Information from 2001 Missouri Rice Research Update, February 2002.

Evaluation of CMS as a Pre-plant Nitrogen Source For Drill-seeded Rice

David Dunn

Green Line

Abstract

Concentrated Molasses Soluibles (CMS) was used as a N source for rice production. In a one year replicated trial preplant applied CMS out yielded preflood urea treatments. Returns to producers were higher for CMS treatments. Soil pH was not adversely affected by CMS applications. Soil SO4-S levels increased with CMS applications. These levels fell with time.

Introduction

Concentrated Molasses Soluibles (CMS) is a secondary product of lysine production. It is a low grade liquid nitrogen and sulfur fertilizer. CMS contains ½ lb of nitrogen and sulfur per gallon.

Materials and Methods

In this three year study the following 3 Nitrogen treatments were evaluated in a randomized complete block design with four replications: 1) Control 75 lb N/a as urea applied preflood, 2) 75 lb N/a as CMS applied preplant, and 3) 150 lb N/a as CMS applied preplant. An additional 30 lb N/a as urea was applied to each plot at ½ inch internode elongation and again in 10 to 14 days .

The 1999 test site was planted in rice during crop year 1998. The 2000 and 2001 test site was planted in soybeans during the previous year. In early May of each year the test site was prepared using a disk and field cultivator. Preplant Nitrogen fertilizer applications were made by hand. Urea treatments were broadcast while CMS was mixed with water and applied using a watering can. Immediately after these applications a field cultivator was used to incorporate the fertilizer. A roller was then used to prepare the seedbed. Then rice was drill seeded on 7.5-inch rows at a rate of 75 lbs/a. In 1999 and 2001 rice was seeded immediately following seedbed preparation while in 2000 seeding was delayed due to rain for two weeks. In 1999 the rice variety Kaybonnett was planted. In 2000 the rice varieties Kaybonnett and Cocodrie were planted. In 2001 the rice varieties Cocodrie and Drew were planted. Weed control was accomplished with a single application of Stam (1 gal/a) + Facet (8 oz/a). No insect control was required. At mid tillering Urea was applied to the control plots and the entire test was flooded to the depth of 4 to 6 inches. Mid season urea applications were made at ½ inch internode elongation and 14 days later. The rice was mechanically harvested and the grain weighed. Soil samples were collected from each plot at the following times: preapplication, Pre flood pre urea application, 2-3 days post flood, Pre 1st mid season application, post 1st mid season application, Pre 2nd mid season application, post 2nd mid season application, and post harvest. These samples were analyzed for pH, NO3-N, NH4-N, and SO4-S. Area board and chlorophyll meter reading were collected prior to midseason N applications. Following harvest the rough rice was analyzed for milling quality.

Soil samples were collected prior to planting and after harvest. These samples were analyzed for soil pH and SO4-S. These plots were mechanically harvested and the grain yields recorded.

Results

Soil sample data showed a similar trend for all samples in terms of post rice harvest pH for all three years (Table 1).

Table 1. Average post rice harvest soil pH for all treatments 1999, 2000 and 2001. >
Year 75 lb N Urea preflood 75 lb N CMS preplant 150 lb N CMS preplant
1999 6.3 6.2 6.1
2000 5.9 5.7 5.6
2001 6.2 6.0 5.9
Mean 6.1 6.0 5.9
Levels for both NO3-N and NH4-N were similar for all treatments prior to the first mid season nitrogen application (Table 2).

Table 2. Three year average NO3-N+ NH4-N levels (ppm) for 0-6 inch soil samples for each treatment.
Time 75 lb N Urea preflood 75 lb N CMS preplant 150 lb N CMS preplant
Pre flood 17.6 53.1 97.3
Post flood 20.8 27.3 58.7
Pre 1st mid 6.2 6.1 10.1
Post 1st mid 6.9 7.5 9.0
Pre 2nd mid 7.3 7.2 11.0
Post 2nd mid 7.0 7.2 9.3
Harvest 4.4 4.7 4.0

SO4-S levels were greater for the CMS treatment (Table 3). The sulfur levels decreased in the CMS treatments with time. The 150 lb N CMS preplant treatment averaged 70.4 ppm SO4-S three weeks following CMS application, this level had dropped to 17.8 ppm following harvest. SO4-S levels were measured for the 1999 rice plots during 2000. By Oct. of 2000 the SO4-S levels for the 150 lb N CMS preplant treatment had fallen to 6.1 ppm. A graphical representation of the SO4-S level change with time can be found in Figure 1.

Table 3. Three year average SO4-S levels (ppm) for 0-6 inch soil samples for each treatment.
Time 75 lb N Urea preflood 75 lb N CMS preplant 150 lb N CMS preplant
Pre flood 9.6 52.0 70.4
Post flood 9.2 39.1 58.7
Pre 1st mid 4.8 15.6 34.1
Post 1st mid 5.8 16.2 39.6
Pre 2nd mid 6.9 15.6 32.4
Post 2nd mid 5.4 17.0 29.3
Harvest 5.0 13.8 17.8

3 year average
Figure 1. Three year average SO4-S levels as a function of time.

In terms of average rice grain yields the preplant CMS treatments were higher yielding than the preplant urea. The highest two-year average yields came from the 75 lb N/a CMS preplant treatment (Table 5).

Table 5. Three year average rice yield for all varieties each treatment.
TreatmentYield bu/a
  1999 2000 2001 Mean
75 lb N Urea preflood 169 164 125 149
75 lb N CMS preplant 174 183 129 160
150 lb N CMS preplant 178 174 131 159

The two milling properties, total % and % head were measured. Milling % of all the preplant treatments were significantly greater than the standard method. The % head measurements were not significantly different for any of the treatments. These differences was not great enough to effect returns to producers.

Chlorophyll Meter readings collected prior to both mid season N applications were greater for the CMS treatment than for the preplant urea treatment and the standard method. Plant area board measurements collected prior to the first mid season application were greater for preplant urea treatment than for the corresponding CMS treatment. Plant area board measurements collected prior to the second mid season application showed no trend.

Net and gross returns to producers were calculated using the following assumptions: Grain price of $3.00/bu, Urea cost of $0.20/ lb N and $5.00/ acre application, CMS cost of application of $15.00/acre for 100 lbs N, and aerial application costs of $4.50/ acre + urea. Under these conditions the CMS treatments had the greater gross and net returns to producers than urea (Tables 5a and 5b).

Table 5a. Three year average gross returns to producers for all varieties.
Treatment Yield Price Gross Return
75 lb N Urea preflood 149 $3.00 $447.00
75 lb N CMS preplant 160 $3.00 $480.00
150 lb N CMS preplant 159 $3.00 $477.00

Table 5b. Three year average net returns to producers for all varieties.
Treatment Gross Return N cost Net return
75 lb N Urea preflood $447 $41 $406
75 lb N CMS preplant $480 $34 $446
150 lb N CMS preplant $477 $23 $454

Soybean grain yields for the plots used in the 1999 rice evaluation were similar for all treatments (Table 6). The 1999 treatment of 75 lb N/a CMS had the highest yield with 47 bu/a while 150 lb N/a was the lowest with 44 bu/a.

Table 6. Average soybean grain yields, harvest soil pH and SO4-S for each treatment 2000.
  75 lb N Urea preflood 75 lb N CMS preplant 150 lb N CMS preplant
Yield bu/a 45 47 44
pH 6.3 6.3 6.1
SO4-S ppm 3.2 4.8 6.1

Conclusions

Based on this study CMS may be used profitably in Southeast Missouri in a rice-soybean rotation. Soil pH was not adversely effected by CMS applications. While soil SO4-S levels were increased with CMS applications, the levels fall with time. Soil SO4-S levels should be monitored by soil testing if CMS is applied.

Further study is needed to determine if these results are the same for other rice varieties and in a rice following soybean rotation.

Acknowledgement

We would like to thank BioKyowa Inc. for their generous support of this project. Green Line Missouri Rice Research Reports