AGRONOMIC NEWS ITEMS
From Agronomists of the
Potash & Phosphate Institute
655 Engineering Drive, Suite 110
Norcross, Georgia 30092-2837
Phone (770) 447-0335
Summer 2003, No. 6
Good farm managers are placing an emphasis on good fertilization practices, and rightly so. Research has shown that fertilization accounts for 30 to 50 percent of crop yields in North America. Optimum plant nutrition raises yields, enhances water use efficiency, increases the annual return on the investment in all crop inputs, protects future productivity, and results in less risk for leaching of nitrate-nitrogen and runoff losses of nitrogen and phosphorus to water resources.
Good farmers base nutrient applications on recent, representative soil samples and test results. Yet, nutrient deficiency symptoms are being reported more frequently. Are soil tests accurately identifying the need for and potential response to fertilization? Have changes in tillage systems affected efficient uptake of nutrients? Do transgenic crops have different nutrient requirements than non-transgenic crops? Are soilborne and foliar disease, nematode, and insect pests interfering with plant health, nutrient uptake, and translocation? Are nutrient deficiency symptoms that reliable, especially considering the potential for multiple nutrient deficiency symptoms? What about the possible confusion with symptoms of disease and insect damage, and also the potential for confusion with herbicide injury symptoms?
Many skilled agronomists believe that plant tissue analysis is probably the most under-utilized nutrient management tool available to farmers. Perhaps the importance of proper plant tissue collection, the time of sampling, the plant parts to sample, the need to collect comparative samples from “good” and “bad” areas, and the need to expedite sample shipment to the analytical laboratory are not well understood.
Whatever the past reasons were for failing to collect plant tissue samples, can one afford not to take advantage of plant tissue analysis in today’s agricultural economy? For as little as $10 to $20 a sample, sufficient plant nutrition can be verified for a field or field management zone. In many cases, the cost is less than about $0.50/A. Timely plant tissue analysis can identify deficiencies before they impair yields, and they are much more reliable than the naked eye. Plant tissue analysis can verify the performance of soil test results and recommendations, identify problems for corrective action, and they can build confidence in nutrient management programs.
While digital cameras, personal computers, the Internet, and e-mail are useful tools in capturing and sharing images of sick plants, they are not as accurate as plant tissue nutrient analyses. Consider the benefits of accurate nutrient diagnostics, or worse, consider the costs of inaccurate diagnostics. Have you seen the need to plant tissue sample this year?
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