Delineating site-specific management zones for pH-induced iron chlorosis

Authors

T. Kyaw, University of Nebraska-Lincoln
Richard B. Ferguson, University of Nebraska-LincolnFollow
Viacheslav I. Adamchuk, University of Nebraska-LincolnFollow
Dennis L. McCallister, University of Nebraska-LincolnFollow
David B. Marx, University of Nebraska-LincolnFollow
D. D. Tarkalson, USDA-ARS Northwest Irrigation and Soils Research LabFollow

Document Type

Article

Date of this Version

3-21-2008

Comments

Published in Precision Agric (2008) 9:71–84.

Abstract

Iron chlorosis can limit crop yield, especially on calcareous soil. Typical management for iron chlorosis includes the use of iron fertilizers or chlorosis tolerant cultivars. Calcareous and non-calcareous soil can be interspersed within fields. If chlorosisprone areas within fields can be predicted accurately, site-specific use of iron fertilizers and chlorosis-tolerant cultivars might be more profitable than uniform management. In this study, the use of vegetation indices (VI) derived from aerial imagery, on-the-go measurement of soil pH and apparent soil electrical conductivity (EC_a) were evaluated for their potential to delineate chlorosis management zones. The study was conducted at six sites in 2004 and 2005. There was a significant statistical relationship between grain yield and selected properties at two sites (sites 1 (2005) and 3), moderate relationships at sites 2 and 4, and weak relationships at site 5. For sites 1 (2005) and 3, and generally across all sites, yield was predicted best with the combination of NDVI and deep EC_a. These two properties were used to delineate chlorosis management zones for all sites. Sites 1 and 3 showed a good relationship between delineated zones and the selected properties, and would be good candidates for site-specific chlorosis management. For site 5, differences in the properties between mapped zones were small, and the zones had weak relationships to yield. This site would be a poor candidate for site-specific chlorosis management. Based on this study, the delineation of chlorosis management zones from aerial imagery combined with soil EC_a appears to be a useful tool for the site-specific management of iron chlorosis.