Institute of Food and Agricultural Sciences
Hendry County Horticulture News
Quite Simply Amazing
Quite simply amazing - is the only way to describe the normally unseen world beneath your garden. The amount of life in a tiny half inch thick pinch of soil from your lawn is difficult to grasp. In this tiny mote, there are millions of miniature insects and some five billion or so bacteria - about as many bacteria as there are human beings on earth. In addition to the extraordinary conglomeration of bacteria that exist in this microscopic world, there are also some one million fungi, 20 million actinomycetes and 300,000 algae. From our human perspective, these numbers are incomprehensible and it seems impossible that so many living things could be crammed into such a small space.
What makes it all possible is the fact that the soil it self is composed of microscopic mineral particles that form a vast apartment block housing all of the millions and billions of soil micro flora and fauna in our half inch cube of soil. Depending of the exact particle mix of sand, silt and clay in our hypothetical soil, a half inch cube of soil may contain up to ten thousand floors with a total living area approaching ten acres. In essence, our tiny block of soil can be thought of as a microscopic city packed with passageways and many hundreds of thousands of separate but interconnected dwellings.
Of all the varied inhabitants of this microcosm beneath the ground, the soil bacteria are of special interest because of their many different activities. There is a large group that specializes in decomposing organic materials into their component parts and making them available as nutrients for plants and other higher life forms. A smaller group obtains energy through the oxidation of minerals such as iron, sulfur and ammonium. Still others, the nitrogen fixing bacteria are capable of converting atmospheric nitrogen from the air into useable forms that can be utilized by plants. Even the gummy residues from deceased bacteria are important in providing the mortar that holds together the soil particles providing soil structure.
Turning to another of the soils microorganisms, many plant species exploit the soil with the help of beneficial fungi called mycorrhizal fungi. The fine threads that make up the fungus branch between soil particles, grow into decomposing organic matter, even explore the shells of dead insects, where they find phosphorus and other vital nutrients. The nutrients are then passed back to the roots of the plant.
The word mycorrhiza comes from the Greek word for roots and refers to any of several types of associations between plant roots and soil fungi.
Mycorrhiza offers several other benefits to the host plant, including faster growth, improved nutrition, greater drought resistance, and protection from pathogens. Additional benefits include higher plant species diversity and improved soil structure.
Although most gardeners are unaware of this teeming mass beneath their feet and are ignorant of their complex life, they are familiar with the many benefits they bestow. Although organic gardeners and others have long proclaimed the value of healthy soils, science is still discovering much about this unseen world. Based on the many contributions made by soil bacteria and other organisms to soil fertility and in supporting other life forms, it has been said that if the microbial activity in the soil were to fail, higher plants and animals would be unable to exist.
While there is still much to be understood about soil microorganisms, gardeners can help ensure successful more productive plantings by managing their soil to encourage and promote a healthy population of soil microbes through the recycling and incorporation of organic materials into the soil and the judicious use of fertilizers and other chemicals. It really is a jungle out there - good luck and good gardening.
Gene McAvoy is the horticulture agent with the Hendry County Extension Service. Direct your horticulture questions to PO Box 68, LaBelle, FL 33975, e-mail - firstname.lastname@example.org or phone 863-674-4092 or 863-983-1598. You are also welcome to visit the Hendry County Extension Office at 225 Pratt Blvd., LaBelle. Office hours are from 8:00 - 5:00.
The Institute of Food and Agricultural
Sciences is an Equal Employment Opportunity - Affirmative Action Employer
authorized to provide research, educational information and other services
only to individuals and institutions that function without regard to race,
color, sex, age, handicap or national origin.
COOPERATIVE EXTENSION WORK IN AGRICULTURE, FAMILY AND CONSUMER SCIENCES, SEA GRANT AND 4-H YOUTH, STATE OF FLORIDA, IFAS, UNIVERSITY OF FLORIDA, U.S. DEPARTMENT OF AGRICULTURE, AND BOARDS OF COUNTY COMMISSIONERS COOPERATING