Home » Nutrient application guidelines for field, vegetable, and fruit crops in Wisconsin (A2809) » Introduction
Introduction
Introduction
Over 200,000 soil samples are analyzed in Wisconsin each year, and the results of these tests guide Wisconsin farmers in the use of lime and nutrient applications. The appropriate use of lime, fertilizer, manure, and other nutrient sources significantly increases Wisconsin farm income.
Just as importantly, following nutrient application guidelines prevents over-application of nutrients. This, in turn, enhances profitability and reduces the potential for environmental degradation.
Why are soil tests important?
Most farmers recognize the importance of a good soil testing program. Soil testing has some limitations, but it is still the best tool available for predicting lime and fertilizer needs. With representative sampling, soil tests can accurately predict lime, phosphorus, and potassium requirements. Soil tests can also serve as a guide for nitrogen and some of the secondary nutrients and micronutrients; however, these require special testing and, in the case of nitrogen, special sampling systems.
The underlying goal of Wisconsin’s recommendation program is to supply enough nutrients to the crop for optimum growth throughout the season. Because nutrient demands are not uniform throughout the season, an adequate supply must be available during the period of peak demand.
The Wisconsin program defines the “critical” level as the cutoff between the “optimum” and “high” soil test levels. If the nutrient supply drops below the critical level, growers face economic losses from reduced yields or poor crop quality. If the supply exceeds the critical level, there is an increased risk of mobile nutrients moving into the groundwater and surface water. In addition, there is no profit in applying nutrients that will not be used. The Wisconsin nutrient application guidelines are designed to help a grower anticipate crop needs and monitor nutrient availability.
The goals of Wisconsin’s soil testing program are to:
- Provide an accurate index of the level of available nutrients in the soil.
- Indicate the degree of nutrient deficiency that may exist for the various crops grown.
- Suggest how the deficiency might be corrected.
- Provide the results in an understandable and meaningful way so that the grower can make the appropriate decision as to what nutrients to add.
Nutrient Application Guidelines for Field, Vegetable, and Fruit Crops in Wisconsin (A 2809) describes how to interpret soil test results, provides nutrient application guidelines, and outlines the assumptions underlying the guidelines.
Natasha Rayne, Ph.D.
Assistant Professor and Extension Specialist – Soil Fertility and Nutrient Management
Manure placement, timing, and nitrogen credits; organic soil amendments and nutrient cycling; climate-smart and site-specific nitrogen management; improvement of nitrogen use efficiency in cereal crop production.
Natasha Rayne, Ph.D.
Assistant Professor and Extension Specialist – Soil Fertility and Nutrient Management
Manure placement, timing, and nitrogen credits; organic soil amendments and nutrient cycling; climate-smart and site-specific nitrogen management; improvement of nitrogen use efficiency in cereal crop production.
