Department of Botany & Plant Sciences


MerhautDonald J. Merhaut

Associate Extension Specialist for Ornamental and Floriculture Crops (Ph.D., 1993, University of Florida) Department Vice Chair for CE

Office: 4118 Batchelor Hall
Phone: (951) 827-7003
Fax: (951) 827-4437
Email: donald.merhaut@ucr.edu

Brief Extension Summary
My laboratory emphasizes the physiological and horticultural aspects of plant production, focusing on the optimization of nutrient use efficiency for nursery and greenhouse crop production. However, our program has broadened over the years to all of agriculture that impacts specific watersheds in California. Therefore, our extension program encompasses the development of Best Management Practices (BMPs) for row crops, orchards, nurseries and greenhouse production. The BMPs that are developed focus on four main areas: 1) irrigation efficiency, 2) fertilizer use efficiency, 3) infrastructural considerations, and 4) Intergrated Pest Management (IPM). With these programs, we have been successful in helping growers comply with new state regulations associated with the mitigation of nutrient and pesticide runoff.

In order to eliminate agricultural nutrient contamination of the environment, it is imperative that more efficient fertilization and irrigation guidelines are developed and more effective fertilizers (compounds, coatings, and applications methods) are designed so that nutrient use efficiency is optimized. Our laboratory continues to address this problem by both applied and basic research methods. Research in our laboratory involves characterizing nitrogen cycling in containerized plants through measurement of ammonium and nitrate in leachates, media and plant tissues and comparing different sources of fertilizers for their release and uptake by plants. The results of this research have been formatted into useable Best Management Practices (BMPs) that have been distributed to the agricultural community through grants funded by the California State Water Board. This type of outreach has allowed us to take research findings from our laboratory and the research of our colleagues and develop BMPs that reduce agriculture’s impact on the environment and make agriculture a sustainable business in California.

Relevant Links:

Relevant Publications:

Merhaut, D. J. 2004. Effects of Magnesium-sulfate on plant growth and nutrient uptake and partitioning in Camellia sasanqua ‘Shishi Gashira’ J. Environ. Hort. 22(3):161-164.

Merhaut, D.J. 2004. Marketing trends and Business Management Practices for the wholesale nursery industry in California. HortTechnology (Accepted-revision stage).

Corkidi, L., E. B. Allen, D. Merhaut, M. F. Allen, J. Downer, J. Bohn, M. Evans. 2004. Effectiveness of Commercial Mycorrhizal Inoculants on the Growth of Liquidambar styraciflua in Plant Nursery Conditions. J. Environ. Hort. (submitted 09-04).

Grusak, M. A., B. W. Stephens and D. J. Merhaut. 1996. Influence of whole-plant net calcium influx and partitioning on calcium concentration in snap bean pods. J. Amer. Soc. Hort. Sci. 121(4): 656-659.

Merhaut, D. J. and R. L. Darnell. 1996. Vegetative growth and nitrogen/carbon partitioning in blueberry as influenced by nitrogen fertilization. J. Amer. Soc. Hort. Sci. 121(5): 875-879.

Merhaut, D. J. and R. L. Darnell. 1995. Ammonium and nitrate accumulation in containerized southern highbush blueberries. HortScience. 30: 1378-1381.

More Information

General Campus Information

University of California, Riverside
900 University Ave.
Riverside, CA 92521
Tel: (951) 827-1012

Career OpportunitiesUCR Libraries
Campus StatusDirections to UCR

Department & Program Information

Department of Botany & Plant Sciences
2142 Batchelor Hall

Tel: (951) 827-4619
Fax: (951) 827-4437
E-mail: bpschair@ucr.edu

Plant Biology Graduate Program
CNAS Grad Student Affairs Office
1140 Batchelor Hall

Toll: (800) 735-0717
Tel: (951) 827-5688
Fax: (951) 827-5517
E-mail: Laura.mcgeehan@ucr.edu