Tobacco farmers will soon be loading up seed trays in greenhouse float beds to begin growing transplants for the field. This makes it the optimal time to test the source water and nutrient solution used in those float beds to help ensure that fertilizer added to the water meets the plant needs and is at the recommended rates.
The N.C. Department of Agriculture and Consumer Services’ Agronomic Services Division offers solution analysis testing for source water and nutrient solutions and can make agronomic recommendations based on the findings.
“Fertilizer is an expensive treatment for any farm, so you only want to add what is needed for optimal plant growth,” said Agriculture Commissioner Steve Troxler. “Testing of water, soil, or other growth mediums, lets growers know exactly what they have and what additives are needed. It’s a way for farmers to save money on crop inputs, while also ensuring successful growth.”
Solution analysis lets a grower know whether a float-bed source water nutrient solution is suitable for tobacco seedling production and if nutrient solutions have reached the target nutrient levels. Samples are analyzed for chemical properties important for plant growth. The test measures total alkalinity, pH, electrical conductivity (soluble salts), sodium and concentrations of 12 essential plant nutrients, said Dr. Kristin Hicks, chief of the Agronomic Services Division’s Plant, Waste, Solution, Media Analysis lab. The solution report also provides comments by an agronomist regarding the suitability of the nutrient solution for transplant production and suggestions for corrective action, if necessary.
Growers are advised to collect a water sample before transplant production begins and nutrient solution samples after adding and thoroughly mixing the first fertilization. It is also good practice to sample again prior to adding the next batch of fertilizer to determine if additional fertilizer is needed and, if so, the appropriate rate.
Collect a source water solutuion sample from the hose end used to fill up the float beds. Let the water run for about 10 minutes to clean any standing water in the pipes. To collect a nutrient sample, first make sure the fertilizer has completely dissolved and been thoroughly mixed in the float bed. Use a clean plastic bottle that will hold 8 to 16 ounces. Before filling the bottle, rinse it with the float-bed water being collected.
Label each sample and fill out a Solution Sample Information form, which can be found online at www.ncagr.gov/agronomi/pdffiles/issoln.pdf. When filling out the form, use the codes, "ST," for source water or "NT" for nutrient solutions. Send the sample, completed form and $5 per sample to the NCDA&CS Agronomic Services Division. The appropriate mailing address will depend on the method of delivery (U.S. Postal Service vs. DHL, FedEx or UPS). Follow the instructions given on the sample information form.
Solution reports are available three to four days after the samples are received, though often within two days. Reports are posted on the web at www.ncagr.gov/agronomi/. From the home page, select “Find Your Report” from the left-column navigation bar.
If abnormal growth or color develops in tobacco seedlings, do not wait. Submit diagnostic samples as quickly as possible, Hicks said. For optimum diagnosis, submit float-bed water, soilless media and tobacco tissue samples. Information on collecting and submiting soilless media and tissue samples is available online.
If you have questions about how to collect samples or interpret your report, contact Kristin Hicks or Aaron Pettit at 919-733-2655. Your NCDA&CS regional agronomist is also a good source of advice. Go to www.ncagr.gov/agronomi/rahome.htm for a list of agronomists and their county assignments.