Managing nitrogen in rice is a complex task compared to N management in other crops. Broadcasted urea before flooding is subject to volatilization. Also, low oxygen in saturated soils creates a microbial environment that is conducive to nitrate-nitrogen losses by denitrification. Because of different nutritional needs among varieties, a standard "one-size-fits-all" nitrogen fertilizer rate is not recommended for all rice varieties.

For many years, rice agronomists have tried to develop an accurate method of determining whether supplemental nitrogen is needed at internode elongation. At the Delta Center we have had marginal success predicting when mid-season N is needed using leaf tissue tests, chlorophyll meter, and leaf color chart. Despite positive university research results with the plant area board method, very few rice farmers practice N management with it because it is time consuming and requires a complicated calculation. In 2004, we developed a simple, low-tech N management method using a standard wooden yardstick. In 3 ½ minutes, plant height can be measured and leaf canopy estimated by counting the inch numerals visible on a yardstick floating between rice row drills. No calculations are needed. Thresholds for applying mid-season N using the yardstick method will be listed on future Missouri Degree Day-50 reports.

Rice that needs mid Season N		Rice with Sufficient N