolo , M.E. and Kruse , E.G. 1993 . Onion Irrigation and Nitrogen Leaching in the Arkansas Valley of Colorado . HortTechnol. , 3 : 184 – 187 .
   Google Scholar
• Lehrsch , G.A. , Sojka , R.E. and Westermann , D.T. 2001 . Furrow Irrigation and N Management Strategies to Protect Water Quality . Commun. Soil Sci. Plant Anal. , 32 : 1029 – 1050 .
   Web of Science ®Google Scholar
• Wells , K.L. 1984 . “ Nitrogen Management in the No-Till System ” . In Nitrogen in Crop Production Edited by: Hauck , R.D. 535 – 552 . Madison, WI : Am. Soc. Agron./Crop Sci. Soc. Agron/Soil Sci. Soc. Am. .
   Google Scholar
• Gallaher , R.N. 1977 . Soil Moisture Conservation and Yield of Crops No-Till Planted in Rye . Soil Sci. Soc. Am. J. , 41 : 145 – 147 .
   Web of Science ®Google Scholar
• Rehm , G.W. 1987 . “ Nutrient Management and Tillage Systems—the Midwest ” . In Future Developments in Soil Science Research Edited by: Boersma , L.L. 205 – 214 . Madison, WI : Soil Sci. Soc. Am. .
   Google Scholar
• Power , J.F. and Follett , R.F. 1987 . “ Tillage Systems and Nutrient Management—Great Plains ” . In Future Developments in Soil Science Research Edited by: Boersma , L.L. 215 – 224 . Madison, WI : Soil Sci. Soc. Am. .
   Google Scholar
• Touchton , J.T. and Sims , J.T. 1987 . “ Tillage Systems and Nutrient Management—in the East and Southeast ” . In Future Developments in Soil Science Research Edited by: Boersma , L.L. 225 – 234 . Madison, WI : Soil Sci. Soc. Am. .
   Google Scholar
• Lentz , R.D. , Shainberg , I. , Sojka , R.E. and Carter , D.L. 1992 . Preventing Irrigation Furrow Erosion with Small Applications of Polymers . Soil Sci. Soc. Am. J. , 56 : 1926 – 1932 .
   Web of Science ®Google Scholar
• Dabney , S.M. , Delgado , J.A. and Reeves , D.W. 2001 . Using Winter Cover Crops to Improve Soil and Water Quality . Commun. Soil Sci. Plant Anal. , 32 : 1221 – 1250 .
   Web of Science ®Google Scholar
• Delgado , J.A. , Sparks , R.T. , Follett , R.F. , Sharkoff , J.L. and Riggenbach , R.R. 1999 . “ Use of Winter Cover Crops to Conserve Soil and Water Quality in the San Luis Valley of South Central Colorado ” . In Soil Quality and Soil Erosion Edited by: Lal , R. 125 – 142 . Boca Raton Fl : CRC Press .
   Google Scholar
• Dabney , S.M. 1998 . Cover Crops Impacts on Watershed Hydrology . Soil and Water Conserv. , 53 : 207 – 213 .
   Web of Science ®Google Scholar
• Mutchler , C.K. and McDowell , L.L. 1990 . Soil Loss from Cotton with Winter Cover Crops . Trans. ASAE , 33 : 432 – 436 .
   Google Scholar
• Holderbaum , J.F. , Decker , A.M. , Meisinger , J.J. , Mulford , F.R. and Vough , L.R. 1990 . Fall-Seeded Legume Cover Crops for No-Tillage Corn in the Humid East . Agron. J. , 82 : 117 – 124 .
   Web of Science ®Google Scholar
• Frye , W.W. , Smith , W.G. and Williams , R.T. 1985 . Economics of Winter Cover Crops As a Source of Nitrogen for No-Till Corn . J. Soil Water Conserv. , 40 : 246 – 248 .
   Web of Science ®Google Scholar
• Kristensen , K.T. 2001 . Are Differences in Root Growth of Nitrogen Catch Crops Important for Their Ability to Reduce Soil Nitrate-N Content, and How Can This Be Measured? . Plant Soil , 230 : 185 – 195 .
   Web of Science ®Google Scholar
• Delgado , J.A. , Ristau , R.T. , Dillon , M.A. , Duke , H.R. , Stab , A. , Follett , R.F. , Shaffer , M.J. , Riggenbach , R.R. , Parks , R.T. , Thompson , A. , Kawanabe , L.R. , Kunugi , A. and Thompson , K. 2001 . Use of Innovative Tools to Increase Nitrogen Use Efficiency and Protect Environmental Quality in Crop Production . Commun. Soil Sci. Plant Anal. , 32 : 1321 – 1354 .
   Web of Science ®Google Scholar
• Delgado , J.A. , Riggenbach , R.R. , Sparks , R.T. , Dillon , M.A. , Kawanabe , L.R. and Ristau , R.T. 2001 . Evaluation of Nitrate-Nitrogen Transport in a Potato–Barley Rotation . Soil Sci. Soc. Am. J. , 65 : 878 – 883 .
   Web of Science ®Google Scholar
• Lal , R. , ed. 1999 . Best Management Practices for Nutrient and Irrigation Management in the San Luis Valley Fort Collins, CO : Colorado State University Cooperative Extension .
   Google Scholar
• Lal , R. , ed. 1991 . Nitrogen Fertilizer Management in Arizona Tucson, USA : Coll. of Agric., Univ. of Arizona .
   Google Scholar
• Soltanpour , P.N. 1969 . Effect of Nitrogen, Phosphorus, and Zinc Placement on Yield and Composition of Potatoes . Agron. J. , 61 : 288 – 289 .
   Web of Science ®Google Scholar
• Soltanpour , P.N. , El Gharous , M. , Azzaoui , A. and Abdelmonem , M. 1989 . Response of Dryland Wheat to P Rates and Placement Methods . Commun. Soil Sci. Plant Anal. , 20 : 597 – 605 .
   Web of Science ®Google Scholar
• Adcock , C.W. , Abaye , A.O. and Alley , M.M. 1999 . Subsurface Liming Effects on Cotton Development and Root Growth: A Greenhouse Study . Commun. Soil Sci. Plant Anal. , 30 : 317 – 327 .
   Web of Science ®Google Scholar
• Sowers , K.E. , Pan , W.L. , Miller , B.C. and Smith , J.L. 1994 . Nitrogen Use Efficiency of Split Nitrogen Applications in Soft White Winter Wheat . Agron. J. , 86 : 942 – 948 .
   Web of Science ®Google Scholar
• Oberle , S.L. and Keeney , D.R. 1990 . Factors Influencing Corn Fertilizer N Requirements in the Northern US Corn Belt . J. Prod. Agric. , 3 : 527 – 534 .
   Google Scholar
• Westermann , D.T. and Kleinkopf , G.E. 1985 . Nitrogen Requirements of Potatoes . Agron. J. , 77 : 616 – 621 .
   Web of Science ®Google Scholar
• Stanford , G. and Legg , J.O. 1984 . “ Nitrogen and Yield Potential ” . In Nitrogen in Crop Production Edited by: Hauck , R.D. 263 – 272 . Madison, WI : ASA/Crop Sci. Soc. Am./Soil Sci. Soc. Am. .
   Google Scholar
• Russelle , M.P. , Deibert , E.J. , Hauck , R.D. , Stevanovic , M. and Olson , R.A. 1981 . Effects of Water and Nitrogen Management on Yield and 15N-depleted Fertilizer Use Efficiency of Irrigated Corn . Soil Sci. Soc. Am. J. , 45 : 553 – 558 .
   Web of Science ®Google Scholar
• Gunasena , H.P.M. and Harris , P.M. 1968 . The Effect of Time of Application of Nitrogen and Potassium on the Growth of the Second Early Potato Variety . Royal J. Agric. Sci. , 71 : 283 – 296 .
   Web of Science ®Google Scholar
• Goos , R.T. and de Padua Cruz , A. 1999 . Effect of Ammonium Sulfate Pretreatment on Ammonia Volatilization After Urea Fertilization . Commun. Soil Sci. Plant Anal. , 30 : 1325 – 1336 .
   Web of Science ®Google Scholar
• Shoji , S. , Delgado , J. , Mosier , A. and Miura , Y. 2001 . Use of Controlled Release Fertilizers and Nitrification Inhibitors to Increase Nitrogen Use Efficiency and to Conserve Air and Water Quality . Commun. Soil Sci. Plant Anal. , 32 : 1051 – 1070 .
   Web of Science ®Google Scholar
• Alva , A.K. and Paramasivam , S. 1998 . Nitrogen Management for High Yield and Quality of Citrus in Sandy Soils . Soil Sci Soc Am. J. , 62 : 1335 – 1342 .
   Web of Science ®Google Scholar
• Delgado , J.A. and Mosier , A.R. 1996 . Mitigation Alternatives to Decrease Nitrous Oxides Emissions and Urea-Nitrogen Loss and Their Effect on Methane Flux . J. Environ. Qual. , 25 : 1105 – 1111 .
   Web of Science ®Google Scholar
• Wang , F.L. and Alva , A.K. 1996 . Leaching of Nitrogen from Slow-Release Urea Sources in Sandy Soils . Soil Sci. Soc. Am. J. , 60 : 1454 – 1458 .
   Web of Science ®Google Scholar
• Mikkelsen , R.L. , Williams , H.W. and Behel , A.D. Jr. 1994 . Nitrogen Leaching and Plant Uptake from Controlled-Release Fertilizers . Fert. Res. , 37 : 43 – 50 .
   Web of Science ®Google Scholar
• Yadvinder-Singh , S.S. , Malhi , M. and Nyborg , E.G. 1994 . Large Granules, Nest or Bands: Methods of Increasing Efficiency of Fall-Applied Urea for Small Cereal Grains in North America . Fert. Res. , 38 : 61 – 87 .
   Web of Science ®Google Scholar
• Ronaghi , A. , Soltanpour , P.N. and Mosier , A.R. 1993 . Nitrapyrin Effect on Corn N-15 Uptake Efficiency, Denitrification and Nitrate Leaching . Commun. Soil Sci. Plant Anal. , 24 : 2629 – 2639 .
   Web of Science ®Google Scholar
• Freney , J.R. , Smith , C.J. and Mosier , A.R. 1992 . Effect of a New Nitrification Inhibitor (Wax Coated Calcium Carbide) on Transformations and Recovery of Fertilizer Nitrogen by Irrigated Wheat . Fert. Res. , 32 : 1 – 11 .
   Web of Science ®Google Scholar
• Lal , R. , ed. 1992 . Controlled Release Fertilizers with Polyolefin Resin Coating Sendai, Japan : Konno Printing Co. .
   Google Scholar
• Thompson , T.L. and Doerge , T.A. 1996 . Nitrogen and Water Interactions in Subsurface Trickle Irrigated Leaf Lettuce. I. Plant Response . Soil Sci. Soc. Am. J. , 60 : 163 – 168 .
   Web of Science ®Google Scholar
• Thompson , T.L. and Doerge , T.A. 1996 . Nitrogen and Water Interactions in Subsurface Trickle Irrigated Leaf Lettuce. II. Agronomic, Economic, and Environmental Outcomes . Soil Sci. Soc. Am. J. , 60 : 168 – 173 .
   Web of Science ®Google Scholar
• Schepers , J.S. , Varvel , G.E. and Watts , D.G. 1995 . Nitrogen and Water Management Strategies to Reduce Nitrate Leaching Under Irrigated Maize . J. Contaminant Hydrol. , 20 : 227 – 239 .
   Web of Science ®Google Scholar
• Westermann , D.T. , Kleinkopf , G.E. and Porter , L.K. 1988 . Nitrogen Fertilizer Efficiencies on Potatoes . Am. Potato J. , 65 : 377 – 386 .
   Web of Science ®Google Scholar
• Hergert , G.W. 1986 . Nitrate Leaching Through Sandy Soil as Affected by Sprinkler Irrigation Management . J. Environ. Qual. , 15 : 272 – 278 .
   Web of Science ®Google Scholar
• Smika , D.E. , Heermann , D.F. , Duke , H.R. and Batchelder , A.R. 1977 . Nitrate-N Percolation Through Irrigated Sandy Soil as Affected by Water Management . Agron. J. , 69 : 623 – 626 .
   Web of Science ®Google Scholar
• Eghball , B. and Power , J.F. 1999 . Phosphorus- and Nitrogen-Based Manure and Compost Applications: Corn Production and Soil Phosphorus . Soil Sci. Soc. Am. J. , 63 : 895 – 901 .
   Web of Science ®Google Scholar
• Waskom , R.M. and Davis , J.G. 1999 . Best Management Practices for Manure Utilization Fort Collins, CO : Colorado State Univ. Coop. Ext. .
   Google Scholar
• Barbarick , K.A. , Ippolito , J.A. and Westfall , D.G. 1998 . Extractable Trace Elements in the Soil Profile After Years of Biosolids Application . J. Environ. Qual. , 27 : 801 – 805 .
   Web of Science ®Google Scholar
• Gerloff , G.C. and Gabelman , W.H. 1983 . “ Genetic Basis of Inorganic Plant Nutrition ” . In Inorganic Plant Nutrition Edited by: Lauchli , A. and Bieleski , R.L. Vol. 15B , 453 – 480 . New York, NY : Springer Verlag .
   Google Scholar
• Mortvedt , J.J. , Soltanpour , P.N. , Zinc , R.T. and Davidson , R.D. 1996 . Fertilizing Potatoes Fort Collins, CO : Colorado State Univ. Coop. Ext. .
   Google Scholar
• Tabook , M. “ Effect of Potato Variety Root Volume on Nitrogen Uptake and Use Efficiency ” . Fort Collins, CO : Colorado State University . 1999
   Google Scholar
• Davis , J.G. and Quick , J.S. 1998 . “ Nutrient Management, Cultivar Development and Selection Strategies to Optimize Water Use Efficiency ” . In Nutrient Use in Crop Production Edited by: Rengel , Z. 221 – 240 . New York : Food Products Press, an Imprint of the Haworth Press, Inc. .
   Google Scholar
• Milburn , P. , Richards , J.E. , Gartley , C. , Pollock , T. , O'Neill , H. and Bailey , H. 1990 . Nitrate Leaching from Systematically Tilled Potato Fields in New Brunswick . Can. J. Environ. Qual. , 19 : 448 – 454 .
   Web of Science ®Google Scholar
• Smith , S.J. , Schepers , J.S. and Porter , L.K. 1990 . “ Assessing and Managing Agricultural Nitrogen Losses to the Environment ” . In Advances in Soil Science Edited by: Stewart , B.A. 1 – 43 . New York : Springer-Verlag .
   Google Scholar
• Lal , R. , ed. 1991 . Managing Nitrogen for Groundwater Quality and Farm Profitability Madison, WI : Soil Sci. Soc. Am. .
   Google Scholar
• McCracken , D.V. , Smith , M.S. , Grove , J.H. , MacKown , C.T. and Blevins , R.L. 1994 . Nitrate Leaching as Influenced by Cover Cropping and Nitrogen Source . Soil Sci. Soc. Am. J. , 58 : 1476 – 1483 .
   Web of Science ®Google Scholar
• Owens , L.B. and Edwards , W.M. 1994 . Groundwater Nitrate Levels Under Fertilized Grass and Grass Legume Pastures . J. Environ. Qual. , 23 : 752 – 758 .
   Web of Science ®Google Scholar
• Sharpley , A.N. , Kleinman , P. and McDowell , R. 2001 . Innovative Management of Agricultural Phosphorous to Protect Soil and Water Quality . Commun. Soil Sci. Plant Anal. , 32 : 1071 – 1100 .
   Web of Science ®Google Scholar
• Lal , R. , ed. 1999 . Soil Quality and Soil Erosion Boca Raton, FL : CRC Press .
   Google Scholar
• Shaffer , M.J. , Wylie , B.K. and Hall , M.D. 1995 . Identification and Mitigation of Nitrate Leaching Hot Spots Using NLEAP-GIS Technology . J. Contaminant Hydrol. , 20 : 253 – 263 .
   Web of Science ®Google Scholar
• Follett , R.F. , Shaffer , M.J. , Brodahl , M.K. and Reichman , G.A. 1994 . NLEAP Simulation of Residual Soil Nitrate for Irrigated and Non Irrigated Corn . J. Soil Water Conserv. , 49 : 375 – 382 .
   Web of Science ®Google Scholar
• Shaffer , M.J. , Halvorson , A.D. and Pierce , F.J. 1991 . “ Nitrate Leaching and Economic Analysis Package (NLEAP): Model Description and Application ” . In Managing Nitrogen for Groundwater Quality and Farm Profitability Edited by: Follett , R.F. , Keeney , D.R. and Cruse , R.M. 285 – 322 . Madison, WI : Soil Sci. Soc. Am. .
   Google Scholar
• Delgado , J.A. 1998 . Sequential NLEAP Simulations to Examine Effect of Early and Late Planted Winter Cover Crops on Nitrogen Dynamics . J. Soil Water Conserv. , 53 : 338 – 340 .
   Web of Science ®Google Scholar
• Delgado , J.A. , Shaffer , M.J. and Brodahl , M.K. 1998 . New NLEAP for Shallow and Deep Rooted Crop Rotations . J. Soil Water Conserv. , 53 : 338 – 340 .
   Web of Science ®Google Scholar
• Delgado , J.A. , Follett , R.F. , Sharkoff , J.L. , Brodahl , M.K. and Shaffer , M.J. 1998 . NLEAP Facts About Nitrogen Management . J. Soil Water Conserv. , 53 : 332 – 338 .
   Web of Science ®Google Scholar
• Delgado , J.A. 1999 . “ NLEAP Simulation of Soil Type Effects on Residual Soil NO3-N in the San Luis Valley and Potential Use for Precision Agriculture ” . In Proc. 4th Int. Conf. on Precision Agriculture Edited by: Robert , P.C. , Rust , R.H. and Larson , W.E. 1367 – 1378 . Madison, WI : Am. Soc. Agron. .
   Google Scholar
• Shaffer , M.J. and Xu , C. 1998 . “ Simulation Modeling in Precision Agriculture: Soil Fertility ” . In Proc. Great Plains Soil Fertility Conference. Denver, Colorado. March 3–4, 1998 Edited by: Schlegel , A.J. 55 – 60 . Manhattan, KS : Kansas State University .
   Google Scholar
• Wylie , B.K. , Shaffer , M.J. , Brodahl , M.K. , Dubois , D. and Wagner , D.G. 1994 . Predicting Spatial Distributions of Nitrate Leaching in Northeastern Colorado . J. Soil Water Conserv. , 49 : 346 – 351 .
   Web of Science ®Google Scholar
• Delgado , J.A. 2001 . “ Use of Simulations for Evaluations of Best Management Practices on Irrigated Cropping Systems ” . In Modeling Carbon and Nitrogen Dynamics for Soil Management Edited by: Shaffer , M. , Ma , L. and Hansen , S. 355 – 381 . Boca Raton, FL : CRC Press .
   Google Scholar
• Ritchie , J.T. , Godwin , D.C. and Otter-Nacke , S. 1985 . CERES Wheat. A Simulation Model of Wheat Growth and Development College Station, Texas : Texas A&M University Press .
   Google Scholar
• in press .
   Google Scholar
• in press .
   Google Scholar
• Wagenet , R.T. and Hutson , J.L. 1989 . LEACHM: Leaching Estimation and Chemistry Model—A Process Based Model of Water and Solute Movement, Transformations, Plant Uptake and Chemical Reactions in the Unsaturated Zone Vol. 2 , Ithaca, NY : Water Resour. Inst., Cornell Univ. . Continuum
   Google Scholar
• Hansen , S. , Jensen , H.E. , Nielsen , N.E. and Svendsen , H. 1991 . Simulation of Nitrogen Dynamics and Biomass Production in Winter Wheat Using the Danish Simulation Model Daisy . Fertil. Res. , 27 : 245 – 259 .
   Web of Science ®Google Scholar
• DeCoursey , D.G. , Rojas , K.W. and Ahuja , L.R. 1989 . Potentials for Non-point Source Groundwater Contamination Analyzed Using RZWQM St. Joseph, MI : ASAE .
   Google Scholar
• Barber , S.A. 1995 . Soil Nutrient Bioavailability—A Mechanistic Approach New York : Wiley-Interscience .
   Google Scholar
• Parton , W.J. , McKeown , B. , Kirchner , V. and Ojima , D. 1992 . Users Guide for the CENTURY Model Fort Collins, CO : Colorado State University .
   Google Scholar
• Hartkamp , A.D. , White , J.W. and Hoogenboom , G. 1999 . Interfacing Geographic Information Systems with Agronomic Modeling: A Review . Agron. J. , 91 : 761 – 772 .
   Web of Science ®Google Scholar
• Shaffer , M.J. , Hanson , J.D. , Ascough , J.C. II , McMaster , G.S. , Buchleiter , G.W. and Ahuja , L.R. 1995 . Development Plan for the Great Plains Framework for Agricultural Resource Management (GPFARM): A Decision Support System for Whole-Farm Strategic Planning Fort Collins, CO : USDA-ARS-NPA .
   Google Scholar
• Barbarick , K.A. and Workman , S.M. 1987 . Ammonium Bicarbonate-DTPA and DTPA Extraction of Sludge-Amended Soils . J. Environ. Qual. , 16 : 125 – 130 .
   Web of Science ®Google Scholar
• Boon , D.Y. and Soltanpour , P.N. 1992 . Lead, Cadmium, and Zinc Contamination of Aspen Garden Soils and Vegetation . J. Environ. Qual. , 21 : 82 – 86 .
   Web of Science ®Google Scholar
• Williams , C.M.J. and Maier , N.A. 1990 . Determination of the Nitrogen Status of Irrigated Potato Crops. II. A Simple on Farm Quick Test for Nitrate Nitrogen in Petiole Sap . J. Plant Nutr. , 13 : 985 – 993 .
   Web of Science ®Google Scholar
• Spiers , T.M. 1984 . Evaluation of a Rapid Method for Plant Sap Nitrate Analysis . Commun. Soil Sci. Plant Anal. , 15 : 673 – 679 .
   Web of Science ®Google Scholar
• Scaife , A. and Stevens , K.L. 1983 . Monitoring Sap Nitrate in Vegetable Crops: Comparison of Test Strips with Electrode Methods, and Effects of Time of Day and Leaf Position . Commun. Soil Sci. Plant Anal. , 14 : 761 – 771 .
   Web of Science ®Google Scholar
• Papastylianou , I. 1989 . Diagnosing Nitrogen Fertilization Requirements of Cereals in Less Than 30 Seconds . Commun. Soil Sci. Plant Anal. , 20 : 1247 – 1259 .
   Web of Science ®Google Scholar
• Westcott , M.P. , Rosen , C.J. and Inskeep , W.P. 1993 . Direct Measurement of Petiole Sap Nitrate in Potato to Determine Crop Nitrogen Status . J. Plant Nutr. , 16 : 515 – 521 .
   Web of Science ®Google Scholar
• Errebhi , M. , Rosen , C.J. and Birong , D.E. 1998 . Calibration of a Petiole Sap Nitrate Test for Irrigated Russet Burbank Potato . Commun. Soil Sci. Plant Anal. , 29 : 23 – 35 .
   Web of Science ®Google Scholar
• Kubota , A. , Thompson , T.L. , Doerge , T.A. and Godin , R.E. 1996 . A Petiole Sap Nitrate Test for Cauliflower . Hort. Sci. , 31 : 934 – 937 .
   Google Scholar
• Kubota , A. , Thompson , T.L. , Doerge , T.A. and Godin , R.E. 1997 . A Petiole Sap Nitrate Test for Broccoli . J. Plant Nutr. , 20 : 669 – 682 .
   Web of Science ®Google Scholar
• Delgado , J.A. and Follett , R.F. 1998 . Sap Test to Determine Nitrate-Nitrogen Concentrations in Aboveground Biomass of Winter Cover Crops . Commun. Soil Sci. Plant Anal. , 29 : 545 – 559 .
   Web of Science ®Google Scholar
• Hartz , T.K. , Smith , R.F. , Schulbach , K.F. and LeStrange , M. 1994 . On-Farm Nitrogen Test Improves Fertilizer Efficiency, Protect Groundwater . Calif. Agric. , 48 : 29 – 32 .
   Google Scholar
• King , B.A. , Stark , J.C. and Taberna , J.P. Jr. 1999 . “ In-Season Spatial Variability of Potato Petiole Nitrogen ” . In Proc. 4th Int. Conf. on Precision Agriculture Edited by: Robert , P.C. , Rust , R.H. and Larson , W.E. 55 – 65 . Madison, WI : Am. Soc. Agron. .
   Google Scholar
• Habte , M. 2001 . Plant Mechanisms and Mycorrhizal Symbiosis to Increase Phosphorus Uptake Efficiency . Commun. Soil Sci. Plant Anal. , 32 : 1101 – 1148 .
   Web of Science ®Google Scholar
• Fleming , K.L. , Westfall , D.G. , Wiens , D.W. , Rothe , L.E. , Cipra , J.E. and Heermann , D.F. 1999 . “ Evaluating Farmer Developed Management Zone Maps for Precision Farming ” . In Proc. 4th Int. Conf. on Precision Agriculture Edited by: Robert , P.C. , Rust , R.H. and Larson , W.E. 335 – 343 . Madison, WI : Am. Soc. Agron. .
   Google Scholar
• Delgado , J.A. and Duke , H.R. 2000 . “ Potential Use of Precision Farming to Improve Nutrient Management on Irrigated Potato–Barley Rotation ” . In Proc. 5th Int. Conf. on Precision Agriculture Edited by: Robert , P.C. Madison, WI : Am. Soc. Agron. . In print
   Google Scholar