Productivity of Organic Cropping in the Eastern Prairies:
On-Farm Survey and Database Development

M. H. Entz, R. Guilford and R. Gulden

Department of Plant Science, University of Manitoba, Winnipeg, MB, R3T 2N2

Executive Summary

Organic field crop production is a small, but growing sector of agriculture in Manitoba. The objective of this study was to determine crop and soil productivity, as well as economic performance of organic cropping. Data from 14 organic farms in the eastern Prairie region was used for the analysis. A total of 1078 field records were collected for the time period 1991 to 1996.

Analysis of cropping data showed that approximately 40% of land on organic farms is dedicated to soil-building crops such as alfalfa, pasture and sweetclover green manure. Organic farmers do not rely heavily on tilled fallow as only 6% of land on survey farms was in summerfallow over the 5 year study period. Grain yields for organically produced wheat, barley and oats averaged about 75% those on comparable conventional farms, while yields of pea, canola and flax were 44 to 54% as high as on comparable conventional farms. Weeds were identified as major yield limiting factors, with wild mustard, red root prgweed and Canada thistle being most important. Soil nutrient status was measured on nine of the survey farms. Results indicate that while soil nitrogen levels are sufficient in many cases, levels of soil phosphorous (P) and sulfur (S) are inadequate for optimum crop production in several instances. It was concluded that low P and S levels will not only limit grain yield, but will limit N fixation ability of legume crops as well. These P and S deficiencies need to be corrected.

Economic analysis showed that without a price premium, organic cropping rarely resulted in a positive net return per acre. Durum wheat, soft white wheat and alfalfa hay were the exception. However, when price premiums typically available to organic growers were used in the analysis, net returns ranged from over $100/acre for durum wheat and flax, approximately $50/acre for oats and soft spring wheat, $30/acre for rye, to less than $15/acre for hard red spring wheat and feed barley. Alfalfa hay was also highly profitable. It was concluded that economically sustainable organic cropping is possible so long as price premiums are available. The limiting factor to profitable organic cropping in the long-term appears to be reduced soil nutrient status, especially for P and S, and weeds.

All data collected in this study was incorporated into a database. Cropping and soils information from survey fields will be added to the database each year. As the dataset grows, so will its value as a research tool for agronomists, financial advisors, and others.

Introduction

Growing interest in organic farming is attributed to the increasing demand for organically-grown farm products, farmers= concerns with high input agriculture, and the desire to adopt a different rural lifestyle. There is every reason to believe that demand for organically grown field crops will increase in the future.

There is a lack of information on organic crop management practices for Manitoba. To date, only one major extension publication has been made available to organic farmers in Manitoba. More information is required not only for organic farmers but for other farmers who wish to apply organic farming principles to their conventional farms as well. For example, organic cropping practices may be used to manage herbicide resistant weeds.

Understanding how crops perform on commercial organic farms is extremely useful in identifying yield-limited factors and determining crop variation due to weather and soil conditions, as well as management factors. Information on organic crop and soil productivity is also important for budgeting and financial planning.

The objectives of this project were: 1) to establish a database of organic crop production practices and outcomes (i.e., yield, pest problems, etc.), in order to better understand the performance of organic cropping, and 2) to develop a database management system which could be used to house future organic crop production information.

Methodology

Crop Production on Organic Farms

Field records were compiled from approximately 200 individual organic fields (on 14 different farms) located mostly in Manitoba (some fields from Saskatchewan and North Dakota were also included). By tracking these fields for a six year period (1991 to 1996), a total of 1078 field records were available for analysis. Most of the information from these fields came from the records maintained by OPAM (Organic Producers' Association of Manitoba, Brandon, MB), however each farm was visited in order to fill gaps in the information. The analysis includes yield trends, types of crop rotations used, soil nutrient status, major weed problems, and economic performance.

Soils were collected in the fall of 1996 and spring of 1997 from nine survey farms. Soil samples were subjected to soil nutrient analysis by Norwest labs in Winnipeg using standard procedures. Soil samples have been archived and it will be possible to resample these fields in the future to determine what changes may have occurred over time.

Establishment of a Long-Term Database Management System

Information collected in this study was entered into a database program (Microsoft Access) for current and future analysis. A number of queries have been written into the program so that some analysis procedures are virtually automatic. The current database has been given to the Organic Producers Association. OPAM plans to use the database system developed in this study for use as a long-term record keeping and research tool.

Results and Discussion

Crop Production on Organic Farms

Crop Rotations

A second notable observation was the low proportion of tradition summerfallow in organic systems. The fact that only 6.4% of the 1078 fields were dedicated to fallow during the study period suggests that organic farmers in this region do not view summerfallow as a desirable part of their systems. This is an encouraging observation, as summerfallow, especially where tillage is used, is very damaging to soils. It appears that green fallow (eg. sweetclover green manuring) is a more popular approach.

Oats and wheat were the most popular cereal crops; fall rye accounted for only 4.5% of the fields (Table 1). Flax, while one of the most profitable crops (Table 7), was grown on only 6.1% of survey fields. It appeared that weeds were a major factor limiting producers= desire to grow flax. Organic farmers did not dedicate a significant area to barley production. This may be attributed to the lack of markets for organically grown barley; grain crops for direct human consumption tended to be more popular.

Organic Crop Yields

Cereal crops included in the survey were wheat, barley, oats, rye, and buckwheat. Wheat yield averaged 25.3 bu/acre for hard red spring, 31.0 bu/acre for durum, and 37.8 bu/acre for soft white wheat (Table 2). When hard red spring wheat was undersown with sweet clover, yields averaged 24.4 bu/acre. Only one record for winter wheat was recorded; the yield was 30 bu/acre. Hard red spring wheat yields on these organic farms averaged 72% as high as on area conventional farms (Table 3). Feed barley yields averaged 41 bu/acre. Barley was intercropped with peas in 3 fields; barley yielded 42.6 bu/acre in these cases (range from 40 to 45 bu/acre). Organic barley yields recorded in this survey were 75% as high as barley grown on comparable conventional farms. Among all crops tested here, organically grown barley came closest to conventional yields (Table 3). This was attributed to the fact that barley is highly competitive against weeds. Oat solo crops yielded an average 48.9 bu/acre, while oats undersown to alfalfa and sweet clover averaged 42.7 and 44.1 bu/acre, respectively. Therefore, the legume understory crop appears to have reduced oat grain yield by about 5 bu/acre. Oat-pea intercrops were grown on 7 fields; oat yields in these instances averaged 41 bu/acre. Four oat/wheat intercrop fields were recorded; the average grain yield in this system was 53.7 bu/acre (range 45 to 65 bu/acre). Oat yields on organic farms were 71% those on comparable conventional farms. Fall rye yields on organic farms averaged 32.1 bu/acre. Buckwheat solo crop yields averaged 14.0 bu/acre (32 fields), while buckwheat/clover intercrops yielded 6.3 bu/acre (11 fields). Low buckwheat yields in the intercrops may be attributed to the fact that buckwheat is often grown at the Aend@ of a rotation, and hence soil N status would be expected to be low. The low soil N status would limit buckwheat growth and shift the competitive advantage to the legume understory crop.

Oilseed crops included flax, canola and sunflower. Flax solo crop yields on organic farms averaged 14.8 bu/acre (Table 2). This was 54% as high as on comparable conventional farms (Table 3). When intercropped with legumes (clover, alfalfa grouped together), flax grain yields averaged 12.2 bu/acre. Flax/lentil intercrops (2 fields) produced an average flax yield of 14 bu/acre. Canola was grown on only 8 fields during the study period. The average canola yield was 12.8 bu/acre, which is only 44% as high as on comparable conventional fields. Sunflower was only grown on 3 fields. Sunflower solo crop yields averaged 720 lb/acre, while sunflower intercropped with sweet clover yielded 800 lb/acre.

The main grain legume crop grown on organic farms was field pea. Average yields for this crop were 20.2 bu/acre (feed peas), 19.6 bu/acre (green peas) and 16.3 (yellow peas). The average yield of peas on conventional farms is 34.5 bu/acre (Table 3). The organic pea yield reported here is based on monocrop production. However, since peas are often intercropped with other grain crops, caution must be exercised when intepreting organic pea yields. Yield data for millet, triticale, lentil, fababean is shown in Table 2.

An attempt was made to determine whether rotational yield benefits were derived from legume crops in the rotation. Results indicated that HRS wheat yields after alfalfa and sweet clover were 26 and 29 bu/acre, respectively vs. 21 bu/acre, respectively after both peas and oats. Therefore, we were able to conclude that some yield benefits from perennial or green manure legumes in rotation were observed. This type of analysis can be expanded once more field records are entered into the dataset.

Weeds

Farmers were asked which weed species presented problems in their fields. They reported that the top five weeds in their fields were wild mustard, Canada thistle, red root pigweed, green foxtail and wild oat (Table 4). These results differ somewhat with those from conventional fields. For example, while wild oat is the second most abundant annual weed in Manitoba conventional fields (Thomas et al. 1997; Ominski et al. 1998), organic farmers considered two broadleaf weeds, namely wild mustard and red root pigweed, more important than wild oat. Fewer wild oat problems on these organic farms may be related to the high proportion of forage hay crops in the rotation. Two recent Manitoba studies showed that wild oat populations in grain crops were reduced by including alfalfa hay (Ominski et al. 1998) or annual forage crops (Schoofs, 1997) in the rotation. It is interesting to note that wild mustard, which was the number one weed in this study, was one of the most important weeds affecting annual crop production prior to use of 2,4-D.

Canada thistle was the second most important weed species observed by organic farmers in this survey (Table 4). This perennial weed is also very abundant in conventional fields in Manitoba (Thomas et al. 1997). Hay crops are known to reduce Canada thistle populations (Ominski et al. 1998).

Soil Quality

Soil quality was assessed by analysing soil from a number of fields on nine survey farms. Results are shown in Table 5. Levels of nitrate-nitrogen ranged from a low of 34 lb/acre to a high of 246 lb/acre. There were some trends relating level of soil nitrate in fall to the crop or land use type. For example, on farms 6 and 8, the highest nitrate-N levels were observed on fields that were fallowed the previous summer (Table 5). The fallow period presumably resulted in the release of organic soil N (Campbell et al. 1994). No clear trends were observed between legumes and soil N status, however this was not surprising as soil nitrate-N levels typically do not increase in legume systems until after the legume crops are killed.

Although grain protein levels were not monitored in this study, many producers commented that low protein levels in wheat is a major concern on their farms. This reflects a lack of available soil nitrogen.

Soil phosphorous levels ranged from extremely low to adequate. The lowest levels were observed on farms 3 and 8. Farm 3 has been farmed organically for approximately 6 decades, while farm 7 and 8 have been farmed organically for several decades. It is well documented that long term cropping, especially with legumes in the absence of P fertilizers, will result in serious depletion of available soil phosphorous (Campbell et al. 1990). The only farm which recorded adequate levels of soil P on all fields was farm 1 (Table 5). One possible reason is the regular soil applications of manure used on this farm. However, regular applications of cattle manure were also used on farm 3, and this did not coincide with high P levels on that farm. Another possible reason for high P levels on farm 1 may be high soil P status prior to conversion to an organic system. All other farms had mild (soil P between 20 to 40 lb/acre) to serious (less than 20 lb/acre P) phosphorous deficiencies. Results for soil P indicate that yields on many of these organic fields will be seriously limited by soil P shortages.

The soil phosphorous depletion which has apparently occurred in a number of organic fields in this survey, is not surprising. In a long-term crop rotation study at Indian Head, SK, researchers have observed serious soil P depletion after 30 years in those rotations which included either 33% or 40% legumes, but did not involve any P fertilizer additions (Campbell et al., 1990). These systems are now seriously limited by P soil status. It is important to note that the Indian Head plots are on a heavy clay soil, with high indigenous soil P levels. Soil P depletion would be expected to be more rapid and more acute on lighter textured soils. Results from South Australia show that long-term organic cropping resulted in low grain P status in wheat crops (Schwartz, pers. comm.).

Soil potassium levels ranged from adequate to low. The lowest levels of soil potassium where observed for farms 1 (Table 5). These low levels were attributed to the sandy nature of the soil. The very high levels of soil K on farms 5, 7 and 8 were attributed to the high soil clay content on these farms.

Soil sulfur levels ranged from adequate on some farms, to moderate to low on farms 7, 8 and 9, and very low on farm 3. The low S levels for farm 3 fields may be attributed to a number if factors: 1) grey-wooded soils know to be low in soil S, 2) long-term organic cropping (6 decades), and 3) high frequency of legume hay crops in the rotation; legume hay crops remove 2 to 4 times more S from soil than grain crops. Although manure was added to these fields, this appeared to be inadequate for replenishment of soil S.

In conclusion, results of soil nutrient analysis indicate that while levels of soil N are adequate on most farms, levels of available soil P, and in some cases S, were found to be quite low. These low P and S levels will limit yield of both grain and forage crops. In fact, because forage legumes rely heavily on both P and S, it can be concluded that forage legume yields will be low in some organic fields in the survey. This represents a serious problem as these legumes are critical for supplying N to the cropping system. The nutrient deficiencies observed here will have to be corrected for cropping on these farms to be sustainable in the long term.

Economic Performance

Gross revenues, costs and net returns were calculated using the long-term organic crop yields from the survey, input costs from Manitoba Agriculture cost of production factsheets (1996), and returns from conventional and organic markets. The commodity prices for conventional markets were taken from Manitoba Agriculture and the Canadian Wheat Board, while commodity prices from OPIS (a organic marketing cooperative, Saskatoon, SK) were used for the organic products (Table 6). 1996 prices were used in all analysis. The machinery costs for the analysis were based on equipment for a 1000 acre farm size, and costs were also derived from Manitoba Agriculture cost of production factsheets.

As expected, net returns were higher when the higher OPIS commodity prices were used in the analysis (Table 7). Over all grain crops, the average return was $-22.37/acre when conventional prices were used compared with $47.19/acre when OPIS prices were used. This observation clearly identifies the need for price premiums in organic crop production. The only organically-grown crops which were profitable at conventional commodity prices were durum wheat, soft white spring wheat and alfalfa hay. When the OPIS price premiums were used in the analysis, net returns ranged from $5.38 to $171.67/acre. The more profitable crops were durum wheat, and flax (both >$100/acre), followed by oats and soft white spring wheat (both >$50/acre), followed by buckwheat>fall rye>peas>hard red spring wheat and barley (Table 7). No OPIS price for alfalfa was available, however some organic producers in Manitoba have sold organic hay for $175; about twice the rate received from the conventional market.

Based on these findings, the most profitable organic rotation includes a combination of durum wheat, flax, buckwheat and fall rye, plus alfalfa hay crops. Fortunately, this rotation is an agronomically sound one. For example, this mix of crops allows for combinations of annual grass and broadleaf crops, as well as alfalfa hay crop phases to be included in the same crop rotation. Therefore, based on this economic analysis, it can be concluded that economically sustainable organic cropping is possible provided that price premiums are can be captured by the farmer.

Construction of an Organic Farm Database

All data from the survey farms was entered into a database (Microsoft Access). This database has been made available to the Organic Producers Association of Manitoba. We have offered to work with the OPAM office staff to help them adapt this database system for all of their field record keeping requirements. In future, we (and others) will simply be able to access the OPAM records (with farmers= permission) to conduct research on organic crop production systems. A copy of the database is included with this report (in Microsoft Access).

Conclusions

1. A high proportion of land on organic farms is dedicated to soil-building crops such as alfalfa, pasture and sweetclover green manure. Only 6% of land was dedicated to summerfallow indicating that organic farmers do not rely heavily on this practice.

2. Crop yields on organic farms are about 70% (barley, wheat, oats) to 50% (flax, pea and canola) those on comparable area conventional farms.

3. Weeds are a major constraint to crop yields on organic farms. Wild mustard, red root pigweed and Canada thistle were viewed as the most problematic weed species. Wild oat was also ranked as an important weed, but was not ranked as the number one weed, which is the case on conventional farms.

4. Soil nutrient status showed that soil P levels are dangerously low on several study farms. Low levels for S were also recorded. These low P and S levels will limit system productivity, and could reduce potential N fixation by legumes. Alternative P sources are urgently required on several of the study farms.

5. For most crops, price premiums were required to ensure positive net returns. The most profitable organic crops were found to be durum wheat, flax, buckwheat, fall rye and alfalfa hay. This combination of crops can be organized into an excellent crop rotation.

6. The success of organic cropping is limited by i) the ability to capture price premiums, ii) the ability of farmers to maintain and improve their soil nutrient status, and iii) the ability to manage weeds.

Recommendations

1. Long-term soil fertility is a major concern on organic farms, especially where organic cropping has been practised for several decades. In order to sustain productivity on these farms, additions of P and S are required. In some cases the need is very urgent. Therefore, we recommend that alternative sources of P and S be identified and used on organic farms in Manitoba. Some alternative nutrient sources are manure, municipal waste or rock phosphate.

2. Price premiums were found to be critical to the economic sustainability of organic cropping in this study. Therefore, concerted efforts are required to ensure that these price premiums are available to farmers on a consistent basis. Efforts could involve market development and/or establishment of marketing agencies with established organic markets; these agencies could pass the price premiums on to farmers.

3. Weeds are a major limiting factor in organic cropping. For example, the role of high value crops (like flax) in organic rotations is currently being limited by weeds. It is recommended that more research be conducted on non-herbicidal weed control.

4. Yields of special crops such as flax, canola and peas are relatively lower than yields for cereal grains. Because yields of oilseed and pulse crops are seriously limited by weed competition, strategies are needed which allow these crops to be grown under the weedier conditions on organic farms. It is recommended that more research be conducted on intercropping pulse and oilseed crops with other grains in an effort to raise productivity of these special crops on organic farms.

5. While soil N levels were not shown to be as deficient as P and S, N shortages were also observed in the survey. Low soil N status results in low bushel weights in many crops, and low grain protein in wheat. Both of these factors can seriously limit the marketability of organic crops. It is recommended that more effort by placed on making N available to cereal crops. This not only involves increasing legume productivity (and hence N fixation), but other approaches such as strategic use of legume grazing at the end of a legume phase (it increases availability of N) as well.

Acknowledgements

We gratefully acknowledge cooperation from the participating farmers. Funding for this project was provided by the Canada-Manitoba Farm Business Management Program.

References

Campbell, C.A., H.H. Janzen, and K.E. Bowren. 1990. Crop rotation studies on the Canadian prairies. Agriculture and AgriFood Canada Special Publication. Gov=t Printing, Ottawa, ON.

Campbell, C.A., G.P. Lafond, R.P. Zentner, and Y.W. Jame. 1994. Nitrate leaching in a Udic Haploboroll as influenced by fertilization and legumes. J. Environ. Qual. 23:195-201.

Ominski, P.D., M.H. Entz, and N. Kenkel. 1998. The influence of alfalfa (Medicago sativa) on weeds in subsequent cereal crops: A comparative study. Weed Science (submitted).

Schoofs, A. 1997. The role of annual forages in integrated weed management. MSc thesis. Department of Plant Science, University of Manitoba, Winnipeg. R3T 2N2.

Thomas, A.G., D. Kelner, R.F. Wise, and B.L. Frick. 1997. Manitoba Weed Survey (Publication 97-1), Comparing Zero and Conventional Tillage Crop Production Systems. 1994. Manitoba Agriculture Soils and Crops Branch, Carman, MB.

Table 1. Proportion of land base on survey farms planted to certain crops. Averaged over the study period (1991 - 1996).

Table 2. Yield statistics for organic crops on survey farms: 1991 - 1996.

¹ Yield for forage crops in ton/acre. Estimated by producers based on number of bales harvested/acre.

Table 3. Average yield for organically and conventionally grown field crops.

Conventional yield source was Manitoba Crop Insurance Corp. data for southwestern Manitoba.

Table 4. Weed observations in organic crops. Values in table represent the number of problem fields for a specific weed species.

Table 5. Soil nutrient status on survey farms in Manitoba, Saskatchewan and North Dakota.

Table 6. Prices received for various organic and conventionally grown crops. Sources include OPIS, MDA, and the CWB.

* Price $/tonne

Table 7. Gross revenue, costs, and net revenues for various crops determined from the OPAM database. The revenues (gross and net) were also determined using prices of conventionally grown crops for comparison.