Landscape Architect Articles

2007 February LSMP Irrigation: Chemigation: Using Irrigation to Deliver Fertilizers and Other Chemicals03-26-07 | News

Chemigation: Using Irrigation to Deliver Fertilizers and Other Chemicals

By Rod N. Blanchard, Fertile Earth Corporation

Fertigation started in large agricultural settings but new hardware like this ProFeeder can be easily installed inside existing valve boxes. This unit operates at 25-125 psi with a capacity of 1.5-30 gpm. Photos courtesy of Fertile Earth

The process of chemigation refers to applying fertilizers and/or pesticides through an irrigation system. It is also known as fertigation (for the application of fertilizer only). The method has been adopted in different sectors of the irrigation industry?EUR??,,????'??+most recently by groundskeepers and homeowners.

The first group to adopt and develop the technology were those applying the most chemicals and whose livelihood depended on producing abundant crops: the agricultural sector. Shortly thereafter, the golf industry, whose livelihood is determined by vibrant healthy turf, saw the merits of chemigation and began to incorporate systems. Now the practice is being introduced to residential and commercial markets.

Over the years, chemigation has been implemented with stunning success?EUR??,,????'??+but also with some less-than-successful results. Hence, the procedure has its proponents, its detractors and self-appointed watchdogs?EUR??,,????'??+all of whom play a role in developing a safe, effective chemigation industry. This document is intended to highlight the positive aspects of chemigation and reflects the industry?EUR??,,????'???s potential, not necessarily the current state of affairs.

A planting of rosemary in poor soil before fertigation. (top) The same shrub planting after weeks of fertigation-driven fertilization. (bottom)

Environmental Advantages

Chemigation is or should be better for the environment than traditional methods of applying chemicals:

Fewer Chemicals ?EUR??,,????'??? because chemigation systems have the ability to apply chemicals with every watering event, the application rates can typically be reduced to levels that plants can readily uptake through foliar and root absorption.
Less Water ?EUR??,,????'??? Studies indicate that the consistent slow feeding of certain nutrients encourages the development of healthy root systems that enable plants to mine water resources in the soil more efficiently.
Energy Savings ?EUR??,,????'??? By allowing each irrigation event to do more than just apply water, no fuel is needed to power heavy equipment or crop dusters to make applications of fertilizers, pesticides or additives.
Facilitates the Use of Natural Products- Many safe botanical pest repellents are not used because they don?EUR??,,????'???t have good residual properties. One of the great advantages of chemigation is the ability to make frequent applications that provide safe results with a less concentrated product.

This Southern California home has been using a fertigation system for over two years. Fertigation is especially useful in sandy soils, where regular feeding helps compensate for the porous nature of the soil.

Botanical & Agronomic Advantages

Chemigation is or should be better for plants and soil than traditional methods of applying chemicals.

Virtues of slow feeding ?EUR??,,????'??? Plants prefer to be fed slowly, and consistently. Steady growth without peaks and valleys makes plants more pest and disease-tolerant, healthier and more productive.
Slow Feed Verses Slow Release ?EUR??,,????'??? Many slow-release products on the market use ingredients that destroy microbial activity in the soil to prevent premature release of nitrogen. With slow-apply chemigation, there is no need to suppress microbial activity so these beneficial bacterias can continue to perform their critical roles – breaking down organic matter, facilitating nutrient uptake, helping salts leach out of soils, naturally aerating the soil and improving the balance and friability of the soil.
Foliar Feeding ?EUR??,,????'??? Many nutrients are readily absorbed through plants?EUR??,,????'??? foliar surfaces?EUR??,,????'??+a process that is facilitated and encouraged through fertigation.