Speciation of phosphorus in reduced tillage systems: placement and source effect.
dc.contributor.author | Khatiwada, Raju | |
dc.date.accessioned | 2011-07-08T13:36:21Z | |
dc.date.available | 2011-07-08T13:36:21Z | |
dc.date.graduationmonth | August | en_US |
dc.date.issued | 2011-07-08 | |
dc.date.published | 2011 | en_US |
dc.description.abstract | Phosphorus (P) management in reduced tillage systems has been a great concern for farmers. Conclusive results for benefits of deep banding of P fertilizers for plant yield in reduced tillage system are still lacking. Knowledge of the dominant solid P species present in soil following application of P fertilizers and linking that to potential P availability would help us to design better P management practices. The objectives of this research were to understand the influence of placement (broadcast- vs. deep band-P or deep placed-P), fertilizer source (granular- versus liquid-P), and time on reaction products of P. Greenhouse and field based experiments were conducted to study P behavior in soils. Soil pH, resin extractable P, total P, and speciation of P were determined at different distances from the point of fertilizer application at 5 weeks (greenhouse and field) and 6 months (field) after P application (at rate 75 kg/ha) to a soil system that was under long-term reduced tillage. X-ray absorption near edge structure spectroscopy technique was used to speciate reaction products of fertilizer P in the soil. The reaction products of P formed upon addition of P fertilizers to soils were found to be influenced by soil pH, P placement methods, and P sources. Acidic pH (below~5.8) tended to favor formation of Fe-P and Al-P like forms whereas slightly acidic near neutral pH soils favored formation of Ca-P like forms. Scanning electron microscope with energy dispersive X-ray analysis of applied fertilizer granules at 5-wk showed enrichment of Al, Fe and Ca in granule- indicating these elements begin to react with applied P even before granules dissolve completely. The availability of an applied P fertilizer was found to be enhanced as a result of the deep banding as compared to the surface broadcasting or deep placed methods. Deep banded liquid MAP was found to be in more adsorbed P like forms and resulted greater resin extractable P both at 5 wk and 6 month after application. Deep banding of liquid MAP would most likely result both agronomically and environmentally efficient solution for no-till farmers. | en_US |
dc.description.advisor | Ganga M. Hettiarachchi | en_US |
dc.description.degree | Master of Science | en_US |
dc.description.department | Department of Agronomy | en_US |
dc.description.level | Masters | en_US |
dc.identifier.uri | http://hdl.handle.net/2097/9973 | |
dc.language.iso | en_US | en_US |
dc.publisher | Kansas State University | en |
dc.subject | Phosphorus | en_US |
dc.subject | Phosphorus speciation | en_US |
dc.subject | Reduced tillage | en_US |
dc.subject | Phosphorus placement | en_US |
dc.subject | X-ray absorption near edge structure spectroscopy | en_US |
dc.subject | Resin extractable phosphorus | en_US |
dc.subject.umi | Agriculture, General (0473) | en_US |
dc.subject.umi | Agronomy (0285) | en_US |
dc.subject.umi | Biogeochemistry (0425) | en_US |
dc.subject.umi | Chemistry, Agricultural (0749) | en_US |
dc.subject.umi | Environmental Sciences (0768) | en_US |
dc.subject.umi | Plant Sciences (0479) | en_US |
dc.subject.umi | Soil Sciences (0481) | en_US |
dc.title | Speciation of phosphorus in reduced tillage systems: placement and source effect. | en_US |
dc.type | Thesis | en_US |