Grain elevator in Cadillac, SK. No longer a registered delivery point.  
source: Off the Beaten Path – with Chris & Connie – BIGDoer.com http://www.bigdoer.com/15824/exploring-history/prairie-sentinels-cadillac-saskatchewan/

Raising Cattle, Losing People: Tracking soil nitrogen in Wise Creek, Saskatchewan

Grain elevator in Cadillac, SK. No longer a registered delivery point. source: Off the Beaten Path – with Chris & Connie – BIGDoer.com http://www.bigdoer.com/15824/exploring-history/prairie-sentinels-cadillac-saskatchewan/

Editor’s Note: This is part of a series showing the work of the Sustainable Farm Systems project.SFS logo

Southwestern Saskatchewan is an isolated area where the low population density makes it easy to find agricultural land but the harsh environment makes it difficult to produce consistently high-yielding grain crops. Cattle, on the other hand, have been thriving. In 2001, there were 26.5 times more cattle than people in the Rural Municipality (RM) of Wise Creek, Saskatchewan, a big change from 1916 when the cattle and human populations were almost equal.[1] At the same time that Wise Creek experienced a 446% increase in cattle, its human population declined by 80%, leaving just 257 people and 106 farms. With such a severe drop, the amount of land under cultivation might be expected to decline as well, but instead it increased by 45%.[2] Smaller numbers of farmers were increasing the size of their farming operations as their neighbours disappeared and were replaced by cattle.

Why did a rural municipality focused on cereal crop cultivation in the early 20th century shift so dramatically to cattle production by the end of the end of the century?

Increasing costs of production at the farm level, combined with shifting infrastructure, increasing rail freight rates, and heavier reliance on truck transportation during the latter part of the 20th century is only half the story of Wise Creek. The other, equally important, half lies in the soils of the area.

Rural Municipality of Wise Creek (red point) source: Google Maps

Figure 1: Rural Municipality of Wise Creek (red point). source: Google Maps

The boundaries of Wise Creek enclose an almost perfect square of 843 km2 in southwestern Saskatchewan about 300 kilometers southwest of Regina. Tracing 85 years of agricultural practices between 1916 and 2001, my analysis of soil nutrient balances in Wise Creek is the first Saskatchewan case study for the Sustainable Farm Systems project.

I pay particular attention to soil nitrogen (N) content over time and how changes in the amount and type of crops harvested, the number of head of livestock, and the level of fertilizer inputs relate to the amount of nitrogen added or removed from the soil.[3]

Soil is a critical part of successful agriculture, so analyzing soil fertility is an important way of assessing whether agricultural practices are, or have ever been, sustainable.[4] The three most important soil nutrients in plant growth are nitrogen, potassium, and phosphorus. In agricultural production, part of these nutrients are removed from the soil each time farmers harvest grains or oilseeds from the land. Consequently, farmers replenish nutrients through the application of fertilizers to maintain agricultural productivity. Tracking nitrogen shows whether farming practices are returning an amount of nitrogen equal to that removed through harvest and natural denitrification processes. While potassium and phosphorous are important for plant development, nitrogen is the most critical of this trifecta and the quickest to change in response to crop growth and natural denitrification processes. A change in nitrogen levels has the most immediate effect on crop yields.

Of the three main components needed for cropping, nitrogen is the most complex to calculate since plants obtain it from multiple sources including atmospheric nitrogen; nitrogen-fixing rhizobia bacteria that live in symbiosis with the roots of legumes; animal manure; green manure, such as clovers, peas or lentils; and synthetic fertilizers. Nitrogen can be lost through natural processes such as erosion, but the largest nitrogen loss is from crop biomass harvesting.

Returning nitrogen to the soil using nitrogen-fixing crops is difficult in Wise Creek due to the low average rainfall of roughly 300 mm per year since nitrogen-fixing crops that require more water do not grow well in the area. Secondly, the low precipitation level is not sufficient to support green-manure plough-down agriculture, another nitrogen source that farmers in areas with higher precipitation use extensively, particularly prior to the introduction of synthetic nitrogen fertilizers. Instead, nitrogen-fixing crops in Wise Creek, such as legume hay crops, are harvested so that not all the nitrogen generated is returned to the soil, unlike plough-down crops where the entire biomass and nutrients, including nitrogen, are returned to the soil.

Farmers also return nitrogen to their soils through the application of livestock manure. If farms do not use other outside sources of fertilizer, manure represents a significant addition to the total nitrogen levels. In 1961, 45.5 tons of nitrogen were used in Wise Creek and of this 42.9 tons came from manure generated by 10,942 head of livestock, the majority of which were cattle and poultry. Yet this was not enough nitrogen to fertilize a return to the historical yield levels.

Synthetic fertilizer was a much quicker, easier, and more reliable way for farmers to add nitrogen to agricultural land than traditional methods.

Figure 2: Nitrogen Inputs Vs Nitrogen Outputs (kg/ha)

Figure 2: Nitrogen Inputs Vs Nitrogen Outputs (kg/ha)

Comparing the difference between nitrogen inputs and outputs shows that farmers in Wise Creek were removing more nutrients from the soil than they returned each year, a process known as soil mining. In this graph, nitrogen inputs (blue line) increase over the last half of the 20th century implying that nitrogen stored in the soil was increasingly supplement with external nitrogen.

The initial use of chemical fertilizers in Wise Creek, which increased the cost of production for farmers, coincided with the beginning of a period of high wheat prices that lasted from roughly 1972 to 1980. The sharp rise in nitrogen inputs appeared as farmers began to use synthetic nitrogen. Nitrogen outputs (red line) act as a proxy for yields. Since farmers added more nitrogen, the yields or nitrogen output should have responded positively by showing a continued increase to match the increased nitrogen input. However, the nitrogen output was erratic, indicating seriously depleted soil fertility. Nitrogen output reached a high point in 1981. It is important to note that this high point was still lower than the beginning point of 1916. The 1980s brought a period of increasing interest rates combined with high farm debt and declining wheat prices. At the same time, the nitrogen output plateaued even though nitrogen inputs continued to rise.

Figure 3: Number of head of livestock in Wise Creek, excluding poultry.

Figure 3: Number of head of livestock in Wise Creek, excluding poultry.

Beginning in 1981, more cattle ranching shifted the balance between soil nitrogen sources from legumes to manure, reflecting the changes in cropping practices. This is not to say that agriculture in Wise Creek deliberately shifted away from field crops as a response to declining nitrogen levels, but rather farms in the Wise Creek area, due to changes in pricing and regulatory regimes, as well as infrastructure changes, became more diversified compared to their mid-century counterparts’ focus on wheat. A gradual plateau in outputs compared to the inputs shows that farms were attempting to increase their production through the application of extra nitrogen, but the amount of nitrogen was not sufficient to raise yields to historic levels.

Figure 4: Hectares under crop in Wise Creek.

Figure 4: Hectares under crop in Wise Creek.

Exploring the nitrogen balance for Wise Creek demonstrates that contemporary agriculture relies on outside sources of nitrogen to encourage plant growth. The initial high yields enjoyed by the early farmers were the result of tapping into accumulated soil nitrogen. As agriculture depleted stored nitrogen, grain yields decreased. To counter this problem, farmers responded by adding significant amounts of chemical fertilizer to offset the nitrogen mined from the soil. However, this solution increased the cost of production but not soil fertility as yields failed to return to their initial levels. A cycle of diminishing returns keeping yields relatively stable has required farmers to invest in greater amounts of expensive synthetic fertilizers thereby increasing their costs of production. At the same time, changes to rail and truck transport burdened farmers with increasing transportation costs to move their product to markets. In Wise Creek, farmers have tried to offset these costs through diversifying into greater animal production but this has not been effective in ending the agricultural soil mining of the area. Instead, an increasing application of synthetic nitrogen to fields holds soil nitrogen levels constant – a trend that is not indefinitely sustainable when considering the monetary and environment costs associated with the production and use of synthetic fertilizers. Farmers in Wise Creek and across the Canadian prairies face the challenge of finding sustainable and cost-effective agricultural production methods. The solutions, both short and long term, to these challenges will determine if the prairies will remain one of the “breadbaskets” of the world.

 

References

[1] In 2001, there 6,828 cattle in Wise Creek with a total human population of 257. Statistics Canada, “Table 19 – Cattle and calves, by province, Census Agricultural Region (CAR), Census Division (CD) and Census Consolidated Subdivision (CCS), May 15, 2001,” 2001 Census of Agriculture, (Statistics Canada. Ottawa. 2002).  In 1916 the population was 1,266 with 1,251 cattle on 522 farms. Dominion Bureau of Statistics, “Table IV,” in Census of Prairie Provinces: Population and Agriculture, Manitoba, Saskatchewan, Alberta, 1916, (Ottawa: J. de L. Tache, 1918), 13; Dominion Bureau of Statistics, “Table XXV,” in Census of Prairie Provinces: Population and Agriculture, Manitoba, Saskatchewan, Alberta, 1916, (Ottawa: J. de L. Tache, 1918), 328.

[2] There were 42,779 acres under crops in 1916 compared to 82,813 acres in 2001.

[3] The nitrogen balance is found using the process created by members of the SFS team. R. Garcia-Ruiz, M. González de Molina, G. Guzmán, D. Soto, and J. Infante-Amate, “Guidelines for Constructing Nitrogen, Phosphorus, and Potassium Balances in Historical Agricultural Systems,” Journal of Sustainable Agriculture 36, no. 6 (2012): 650-682, doi: 10.1080/10440046.20111.648309.

[4] Members of the Sustainable Farm Systems group have published extensively on using soil fertility as a measure of sustainability from a historical perspective. For example see E. Tello, R. Garrabou, X. Cussó, J. Ramón Olarieta, and E. Galán, “Fertilizing Methods and Nutrient Balance at the End of Traditional Organic Agriculture in the Mediterranean Bioregion: Catalonia (Spain) in the 1860s,” Human Ecology 40 (2012): 369-383, doi: 10.1007/s10745-012-9485-4.; G. Cunfer and F. Krausmann, “Sustaining Soil Fertility: Agricultural Practice in the Old and New Worlds,” Global Environment 4 (2009): 8-47.

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Laura Larsen

Laura Larsen is a PhD Candidate in the Department of History at the University of Saskatchewan. Her dissertation explores rail rationalization and agricultural policy under the Pierre Trudeau Liberal government.