Sensor‐based Nitrogen Fertilization for Midseason Rice Production in Southeast Missouri

Core Ideas Sensor‐based N management used with a nitrogen‐rich strip was a very effective decision support tool for midseason N management. Sensor‐based N management provided opportunity to take advantage of year‐to‐year environmental variation. Sensor‐based N management approach reduced the amount of total N applied without any yield penalty compared with the traditional practice.Sensor‐based nitrogen (N) decision management tools have shown potential to improve N fertilizer efficiency, yield, and profitability. Small‐plot experiments were conducted to evaluate the use of sensor‐based management in guiding midseason N application decisions. Treatments were two rice ( Oryza sativa L.) cultivars (Jupiter, a medium grain, and Roy J, a long grain) and eight N treatments: (i) check (no N fertilizer); (ii) 60 lb N/acre applied preflood + midseason N applied based on sensor reading (sensor‐based management); (iii) 90 lb N/acre applied preflood + midseason N applied based on sensor reading (sensor‐based management); (iv) 120 lb N/acre applied preflood; (v) 120 lb N/acre applied preflood + 30 lb N/acre applied at midseason (traditional practice); (vi) 120 lb N/acre applied preflood + midseason N applied based on sensor reading (sensor‐based management); (vii) 150 lb N/acre applied preflood; and (viii) 180 lb N/acre applied preflood (N reference strip). Grain yield and nitrogen use efficiency (NUE) were compared among N treatments. Results showed sensor‐based management for midseason application recommended lower total N application rate by 15 to 90 lb N/acre over the traditional practice. These results indicate that N fertilization made by a sensor‐based midseason recommendation can optimize yield and NUE in southeast Missouri.