Thesis - Amsterdam.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1959. / Typescript. Abstracted in dissertation abstracts, v. 20 (1959) no. 2, p. 450-451. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 54-59).

Thesis (Ph. D.)--Texas Christian University, 2009. / Title from dissertation title page (viewed Apr. 19, 2010). Includes abstract. Includes bibliographical references.

Thesis (Ph. D.(Agric.)) (Agronomy)--University of Pretoria, 2009. / Includes summary. Available in print and online. Includes bibliographical references.

No description available.

Traditional application methods in which manure is simply broadcast on the soil surface are being replaced by innovative methods that place the manure in the soil in bands, potentially increasing efficiency of manure nutrient utilization by crops and reducing losses to the environment. Limited information exists on the pools and mobility of phosphorus (P) and nitrogen (N) in soils receiving repeated applications of animal manure using different application methods. The overall objective of the thesis research is to determine the fate of manure nutrients applied using new subsurface banding technology, as it affects crop response and uptake, residual nutrients in the soil, and transport (lateral and vertical) by water off-site. Specific objectives were: 1) to determine yield response to solid cattle manure (SCM) and the recovery of SCM and liquid hog manure (LHM) P and N using broadcast manure placement and new subsurface banding technology, 2) to determine the amount of soluble reactive phosphorus (SRP) and N that is transported in snowmelt water moving across soils receiving different rates and methods of application of manure, and 3) to determine the amount and proportion of SRP and N that are transported downward in a SCM amended soil profile with leaching water as influenced by manure rate and placement. In-soil placement of SCM in bands had a small impact on improving crop yield and nutrient uptake in a 3 year crop rotation in east-central Saskatchewan compared to broadcast, and broadcast and incorporate application strategies. In-soil placement of manure was also not effective in reducing P and N export in snowmelt water. Export of P and N downward in leachate water in intact cores was increased by in-soil manure placement, especially when placed in bands. This is attributed to reduced fixation of manure N and P and enhanced solubilization when manure is placed in soil in bands versus a broadcast application. Overall, nutrient export was significantly lower in frozen versus thawing soils, and export of P in soils receiving liquid hog manure was much less than in soils receiving solid cattle manure which is attributed to the higher P content in cattle manure.

Univ., Diss.--Utrecht, 2008.

Thesis--Oregon State University. / Bibliography: p. 117-122. Also available on the World Wide Web.

Bryophytes form an important component of northern vegetation communities. Mosses efficiently capture aerially deposited nutrients, restricting nutrient availability to the soil. Given that key ecosystem processes of northern ecosystems are nutrient-limited, understanding nutrient cycling of the moss layer is key to understanding ecosystem nutrient and C cycling in these systems. However, the role of the moss layer in regulating ecosystem-scale nutrient and C cycling, while potentially significant, is largely unknown. The aim of this thesis is to investigate the effect of the relative availability of N and P on aspects of bryophyte nutrient uptake, retention and C acquisition. The hypothesis investigated is that the availability of one nutrient will influence the demand for the other and thereby moss nutrient acquisition and retention mechanisms. To test this hypothesis, various aspects of moss nutrient cycling in response to the relative availability of N and P were investigated. As the C cycle is tightly linked to the N and P cycles, the hypothesis extended to include bryophyte C assimilation and decomposition processes of an arctic tundra. Bryophyte nutrient demand was chiefly governed by the tissue N:P ratio. Consequently, nutrient uptake, both from aerially deposited nutrients and through moss-cyanobacteria N2 fixation, and nutrient losses after a simulated rainfall event were mostly in response to the relative availability of N and P rather than the availability of one nutrient alone. This thesis provides novel evidence that ectohydric mosses have the ability to internally translocate nutrients. In conjunction with efficient nutrient capture, this trait makes mosses strong nutrient sinks which are likely to exert considerable control over ecosystem nutrient cycling. The relative availability of N and P played a role in C uptake of mosses. Through the production of recalcitrant litter and their insulating effect on soil microclimate mosses exerted an influence over ecosystem C cycling.

No description available.