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Forage Resource Management and Integration
 
 
     

Pasture & Range: December 2003
Other Pasture & Range Articles

by Chuck Coffey

  Energy Requirements for Plant Growth
How Plants Manufacture Food
Factors Affecting a Plant's Response to Grazing
Management for Sustainability
Integrating Forage Resources
Literature Cited

The proper management and integration of available forage resources is critical to the sustainability of these resources and the land. As time progresses, it becomes more and more evident that we, as agricultural producers, must become increasingly efficient with each unit of product produced. To better understand forages and their integration, let's take a look at their energy requirements, how they manufacture food, how they might respond to grazing, their management for sustained use and their integration.

Energy Requirements for Plant Growth (page 1 of 6)
Plants require numerous nutrients and compounds for sustained production. There are 20 elements that are used by plants and are considered to be essential. They are:
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Many of us put forth significant effort to maintain a plant's requirement for nitrogen (N), phosphorus (P) and potassium (K) while taking for granted its need for carbon (C), hydrogen (H) and oxygen (O). Secondary nutrients and micronutrients are needed in such small quantities that we tend to disregard their importance and rightfully so. They may be present in insufficient amounts for a specific crop being grown or a given soil type, but can usually be corrected by adjusting a soil's pH, especially in grazing situations. Henceforth, the focus will be on a plant's need for carbon, hydrogen and oxygen. Let's take a look at the makeup of a typical plant in order to put our thoughts into perspective. Below is a listing of the elemental composition of a typical plant:
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An interesting point to note about the preceding table is that 95.5 percent of a plant's makeup is carbon, hydrogen and oxygen. These elements come from carbon dioxide (CO2) and water (H2O). The carbon dioxide, located in the atmosphere, is responsible for contributing the carbon and oxygen found in plants. It is taken up by plants through small pores located in the leaves. Water, on the other hand, is taken up by the roots of plants and is responsible for contributing only hydrogen to a plant's makeup. However, the hydrogen used to produce water also comes from the atmosphere. Therefore, we can now make the following assumptions: (1) the atmosphere and sun provide 95.5 percent of the necessary ingredients for plant growth; and (2) minerals provide 4.5 percent of the necessary ingredients for plant growth. The following diagram is a simplistic picture of how most plants derive nutrients needed for growth.

In short, we need to be managing the above-ground portion of plants (leaves and stems) in order to achieve maximum sustained yield of our forages. This will allow plants to be much more efficient in their uptake of water and nutrients.


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