Dawn Pettinelli, Soil Test Expert
Dawn Pettinelli is the assistant extension educator at the University of Connecticut Department of Plant Science and Landscape Architecture. Part of her job includes managing the University of Connecticut’s Soil Nutrient Analysis Laboratory, which provides soil fertility analysis to residential and commercial clientele and also serves as a springboard for numerous educational programs.
Dawn has a B.S. in agricultural production - land resources from Montana State University and an M.S. in forest science with a minor in forest soils from Oregon State University. To become a soil scientist, Dawn had to take a minimum of 15 soil science credits, and after working for several years, was eligible to become a member, in professional standing, of the Soil Science Society of Southern New England.
How did you initially get into the field of soil research?
Despite my love of gardening, which I acquired at a very early age, I never even thought about working with soils. During my junior year in college, I was required to take a basic soil science course and have been in love with the field ever since. I became interested in research when, as a work study student, I worked for a forestry professor and assisted him in studying differences in soils related to various logging techniques. I also worked at a soil testing lab as a student when I attended Montana State University.
Why is it important to conduct soil tests?
In regard to soil fertility tests, you can't really tell what your soil's pH or fertility levels are just by looking at it. Soil testing is an inexpensive but valuable tool for gardeners and commercial growers to assess their soil's nutrient and pH status. Recommendations for how much limestone and/or fertilizer to apply are made according to the test results so that takes the guesswork out of which amendments to purchase and how much to apply. Not only does this usually save people money and often, valuable time, but if the environmentally-friendly recommendations are followed, both plants and the environment will benefit.
It seems reasonable to assume that soil located in urban areas differs greatly from that found in rural, less-developed areas. Is there anything that urban gardeners should be particularly aware of in regard to soil quality?
With more and more people looking to raise vegetables and other edible crops to lower their grocery bills or just for pesticide-free produce, it is essential that they are aware of any possible contamination issues. Our laboratory is able to screen for soil lead, which is a problem, especially in urban areas. There are other contamination issues and some other university labs and also private environmental labs may be able to address these concerns.
What elements (or lack of elements) determine whether a plot of land is fertile or not?
Healthy soil, for the majority of garden plants, should contain all of the essential elements for plant growth, a soil pH in the range preferred by the type of plants being grown, good aggregation so that air, water and plant roots can pass through the soil freely, and a moderate to high amount of organic matter to help retain nutrients and water and to serve as a source of food and energy for the soil microbes. Some of the elements plants require include nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, zinc, molybdenum, copper, boron, chlorine, nickel, manganese and possibly selenium, silicon, etc.
What are the most important pieces of equipment and supplies that soil testing laboratories must have?
This would vary by lab, of course, but we think that having a pH meter, a muffle furnace, drying oven, ICP, colormetric autoanalyzer, CN analyzer, scales, pipetters, shakers, water purification system, chemicals, filter papers, glassware and computers are all necessary.
What degree of education and training is necessary to do soil testing and who provides it?
At our small University of Connecticut soil testing lab, the manager has an M.S. and the technician has a B.S. Having taken laboratory classes and having previous experience in a lab would be prerequisites for a job like this. Graduate school is often an ideal opportunity to hone one’s laboratory skills. To actually perform the soil fertility tests, it is not necessary but helpful to take soil science classes. Chemistry and laboratory skills would be essential. A soil fertility or plant nutrition background would be important for making fertilizing recommendations, assisting with nutrient management plans, and perhaps developing laboratory procedures.
Do you have any advice or suggestions for people who wish to get their soil tested?
I highly recommend soil fertility testing at least once to see how well you have been meeting your plants' soil pH and fertility requirements. I think about a quarter of the problems people have with their plants can be attributed to poor soil conditions. Thereafter, a periodic testing every three to five years will serve as a check to make sure the soil continues to supply plant growth demands.
Do you have any advice or suggestions for people who wish to get a job in the soil testing field?
I would encourage them to try working in almost any lab to see if they really enjoy laboratory work. It is often fairly repetitive and careful attention to detail and following protocol is important. I would also encourage them to contact people working at labs for informational interviews. Those interested in soil testing might want to find out about chemistry, soil and environmental science classes offered at colleges they would be interested in attending. Also, if anyone is interested in soil fertility testing, it would be good if they had some experience with growing plants so they could see how the two fields are interrelated.