Toward net-zero farming systems using diversity, integration, and perenniality in the Black Soil Zone of the Canadian prairies: A co-design approach

Summerfallow is cropland that is purposely kept out of production during a growing season to conserve soil moisture. On the Canadian Prairies, a trend to continuous cropping with a reduction in summerfallow began after the summerfallow area peaked in 1976. This study examined the impact of this land-use change on convective available potential energy (CAPE), a necessary but not sufficient condition for moist deep convection. All else being equal, an increase in CAPE increases the probability-of-occurrence of convective clouds and their intensity if they occur. Representative Bowen ratios for the Black, Dark Brown, and Brown soil zones were determined for 1976: the maximum summerfallow year, 2001: our baseline year, and 20xx: a hypothetical year with the maximum-possible annual crop area. Average mid-growing-season Bowen ratios and noon solar radiation were used to estimate the reduction in the lifted index (LI) from land-use weighted evapotranspiration in each study year. LI is an index of CAPE, and a reduction in LI indicates an increase in CAPE. The largest reductions in LI were found for the Black soil zone. They were −1.61 ± 0.18, −1.77 ± 0.14 and −1.89 ± 0.16 in 1976, 2001 and 20xx, respectively. These results suggest that, all else being equal, the probability-of-occurrence of moist deep convection in the Black soil zone was lower in 1976 than in the base year 2001, and it will be higher in 20xx when the annual crop area reaches a maximum. The trend to continuous cropping had less impact in the drier Dark Brown and Brown soil zones.

Statistics on annual crop production for the Canadian prairies, Canada’s largest agricultural region, were summarized by crop, soil zone, and province for the period 1976-1998. A brief discussion, demonstrating how these data can be used by agronomists and policy analysts to derive other information of interest to society (e.g., how much raw material is available for ethanol or strawboard production, or for C storage in soils), was presented. The results show that land seeded to cereals has remained fairly constant, but there has been a sharp decrease in the summerfallow area, with the rate of decrease on the Canadian prairies being 1.26% yr-1 in the Brown soil zone, 7.5% yr-1 in the Dark Brown, and 14.3% yr-1 in the combined Black, Gray and Dark Gray soil zones. The rate of decline in summerfallow area was greater in Saskatchewan than in Alberta, and Manitoba (Black soils only) for unknown reasons. The decline in summerfallow area was accompanied by a steady increase in oilseed crops, especially canola (Brassica napus L.) and, since 1987, in pulse crops, especially lentil (Lens culinaris Medikus) and dry pea (Pisum satiuum L.). Key Words: Seeded area, summerfallow, oilseeds, pulses, cereals

The usefulness of the average slope measurements available from soil surveys in the development of regional erosional inventories depends on the relationship between the average slope measurements of the mapped area and the mean rates of soil redistribution within the areas. Using 137Cs redistribution techniques we examined the relationship between mean rates of soil redistribution and average slope characteristics at 21 areas in the Brown, Dark Brown, and Black Chernozem soil zones of southern Saskatchewan. Net soil losses averaged 5.8 t ha−1 yr−1 for areas with mean gradients between 0 and 1.5°, 7.8 t ha−1 yr−1 for areas with mean gradients between 1.0 and 3°, and 11.3 t ha−1 yr−1 for areas with mean gradients between 3.5 and 8.5°. For all three slope classes, the highest rates of soil loss were found in the Dark Brown soil zone and the lowest rates in the Black soil zone. Net soil loss alone was, however, an inadequate indicator of the rate of loss within the areas because a considerable proportion of eroded soil was deposited within the confines of the study areas. Our results indicate that a distinct rate of soil loss was associated with the average slope characteriestics of the study area, but that both net soil loss from the field and mean soil loss within the field need to be considered together if a complete erosional assessment is to be made of an area. Key words: Soil erosion, soil deposition, 137Cs redistribution, slope gradient, Saskatchewan

Crop production in Europe is intensive, highly specialized and responsible for some negative environmental impacts, raising questions about the sustainability of agricultural systems. The (re)integration of grain legumes into European agricultural systems could contribute to the transition to more sustainable food production. While the general benefits from legume cultivation are widely known, there is little evidence on how to re-design specific cropping systems with legumes to make this option more attractive to farmers. The objectives of this study were to describe the constraints and opportunities of grain legume production perceived by farmers, explain the agronomic impacts of current grain legume cropping, explore technical options to improve grain legume agronomy, and to re-design current grain legume cropping systems in a participatory process with farmers. A co-design approach was implemented with farmers, advisors and scientists on 25 farms in northern Germany, that were part of two large demonstration networks of about 170 farms supporting grain legumes across Germany. We used the DEED research cycle (Describe, Explain, Explore and Design) as a conceptual framework combining on-farm research, crop rotation modelling, and on-station experiments. From it, we identified nine agronomic practices that either were novel or confirmed known strategies under new conditions, to re-design grain legume cropping systems at the field and farm level. The practices included (i) inter-row hoeing, (ii) direct seeding into a cover-crop, (iii) species-specific inoculation, (iv) cover crops to reduce leaching, (v) reduced tillage, (vi) soybean for increased gross margins, (vii) cultivars for food and feed use, (viii) flexible irrigation, (ix) grain legumes with cover crop to enhance subsequent crop yields. We also demonstrate how to complement knowledge of farmers’ perceptions (Describe step) and formal knowledge from classical on-station experiments and modelling (Explain step) with on-farm research including the local views of farmers (Explore step) to identify tailored options for specific farm contexts rather than prescriptive solutions (Design step) to intensify legume production. This approach therefore contrasts with traditional methods that are often solely participatory and qualitative or model/experimental-based and quantitative. Hence, our results provide new insights in how to re-design cropping systems using a combination of participatory and quantitative approaches. While participatory approaches are common in developing countries, this study shows their potential in an industrialized context with large-scale farmers in Europe. These novel findings can be used as a starting point for further adaptations of cropping systems and contribute to making grain legume production economically and environmentally more sustainable.

The Framework for Evaluation of Sustainable Land Management (FESLM) was used to assess the sustainablility of two land-use systems in the Canadian Prairies. The FESLM provided a means of identifying the factors impacting on sustainability, the processes by which these factors operate and interact, and the indicators and thresholds by which they could be measured to attain an assessment end point. On the basis of the framework, it was possible to expand sustainability assessment beyond traditional factors of productivity and economic viability to include ones pertaining to production risk, protection of the natural resource base, and social acceptability. In conducting the FESLM-based analysis, the decision-making characteristics of the producer were identified as important components of sustainability. Preliminary indications are that substantially greater amounts of farm-specific and regional data are required to make a conclusive FESLM-based sustainability assessment. Nevertheless, application of the framework suggests that, for the farming systems and the type of producer under consideration, the conservation-based land-use system is more sustainable than the conventional land-use system. Key words: Sustainable land management, Black Chernozemic soil zone, livestock farming

Farmer-centred design: An affordances-based framework for identifying processes that facilitate farmers as co-designers in addressing complex agricultural challenges

Soil carbon content drives the biogeographical distribution of fungal communities in the black soil zone of northeast China

Annual crop production in the Canadian prairies is undergoing significant change. Traditional monoculture cereal cropping systems, which rely on frequent summer-fallowing and use of mechanical tillage, are being replaced by extended and diversified crop rotations together with the use of conservation tillage (minimum and zero-tillage) practices. This paper reviews the findings of western Canadian empirical studies that have examined the economic forces behind these land use and soil tillage changes. The evidence suggests that including oilseed and pulse crops in the rotation with cereal grains contributes to higher and more stable net farm income in most soil–climatic regions, despite a requirement for increased expenditures on purchased inputs. In the very dry Brown soil zone and drier regions of the Dark Brown soil zone where the production risk with stubble cropping is high, the elimination of summer fallow from the cropping system may not be economically feasible under present and near-future economic conditions. The use of conservation tillage practices in the management of mixed cropping systems is highly profitable in the more moist Black and Gray soil zones (compared with conventional mechanical tillage methods) because of significant yield advantages and substantial resource savings that can be obtained by substituting herbicides for the large amount of tillage that is normally used. However, in the Brown soil zone and parts of the Dark Brown soil zone, the short-term economic benefits of using conservation tillage practices are more marginal and often less profitable than comparable conventional tillage practices.

Changes in cropping patterns in the Canadian Prairies are examined from the early 1960s to the mid‐1990s using census data. Patterns of change within the region are mapped by census division using averaged proportions of land in crops occupied by the main crops for three pairs of census years. Spring wheat and oat have undergone the most significant relative declines. Canola increased dramatically from being the sixth‐ranked crop by area in the early 1960s to the third‐ranked crop by area by the 1990s. The main change in the Brown soil zone has been a large decline in spring wheat and a compensatory gain in durum wheat. Increases in special crops, especially pulse crops, canola and durum wheat have offset a substantial decline in spring wheat in the Dark Brown soil zone. Barley, tame hay and especially canola have increased at the expense of spring wheat, oat and flaxseed in the Black and Gray soil zones. Prices, transportation costs, changing export markets, crop breeding and local processing all have contributed to these changes.

Annual crop production in the Canadian prairies is undergoing significant change. Traditional monoculture cereal cropping systems, which rely on frequent summer‐fallowing and use of mechanical tillage, are being replaced by extended and diversified crop rotations together with the use of conservation tillage (minimum and zero‐tillage) practices. This paper reviews the findings of western Canadian empirical studies that have examined the economic forces behind these land use and soil tillage changes. The evidence suggests that including oilseed and pulse crops in the rotation with cereal grains contributes to higher and more stable net farm income in most soil–climatic regions, despite a requirement for increased expenditures on purchased inputs. In the very dry Brown soil zone and drier regions of the Dark Brown soil zone where the production risk with stubble cropping is high, the elimination of summer fallow from the cropping system may not be economically feasible under present and near‐future economic conditions. The use of conservation tillage practices in the management of mixed cropping systems is highly profitable in the more moist Black and Gray soil zones (compared with conventional mechanical tillage methods) because of significant yield advantages and substantial resource savings that can be obtained by substituting herbicides for the large amount of tillage that is normally used. However, in the Brown soil zone and parts of the Dark Brown soil zone, the short‐term economic benefits of using conservation tillage practices are more marginal and often less profitable than comparable conventional tillage practices.

High throughput sequencing analysis of biogeographical distribution of bacterial communities in the black soils of northeast China

Bacillus-like species are gram-positive bacteria that are ubiquitous in soils. Many of Bacillus-like bacteria are demonstrated as beneficial microbes widely used in industry and agriculture. However, the knowledge related to their diversity and distribution patterns in soils is still rudimentary. In this study, we developed a combined research method of using culture-dependent and high-throughput sequencing to investigate the composition and diversity of cultivable Bacillus-like bacterial communities across 26 soil samples obtained from the black soil zone in northeast China. Nearly all bacterial 16S rDNA sequences were classified into the order Bacillales. Fifteen genera were detected, with Bacillus, Paenibacillus, and Brevibacillus being the three most abundant genera. Although more than 2,000 OTUs were obtained across all samples, 33 OTUs were confirmed as the abundant species with a relative abundance over 5% in at least one sample. Pairwise analysis showed that the diversity of Bacillus-like bacterial communities were significantly and positively correlated with soil total carbon contents and soil sampling latitudes, which suggests that a latitudinal gradient diversity of Bacillus-like bacterial communities exists in the black soil zone. The principal coordinates analysis revealed that the Bacillus-like bacterial communities were remarkably affected by soil sampling latitudes and soil total carbon content. In general, this study demonstrated that a distinct biogeographic distribution pattern of cultivable Bacillus-like bacterial communities existed in the black soil zone, which emphasizes that the strategy of local isolation and application of beneficial Bacillus-like strains is rather important in black soil agriculture development.

Zou, W., Si, B., Han, X. and Jiang, H. 2012. The effect of long-term fertilization on soil water storage and water deficit in the Black Soil Zone in northeast China. Can. J. Soil Sci. 92: 439-448. The Black Soil Zone in northeast China is one of the most important areas of agricultural production in China and plays a crucial role in food supply. However, further improvement in crop yield hinges on effective management of soil water. There is a poor understanding of how different fertilization methods affect crop water use efficiency. The objective of this study was to examine the effect of different fertilization methods on soil water storage and deficit in Black soils. A long-term experiment was conducted at the National Field Research Station of Agro-ecosystems, at Hailun County, Heilongjiang province in northeastern China from 1999 to 2008. Three fertilizer treatments including no fertilizer (CK), inorganic fertilizer (NP) and inorganic fertilizer plus organic material (NPM) were tested. The results sh...

This study aims to capture the spatial and time influence of climate change on crop production efficiency (CPE) using the SE-SBM model combined with DEA window analysis. The model is validated with the data from 1976 to 2016 in Saskatchewan, one of the three Canadian prairie provinces. By categorising Saskatchewan into three regions: black soil zone, dark brown soil zone, and brown soil zone, differences are analysed between CPE without considering climate change and CPE under climate change. We find that CPE under climate change is significantly larger than CPE without consideration of climate change, and the positive influence of temperature fluctuations during the growth period on CPE is more important than that of humidity fluctuations, and the beneficial impact of average humidity on CPE is significantly greater than that of average temperature.

There is a need to develop verifiable algorithms that can be easily applied to estimate carbon sequestration in soils. A simple process-based empirical model, driven primarily by soil texture and crop residue input, was developed to account for changes in soil organic carbon (SOC) in Chernozemic soils on the Canadian prairies. The model was used to estimate SOC change under no-till and continuous cropping compared with conventional tillage and rotations with fallow. Using this model, C sequestration due to continuous cropping compared with fallow-containing rotations was determined to be 0.09 Mg C ha-1yr-1 for the Brown and Dark Brown, and 0.05 Mg C ha-1 yr-1 for the Black and Dark Gray/Gray soil zones. The rate of C sequestration as a result of continuous cropping was positively related to the frequency of fallow, which decreases on the prairies from the Brown, Dark Brown, and Black to the Dark Gray/Gray soil zones. Using this model average C sequestration when conventional tillage was converted to no-till, was 0.13, 0.23, 0.34, and 0.25 Mg C ha-1 yr-1 for the same soil zones, respectively. Combined gains due to no-till and continuous cropping in comparison with conventional tillage and fallow-containing rotations were determined to be 0.22, 0.32, 0.39, and 0.30 Mg C ha-1 yr-1 for the Brown, Dark Brown, Black and Dark Gray/Gray soil zones, respectively. Based on Agricultural Census of Canada data in 1996 and 2001, the amount of “C sequestered” due to the adoption of no-till was estimated to be 1.23 million Mg of C in 1996 and 1.72 million Mg of C in 2001, which is approximately 10% of the total greenhouse gas emissions from the agricultural sector in Canada. This simple process-based empirical model could serve as a useful tool for soil scientists to use in assessing soil sustainability and C sequestration in the Canadian prairies. It would also assist policy makers in understanding how various scenarios of improved management will influence future greenhouse gas emissions on agricultural soils. Key words: Soil organic carbon, no-till, fallow, crop rotation