Information from 1999 Missouri Rice Research Update, February 2000.

Nitrogen Rates for Rice After Rice

Alan Sheckell, Gene Stevens, Chris Moylan, Holly Wilson, and Keith Birmingham


A field study was done at the Missouri Rice Farm at Glennonville to evaluate the most productive amount of preflood fertilizer to be used on rice after rice. Results from 1999 showed that no additional N was needed for rice after rice as compared to the standard recommendation of 90 lb N/acre preflood. Two 30 lb N/acre mid-season N applications were made to all treatments.


Our current recommendation is a 20% increase in fertilizer if the producer grows rice after rice. This is the standard for many farmers.

Materials and Methods

Cypress rice was drill seeded on May 12, 1999. There were seven different fertilizer rates applied and replicated four times. The treatments were 0, 30, 60, 90, 120, 150, and 180 lbs of nitrogen (urea) applied at the preflood stage. The recommended fertilizer rate for Cypress is 90 lb N/acre. There was a 30 Lb. nitrogen rate applied at 1/2 IE and at 1/2 IE + 1 week.


The first year results showed that the 20% increase might not be necessary to achieve good yields (Table 1). The highest yields were obtained with 60 lb N/acre, which is lower than the recommended rate. After this treatment the yield declined by 10 bu/acre. The yields continued to decreases until the 180 lb N/acre treatment where they then returned to 140 bu/acre.

Table 1. Yields on rice following rice.

  Preflood N          Yields   
  Lb N/acre          Bu/ acre 
  ----------         --------
      0                 96
     30                121
     60                146
     90                135
    120                136
    150                130
    180                140


The first year data shows that there was no yield increase when the extra 20% fertilizer was applied. The recommended 90 lb N/acre treatment yielded less than the 60 lb N/acre treatment. This test will be replicated next year to obtain more data.

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