Efficient Use of Fertilizers
Efficient Fertilizer Use — Fertigation: by Dr. Bill Segars
SECTION CONTENTS: • Introduction • Soil Chemistry • Water Quality Concerns • Fertilizers for Injection Into Irrigation • Use Fertigation Properly and According to Regulations • Irrigation Scheduling & Fertigation • Other Important Factors to Consider When Fertigating
Fertigation is defined as the application of nutrients using an irrigation system by introducing the nutrients into the water flowing through the system. The first reported application of commercial fertilizer through a sprinkler irrigation system was in 1958. Today, we routinely inject fertilizer solutions and suspensions into irrigation systems via calibrated injection pumps that insure precision over both space and time.
Fertigation has increased dramatically in the past 15 years, particularly for sprinkler and drip systems. For drip systems, the expansion is mostly in horticultural and high value crops. In agricultural areas with declining water supplies, drip systems have also increased. With increased irrigation, a corresponding increase in fertigation has taken place. It will continue to grow since such Figure 10.1 Overhead sprinkler irrigation system. systems result in less water usage and better uniformity and lend themselves to the technique much more readily than the less water-efficient and non-uniform furrow and flood systems being replaced. Effective fertigation requires knowledge of certain plant characteristics such as optimum daily nutrient consumption rate and root distribution in the soil. Nutrient characteristics such as solubility and mobility are important and irrigation water quality factors such as pH, mineral content, salinity and nutrient solubility must be considered. The need for irrigation is the main factor in fertigation because the irrigation system is primarily installed to provide water. The opportunity to fertigate is an added benefit. This chapter will address issues that must be considered to
SECTION CONTENTS: • Introduction • Soil Chemistry • Water Quality Concerns • Fertilizers for Injection Into Irrigation • Use Fertigation Properly and According to Regulations • Irrigation Scheduling & Fertigation • Other Important Factors to Consider When Fertigating
Fertigation is defined as the application of nutrients using an irrigation system by introducing the nutrients into the water flowing through the system. The first reported application of commercial fertilizer through a sprinkler irrigation system was in 1958. Today, we routinely inject fertilizer solutions and suspensions into irrigation systems via calibrated injection pumps that insure precision over both space and time.
Fertigation has increased dramatically in the past 15 years, particularly for sprinkler and drip systems. For drip systems, the expansion is mostly in horticultural and high value crops. In agricultural areas with declining water supplies, drip systems have also increased. With increased irrigation, a corresponding increase in fertigation has taken place. It will continue to grow since such Figure 10.1 Overhead sprinkler irrigation system. systems result in less water usage and better uniformity and lend themselves to the technique much more readily than the less water-efficient and non-uniform furrow and flood systems being replaced. Effective fertigation requires knowledge of certain plant characteristics such as optimum daily nutrient consumption rate and root distribution in the soil. Nutrient characteristics such as solubility and mobility are important and irrigation water quality factors such as pH, mineral content, salinity and nutrient solubility must be considered. The need for irrigation is the main factor in fertigation because the irrigation system is primarily installed to provide water. The opportunity to fertigate is an added benefit. This chapter will address issues that must be considered to
Links: to other sections of the Efficient Fertilizer Use Manual History • Mey • Soil • pH • Nitrogen • Phosphorus • Potassium • Secondary • Micronutrients • Fluid-Dry • Sampling • Testing • Site-Specific • Tillage • Environment • Appendices • Contributors 11