Evaluation of CMS as a Pre-plant Nitrogen Source For Drill-seeded Rice
David Dunn
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.
Concentrated Molasses Soluibles (CMS) is a secondary product of lysine production. It is a low grade liquid nitrogen and sulfur fertilizer. CMS contains 1/2 lb of nitrogen and sulfur per gallon.
In this two 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 10 to 14 days later.
The 1999 test site was planted in rice during crop year 1998 while the 2000 test site was planted in soybeans during crop year 1999. 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 and 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 rice was seeded immediately following seedbed preparation while in 2000 seeding was delayed due to rain for two weeks. In both 1999 and 2000 the rice variety Kaybonnett was 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 1/2 inch internode elongation and 14 days later. When the rice matured 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.
In 2000 the rice plots used in 1999 were planted in soybeans. Soil samples were collected prior to planting and following harvest. These samples were analyzed for pH and SO4-S. These plots were mechanically harvested and the grain yields recorded.
Soil sample data showed a similar trend for all samples in terms of post rice harvest pH for both years (Table 1).
Table 1. Average post rice harvest soil pH for all treatments 1999 and 2000. 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 Mean 6.1 6.0 5.9Levels for both NO3-N and NH4-N were similar for all treatments prior to the first mid season nitrogen application (Table 2).
Table 2. Average NO3-N+ NH4-N levels (ppm) for 0-6 inch soil samples for each treatment 1999 and 2000. Time 75 lb N Urea preflood 75 lb N CMS preplant 150 lb N CMS preplant Preflood 17.6 53.1 97.3 Postflood 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 4.0SO4-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. Average SO4-S levels (ppm) for 0-6 inch soil samples for each treatment 1999 and 2000. Time 75 lb N Urea preflood 75 lb N CMS preplant 150 lb N CMS preplant Preflood 9.6 52.0 70.4 Postflood 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
Figure 1. Average SO4-S levels as a function of time 1999 through 2000.
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 4).
Table 4. Average rice yield for each treatment 1999 and 2000.
Treatment Yield bu/a
1999 2000 Mean
75 lb N Urea preflood 169 153 161
75 lb N CMS preplant 174 174 174
150 lb N CMS preplant 178 156 167
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. Average gross returns to producers for each treatment 1999 and 2000. Treatment Yield Price Gross Return 75 lb N Urea preflood 161 $3.00 $483.00 75 lb N CMS preplant 174 $3.00 $522.00 150 lb N CMS preplant 167 $3.00 $501.00 Table 5b. Average net returns to producers for each treatment 1999 and 2000. Treatment Gross Return N Cost Net Return 75 lb N Urea preflood $483 $41 $442 75 lb N CMS preplant $522 $34 $488 150 lb N CMS preplant $501 $23 $478
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 45.0 45.0 44.0
pH 6.3 6.3 6.1
SO4-S ppm 3.2 4.8 6.1
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.
We would like to thank BioKyowa Inc. and Liqua-Tech for their generous support of this project.