T I Lgronomy VOLUME 49 Advisory Board Martin Alexander Eugene J Kamprath Cornell University North Carolina State University Kenneth J Frey Larry P Wilding Iowa State University Texas A&M University Prepared in cooperation with the A m ' c a n Society of Agronomy Monographs Committee S H Anderson P S Baenziger L P Bush M A Tabatabai, Chairman R N Carrow W T Frankenberger, Jr S E Lingle R J Luxrnoore G A Peterson S R Yates D V A N C E S IN VOLUME 49 Edited by Donald L Sparks Department of Plant and Soil Sciences University of Delaware Newark, Delaware ACADEMIC PRESS, INC Harcourt Brace & Company San Diego New York Boston London Sydney Tokyo Toronto This book is printed on acid-free paper Copyright 1993 by ACADEMIC PRESS, INC All Rights Reserved No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher Academic Press, Inc 1250 Sixth Avenue, San Diego, California 92 101.431 United Kingdom Edition published by Academic Press Limited 24-28 Oval Road, London NW1 7DX Library of Congress Catalog Number: 50-5598 International Standard Book Number: 0- 12-000749-5 PRINTED IN THE UNITED STATES OF AMERICA 9 9 9 BB Contents CONTRIBUTORS PREFACE vii ix USEOF COMPUTER-ASSISTED TOMOGRAPHY IN STUDYINGWATER MOVEMENT AROUND PLANT ROOTS L A G Aylmore I I1 I11 IV V VI VII VIII IX Introduction Computer-Assisted Tomography X-Ray CATScanners y-Ray C A T Scanners Application of Computer-Assisted Tomography to Soil- Water Studies Nuclear Magnetic Resonance Imaging Dual-Energy Scanning Recent and Future Developments Summary and Conclusions References 13 22 26 41 43 47 49 50 PHOSPHOGYPSUM IN AGRICULTURE: A REVIEW Isabel0 S Alcordo and Jack E Rechcigl I Introduction I1 Uses of Phosphogypsum in Agriculture 111 Environmental Considerations IV Conclusions References 55 65 93 100 102 NUTRIENT CYCLING AND SOILFERTILITY IN THEGRAZED PASTURE ECOSYSTEM R J Haynes and P H Williams I Introduction 119 121 The Pasture System and Its Effect on Soil Properties I1 I11 Nutrient Returns in Feces and Urine IV Soil Processes and Pasture Response in Excreta-Affected Areas V 130 144 vi CONTENTS V Modeling Nutrient Cycling under Pasture VI Summary and Conclusions References 174 189 191 ELECTRICAL CONDUCTMTY METHODS FOR MEASURING AND MAPPINGSOILSALINITY J D Rhoades I Introduction I1 Determination of Soil Salinity from Aqueous Electrical Conductivity 111 Determination of Soil Salinity from Soil Paste or Bulk Soil Electrical Conductivity IV Conclusions and Summary References 201 204 212 246 246 BREEDING.PHYSIOLOGY CULTURE.AND UTILIZATION OF CICERMILKVETCH (AJtragaZm cicer L.) C E Townsend I Invoduction I1 Morphology and Anatomy 111 Physiology IV V VI VII Culture Utilization Breeding Genetics and Cytology Summary and Conclusions References INDEX 254 254 256 265 276 289 300 301 09 Contributors Numbers in parentheses indicate the pages on which the authors’ contributions begin ISABEL0 S ALCORDO ( 5 ) , Institute of Food and Agricultural Sciences, Agricultural Research and Education Center, University of Florida, Ona, Florida 33865 L A G AYLMORE (l), Department of Soil Science and Plant Nutrition, The University of Western Australia, Nedlands, Western Australia 6009, Australia R J HAYNES (119), New Zealand Institute for Crop and Food Research, Canterbury Agriculture and Science Centre, Christchurch, New Zealand JACK E RECHCIGL (55), Institute o f Food and Agricultural Sciences, Agricultural Research and Education Center, University of Florida, Ona, Florida 33865 J D RHOADES (20l), United States Salinity Laboratory, United States Department o f Agriculture, Agricultural Research Service, Riverside, Calqornia 92501 C E T O W S E N D (25 3), Crops Research Laboratory, Agricultural Research Service, United States Department of Agriculture, Fort Collins, Colorado 80526 P H WILLIAMS (1 19), New Zealand Institute for Crop and Food Research, Canterbury Agriculture and Science Centre, Christchurch, New Zealand vii This Page Intentionally Left Blank Preface Volume 49 brings together a number of plant and soil scientists who discuss some exciting and significant advances in agronomy The first chapter deals with the use of computer-assisted tomography (CAT) in investigating water mobility around plant roots Topics that are discussed include background information on CAT, application of CAT to soilwater studies, nuclear magnetic resonance, and future developments and uses of CAT in agronomy The second chapter is a comprehensive review of phosphogypsum in agriculture, including its utilization as a source of sulfur and calcium and as an ameliorant of aluminum toxicity, salinity, nonsodic dispersive soils, hard pans, and hard setting clay soils The third chapter discusses nutrient cycling and soil fertility in the grazed pasture ecosystem Topics that are treated include the pasture system and its effect on soil properties and nutrient cycling modeling The fourth chapter covers important advances in methods of measuring and mapping soil salinity Sensors and procedures for measuring bulk soil electric conductivity are discussed in detail, including the use of four-electrode, electromagneticinduction, and time-domain reflectometry sensors The morphology and anatomy, physiology, culture, utilization, breeding, genetics, and cytology of cicer milkvetch are treated in the fifth chapter This legume is becoming increasingly useful in parts of North America as a pasture, hay, and conservation species under irrigated and dryland conditions I appreciate the fine contributions of the authors DONALD L SPARKS ix 302 C E TOWNSEND Bowman, R A., and Townsend, C E 1990 Growth response of cicer milkvetch to different soil reactions Agron Abstr p 263 Burton, J C 1972 Nodulation and nitrogen fixation in alfalfa Agronomy 15,229-246 Buyanova, V F 198 Biology of some Astragalus spp in the flora of the USSR, cultivated in Leningrad Russian-SFSR1 Rastit Resur 17, 420-433 [Biol Abstr 74, 059044 (1982)l Carleton, A E., Austin, R D., Stroh, J R., Wiesner, L E., and Scheetz, J G 1971 Cicer milkvetch (Astragalus cicer L.) seed germination, scarification and field emergence studies Bull. Mont., Agric Exp Stn 655 Church, D C 197 The macro (major) minerals Dig Physiol Nutr Ruminants 2,4 13 -45 I Cook, C W., Hyde, R M., and Sims, P L 1974 Revegetation guidelines for surface mined areas Range Sci Dep Sci Ser (Colo.State Univ.)16 Cooper, C S 1979 Evaluation of legume mixtures for hay planting Agron J 71,81-83 Cooper, C S., and Watson, C A 1968 Total available carbohydrates in roots of sainfoin (Onobrychis viciaefolia Scop.) and alfalfa (Medicago sativa L.) when grown under several management regimes Crop Sci 8,83 - 85 Cooper, C S.,Eslick, R F., and McDonald, P W 1966 Foam formation from extracts of 27 legume species in vitro Crop Sci 6, I5 -2 16 Cooper, C S., Welty, L E., Laudert, S B., and Wiesner, L E 1978 Evaluation of Regar meadow bromegrass in Montana Bull -Mont Agric Exp Stn 702 Cornelius, D R., and Talbot, M W 1955 Rangeland improvement through seeding and weed control of east slope Sierra Nevada and on southern Cascade Mountains US., Dep Agric., Agric Handb 88 Davis, A, M 1972 Selenium accumulation in Astragalus species Agron J 64, 751 -754 Davis, A M 1973 Protein, crude fiber, tannin, and oxalate concentrations of some introduced Astragalus species Agron J 65,6 I3 -6 15 Davis, A M 1982a Nitrogen production by selected Astragalus species Agron J 74, 454-456 Davis, A M 1982b Crude protein, crude fiber, tannin, and oxalate concentrations of 33 Astragalus species J Range Manage 35,32 -34 Davis, M R 1981 Growth and nutrition of legumes on a high country yellow-brown earth subsoil Phosphate response of Lotus, Trifolium, Lupinus, Astragalus, and Coronilla species and cultivars N.Z J Agric Res 24, 321 -332 Dobson, J W., Fisher, C D., and Beaty, E R 1976 Yield and persistence of several legumes growing in tall fescue Agron J 68, 123- 125 Ellsbury, M M., and Nielson, M W 198 Comparative host plant range studies of the blue alfalfa aphid, Acyrthosiphon kondoi Shinji, and the pea aphid, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae) US.,Dep Agric., Sci Educ Adm., Tech Bull 1639 Etra, J., Cuany, R L., and Thor, G L 1984 Persistence and performance of grass and legume strains at subalpine test plots in Colorado Inf: Ser -Colo Water Resour Res Znst 53, 59-77 Evans, R K., and Abernethy, R H 1983 Identification of cicer milkvetch cultivars using SDS-polyacrylamide gel electrophoresis Can J Plant Sci 63, 1087- 1090 Faris, M A., and Ta, T C 1985 Performance of double and single cut red clover and cicer milkvetch entries at the Ottawa Research Station Forage Notes 29, 15 - 18 Fay, J P., Cheng, K.-J, Hanna, M R., Howarth, R E., and Costerton, J W 1980 Zn vitro digestion of bloat-safe and bloatcausing legumes by rumen microorganisms: Gas and foam production J Dairy Sci 63, 1273- 128I Fay, J P., Cheng, K.-J, Hanna, M R., Howarth, R E., and Costerton, J W 198 A scanning CICER MILKVETCH (Astrugahs cicer L.) 303 electron microscope study of the invasion of leaves of a bloat-safe and bloat-causing legume by rumen microorganisms Can J Microbiol 27, 390-399 Gabrielsen, B C., Smith, D H., and Townsend, C E 1985 Cicer milkvetch and alfalfa as influenced by two cutting schedules Agron J 77,416-422 George, J R 1984 Grass sward improvement by frost-seeding with legumes Proc Forage Grassl Conj pp 265-269 Hafenrichter, A L., Foster, R B., and Schwendiman, J L 1965 Effect of storage at four locations in the west on longevity of forage seeds Agron J 57, 143- 147 Hafenrichter, A L., Schwendiman, J L., Harris, H L., MacLauchlan, R S., and Miller, H W 1968 Grasses and legumes for soil conservation in the Pacific Northwest and Great Basin States U.S.,Dep Agric Agric Handb 339 Haraszti, E., and Vetter, J 1989 Phytochemical data on the Astragalus species of Hungary Bot Kozl 74-75, 379-390 [Biol Abstr 90,080028 (1990)) Hart, R H., and Dean, J G 1986 Forage establishment: Weather effects on stubble vs fallow and fall vs spring seeding J RangeManage 39,228-230 Hewitt, G B 1969 Twenty-six varieties of forage crops evaluated for resistance to feeding by Melanoplus sanguinipes Ann Entomol Soc Am 62,731 -74 I Hewitt, G B., Wilton, A C., and Lorenz, R J 1982 The suitability of legumes for rangeland interseeding and as grasshopper food plants J Range Manage 35,653-656 Holechek, J L., Depuit, E J., Coenenberg, J G., and Valdez, R 1981 Fertilizer effects on establishment of two seed mixtures on mined land in southeastern Montana J Soil Water Conserv 36,24 - 244 Holechek, J L., Depuit, E J., Coenenberg, J G., and Valdez, R 1982 Legume establishment on strip mined lands in southeastern Montana J Range Manage 35,298 - 300 Howarth, R E., Goplen, B P., Fesser, A C., and Brandt, S A 1978 A possible role for leaf cell rupture in legume pasture bloat Crop Sci 18, 129- 133 Howarth, R E., Goplen, B P.,Brandt, S A., and Cheng, K.-J 1982 Disruption of leaf tissues by mmen microorganisms: An approach to breeding bloat-safe forage legumes Crop Sci 22, 564-568 Ingham, J L., and Dewick, P M 1980 Astraciceran: A new isoflavan phytoalexin from Astragalus cicer Phytochemistry 19, 1767 - 1770 Johnston, A., Smoliak, S., Hironaka, R., and Hanna, M R 1971 Oxley cicer milkvetch Can J Plant Sci 51,428-429 Johnston, A., Smoliak, S., Hanna, M R., and Hironaka, R 1972 Registration of Oxley cicer milkvetch CropSci 12,715 Johnston, A., Smoliak, S., Hanna, M.R., and Hironaka, R 1975 Cicer milkvetch for western Canada Agric Can Publ 1536 Kaldy, M S., Smoliak, S., and Hanna, M R 1978 Amino acid composition of cicer milkvetch forage Agron J 70, I3 I - 132 Kenno, H., Brick, M A., and Townsend, C E 1987 Establishment of cicer milkvetch with four cool-season grasses Crop Sci 27,8 10- 12 Kephart, K D., Higley, L G., Buxton, D R., and Pedigo, L P 1990 Cicer milkvetch forage yield, quality, and acceptability to insects Agron J 82,477-483 Kerr, H D., and Klingman, D L 1960 Weed control in establishing birdsfoot trefoil Weeds 8, 157- 167 Kinder, S D., and Springer,T L 1989 Alternate hosts of Russian wheat aphid (Homoptera: Aphididae) J Econ Entomol 82, 1358- 1362 Kneebone, W R 1959 An evaluation of legumes for western Oklahoma rangelands Okla., Agric Exp Stn./U.S Dep Agric Bull B-539 04 C E TOWNSEND Komarov, V L (ed.) 1965 “Flora of the USSR,” Vol XII Leguminosae: Astragalus (translated by the Israel Program for Translation Ltd and published for the Smithsonian Institution and the National Science Foundation, Washington, D.C.) Latterell, R L., and Townsend, C E 1982 Cytology and breeding behavior of cicer milkvetch Proc Int Grassl Congr., 14th pp 174- 176 Ledingham, G F 1960 Chromosome numbers in Astragalus and Oxytropis Can J Genet Cytol 2, 119- 128 Ledingham, G F., and Rever, B M 1963 Chromosome numbers of some southwest Asian species of Astragalus and Oxytropis (Leguminosae) Can J Genet Cytol 5, 18 - 32 Lees, G L 1984 Cuticle and cell wall thickness relation to mechanical strength of whole leaves and isolated cells from some forage legumes Crop Sci 24, 1077- 1081 Lees, G L., Howarth, R E., Goplen, B P., and Fesser, A C I98 Mechanical disruption of leaf tissues and cells in some bloat-causing and bloat-safe forage legumes Crop Sci 21, 444-448 Lees, G L., Howarth, R E., and Goplen, B P 1982 Morphological characteristics of leaves from some legume forages: Relation to digestion and mechanical strength Can J Bot 60,2126-2132 Major, D J., Hanna, M R., Smoliak, S., and Grant, R 1979 Estimating nodule activity of sainfoin, alfalfa, and cicer milkvetch seedlings Agron J 71,983-985 Malik, N., and Waddington, J 1989 Weed control strategies for forage legumes Weed Technol 3,288-296 Malik, N., and Waddington, J 1990 No-till pasture renovation after sward suppression by herbicides Can J Plant Sci 70,261 -267 Marten, G C., Ehle, F R., and Ristau, E A 1987 Performance and photosensitization of cattle related to forage quality of four legumes Crop Sci 27, 138- 145 Marten, G C., Jordan, R M., and Ristau, E A 1990 Performance and adverse response of sheep during grazing of four legumes Crop Sci 30,860-866 Martin, S S., and Townsend, C E 1989 Isoflavan stress metabolites in North American cultivars of Astragalus cicer Am J Bot., Suppl 76(6), 194 McGinnies, W J., and Crofts, K A 1986 Effects of N and P fertilizer placement on establishment of seeded species on redistributed mine topsoil J Range Manage 39, 118-121 McGraw, R L., and Marten, G C 1986 Analysis of primary spring growth of four pasture legume species Agron J 78,704-7 10 Melton, B 1973 Evaluations of sainfoin and cicer milkvetch in New Mexico Res Rep -N M Agric Exp Stn 255 Miklas, P N., Townsend, C E., and Ladd, S H 1987 Seed-coat anatomy and scarification of cicer milkvetch seed Crop Sci 27, 766-772 Miroslavov, E A., and Bubolo, L S 1980 Ultrastructure of leaf chlorenchyma cells of some arctic plants Herb Abstr 51,6078 Moyer, J R 1989 Weed control during cicer milkvetch establishment and yields in subsequent years Can J Plant Sci 69,2 I3 - 222 Moyer, J R., Smoliak, S.,and Johnston, A 1979 Tolerance of seedling cicer milkvetch to herbicides Can J Plant Sci 59, 155- 157 Nicholas, P J., and McGinnies, W J 1982 An evaluation of 17 grasses and legumes for revegetation of soil and spoil on a coal strip mine J Range Manage 35,288-293 Nichols, J T., Gray, A M., Clanton, D C., and Myran, D 1982 Alfalfa, cicer milkvetch, cool-season grasses Imgated pasture-animal production Nebr., Agric Exp Stn., Beef Cattle Rep pp - 32 CICER MILKVETCH (Astraguh cicer L.) 305 Peterson, P R., Sheaffer, C C., and Hall, M H (1992) Drought effects on perennial forage legume yield and quality Agron J 84,774-779 Plummer, A P., Christensen, D R., and Monsen, S B 1968 Restoring big game range in Utah Utah Division of Fish and Game Pub 68-3 Podlech, D 1986 Taxonomic and phytogeographical problems in Astragalus of the Old World and south-west Asia Proc.-R Soc Edinburgh, Sect B: Biol Sci 89, 37-43 Richards, K W., 1986 Pollination requirements of cicer milkvetch, Astragalus cicer L J Range Manage 39,457-459 Rumbaugh, M D., Johnson, D A., and Van Epps, G A 1982 Forage yield and quality in a Great Basin shrub, grass, and legume pasture experiment J Range Manage 35,604609 Rumburg, C B 1978 Grazing of grass and cicer milkvetch-grass pastures with yearling calves Agron J 70,850-852 Russell, K D., Hironaka, R., and Wilson, D B 1982 An economic analysis of alternative management techniques for beef production on imgated pastures in Alberta Can Farm Econ 16, 1-7 Russelle, M P., and Buzicky, G C 1988 Legume response to fresh dairy cow excreta Proc Forage G r a d Conf pp 166- 170 Sant, F I., and Wilson, D 1982 Use of a cellulolytic enzyme digestion technique to distinguish bloat-causing from non-bloat-causing legumes and to select for speed of mesophyll cell wall disintegration in red clover (Trifolium pratense L.) J Agric Sci 98, 99- 102 Sarkar, S K., Howarth, R E., and Goplen, B P 1976 Condensed tannins in herbaceous legumes Crop Sci 16,543-546 Scheetz, J G., and Stroh, J R 1982 Compatibility of ‘Lutana’ cicer milkvetch in alternate row mixtures with 12 grass species.Agron Abstr p 128 Scheetz, G., Carleton, A E.,and Stroh, J R 1972 Fertility and inbreeding studies of cicer milkvetch (Astragalus cicer L.) Crop Sci 12,758- 759 Schultz, R D., and Stubbendieck, J 1982 Herbage yield of fertilized cool-season grasslegume mixtures in western Nebraska J Range Manage 35,473-476 Schultz, R D., and Stubbendieck, J 1983 Herbage quality of fertilized cool-season grasslegume mixtures in western Nebraska J Range Manage 36,57 1-575 Seamands, W J., Lang, R L., Corbridge, M., and Boilsen, E A 1972 Lutana cicer milkvetch-Eski sainfoin imgated pasture studies Univ Wyoming, Agric Exp Stn Res J 56 Sheaffer, C C., and Marten, G C 1991 Kura clover forage yield, forage quality, and stand dynamics Can J Plant Sci 71, 169 - 172 Smith, D 1962 Carbohydrate root reserves in alfalfa, red clover, and birdsfoot trefoil under several management schedules Crop Sci 2,75-78 Smoliak, S., and Hanna, M R 1975 Productivity of alfalfa, sainfoin, and cicer milkvetch on subimgated land when grazed by sheep Can J Plant Sci 55,4 15 -420 Smoliak, S., and Hanna, M R 1977 Seedling competition of some forage legumes in monoand mixed culture under greenhouse conditions Can J Plant Sci 57,897-903 Smoliak, S., and Johnston, A 1976 Variability in forage and seed production and seedling growth in Astragalus cicer Can J Plant Sci 56,487-491 Smoliak, S., Johnston, A., and Hanna, M R 1972 Germination and seedling growth of alfalfa, sainfoin and cicer milkvetch Can J PZant Sci 52,757-762 Solum, D J., and Lockerman, R H 1991 Seed coat surface patterns and structures of 306 C E TOWNSEND Oxytropis riparia, Oxytropis campestris, Medicago sativa, and Astragalus cicer Scanning Microsc 5,779-786 Stroh, J R., Carleton, A E., and Thornburg, A A 1971 Registration of Lutana cicer milkvetch Crop Sci 11, 133 Stroh, J R., Carleton, A E., and Seamands, W J 1972 Management of Lutana cicer milkvetch for hay, pasture, seed, and conservation uses Bull -Mont., Agric Exp Sin 666 Thornburg, A A 1982 Plant materials for use on surface-mined lands in arid and semiarid regions U.S Dep Agric SCSTP-157 and EPA-600/7-79-134 Townsend, C E 1970 Phenotypic diversity for agronomic characters in Astragalus cicer L Crop Sci 10,69 -692 Townsend, C E 1971a Association among characters related to seed production in Astragalus cicer L Crop Sci 11,307-308 Townsend, C E 1971b Self-compatibility studies with Astragalus cicer L Crop Sci 11, 769-770 Townsend, C E 1972a Influence of seed size and depth of planting on seedlingemergence of two milkvetch species Agron J 64,627-630 Townsend, C E 1972b.Comparison of S,and open-pollination progenies ofAstragalus cicer L for certain agronomic characters Crop Sci 12,793-795 Townsend, C E 1974a Selection for seedling vigor in Astragalus cicer L Agron J 66, 241 -245 Townsend, C E I974b Productivity of several perennial forage legumes under imgation and frequent cutting Bull -Cola., Agric Exp Stn 5624 Townsend, C E 1975 General and specific combining ability for several agronomic traits in diallel cross progenies of cicer milkvetch Crop Sci 15,341 -343 Townsend, C E 1976 Combining ability for seedling dry weight and forage yield in cicer milkvetch Crop Sci 16,480-482 Townsend, C E 1977a Recurrent selection for high seed weight in cicer milkvetch Crop Sci 17,473-476 Townsend, C E 1977b Germination of polycross seed of cicer milkvetch as aEected by year of production Crop Sci 17,909 - 12 Townsend, C E 1979a Registration of C-4 and C-5 cicer milkvetch germplasm Crop Sci 19,298 Townsend, C E 1979b Breeding cicer milkvetch for improved seedling emergence Crop Sci 19,613-616 Townsend, C E 1979c Registration of C-9 cicer milkvetch germplasm Crop Sci 19,934 Townsend, C E 1979d Associations among seed weight, seedling emergence, and planting depth in cicer milkvetch Agron J 71,410-414 Townsend, C E 1980a Forage legumes In “Hybridization ofCrop Plants” (W R Fehr and H H Hadley, eds.), pp 367 - 380 American Society of Agronomy/Crop Science Society of America, Madison, Wisconsin Townsend, C E 1980b Flowering characteristics of cicer milkvetch clones and their polycross progenies Crop Sci 20,479-483 Townsend, C E 1980~.Registration of Monarch cicer milkvetch Crop Sci 20,670-67 Townsend, C E 1981a Breeding cicer milkvetch for improved forage yield Crop Sci 21, 363-366 Townsend, C E 198I b Vernalization and photoperiod requirements for maximum flowering of cicer milkvetch Crop Sci 21,9 17-92 Townsend, C E 1982 Influence of seedling age and duration of vernalization on flowering of cicer milkvetch Agron J 22, 1242- 1245 CICER MILKVETCH (Astragah cicer L.) 307 Townsend, C E 1984 Inheritance of flowering date in cicer milkvetch Crop Sci 24, 196-200 Townsend, C E 1985 Recurrent selection for improved seed germination, seedling elongation, and seedling emergence Crop Sci 25,425 -429 Townsend, C E 1986 Evaluation of polycross progenies of cicer milkvetch for palatability by sheep Crop Sci 26,377-380 Townsend, C E 1987 Registration of four germplasm lines of cicer milkvetch Crop Sci 27, 368 Townsend, C E 1988 Breeding cicer milkvetch for increased forage yield during the decreasing photoperiods of mid- to late-summer Agron Abstr p 98 Townsend, C E 1990a Registration of four germplasm lines of cicer milkvetch Crop Sci 30, 428-429 Townsend, C E 1990b Changes in seed germination with time for polycross progenies of cicer milkvetch Crop Sci 30,694-698 Townsend, C E (1993) Registration of Windsor cicer milkvetch Crop Sci (in press) Townsend, C E., and Ackerman, W D 1975 Variability for vigor, height, and flowering in introductions ofcicer milkvetch Can J Plant Sci 55,843-845 Townsend, C E., and Ditterline, R L (1993) Registration of C-18, C-19, C-20, and C-21 germplasms of cicer milkvetch Crop Sci (in press) Townsend, C E., and Hinze, G 1979 Registration of C-7 and C-8 cicer milkvetch germplasm Crop Sci 19,934 Townsend, C E., and McGinnies, W J 1972a Establishment of nine forage legumes in the central Great Plains Agron J 64,699 - 702 Townsend, C E., and McGinnies, W J 1972b Temperature requirements for seed germination of several forage legumes Agron J 64,809-812 Townsend, C E., and McGinnies, W J 1973 Factors influencing vegetative growth and flowering in Astragalus cicer L Crop Sci 13,262- 264 Townsend, C E., and Schweizer, E E 1984 Tolerance of cicer milkvetch (Astragalus cicer) seedlingsto herbicides Weed Sci 32,37-42 Townsend, C E., and Wilson, A M 1978 Seedling growth of cicer milkvetch in controlled environments Crop Sci 18,662-666 Townsend, C E., and Wilson, A M 1981 Seedling growth of cicer milkvetch as affected by seed weight and temperature regime Crop Sci 21,405-409 Townsend, C E., Hinze, G O., Ackerman, W.D., and Remmenga, E E 1975 Evaluation of forage legumes for rangelands of the central Great Plains Gen Ser -Colo., Agric Exp Stn 942 Townsend, C E., Christensen, D K., and Dotzenko, A D 1978 Yield and quality of cicer milkvetch forage as influenced by cutting frequency Agron J 70, 109- 113 Townsend, C E., Remmenga, E E., Dewald, C L., Ditterline, R L., Melton, B A., and Smoliak, S 1979 Evaluation of seedling emergence in cicer milkvetch by linear regression Crop Sci 19,694-697 Townsend, C E., Kenno, H., and Brick, M A 1990 Compatibility of cicer milkvetch in mixtures with cool-season grasses Agron J 82,262-266 Vickers, J C., Zak, J M., and Odurukwe, S 1977 Effects of pH and Al on the growth and chemical composition of cicer milkvetch Agron J 69, I 13 Walsh, J F., Bezdicek, D F., Davis, A M., and Hoffman, D L 1983 Nitrogen fixation capabilities of plant introduction accessions of pasture and range forage legumes Agron J 75,474-478 Wasser, C H 1982 Ecology and culture of selected species useful in revegetating disturbed lands in the West, U.S Dep Inter., Fish Wildl Sew Biol Sew Program 82/56 - 308 C E TOWNSEND Wegert, W L 1977 “Production and Forage Quality of Cicer Milkvetch (Astragalus cicer L.) Hay at Six Stages of Maturation,” M.S.thesis Western State College, Gunnison, Colorado Weimer, P J., Buxton, D R., and Hatfield, R D 1991 Inhibition of ruminal cellulolysis in Vitro by extracts of cicer milkvetch (Astragalus cicer) Proc Znt Symp Forage Cell Wall Struct Digestibility poster abstr B-8 White, L M., and Wight, J R 1981 Seasonal dry matter yield and digestibility of seven grass species, alfalfa, and cicer milkvetch in eastern Montana Agron J 73,457-462 Williams, M C., James, L F., and Bleak, A T 1976 Toxicity of introduced nitrocontaining Astragalus to sheep, cattle, and chicks J RangeManage 29,30-33 Wilson, D B., and Rode, L M 1991 Irrigated pastures in western Canada Agric Can.Publ 1862/E Yakimova, Y., and Kolev, I D 1981 Phytocenotic characteristicsof species belonging to the genus Astragalus (milkvetch) in Bulgaria Rasteniev’d Nauki 18,63-71 [Biol Abstr 74, 016386 (1982)l Zak, J M., Troll, J., Havis, J R., Hyde, L C., Kaskeski, P A., and Hamilton, W W 1972 “A Handbook for the Selection of Some Adaptable Species for Massachusetts Roadsides,” Rep 24-R5-2656 Roadside Dev Department of Plant and Soil Science, University of Massachusetts, Amherst, Massachusetts Index content of excreta, 136- 137 phosphogypsum source, 66 Absorption edge phenomena, X-ray CAT Cereal crops,phosphogypsum use, 67-68 scanners, 20 - Cicer milkvetch, 253-301 Acid soil adaptation, 265 -266 amelioration, aluminum toxicity indices, breeding, genetics, and cytology 74-75 breeding methodology, 29 -292 crop response to gypsum and phosphogyp cultivars, 299 -300 sum, 80-82 cytology and inbreeding depression, formation, 73-74 290-29 serious acidity, phosphogypsum, 75 - 78 flowering date, 299 weathered, reactions to gypsum and phosforage yield, 295-297 phogypsum, 78 - 80 objectives, 289-290 Aliasing artifacts, 12- 13 seedling vigor, 292-295 Aluminum seed weight, 296,298 - 299 aggregation and aggregate stability, 87-90 establishment, 269-271 toxicity flowering, 26 -262 indices, subsoil acidity amelioration, herbicide tolerance, 274-276 74-75 morphology and anatomy, 254-256 serious subsoil acidity, 75-78 flower, 255 -256 Ambient atmosphere, phosphogypsum efroot, 254-255 fects, 98- 100 seed coat, 256 Ammonia stem and leaf, 255 nitrification, 164- I66 pest resistance, 271-272 volatization, 16I - 164 photoperiod, 263-264 Animals, nutritional disorders, urine-afplanting patterns, 269-270 fected pasture, 173 pollination requirements, 272 - 273 Astragalus cicer L see Cicer milkvetch seed germination, 256-259 Attenuation theory, 5-8 optimum temperature, 256-257 rate, 257, 259 B seedling emergence and seed weight, 270 seedling growth, 259-26 Back-projection reconstruction, 10 seed production, 273 Beam hardening, X-ray CAT scanners, 17seed scarification and inoculation, 26720 269 Beer's Law, seed weight and seedling growth parameBiological activity, soil, 127- 129 ten, 260 Breeding, cicer milkvetch, see Cicer milksoils and soil fertility, 266-267 vetch utilization hay, see Hay C Pasture, 286 -289 vernalization, 26 -263 Cadmium, in phosphogypsum, 96 weed control, 274-276 Calcium Collimation, X-ray CAT scanners, I5 A 309 10 INDEX Compton scattering, Computer-assisted tomography, 1- 50, see also pray CAT scanners; X-ray CAT scanners application to dual-energy scanning, 4447 attenuation theory, - industrial systems, 47 potential applications, principles, - 13 aliasing artifacts, 12 - 13 back-projection reconstruction, 10 6ltered back-projection, 11- 12 iterative reconstruction, 10- 11 numerical reconstruction, 10- 12 recent and future developments, 47 -49 soil water studies, 26-41 attenuation coefficient differences, 28 29 bulk density, 30 - Hounsfield values, 33-34 linearity, 26- macroporosity, 35 m a s attenuation coefficient, 27-28 mathematical anomalies, 33-34 mean bulk density, 34-35 soil water extraction, 38 spatial distribution of soil water content, Dinitrogen gas,losses, 166- 168 Dual-energy scanning theory, 43 water movement, 43-47 CAT application, 44 - 47 source choice, 44 Dynamic models, nutrient cycles, 18 1- 183 E Earthworms, population densities, 129 Electrical conductivity, see also Soil salinity aqueous, principles, 204 - 206 bulk soil, principles, 12- 19 correlation with clay percentage, 15 relation between bulk soil and saturation paste extract, electrical conductivity, 217-218 soil paste, principles, 19-220 two-component model, 12- 13 Electrolytic conductivity, soil salinity, 205 Electromagnetic induction soil conductivity sensor, 224,226-227 Electron-positron pair production, EPA rule, phosphogypsum, 64 - 65 Excreta, see Nutrients, returns in excreta F 38,45-46 spatial resolution of objects, 32-33 structural definition, 1- 36 water drawdowns, 38-40 water movement to plant roots, 36-41 Conductance, specific, see Soil salinity Cornforth-Sinclair model, phosphorus cycling, 185- 187 cows excretion and retention of nutrient, 130131 feces composition, 145 nitrogen content of excreta, 132- 134 number and size of excretions, 137- 140 Crop tissues, phosphogypsum effects, 95 -97 Cultivars, cicer milkvetch, 299 - 300 Cytology, inbreeding depression, cicer milkvetch, 290-291 D Denitrification, losses from grazed pastures, 166- 168 F w s , see also Nutrients, returns in excreta composition, 144- 145 degradation, 145- 149 rainfall and, 148- 149 nitrogen release, 149- 15 phosphorus release, 15 1- 152 sulfur release, 15 Fertilizer low-analysis, phosphogypsum as bulk carrier, 93 recommendations, using nutrient cycling models, 183-189 role in pastures, 122- 123 Filtered back-projection, 11- 12 Flower, cicer milkvetch, 255-256,261-262 Flowering date, cicer milkvetch, 299 Fluoride Al toxicity amelioration, 76-77 phosphogypsum effects, 95-96 Forage crops cicer milkvetch, 279-280,282-286 yield, 295-297, 301 INDEX 311 phosphogypsum uses, 70-72 Fourelectrode soil conductivity probes, 223-225 Fruits, phosphogypsum uses, 70 Herbicides, cicer milkvetch tolerance, 274276 Hounsfield units, 16- 17 Hydrolysis, urea, 160 - 161 G I pray CAT scanners, 22-25 advantages, 22 application to dualenergy scanning, 4447 improved image and data analysis software, 47 logistic system, 23 -25 radiation detection, 25 utility, 49 Geonics EM-38 device, 230 Grain legumes, phosphogypsum uses, 68-69 Grasslands, man-made, 121 Grazed pastures, see Pasture ecosystem Grazing, surface soil properties, 128 Ground water, surficial, phosphogypsum effects, 93 - 94 Gypsum agregation and aggregate stability, 87-90 by-products, see Phosphogypsum crop response on acid soils, 80- 82 nonsodic dispersive soils, 90-9 reactions with weathered acid soils, 78 - 80 self-liming mechanism, 89 sodic soil reclamation, S4-86 Inbreeding depression, cytology, cicer milkvetch, 290-291 Iron aggregation and aggregate stability, 87 - 90 Al toxicity amelioration, 76 Irrigation, surface soil properties, 128 Isoflavonoid phytoalexins, cicer milkvetch, 278 Iterative reconstruction, 10- 1 H Hardpans, phosphogypsum effect, 1- 92 Hard-setting clay soils, phosphogypsum effect, 92 - 93 Hay, cicer milkvetch, 276-286 amino acid composition, 276 carbohydrate reserves, 279-281 competitivenessin mixtures, 280, 283 forage yield, 279-280,282-286 isoflavonoid phytoalexins, 278 quality factor and mineral concentrations, 276-277 spring growth patterns, 278 Herbage chemical composition, 156, 172- 173 in dung application zone, 155 utilization, in grazed pastures, 156- 158 L Leaching, nutrient losses, 168- 170 Leaf, cicer milkvetch, 255 M Magic-angle spinning, 42 Magnesium, content of excreta, 136- 137 Mass attenuation coefficient, 27-28 Mass balance models, nutrient cycling, 175181 Mathematical models, excretal distribution, 142- 143 Micronutrients, phosphogypsum as bulk carrier, 93 “Model/Field-Estimates” technique, 235 237 Molybdenum, phosphogypsum effects, 95 N Nitrate, accumulation in urine patches, 165 Nitrification, ammonia, 164- 166 Nitrogen content of excreta, 132- 134 major fluxes in farm types, 176- 180 release from feces, 149- 15 Nitrous oxide gas, losses, 166- 168 Nonsodic dispersive soils, use of gypsum and phosphogypsum, 90-91 Nuclear magnetic resonance imaging, water movement, -42 312 INDEX Nutrient cycling excreta role, 143- 144 modeling, 174- 189 dynamic models, 18 1- 183 major pools and fluxes, 174- 175 mass balance data, 176- 181 types, 175-176 use for fertilizer recommendations, 183-189 soil/plant/animal system, 120 Nutrients immobilization into organic forms, 166 leaching losse~,168- 170 loss from pasture systems, 122 release from feces composition, 144- 145 degndation, 145- 149 nitrogen, 149-151 PhOSphoms, 15 - 152 soil property effect, 152- 154 sulfur, 15I returns in excreta, 130- 144 calcium, 136 distribution models, 142- 143 distribution of returns, 140- 142 magnesium, 136 nitrogen, 132- I34 number, size, and area covered, 137140 nutrient cycling role, 143- 144 phosphorus, 135- 136 potassium, 136 quantities returned, 130- 132 sulfur, 134- 135 trace elements, 137 status and soil organic matter, 123- 126 Nutritional disorders, animals, urine-affected pasture, 173 Organic matter, soil nutrient status, 123126 P Pasture, cicer milkvetch, 286-289 Pasture ecosystem, 19- 19I annual nutrient uptake, 189 biological activity, 127- 129 botanical instability, 121 earthworm populations, 129 fertilizer role, 122- I23 grazing animals, 121 nutrient movement, 120 modeling nutrient cycling, see Nutrient cycling movement and transformations of nutrients from urine, f 58- 170 composition, 158 dinitrogen and nitrous oxide gases loss, 166- 168 leaching ~OSS~S,168- 170 macropore flow, 158- I60 nitrification, 164- 166 nutrient immobilization into organic forms, 166 soil pH and charge characteristics, 164 urea hydrolysis and ammonia volatization, 160- 164 nature of, 12I nutrient release from feces, see Nutrients response in fecal patch, 154- 158 direct adverse affect, 154- 155 herbage chemical composition, I56 herbage utilization, 156- I58 positive pasture response, 155 response in urine patch, 170- 173 herbage chemical composition, 172173 nutritional disorders of animals, 173 positive growth response, 170 - 17 I urine scorch, 171- 172 soil organic matter and nutrient status, 123- 126 soil pH, 126-127 soil physical properties, 129- 130 Pest resistance, cicer milkvetch, 27 -272 pH, soil pastures, 126- 127 urine patches, 164 Phosphogypsum, 55- 102 agricultural uses acid soil formation, 73 -74 aggregation and aggregate stability, 87 90 ameliorant for aluminum toxicity and subsoil acidity, 73- 82 ameliorant for sodic soils 83-87 INDEX bulk carrier for micronutrients and lowanalysis fertilizers, 93 cereal crops, 67 - 68 forage crops, 70- 72 fruits and vegetables, 70 grain legumes, 68-69 hardpans, -92 hard-setting clay soils, 92-93 nonsodic dispersive soils, 90- sodic soil reclamation, 84-86 sugarcane, 69 - 70 sulfur deficiency and need for Ca source other than lime, 65 -66 ambient atmosphere effects, 98- 100 background y-radiation, 99 - 100 crop response on acid soils, 80-82 crop tissue effects, 95-97 physical and chemical properties, 58-65 analysis from countries, 58 - 59 elemental impurities, 58, 60 EPA rule, 64-65 radioactivity, 63-64 Solubility curves, 60-62 toxicity index metals solubility, 60, 63 reactions with weathered acid soils, 7880 soil effects, 94-95 surficial ground water effects, 93-94 world production and utilization, 56 - 58 Phosphorus content of excreta, 135- 136 major fluxes in farm types, 176- 180 release from excreta, 151- 152 requirement estimations using nutrient cycling models, 183- 187 Photoelectric absorption, -6 Photoperiod, cicer milkvetch, 263 -264 Pigs, phosphate content of feces, 135136 Plant roots, water movement around, see Computer-assisted tomography Pollination, cicer milkvetch requirements, 272-273 Porosity, soil, pastures, 129- 130 Potassium content of excreta, 136 major fluxes in fann types, 176- 180 requirement estimations using nutrient cycling models, 187- 188 313 R Radioactivity, phosphogypsum, 63 Radionuclide, uptake and phosphogypsum, 96-97 Radon, phosphogypsum and, 98-99, 101 Rayleigh scattering, Ray sum, Recolonization, fecal patch areas, 154- I55 “Regression ModellGround-Truthing” technique, 237-239 Rhizobium leguminosarum, cicer milkvetch seed inoculation, 268 Root, cicer milkvetch, 254-255 S salinity sensors, 208-210 Saturation extract method, 1 Seedling growth, cicer milkvetch, 259-261 vigor, cicer milkvetch, 292-295 Seeds coat, anatomy, cicer milkvetch, 256 germination, cicer milkvetch, 256-259 production, cicer milkvetch, 273 scarification and inoculation, cicer milkvetch, 267-269 weight, cicer milkvetch, 296,298-299 Sheep feces composition, 145 number and size of excretions, 137- 140 phosphorus content of excreta, 135 sulfur content of excreta, 134- 135 SO,, adsorption in acid soils, 77 - 79 Sodic soils characteristics, 83-84 reclamation, gypsum or phosphogypsum, 84 - 86 use of gypsum and phosphogypsum, 8687 Soil, see also Acid soil aggregation, Al, Fe, gypsum and phosphogypsum, 87-90 cicer milkvetch, 266 - 267 extract salinity, 210-212 fertility, cicer milkvetch, 266-267 organic matter and nutrient status, 123I26 14 INDEX pH and charge characteristics, urine patches, 164 phosphogypsum effects, 94-95 porosity, pastures, 129- 130 properties nutrient release from excreta effect, 152-154 pastures, 129- 130 Soil loss factor, 185 Soil salinity, 201 -246 aqueous electrical conductivity salinity sensors,208 - 10 soil extract salinity, 210-212 soil water salinity, 206 - 10 assessment, 202-203 bulk soil electrical conductivity, 221, 223-245 attenuation coefficient, 228 electromagnetic induction unit, 224, 226-227 fourelectrode units, 223-225 large-volume measurements, 229 -233 “Model/Field-Estimates” technique, 235-237 new relations, 232-233 “Regression Model/Ground-Truthing” technique, 237-239 sensors, 223-229 small-volume measurements, 233-234 “soil-type calibration” technique, 234235 surface-array method, 229-230 time domain reflectometry unit, 226, 228-229 definition, 201 instrumental system use examples, 242245 measurement method comparisons, 23924 measurement site location determination, 24 I - 242 salinity maps, 242-245 saturated paste electrical conductivity, 220-222 soil water content variance effect, 18 “Soil-type calibration” technique, 234-235 Soil water potential, sample collection, 206-207 sampling errors, 207 - 208 studies, 26 volumetric content as function of total water content, 215-216 Stems, cicer milkvetch, 255 Sugarcane, phosphogypsum uses, 69-70 Sulfur content of excreta, 134- 135 deficiency forage crops, 70 phosphogypsum use, 65-66 major fluxes in farm types, 176- 180 release from excreta, I5 requirement estimations using nutrient cycling models, 187- 188 Superphosphate effect on organic matter accumulation, 125 surface soil properties, 128 T Time domain reflectometry unit, soil salinity, 226,228-229 U Urea, hydrolysis, 160 - 16 Urine, see also Nutrients, returns in excreta scorch, 171-172 V Vegetables, phosphogypsum uses, 70 Vernalization, cicer milkvetch, 26 1- 263 Volatization, ammonia, 161 - 164 W Water drawdowns, 38-40 flow, total resistance, 37 movement around plant roots, see also Computer-assisted tomography dual-energy scanning, 43-47 NMR, -42 Weed control, cicer milkvetch, 274-276 Wenner array, 230 315 INDEX X X-ray CAT scannen, -4, 13 - 22 absorption edge phenomena, 20-2 beam hardening, I7 -20 collimation, 15 - construction, 13 14 detection, 14- 15 Hounsfield units, 16- limitations, I - 22 reconstruction, I5 - 16 ... In Eq (6),p(x, y) is determined using many independent views or projections through the object In the simplest scanning systems these are obtained using a scanning procedure involving both linear... Point-by-point correction: each point is corrected simultaneously for all rays passing through it and corrections are incorporated before moving to other points This technique was introduced in. .. treated include the pasture system and its effect on soil properties and nutrient cycling modeling The fourth chapter covers important advances in methods of measuring and mapping soil salinity