HYDROPHOBIC SOILS AND LDS
The occurrence of localized dry spots (LDS) continues to be a significant management challenge for golf course superintendents throughout the world. There is much confusion concerning the causes, detection and management of LDS. This is particularly true when LDS is caused by water repellent soil. Dr. Karnok has spent more than 15 years investigating the causes and control of water repellent soils in turfgrass areas. He has studied the influence of turfgrass species, cultivars, sand particle size, soil organic matter content, thatch/mat, pH and fairy ring on the development and or management of hydrophobic soils. Dr. Karnok has also devoted considerable time investigating the use of wetting agents to combat this chronic turfgrass management problem. He has written numerous articles on LDS, hydrophobic soils and the use of wetting agents. Furthermore, he has made numerous presentations on the subject around the country (see presentations).

WETTING AGENTS
Over the past several years while investigating the causes, detection and management of localized dry spots, a great deal has been learned about wetting agents. Wetting agents are the primary management tool for combating LDS caused by water repellent soil. However, in addition, wetting agents are used by golf superintendents for water management, dew control, improving drainage, relieving compaction, etc. Unfortunately, there is little research to support the use of wetting agents in these ways . Over the past several years, we have studied the effects of wetting agents on turfgrass rooting, irrigation efficiency, salt removal, organic coating removal, etc. In addition, we have determined the effects of organic matter on wetting agent efficacy. We continue an extensive ongoing testing program for wetting agent manufacturers interested in learning more about new wetting agent chemistries or how current products perform under various field conditions. Depending on the objectives, research is conducted in a state-of-the-art rhizotron (underground root laboratory), field, greenhouse or laboratory. Cooperative research projects with 10 to 14 wetting agent manufacturers are completed each year.

MANAGING TURFGRASS ROOT SYSTEMS
It is generally agreed among golf course superintendents that managing turfgrasses to ensure optimum rooting is one of the primary keys to successful turfgrass management. Unfortunately, compared to above-ground plant parts, there is little known about plant root systems. This is particularly true for turfgrasses. Dr. Karnok has spent more than 25 years investigating those factors that affect turfgrass root growth. His background includes the design, construction and operation of two underground root observation laboratories called rhizotrons (Ohio State University and the University of Georgia). He has studied the seasonal root and shoot responses of both cool and warm season turfgrasses. In addition, his research has involved the effects of growth regulators, nitrogen rates, nitrogen form, wetting agents, biostimulants, water stress and endophyte infection on turfgrass root growth. Dr. Karnok has presented numerous conferences and seminar presentations on the subject (see presentations).

TURFGRASS BIOSTIMULANTS
Over the past several years, "biostimulants" have proliferated in the turfgrass industry. Though not marketed as fertilizer or pesticides, these products purportedly improve turfgrass health, vigor and overall quality, especially in turf that is under environmental or cultural stress. In theory, the unique blends supply the turf with necessary substances that are, for some reason, deficient in the plant or soil. Although biostimulants hold great potential in turfgrass management, there has been insufficient university research to support most of the claims made. With this in mind, over the past several years we have conducted various experiments to better understand the effects of biostimulants on turfgrass. In one study, we utilized our underground root observation laboratory (rhizotron) to evaluate root responses to the application of various biostimulants. From our experiences, the reader is encouraged to read "Promises, promises: Can biostimulants deliver?" Golf Course Management, August 2000, pages 67-71. Also, Dr. Karnok has presented numerous conferences and seminar presentations on the subject (see presentations).