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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Modeling phosphorus transport in soil and water

Abou Nahra, Joumana January 2006 (has links)
No description available.
42

The fate and distribution of phosphate applied to Davidson clay loam

Singh, Rabindar Nath January 1965 (has links)
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. / Ph. D.
43

Phosphorus fixation by horizons of various soil types in relation to easily extractable iron and aluminum

Romine, Dale Servetus. January 1938 (has links)
Call number: LD2668 .T4 1938 R62
44

Effect of liming upon phosphorus availability and growth of alfalfa on Parsons silt loam and Geary silt loam soils

Larson, Delbert Leon. January 1956 (has links)
Call number: LD2668 .T4 1956 L33 / Master of Science
45

An evaluation of three chemical extractants for the determination of phosphorus in soils

Herndon, James David. January 1979 (has links)
Call number: LD2668 .T4 1979 H47 / Master of Science
46

Phosphorus dynamics in coastal and inland lakes and reservoirs in British Columbia with special reference to water level fluctuation and climate variability

Nowlin, Weston Hugh. 10 April 2008 (has links)
No description available.
47

Phosphorus effects on arbuscular mycorrhizal fungi

Stewart, Lynda Irene. January 2006 (has links)
No description available.
48

A mathematical model of seasonal and spatial variation in phosphorus concentrations in the surface waters of Lake Memphremagog, Quebec /

Spiller, Gary B. January 1977 (has links)
No description available.
49

Phosphorus loading in Baker Creek, Oregon

Stewart, Scott R. 31 August 1992 (has links)
Graduation date: 1993
50

Some important inorganic nitrogen and phosphorus species in Georgia salt marsh

Maye, Peter Robert 05 1900 (has links)
No description available.

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