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United States Department of Agriculture

Agricultural Research Service

Research Project: DEVELOP AND IMPROVE STRATEGIES FOR MANAGEMENT OF IRRIGATED AGRICULTURAL CROPS AND SOILS

Location: Northwest Irrigation and Soils Research

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

Authors
item Kyaw, T - UNIVERSITY OF NEBRASKA
item Ferguson, R - UNIVERSITY OF NEBRASKA
item Tarkalson, David
item Mccallister, D - UNIVERSITY OF NEBRASKA
item Adamchuk, V - UNIVERSITY OF NEBRASKA

Submitted to: Precision Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 14, 2008
Publication Date: March 9, 2008
Citation: Kyaw, T., Ferguson, R.B., Tarkalson, D.D., Mccallister, D.L., Adamchuk, V.I. 2008. Delineating site-specific management zones for pH-induced iron chlorosis. Precision Agriculture. 9:71-84.

Interpretive Summary: Iron chlorosis can be a yield limiting factor in crop production especially on calcareous soils. Typical management for iron chlorosis includes the use of soil or foliar application of iron fertilizers, or the use of chlorosis tolerant cultivars. However, due to the interspersion of calcareous and non-calcareous soils within fields, site-specific use of these practices may be more profitable than uniform management, if chlorosis-prone areas within fields can be accurately predicted. This study was conducted at six sites in 2004 and 2005 to evaluate the use of site-specific management tools (aerial imagery and on-the-go measurement of soil pH and apparent soil electrical conductivity) for their potential to delineate chlorosis management zones. At most sites, the derived chlorosis management zones (based on information from different combinations of the site-specific management tools) were correlated with grain yield. Based on this study, chlorosis management zones derived from aerial imagery seem likely to be useful as a tool which can facilitate site-specific management according to the potential for chlorosis pressure.

Technical Abstract: Iron chlorosis can be a yield limiting factor in crop production especially on calcareous soils. Typical management for iron chlorosis includes the use of soil or foliar application of iron fertilizers, or the use of chlorosis tolerant cultivars. However, due to the interspersion of calcareous and non-calcareous soils within fields, site-specific use of these practices may be more profitable than uniform management, if chlorosis-prone areas within fields can be accurately predicted. In this study, the use of aerial imagery and on-the-go measurement of soil pH and apparent soil electrical conductivity spatial information which is relatively dense and related to crop response to chlorotic conditions were evaluated for their potential to delineate chlorosis management zones. The study was conducted at six sites in 2004 and 2005. For four site-years, vegetation indices (VI) derived from in-season aerial imagery delineated chlorosis management zones with reasonable correlation to grain yield. At one site, chlorosis management zone correlation to grain yield was improved with the use of deep soil electrical conductivity along with VI information. At two sites, chlorosis management zones could not be delineated, likely due to factors other than chlorosis limiting yield. At one site where aerial imagery was unavailable, soil electrical conductivity was useful in delineating management zones related to yield, though this site did not have evident chlorosis. For the five locations where chlorosis management zones were delineated, grain yield was significantly reduced in the chlorosis-prone zone. Three of the five locations had significantly higher pH in the chlorosis -prone zone. Soil electrical conductivity was useful in predicting chlorosis-prone zones only at sites with poorly drained soils. Based on this study, chlorosis management zones derived from aerial imagery seem likely to be useful as a tool which can facilitate site-specific management according to the potential for chlorosis pressure.

Last Modified: 7/10/2014
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