Final Report for LS98-092

Development of Sustainable Cropping Systems for Canola on Limited-Resource Farms in Alabama

Project Type: Research and Education
Funds awarded in 1998: $124,488.00
Projected End Date: 12/31/2001
Region: Southern
State: Alabama
Principal Investigator:
Udai R. Bishnoi
Alabama A&M University
Expand All

Project Information


• Summary

Results from production practices and on-farm demonstrations for sustainability of canola with popular summer crops showed that the highest seed yield of 3,204 kg ha-1 was obtained with October 1-10 planting dates, 180 kg N and 6.0 kg ha-1 seeding rates. Per acre yield and income from canola was equal or higher than wheat, it fits well in rotation with wheat and summer crops. Experiment station research and on-farm demonstration results from limited resource farms showed that canola as a winter crop is promising in southeast US if a regional oil extracting mill and markets are made available.

Project Objectives:

• Objectives/Performance Targets
The specific objectives of this project are:

1. To develop efficient cultural practices for canola production and determine nitrogen rates for economical (optimum) yield of canola.
2. To compare the agronomic and economic performance of canola using no-till versus conventional tillages system on a few limited resource farms.
3. To develop sustainable and viable cropping systems which include canola in sequences with soybean, wheat, sorghum, various millets and corn.
4. To provide information about the economics and the profitability of canola on its own merits and in comparison with wheat.

The project’s performance and success of targeted goals will introduce a new crop with great potential and will have the following economic effects on the rural communities in Alabama.
1. Demonstrate the feasibility of producing canola as an alternative crop by providing research-based production recommendations for farmers.
2. Provide economic information about the profitability of producing canola and the extended market opportunities for one of the healthiest edible and multi-purpose industrial oils.
3. Through on-farm demonstrations and extension programs, create new opportunities in the rural communities of Alabama by educating farmers about the potential profits of growing canola.


• Introduction
Canola (Brassica napus L.) is a genetically improved version of rapeseed and is low in both erucic acid and glucosinolates which distinguish it from ordinary rapeseed. The name ‘canola’ is not a biological classification but is an internationally registered trademark of the Canola Council of Canada, based on the quality standard of edible oil and a high value animal feed. In order for rapeseed to be considered as canola, the standard requirements are that the oil should contain less than 2% erucic acid and that an air-dried oil free meal should not contain more than 30 mol of glucosinolates per gram of meal (Murdock and Herbek, 1989).
Biologically and botanically, canola is a member of the Brassicaceae and is a cool season annual crop grown mainly in Europe and Canada (Younts, 1990). Canola seed contains 35-40% edible oil by weight and has only 6% saturated fats, the lowest among all vegetable oils. The canola meal contains about 37% protein and is used as a high protein livestock and poultry feed (Murdock and Herbek, 1989). For commercial production of such an important crop, research information on seeding rates, planting dates, nitrogen requirement, adoption on limited resource farms, etc., is very limited.
Seeding date plays a major role in determining the seed yield and quality in canola. Studies have shown that the optimum seeding date for canola varies from region to region (Christensen et al., 1984). Planting date requirements dictate to fit into existing cropping systems. In cool season areas, including mid South US, wheat more or less, is the only winter crop. Because of similarities of life cycles and management requirements, canola could fit as an alternative to winter wheat and also as a crop in rotation with summer annuals. Winter wheat is usually planted from mid-September through early November and harvested by mid June. The late planting dates of wheat should give producers an opportunity to grow canola as cash crop or use it for double cropping with summer crops of the southeast region. The relative profitability of canola to wheat will provide a choice to producers of an alternative winter crop and will give farmers an opportunity for competitive multi-cropping systems.
Canola is an indeterminate plant and, therefore, it can compensate well for variations in planting spacings and plant population due to its ability to branch (Murdock et al., 1989). Such crops can respond well to application of nitrogen, which is most common element limiting to canola production (Murdock and Herbek, 1989). Nitrogen requirements of canola can change with alterations in plant numbers and an effective N management, therefore, is important to ensure canola yield (Bailey and Grant, 1993).
In spite of the fact that no additional investment is needed to grow canola, farmers are skeptical to adopt it as an alternative to wheat into their traditional crop rotations. Lack of published research data on the economic profitability, the proper production practices, and how canola fits into various cropping systems, are among the reasons for this skepticism. Another major constraint preventing farmers from adopting canola is the perception that canola production involves more problems than other crops. Some of these problems include non-availability of published information on date of planting, seeding and nitrogen rates for optimum canola yield (Scott et al., 1973; Scarsbrick et al., 1982; Bailey and Grant, 1993). To provide answers for a few of these production problems, the influence of sowing dates, seeding and nitrogen rates for seed yield and maturity of canola was undertaken.


Click linked name(s) to expand
  • Ernst Cebert
  • Bruce Harvelle
  • Sam Hopkinson
  • Bobby Jones
  • Paul Mask
  • Omer Saihou Mbenga
  • Drs. Rufina and Ken Ward


Materials and methods:

• Materials and Methods
The research and other project activities were carried out during the 1998 – 2002 growing seasons using canola cv. Jetton at The Winfred Thomas Agriculture Research Experiment Station located in Hazel Green, North Alabama, having a Decatur silty clay loam soil type with good drainage and high water holding capacity. Based on an extensive three year (1998 – 2000) canola variety trial at our experiment station, we were able to select the early maturing and high yielding cv. Jetton for planting in our research and demonstration plots as well as on limited-resource farms.
The experiments were conducted by using a split-split plot design with four replicates, where planting dates were main plots and the three seeding rates and the four nitrogen levels were randomized in the sub-plots. Because of the dependency on rain, only two planting dates (24 September and 10 October) were planted in 1998 but in 1999, due to the availability of sprinkler irrigation, it was possible to use three planting dates (20 September, 1 October and 10 October). Seeding rates were 1.5, 3.0 and 6.0 kg ha-1 and the nitrogen rates were 0, 60, 120 and 180 kg ha-1. The application of N was split applied, half at two weeks after emergence and half at the time of canola regrowth in mid-February.
Individual plots consisted of six rows, each 20 cm apart, and were 6 m long and 1 m wide. The land for the experimental site was disc-harrowed and weeds were controlled by applying Treflan (Trifluralin) prior to seeding at a rate of 1.2 kg ha-1. Soil samples taken from the experimental site were analyzed for pH, total available nitrogen (N), available phosphorus (P) and available potassium (K). Based on soil tests, the recommended rates of P and K were applied before planting. Canola seeds were planted using a four-row planter. Seed was harvested from the entire plot by use of combine and the yield was determined by weighing the seeds after cleaning and drying the seeds to a moisture content of 8.5%. The seed yield was expressed in kg ha-1. Oil content was determined by using the NMR analysis method (Jenkins and Leitch, 1986).
Canola is a winter crop and is being presented as an alternate or complementary crop with wheat and it fits well in rotation with southeastern summer crops. Therefore, the replicated trial of canola cv. Jetton was planted @ 8lbs of seed per acre at 0.5-.75” deep in 4’ wide and 120’ long strips side by side along with wheat as well as after corn, sorghum, bull rush millet, soybeans and canola.
Similiarly, two demonstrations on canola production were established on limited resource farms. One farmer planted canola by using conventional cultural practices, while the other farmer used no-till practices following soybean.
Since canola is a new crop and very little is known about its insect pests, Therefore, in the 2000 and 2001 growing seasons, with the help of our department’s two entomologists, a cursory survey of Brassicaceae-feeding insects on canola were carried out.
Based on our canola yield data and cost of production practices, the Department of Agricultural Economics at Alabama A&M University was asked to complete a comparative economic study of canola vs. winter wheat for the North Alabama region.

Research results and discussion:

Results from analysis of variance and single degree of freedom contrasts for seed yield, and oil content are reported in Tables 1 and 2. A significant linear and/or quadratic response to applied N was observed for seed yield for both the 1998 and 1999 growing seasons.

Seed Yield

Seed yield was significantly different at all the planting dates, seeding and nitrogen rates in both the growing seasons of 1998 and 1999 (Appendix Figure 1). Seed yield increased quadratically with increasing application of Nitrogen. Similar results have been reported by Yusuf and Bullock (1993). Seeding rate also increased seed yield. These results were observed at all planting dates in both the 1998 and 1999 growing seasons. However, the average seed yield of 2744 kg ha-1 was significantly higher in the1999 growing season, compared with 2146 kg ha-1 in 1998. A higher yield was mainly as a result of the better field stand establishment in 1999 due to use of irrigation before planting in comparison to the rain-dependent planting in 1998. There was also a better distribution of rainfall in the 1999 growing season. The early October planting (1 October) in 1999 produced consistently higher seed yields at all treatments, compared to the other planting dates in both the 1998 and 1999 growing seasons. This result seemed to suggest that the canola crop did well when planted in early October, supporting the findings of Yusuf and Bullock (1993), who concluded that rapeseed should be planted by October 4 for optimum production.
When averaged over growing seasons, the highest average seed yields were consistently produced at the seeding rate of 6.0 kg ha-1. The highest seed yield of 3,779 kg ha-1 was produced in the 1999 growing season at the highest seeding and nitrogen rates of 6.0 and 180 kg ha-1, respectively.
Oil Content
The early October plantings during both the growing seasons resulted in a higher % oil content in the seed. Oil content was only significantly affected by N application on both the planting dates in 1998. Oil content decreased as the nitrogen rate increased (Appendix Table 2). Similar results on oil content due to nitrogen application have been reported by Krogman and Hobbs (1975). They reported that oil content decreased with increasing nitrogen rates. However, this was contrary to the findings of Yusuf and Bullock (1993) who reported that oil content did not decline with increasing nitrogen rates. The canola crop is grown primarily for the oil content and, therefore, the increase in seed yield at the expense of decrease in the total oil is undesirable.

Seed Rates and Seed Yield
The effect of seeding rate in relationship to planting dates on seed yield is shown in Appendix Fig. 1. In both the 1998 and 1999 growing seasons, seed yield increased as the seeding rate increased. The highest seed yields were obtained from the early October plantings (1 and 10 October) in 1998 and 1999, in comparison to September or late October plantings.
Canola is a winter crop, fits well in rotation with southeastern summer crops, and is a complimentary with or an alternative crop to winter wheat. Therefore, a replicated trial of canola crop (cultivar Jetton) was planted alone, in strips along side with wheat, and in rotation after corn, sorghum, bulrush millet, canola and soybeans. Data obtained from these different rotation systems showed that significant differences exist among these cropping systems for establishing plant population (Appendix Fig. 2), blackleg disease (Appendix Fig. 3), height and seed yield (Appendix Fig. 4 & Fig. 5). Emergence was highest in rotation with soybean groups IV (47 plants m-2) and V (34 plants m-2). Blackleg disease infection rating was highest (2.7, on a scale from 1 to 3) when canola followed canola, while this disease was not present when canola was rotated with other crops. Average seed yield of 2,878 kg ha-1, obtained in rotation with group IV soybean, was significantly greater than average yields of 1,474 and 1,360 kg ha-1for rotation with corn and canola itself, respectively. The canola produced an economic yield in North Alabama when planted in rotation with other summer crops.
Seed yield from conventionally planted canola was higher or equal when compared with wheat (Appendix Fig. 6) on the limited resource farm, ranging from 2,018 to 3,429 Kg ha-1 in rotation with soybeans. The no-till planted canola produced an excellent early field stand in the fall, but failed to produce a successful crop due to a residual effect of herbicide used in the previous crop of soybean.

Participation Summary

Educational & Outreach Activities

Participation Summary

Education/outreach description:

• Publications/Out reach
A. Publication:
1. Hopkinson, S., U.R. Bishnoi, and E. Cebert. Sowing Dates Seeding and
Nitrogen Rates Affects Yield and Yield Components of Canola. Crops Res. 24(3): 407-416. 2002.

B. Published Abstracts:
1. Bishnoi, U.R., E. Cebert, Use of Canola as a Sustainable Crop in North Alabama.
American Soc. of Agron/Southern Branch. Jan 30-31, 2000. Lexington, KY. page 9.

2. Hopkinson, S., U.R. Bishnoi, and E. Cebert. Agronomic Performance of Canola under Different Planting Date, Seeding and Nitrogen Rates. American Soc. of Agron/Southern Branch. Jan 27-30, 2001. Fort Worth, TX., page 8.

3. Cebert, E.,. U.R. Bishnoi, R. Ward, K. Ward, S. Hopkinson, and L. Devoux. Damage indices among canola cultivars caused by cabbage seedpod weevil. American Soc. of Agron/Southern Branch. Feb. 3-5, 2002. Orlando, FL. page 25.

4. Cebert, E., R. Ward, and K. Ward,. Survey of major insect species associated with
Canola in North Alabama. Southern Branch, ESA. Mar. 4-6, 2002. Little Rock, AR.

Project Outcomes

Project outcomes:

• Impacts of the Results/Outcomes
This project has provided information on:
1. Establishment of cultural and agronomic production practices of canola
2. Development of sustainable cropping systems for canola in sequences with other crops
3. Comparison of conventional and no-till planting systems in canola production in Alabama
4. The economics and profitability of canola in the southeast United States.

Economic Analysis

Economic Analysis: Information on operating expenses, yield and price of canola in comparison to wheat from the two demonstrations carried out on the limited resource farms were provided to our co-operators in the Department of Agricultural Economics, at Alabama A&M University. Appendix Table 3 represents the gross margin analysis for the two winter crops with local market prices; it includes total gross return, total variable costs, and gross margin. The analysis shows a gross return of $ 125.40 for wheat and $187.25 for canola. The difference in gross return could be attributed to canola’s higher market price. However, profitability was $ 54.99 per acre of canola compared to $ 32.32 from wheat.
The preceding indicate that average production cost (per bushel) for wheat was $2.11 and $2.92 for canola , obtained from by dividing total costs by total output. The average return (price per bushel) profit margin per bushel was $0.74 for wheat and $2.43 for canola. The average profit margin was calculated by subtracting the cost per bushel from the average return per bushel. Therefore, switching land from wheat production to canola resulted in a net gain of $1.69 per bushel to farmers in North Alabama area (Appendix Fig. 7).
The results from insect/pest studies revealed that several species of insects can infest the crop (Appendix Table 4). Based on total number of insects collected, cabbage seedpod weevil was most abundant. Table 5 shows the percentage infestation of clover stem borer among the canola cultivars. The cv. Jetton and Winfield had no infestation of stem borer and are thus considered to be resistant to the pest. However, despite the considerable number of insects and levels of infestations and/or damage, the seed yield of some cultivars was not severely affected, particularly in Acropolis and GA 96038A cultivars.
The findings of this four year project clearly establishes that canola can be adopted as one of the southeast winter cash crops and economically can generate equal or better yields and income than wheat. The crop also can fit in rotation with most summer crops if date of planting and harvesting is monitored and the weather does not fluctuate severely.

Farmer Adoption

• Farmer Adoption
Most limited resource and other area farmers have seen success of the canola crop grown in this area. Through extension agents, farmers can have a full information package on cultural and other production practices to grow this crop. They have seen that canola can outperform wheat in per acre profit and that it can be adopted as an alternative to growing wheat during the winter. However, before adopting it, they specifically wanted to see the availability of canola’s market and/or oil crushing/processing facilities in the southeast United States region or arrangements made for its transport and acceptability in North Dakota and/or Canada.


Areas needing additional study

• Areas Needing Additional study

1. To assist adoption of the crop the regional oil industry or state business bureau need to
promote or establish:
(1) premium price for canola
(2) a regional market, and
(3) oil crushing/processing facilities in the central part of Southeast United States.
2. New dual purpose (forage and oilseed) canola varieties resistant to unusual occurrences
of low temperature during winter in southeast need to be developed.
3. Stand establishment is a constant problem in canola and needs to be solved through
seed vigor, soil operations or by use of seed polymers, etc.
4. Canola leaves have been found to be useful as a green leafy vegetable just like collard greens.
Therefore, selection or development of such a leafy cultivar(s) and evaluation of its use and market need attention and demonstration as another added value to growing canola.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.