Document Type

Thesis - University Access Only

Award Date

2005

Degree Name

Master of Science (MS)

Department / School

Plant Science

First Advisor

David E. Clay

Abstract

To meet U.S. energy and food demands (ethanol production), farmland needs to become more productive. Manure applications, ripping, and deep fertilizer injection have been proposed as techniques to increase field productivity. The objective of this study was to examine the effects deep plowing and/or deep ripping with the application of subsurface livestock manure and/or subsurface liquid fertilizer on yields, water infiltration, and bulk density in fields that have received prior manure applications. Research was conducted at Brookings and Beresford, South Dakota in 2003 and 2004. Research at Brookings showed that water infiltration could be increased and bulk densities could be decreased with deep ripping in a field that received prior manure applications. These results suggest that in fields where runoff is likely, ripping can reduce runoff and if crops are water limited, then ripping should increase yield. However, this hypothesis was not tested. Deep fertilizer injection at both sites did not increase yields. These results were attributed to prior manure applications, which resulted in very high P concentrations in the soil. Manure applications increased yields at Brookings. Even though an N response was not expected, 13C discrimination analysis suggests that yield enhancement resulted from reduced N stress. These results suggest that N timing plays an important role in com growth and development. Similar research needs to be conducted in fields that have not received extensive manure treatments.

Library of Congress Subject Headings

Phosphatic fertilizers
Soil ripping
Soils -- Quality
Corn -- Yields

Publisher

South Dakota State University

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Rights Statement

In Copyright