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United States Department of Agriculture

Agricultural Research Service

Title: Chapter 2. Normal Plant Appearance and Development

item Abendroth, Lori
item Jackson, Tamra
item Elmore, Roger
item Wilhelm, Wallace
item Mcmaster, Gregory - Greg

Submitted to: Nebraska Agricultural Experiment Station Bulletin
Publication Type: Proceedings
Publication Acceptance Date: 10/1/2006
Publication Date: 12/12/2006
Citation: Abendroth, L., Jackson, T., Elmore, R., Wilhelm, W.W., Mcmaster, G.S. 2006. Chapter 2. Normal Plant Appearance and Development. Field Crop Diagnostic Manual. Nebraska Agricultural Experiment Station Bulletin.

Interpretive Summary: Agronomists evaluate crop health by examining aboveground plant growth and canopy appearance. To identify stress or pest impacts, it is critical to understand normal crop development. In addition, it is important to know how stress as specific stages of development will influence development, growth, and yield as the season progresses. The ultimate goal of crop management is to provide a stress-free environment for crop growth. However, this goal is difficult and expensive to achieve. Alternatively, managers need to quickly identify problems (stresses or pests), address the right problem with the right corrective measure at the right time. Chapter 2 describes normal development of corn, soybean, and wheat relative to standard scales by Ritchie for corn and soybean and Feekes for wheat, through text, photos, and drawings. Relationships between outwardly visible events, such as jointing in wheat, and occurrence of important internal processes, terminal spikelet in roughly 100 degree-days, in this case, are presented. In addition we briefly explain of how knowledge of crop development and its interaction with cultural activities or weather events can be used to understand how crop yield was achieved, or limited, within a specific field or season.

Technical Abstract: Most often, agronomists evaluate crop health by examining aboveground plant growth and canopy appearance. It is important to know when stresses occur relative to critical events in the development of the crop. This enables an agronomist to more effectively and efficiently employ management practices that may alleviate or help reduce overall crop stress. A critical component in crop management is to properly identify and address the problem using the right corrective measure at the right time. Other chapters in this manual address steps necessary in formulating a proper diagnosis. This chapter examines normal growth and development of three major crops: corn, soybean, and wheat. Understanding how a crop should develop equips practitioners with a strong knowledge base when evaluating these crops in a field setting. The developmental stage scales for corn and soybean, outlined by Ritchie et al., and the Feekes scale for wheat are described in detail in text, photos, and drawings. A list of printed and online resources is provided as further readings for clients.

Last Modified: 10/19/2017
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