Conference Agenda

In Canadian prairie cropping systems, most farmers apply urea during the fall before freezing. This practice is inspired by lower fertilizer prices in the fall and the need to minimize tillage and other farm operational tasks in the spring. Farmers are advised to apply fertilizers at a temperature of 5°C or lower to reduce nitrogen (N) losses. However, N losses such as nitrous oxide (N2O) emissions occur during thawing even when fertilizers are treated with inhibitors. This is due to the coupled effects of soil moisture and temperature in driving these emissions. However, there is a lack of information on the extent of these effects in Manitoba. The objective of this study was to evaluate the effects of soil freezing and varying thawing temperatures on N2O emissions from urea treated with double inhibitors (SuperU) under varying moisture contents. Treatment effects were tested using a sandy loam soil collected from Carman, Manitoba. The soil was homogenized and packed into Nalgene containers at a bulk density of 1.2 g/cm-3, followed by band-application of SuperU. The units were watered with deionized water to attain moisture levels of 25%, 50%, and 100% saturation. The soils were then frozen at -20 °C, followed by thawing at 4, 8, 12, and 16°C. Gas samples were taken at 0, 1, 3, 6, 10, 20, 30, 40, 50, and 60 h using the static chamber technique. Results on the effects of temperature and moisture levels on N2O emission will be reported. Findings will help design nutrient management practices.

Soybean is the third most important crop in Manitoba based on seeded area and farm income. However, drought and excess moisture affects potential crop yield. Tile drainage is becoming popular as a method to remove excess moisture. To overcome drought conditions, subirrigation through tile drains was investigated as a viable alternative to overhead irrigation. This study investigated the effects of subirrigation through the drainage systems on soybean (Glycine max (L.) Merr.) grain yield and yield components, actual crop evapotranspiration, yield response factor (Ky), and harvest index (HI). Field experiments were conducted in 2023 at Prairies East Sustainable Agriculture Initiative (PESAI), Arborg, Manitoba, Canada. Two subsurface irrigation treatments (on tile and midway between tiles) and rainfed conditions were evaluated with soybean seeded at 444,789 plants per ha (180,000 plants/ac) in three replicated plots. Soybean yield, nodule counts, above and below ground biomass, height, number of pods, number grains, and grain weight were significantly higher (p < 0.05) in the subirrigated through tile drainage treatment compared to the rainfed control treatment. Grain yield on the tile treatment was significantly higher at 2820.9 kg ha-1 compared to 2216.9 kg ka-1 in the rainfed treatment. Nodule counts ranged from 67 for the rainfed to 614 for on tile treatment. Seasonal ETa was 189.6 mm for the rainfed compared to 299.7 mm in the midway between tiles. The average irrigation water requirement was 182.8 mm. This study showed that subirrigation through tile drains is important for better soybean yield in an area subjected to drought.

The study of watershed management has become essential in an era of increasing environmental challenges and developed agricultural activity. Increasing attention is being given to the complex relationships that exist between the water quality of freshwater and agricultural activities. The role of non-point source (NPS) pollution is crucial to understand since it is an important issue for preserving the environmental quality of water bodies. The relationship between agricultural practices and the quality of water is being examined more closely, considering NPS pollution. The spatio-temporal patterns of precipitation events that significantly contribute to sediment and phosphorus loads are the focus of the comparative study. The frequency as well as the magnitude of threshold events, both annually and seasonally, are examined for different watersheds in Southern Ontario (Canada). The primary emphasis of this study is on threshold precipitation events, which create significant hydrological responses, including higher levels of sediment and phosphorus loads and surface runoff. These events are critical to understand the NPS pollution and their correlation with land use changes. By focusing on threshold events, the study elucidates the direct relationship between precipitation events and the subsequent hydrological processes, such as surface runoff, sediments, and phosphorus loads. This work contributes to our understanding of the diverse patterns exhibited by watersheds in response to NPS pollution during these threshold events. The ultimate objective of this research is to contribute towards the assessment of effective of Best Management Practices.

Subsurface drainage is a water management strategy that uses tile drains to remove excess water from poorly drained soils and maintain soil conditions near field capacity following heavy rainfall. Due to spring snowmelt, Manitoba experiences excess soil water during the early growing season. High-intensity storm events during the growing season also led to fluctuating water table depths. This research aimed to evaluate soybean yield under different water table depths under subsurface drainage and no drainage conditions in heavy clay soil in the Interlake region of Manitoba. Tile drains were installed at a depth of 0.9 to 1.1 m at 4.5, 9, 13.7 m (14, 30, 45 ft) spacing. The soybean yield was obtained over the tile, midway between tiles, and in no tile plots. Water table depths were continuously monitored. During the dry years of 2020 and 2021, the yield was lower in all the plots. During the wet year of 2022, the over the tile yield was significantly higher than the control because the watertable was maintained lower during vegetative stage.

Soil quality plays a crucial role in sustainable agricultural practices and the mitigation of climate change. A major indicator of soil quality and fertility is soil organic matter (SOM) which is derived from decomposed organic material. High levels of SOM have been shown to resist erosion, preventing nutrient loss and retain water. However, conventional practices like soil tilling degrade arable lands by disrupting soil structure and depleting organic matter. Current research on agricultural applications of nanoparticles (NPs) is gaining attention from farmers and agrochemical industries, providing successful alternatives to chemical-based fertilizers. NPs improve nutrient release timing, duration, and rate, enhancing plant absorption. Their use reduces soluble salt volumes in fields, leading to increased crop growth, biomass, and nutritional content. The work presented here has focused on the development and application of iron oxide nanoparticles (IONPs) as soil amendments with the intention of enhancing soil organic matter and retaining nutrients. The interaction of IONPs with various nutrients (phosphate and nitrate) along with organic matter was assessed using breakthrough experiments and soil columns under various conditions including NP condemnation, water flow rate, and mixing style. Additionally, the impact of NPs on the microbial community will be discussed.

Globally, climate change poses substantial challenges to agricultural sustainability. The Upper Humber River Watershed (UHRW), a vital agricultural producing region in western Newfoundland, similarly faces significant challenges due to climate change. This study investigates the potential impacts of climate change on agricultural sustainability in UHRW using the SWAT model and downscaled CMIP5 climate data from General Circulation models. Based on emission scenarios RCP8.5 and RCP4.5, by the 2080s, the annual average temperature is projected to increase by 4.8°C and 2.6°C, respectively and the annual average precipitation to increase by 146 mm and 65 mm, respectively. Spring temperature and winter precipitation show the most significant increases with 0.04°C/10a (0.03°C/10a) and with 0.59 mm /10a (0.35 mm /10a) under scenario RCP8.5 (RCP4.5). Simulations indicated an increase in mean values of flow across RCP scenarios by the 2030s, 2050s, and 2080s, where mean streamflow projections increased from the baseline by 11.1% (RCP8.5) and 3.7% (RCP4.5) by the 2080s. Due to this, it is expected that the monthly average total nitrogen and phosphorous loads will increase from May to November and decrease from December to April by the 2080s. Additionally, anticipated climate fluctuations are likely to result in substantial alterations to crop yields within UHRW, with resultant outcomes influenced by the inherent uncertainties associated with predictive modeling. Increased winter precipitation and temperature will lead to earlier melting of spring snowpack and increasing trends in non-point source pollution. Consequently, the paper emphasizes the imperative of implementing adaptation measures to ensure agricultural sustainability in the watershed.

As the competing demand for water increases, effective water management is necessary to optimize water use in agricultural fields. Knowledge of soil water content and crop water uptake pattern with different drain spacing will help farmers optimize water use and maintain a stable ground water table to maximize production by protecting the crops from water stress. On the other hand, the challenge posed by poor drainage in heavy clay soils affect crop performance. This research aims to analyze soil moisture patterns within the wheat root zone at different growth stages using multi-layer remote sensing, comparing different drain spacings (13.7 m (45ft) and 9.1 m (30ft) and control). METER soil moisture sensors were installed at depths of 20, 60, and 90 cm to measure soil moisture and soil temperature. Continuous measurement of water table elevations was carried out using Solinst dataloggers. The field data will be simulated using DRAINMOD. Weather parameters were collected throughout the season. The data collected will be used in the simulation model, predicting the impact of drain tile spacing and soil moisture on wheat crop performance, estimating maximum yield, and comparing it with actual yields. This research has the potential to optimize water management and contribute valuable insights into global agricultural sustainability.

Amending soils with hydrogels is known to improve soil fertility. Use of acrylamide-based synthetic hydrogels (SH) in soil could be problematic due to concerns about their toxicity and slower biodegradability. Therefore, the development of natural hydrogels as soil amendments is gaining popularity as a greener alternative. A two-year field study using pots, filled with sandy soil, was conducted to compare the effects of SH and wastepaper-based natural (NH) hydrogels on green pepper plant growth and yield under water stress levels. Both hydrogels were applied at the rate of 0.5% (w/w), and the pots were arranged in a randomized complete block design with three treatments (SH, NH, and non-amended control) and four blocks (rows). Both hydrogels increased green pepper yield by improving water-use and nutrient-use efficiencies. No significant differences (p<0.05) were observed in the performance of SH and NH hydrogels in terms of plant yield and nutrient leaching at 100% irrigation level. Therefore, the wastepaper-based natural hydrogel can serve as an environment-friendly alternative to synthetic acrylamide-based commercial hydrogels as it eliminates the potential threat of acrylamide monomer to the environment.