{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/94519"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/94519","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"The fate and distribution of phosphate applied to Davidson clay loam","abstract":"The objectives of the investigation were to relate yield and P uptake of orchard grass grown on Davidson clay loam to P fertilization and to determine the fate and availability of applied and native P in this soil. A further aim of the investigation was to elucidate mechanisms controlling the availability of P to plants in Davidson clay loam that was limed to several pH values. These objectives were accomplished by a study of orchard grass yield data obtained during a long term field investigation and by performance of greenhouse and laboratory experiments. Annual surface application of 21 lb P/A increased orchard grass yield during the initial phase of the field experiment, from 1948 to 1957. Thereafter, from 1958 to 1962, continued application of 21 lb P/A no longer increased yield. Lack of yield response to P application was attributed to plant uptake of residual P. The conclusion was supported by data from a greenhouse study. In the study, P application did not significantly affect yield or P uptake of alfalfa grown on Davidson clay loam that had received annual application of 21 lb P/A for 15 years. Total inorganic P analysis indicated that the major portion of surface applied P remained in the 0-2 inch soil layer. However, statistical analysis of the total inorganic P data showed a significant downward movement of P into the 4-6 inch soil layer. Fractionation analysis indicated the applied and native P was present in Davidson clay loam predominantly as Fe-P. Iron-P made up greater than 70% of the total inorganic P at the 0-2, 2-4, 4-6 and 6-12 inch soil depths. High accumulation of applied P as Fe-P in Davidson clay loam was explained on the basis of the high free Fe oxide content of the soil. Application of either lime or P increased yield and P uptake of alfalfa grown on Davidson clay loam which received annual application of 0 or 10.5 lb P/A for 15 years. From these results it was concluded that liming increased the availability of native and residual P in the soil. Fractionation analysis indicated that the Fe-P fraction decreased to a greater extent than Al-P or Ca-P during growth of alfalfa on the limed soil. These data indicated that liming increased the availability of the Fe-P. Iron P decreased to a greater extent than Al-P or Ca-P during growth of alfalfa on Davidson clay loam that received annual application of O, 10.5 and 21 lb P/A for 15 years. Coefficients of simple correlation for the data, showed a higher correlation between Fe-P than Al-P or Ca-P with P uptake by alfalfa plants. From these data it was concluded that Fe-P was more important than Al-P or Ca-P in supplying P to plants grown on Davidson clay loam. Higher uptake of P from Fe-P rather than from Al-P or Ca-P was explained on the basis of the greater amount of Fe-P in Davidson clay loam. It is suggested that a large percentage of the Fe-P fraction in the soil consists of relatively soluble amorphous compounds. The presence of relatively soluble amorphous Fe-P as well as the high percentage of this compound in the soil then may account for Fe-P being more available than was anticipated.","abstract_html":"The objectives of the investigation were to relate yield and P uptake of orchard grass grown on Davidson clay loam to P fertilization and to determine the fate and availability of applied and native P in this soil. A further aim of the investigation was to elucidate mechanisms controlling the availability of P to plants in Davidson clay loam that was limed to several pH values. These objectives were accomplished by a study of orchard grass yield data obtained during a long term field investigation and by performance of greenhouse and laboratory experiments. Annual surface application of 21 lb P/A increased orchard grass yield during the initial phase of the field experiment, from 1948 to 1957. Thereafter, from 1958 to 1962, continued application of 21 lb P/A no longer increased yield. Lack of yield response to P application was attributed to plant uptake of residual P. The conclusion was supported by data from a greenhouse study. In the study, P application did not significantly affect yield or P uptake of alfalfa grown on Davidson clay loam that had received annual application of 21 lb P/A for 15 years. Total inorganic P analysis indicated that the major portion of surface applied P remained in the 0-2 inch soil layer. However, statistical analysis of the total inorganic P data showed a significant downward movement of P into the 4-6 inch soil layer. Fractionation analysis indicated the applied and native P was present in Davidson clay loam predominantly as Fe-P. Iron-P made up greater than 70% of the total inorganic P at the 0-2, 2-4, 4-6 and 6-12 inch soil depths. High accumulation of applied P as Fe-P in Davidson clay loam was explained on the basis of the high free Fe oxide content of the soil. Application of either lime or P increased yield and P uptake of alfalfa grown on Davidson clay loam which received annual application of 0 or 10.5 lb P/A for 15 years. From these results it was concluded that liming increased the availability of native and residual P in the soil. Fractionation analysis indicated that the Fe-P fraction decreased to a greater extent than Al-P or Ca-P during growth of alfalfa on the limed soil. These data indicated that liming increased the availability of the Fe-P. Iron P decreased to a greater extent than Al-P or Ca-P during growth of alfalfa on Davidson clay loam that received annual application of O, 10.5 and 21 lb P/A for 15 years. Coefficients of simple correlation for the data, showed a higher correlation between Fe-P than Al-P or Ca-P with P uptake by alfalfa plants. From these data it was concluded that Fe-P was more important than Al-P or Ca-P in supplying P to plants grown on Davidson clay loam. Higher uptake of P from Fe-P rather than from Al-P or Ca-P was explained on the basis of the greater amount of Fe-P in Davidson clay loam. It is suggested that a large percentage of the Fe-P fraction in the soil consists of relatively soluble amorphous compounds. The presence of relatively soluble amorphous Fe-P as well as the high percentage of this compound in the soil then may account for Fe-P being more available than was anticipated.","abstract_has_math":false,"creators":["Singh, Rabindar Nath"],"institution":"Virginia Polytechnic Institute","degree_name":"Ph. D.","degree_level":"doctoral","degree_discipline":"Agronomy","degree_department":"Agronomy","school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1965,"date_issued":"1965","date_published":"1965","updated_at":"2026-07-22T22:19:16Z","subjects":[],"languages":["en_US"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10919/94519","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.department","label":"Department","values":["Agronomy"]},{"key":"dc:creator","label":"Author","values":["Singh, Rabindar Nath"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2019-10-10T19:27:47Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2019-10-10T19:27:47Z"]},{"key":"dc:date.issued","label":"Date","values":["1965"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Polytechnic Institute"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation"]},{"key":"dc:type.dcmitype","label":"Dc Type Dcmitype","values":["Text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Agronomy"]},{"key":"thesis:degree_level","label":"Degree Level","values":["doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph. 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A further aim of the investigation was to elucidate mechanisms controlling the availability of P to plants in Davidson clay loam that was limed to several pH values. These objectives were accomplished by a study of orchard grass yield data obtained during a long term field investigation and by performance of greenhouse and laboratory experiments. Annual surface application of 21 lb P/A increased orchard grass yield during the initial phase of the field experiment, from 1948 to 1957. Thereafter, from 1958 to 1962, continued application of 21 lb P/A no longer increased yield. Lack of yield response to P application was attributed to plant uptake of residual P. The conclusion was supported by data from a greenhouse study. In the study, P application did not significantly affect yield or P uptake of alfalfa grown on Davidson clay loam that had received annual application of 21 lb P/A for 15 years. Total inorganic P analysis indicated that the major portion of surface applied P remained in the 0-2 inch soil layer. However, statistical analysis of the total inorganic P data showed a significant downward movement of P into the 4-6 inch soil layer. Fractionation analysis indicated the applied and native P was present in Davidson clay loam predominantly as Fe-P. Iron-P made up greater than 70% of the total inorganic P at the 0-2, 2-4, 4-6 and 6-12 inch soil depths. High accumulation of applied P as Fe-P in Davidson clay loam was explained on the basis of the high free Fe oxide content of the soil. Application of either lime or P increased yield and P uptake of alfalfa grown on Davidson clay loam which received annual application of 0 or 10.5 lb P/A for 15 years. From these results it was concluded that liming increased the availability of native and residual P in the soil. Fractionation analysis indicated that the Fe-P fraction decreased to a greater extent than Al-P or Ca-P during growth of alfalfa on the limed soil. These data indicated that liming increased the availability of the Fe-P. Iron P decreased to a greater extent than Al-P or Ca-P during growth of alfalfa on Davidson clay loam that received annual application of O, 10.5 and 21 lb P/A for 15 years. Coefficients of simple correlation for the data, showed a higher correlation between Fe-P than Al-P or Ca-P with P uptake by alfalfa plants. From these data it was concluded that Fe-P was more important than Al-P or Ca-P in supplying P to plants grown on Davidson clay loam. Higher uptake of P from Fe-P rather than from Al-P or Ca-P was explained on the basis of the greater amount of Fe-P in Davidson clay loam. It is suggested that a large percentage of the Fe-P fraction in the soil consists of relatively soluble amorphous compounds. The presence of relatively soluble amorphous Fe-P as well as the high percentage of this compound in the soil then may account for Fe-P being more available than was anticipated."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Ph. D."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["The fate and distribution of phosphate applied to Davidson clay loam"]}]}],"canonical_facts":{"dc:contributor.department":["Agronomy"],"dc:creator":["Singh, Rabindar Nath"],"dc:date.accessioned":["2019-10-10T19:27:47Z"],"dc:date.available":["2019-10-10T19:27:47Z"],"dc:date.issued":["1965"],"dc:description.abstract":["The objectives of the investigation were to relate yield and P uptake of orchard grass grown on Davidson clay loam to P fertilization and to determine the fate and availability of applied and native P in this soil. A further aim of the investigation was to elucidate mechanisms controlling the availability of P to plants in Davidson clay loam that was limed to several pH values. These objectives were accomplished by a study of orchard grass yield data obtained during a long term field investigation and by performance of greenhouse and laboratory experiments. Annual surface application of 21 lb P/A increased orchard grass yield during the initial phase of the field experiment, from 1948 to 1957. Thereafter, from 1958 to 1962, continued application of 21 lb P/A no longer increased yield. Lack of yield response to P application was attributed to plant uptake of residual P. The conclusion was supported by data from a greenhouse study. In the study, P application did not significantly affect yield or P uptake of alfalfa grown on Davidson clay loam that had received annual application of 21 lb P/A for 15 years. Total inorganic P analysis indicated that the major portion of surface applied P remained in the 0-2 inch soil layer. However, statistical analysis of the total inorganic P data showed a significant downward movement of P into the 4-6 inch soil layer. Fractionation analysis indicated the applied and native P was present in Davidson clay loam predominantly as Fe-P. Iron-P made up greater than 70% of the total inorganic P at the 0-2, 2-4, 4-6 and 6-12 inch soil depths. High accumulation of applied P as Fe-P in Davidson clay loam was explained on the basis of the high free Fe oxide content of the soil. Application of either lime or P increased yield and P uptake of alfalfa grown on Davidson clay loam which received annual application of 0 or 10.5 lb P/A for 15 years. From these results it was concluded that liming increased the availability of native and residual P in the soil. Fractionation analysis indicated that the Fe-P fraction decreased to a greater extent than Al-P or Ca-P during growth of alfalfa on the limed soil. These data indicated that liming increased the availability of the Fe-P. Iron P decreased to a greater extent than Al-P or Ca-P during growth of alfalfa on Davidson clay loam that received annual application of O, 10.5 and 21 lb P/A for 15 years. Coefficients of simple correlation for the data, showed a higher correlation between Fe-P than Al-P or Ca-P with P uptake by alfalfa plants. From these data it was concluded that Fe-P was more important than Al-P or Ca-P in supplying P to plants grown on Davidson clay loam. Higher uptake of P from Fe-P rather than from Al-P or Ca-P was explained on the basis of the greater amount of Fe-P in Davidson clay loam. It is suggested that a large percentage of the Fe-P fraction in the soil consists of relatively soluble amorphous compounds. The presence of relatively soluble amorphous Fe-P as well as the high percentage of this compound in the soil then may account for Fe-P being more available than was anticipated."],"dc:description.degree":["Ph. D."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["http://hdl.handle.net/10919/94519"],"dc:language.iso":["en_US"],"dc:publisher":["Virginia Polytechnic Institute"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:title":["The fate and distribution of phosphate applied to Davidson clay loam"],"dc:type":["Dissertation"],"dc:type.dcmitype":["Text"],"thesis:degree_discipline":["Agronomy"],"thesis:degree_level":["doctoral"],"thesis:degree_name":["Ph. D."],"thesis:institution_name":["Virginia Polytechnic Institute"]},"updated_at":"2026-07-22T22:19:16Z"}