Soils - Part 9 addressed how soil testing works and the proper method of taking soil samples. The purpose of soil testing is to provide a rational basis for making fertilizer recommendations. The impact of not having the optimum crop nutrition can be yield loss, economic expense and environmental contamination. For many years, it has been widely known that fertilizer recommendations for a given crop often vary widely, depending on who is making the recommendation. With the development of site- specific nutrient management, more emphasis is being placed on soil sampling as a basis for predicting response to applied fertilizer. This lesson will explain several approaches to making fertilizer recommendations and will discuss why recommendations may vary widely when different approaches are used to interpret soil tests.
[This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
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Sixteen elements are known to be essential for plant growth. These are divided into two groups: macronutrients — those elements used in relatively large quantities and micronutrients — those needed in very small amounts.
Macronutrients | ||
Carbon (C) | Nitrogen (N) | Calcium (Ca) |
Hydrogen (H) | Phosphorus (P) | Magnesium (Mg) |
Sulfur (S) | Potassium (K) | Oxygen (O) |
Micronutrients | ||
Zinc (Zn) | Copper (Cu) | Boron (B) |
Iron (Fe) | Manganese (Mn) | Molybdenum (Mo) |
Chlorine (Cl) |
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[This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
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During the first seven lessons, we have discussed a variety of topics related to soils, ranging from their formation to how nitrogen reacts in the soil. In Soils - Part 8, we are going to shift gears and discuss some common fertilizers and their characteristics. These will include the common nitrogen and phosphorus fertilizers, as well as many fertilizers that provide micronutrients to the soil. In this chapter, no attempt is made to judge the value of each type of fertilizer.
[This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
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Soil tests are part of a four-step process of determining and providing nutrients to agronomic crops. The four steps are:
1) soil sampling,
2) soil analysis,
3) result interpretation and decision making, and
4) fertilizer application.
This chapter will focus on Steps 1 and 3 — soil sampling and result interpretation and decision making. It will not examine specific laboratory procedures or address fertilizer application issues. Until very recently, soil testing was conducted on a field basis. Site-specific management and the associated technologies of fertilizer application and yield monitoring are enabling agriculture management to reduce the area associated with each soil test to the subfield level. The article, "Soil Testing and Nutrient Recommendations," from Nutrient Management for Agronomic Crops in Nebraska, includes further information on soil testing.
[This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
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