Mervin St. Luce

Agriculture and Agri-Food Canada | AAFC · Swift Current Research and Development Centre

Assessment and monitoring of soil organic matter (SOM) quality are important for determining and developing management practices that will enhance and maintain the productivity of agricultural soils. This requires routine analysis of multiple soil parameters, which can be time-consuming and expensive. Research has suggested that visible near infrar...

Various soil health indicators that measure a chemically defined fraction of nitrogen (N) or a process related to N cycling have been proposed to quantify the potential to supply N to crops, a key soil function. We evaluated five N indicators (total soil N, autoclavable citrate extractable N, water‐extractable organic N, potentially mineralizable N...

Drought imposes a significant challenge for crop production. However, little is known about the impact of drought priming and nitrogen (N) application and their interactive effects on drought resilience, yield, and grain quality in wheat. Spring wheat (cv. Stettler) was grown in plastic pots (25 cm diameter) with high, moderate, and low soil water...

Aggregate stability is a commonly used indicator of soil health because improvements in aggregate stability are related to reduced erodibility and improved soil–water dynamics. During the past 80 to 90 years, numerous methods have been developed to assess aggregate stability. Limited comparisons among the methods have resulted in varied magnitudes...

There is much interest in the use of large visible near infrared (vis–NIR) soil spectral libraries for rapid soil analysis and to further soils research. However, the use of such large and diverse spectral libraries often provides biased predictions at local scales. Here, we present a new approach, GLOBAL-LOCAL, which aims to use large libraries to...

Canada’s interest in agricultural lands has changed with time from a desire of crop yields at Confederation through to discussions in the Senate on adaptation and resilience in 2018. Long-term research experiments (LTRs) have been present and utilized by federal and university researchers to provide answers throughout. Here we highlight the importa...

Farmers, scientists, and other soil health stakeholders require interpretable indicators of soil hydraulic function. Determining which indicators to use has been difficult because of measurement disconformity, spatial and temporal variability, recently established treatments, and the effect of site characteristics on management practice differences...

Soil organic carbon (SOC) is closely tied to soil health. However, additional biological indicators may also provide insight about C dynamics and microbial activity. We used SOC and the other C indicators (potential C mineralization, permanganate oxidizable C, water extractable organic C, and ß-glucosidase enzyme activity) from the North American P...

Soil organic carbon (SOC) is closely tied to soil health. However, additional biological indicators may also provide insight about C dynamics and microbial activity. We used SOC and the other C indicators (potential C mineralization, permanganate oxidizable C, water extractable organic C, and β-glucosidase enzyme activity) from the North American P...

Currently accepted pedotransfer functions show negligible effect of management induced changes to soil organic carbon (SOC) on plant available water holding capacity (θAWHC), while some studies show the ability to substantially increase θAWHC through management. The Soil Health Institute’s North America Project to evaluate soil health measurements...

Potential carbon mineralization (Cmin) is a commonly used indicator of soil health, with greater Cmin values interpreted as healthier soil. While Cmin values are typically greater in agricultural soils managed with minimal physical disturbance, the mechanisms driving the increases remain poorly understood. This study assessed bacterial and archaeal...

Currently accepted pedotransfer functions show negligible effect of management-induced changes to soil organic carbon (SOC) on plant available water holding capacity (θAWHC), while some studies show the ability to substantially increase θAWHC through management. The Soil Health Institute's North America Project to Evaluate Soil Health Measurements...

Adoption of conservation practices such as no‐tillage (NT) may benefit soil properties and related yields in a corn (Zea mays L.)‐soybean [Glycine max (L.) Merr.] rotation. However, magnitude of changes varies according to time scale, soil characteristics, and climatic conditions, which has received little attention in eastern Canada. A 26‐year fie...

Potential carbon mineralization (Cmin) is a commonly used indicator of soil health, with greater Cmin values interpreted as healthier soil. While Cmin values are typically greater in agricultural soils managed with minimal physical disturbance, the mechanisms driving the increases remain poorly understood. This study assessed bacterial and archaeal...

Tillage and nitrogen (N) fertilization can influence soil organic matter (SOM) dynamics, but their interactive effects remain contradictory. A long-term (25 yr) corn (Zea mays L.)-soybean (Glycine max L. Merr.) rotation was used to investigate the effect of tillage [moldboard plow (MP) and no-till (NT)] and N rates (0, 80 and 160 kg N ha-1) on soil...

Efficient phosphorus (P) management is important for crop production and environmental sustainability of cropping systems. The effects of the agricultural management practices of crop rotation and fertilization on soil P forms and cycling were investigated in plots in Swift Current, SK, Canada, under three crop rotation phases [fallow (F), wheat af...

Tillage and crop residue management can have large impacts on soil organic carbon (SOC) sequestration, as well as additional feedbacks on crop productivity and agricultural sustainability. The objectives of this study were to (i) evaluate the effects of summer fallow, legume green manure, pea or canola in rotation with spring wheat on crop yields,...

In Canada, the agricultural sector has long held a prominent economic, social and cultural position, from substantial evidence of extensive fishing and farming since the times of the first human settlements, to currently accounting for over 100 billion dollars of production and employing 2.3 million people. Steady growth in agricultural production...

Canada is one of the top wheat grain exporters, with a share of more than 10% in the world wheat market. The majority of Canadian wheat production takes place in the Prairies where 6.2 million ha of the area is seeded to spring wheat. The climate is semiarid with an estimated precipitation deficit of about 300 mm during the crop growing season, ind...

Water deficit is the major constraint to crop production in dry temperate climates and no-till (NT) has been widely recommended to increase water conservation, crop yields, and soil organic carbon (SOC) content. In this study, tillage practice [conventional tillage (CT), minimum tillage (MT), NT and annually alternating tillage with NT (NT/MT)]] an...

Legume crop rotational effects are usually studied in only the first subsequent nonlegume crop even though several consecutive crops usually follow a legume. We studied the effects of field pea (Pisum sativum L.), faba bean (Vicia faba L.), faba bean green manure (faba GM), lentil (Lens culinaris Medik.), canola (Brassica napus L.), and wheat (Trit...

The Canadian prairies account for about 85% of Canada’s arable land. Historically, cropping systems were primarily summer fallow-cereal based, which led to severe soil degradation, loss of productivity, and negative environmental consequences. Efforts were taken by all stakeholders to arrest this grave situation, and one of the key measures was ret...

Acidification and metal mobility may present challenges in soil receiving paper mill biosolids (PB). Co-applying biochar and PB could help prevent these issues, but its effect must be assessed. The objective of this 224-day incubation study was to evaluate the effect of amending two acidic soils, a clay and sandy‒loam, with two PB types varying in...

Assessment of the impact of climate change on agricultural sustainability requires a robust full system estimation of the interdependent soil-plant-atmospheric processes coupled with dynamic farm management. The simplification or exclusion of major feedback mechanisms in modelling approaches can significantly affect model outcomes. Using a biogeoch...

Long‐term field experiments are useful for determining cropping system productivity, stability, and resource use efficiency. With 12 yr (2004–2015) of data from five cropping systems on a long‐term experiment (> 30 yr) under semiarid conditions in Saskatchewan, Canada, a systems‐approach was used to compare grain and protein yield, stability, nitro...

In the Canadian Prairies, organic agriculture has traditionally relied on summer fallow and mechanical tillage for nutrient and pest management. More recently, there has been a substantial increase in the use of legume green manure, diversified crop rotations, and reduced tillage. The objectives of this study were to determine if diversified crop r...

Currently available regression equations developed to predict pre‐harvest nutritive attributes from simple field measurements taken in alfalfa ( Medicago sativa L.)–grass mixtures can help producers determine when to best harvest their forages but they are applicable to only spring growth. Our objective was to develop and validate predictive equati...

Adding biochar to paper mill biosolids (PB)amendments may affect PB mineralization rate and nitrogen (N)availability. The objective of this 224-day incubation study was to evaluate the effect of amending two PB types varying in carbon (C)/N ratio (PB1, C/N = 24; and PB2, C/N = 13)with three rates (0%, 2%, and 5%)of pine (Pinus strobus L.)biochar pr...

Core Ideas An organic field trial in the Brown soil zone examined tillage intensity in a simplified (wheat‐green manure) and a diversified (wheat‐oilseed‐pulse‐green manure) cropping system. Yield variation was explained more by precipitation and soil nitrate levels than by weed infestations. Wheat yields were higher under high than low tillage, an...

Core Ideas A 6‐year organic field trial evaluated two tillage intensities (high and low) and two rotation sequences, simplified (wheat‐green manure) and diversified (wheat‐oilseed‐pulse‐green manure). Soil moisture and NO3‐N content were highest in the simplified rotation under high tillage. There were few soil P differences, although levels were h...

Core Ideas A 12 site‐year study representing four soil surface textural group was conducted. Soil texture significantly influenced the economic optimum N rate (EONR). Overall, clay and loam soils showed lower EONR and higher optimum corn yield. Residual soil NO 3 –N (RSN) at EONR was higher in sandy soils. At ∆EONR higher than zero, RSN was lower i...

For both agronomic and environmental purposes, it is relevant to assess the effect of various land management practices on soil organic carbon (SOC). In the North American Great Plains, fallowing was used to increase soil water storage and production of succeeding crops. In addition, tillage was done to prepare seed beds and to control weeds. But t...

We used visible near infrared reflectance spectroscopy (VNIRS) to characterize a set of organic materials (n = 75). Good predictions for total carbon (C), excellent predictions for total nitrogen (N), but poor predictions for pH were found. This preliminary study showed that VNIRS could rapidly characterize organic materials before soil application...

Continuous assessment of soil heavy metal concentrations in agricultural soils is critical for ensuring ecosystem health and minimizing potential adverse effects. However, conventional laboratory determinations are time-consuming, expensive and involve hazardous chemicals. We evaluated the potential of visible near infrared reflectance spectroscopy...

Core Ideas Study on the residual effects of preceding crops and past N management on wheat and canola. Initial positive impact of legume preceding crops on net revenue diminished over time. Residual N had positive effects on net revenue, especially at the highest N rate. Annual fertilization based on production capacity of the region gave the best...

This small-plot field study evaluated food processing liquid slurry (FPLS) as a potential fertilizer for tanner grass (Brachiaria arrecta) production on an acidic loam soil. The treatments, arranged in a randomized complete block design with three replicates, consisted of an unfertilized control, inorganic fertilizer applied at 50 and 200 kg nitrog...

Information on how soil texture and related soil properties affect corn (Zea mays L.) nitrogen (N) response is needed to improve N management in corn production. We conducted a study at 12-site yr in Quebec to assess the effect of N rate (0-250 kg N ha⁻¹) and soil surface textural groups [clay, loam, sandy belonging to the gleysolic soil order (Sg)...

Past agronomic practices, particularly cropping sequence and the balance between N applications and crop N removal, will influence soil N supply and crop yield potential. Nitrogen (N) fertilizer applications required to optimize crop yield and quality will be a function of the difference between crop N demand and the amount of N supplied by the soi...

Management strategies to reduce N losses to the environment from potato (Solanum tuberosum L.) production while maintaining yields depend on selecting the right N source and rate. A 5-yr (2008-2012) field experiment was conducted on an irrigated sandy soil in Quebec, Canada, to examine the effect of N fertilizer source and rate on total (TY) and ma...

Polymer-coated urea (PCU) is used in potato (Solanum tuberosum L.) production to maintain or improve tuber yield while minimizing N losses, but the mode of N release is different from conventional soluble N sources. Hence, it is not known how soil- and plant-based indices of N availability would perform in response to PCU application. A 3-yr study...

Accurate estimation of potential nitrogen (N) availability from preceding crops is essential to improve N fertilizer management in agricultural soils. Labile organic N fractions such as microbial biomass N (MBN), water-extractable organic N (WEON), particulate and light fraction organic matter N (POMN, LFOMN) are sensitive to management-induced cha...

Near infrared refl ectance spectroscopy (NIRS) holds promise for rapid assessment of soil total N and organic C contents, but its ability to predict soil N supply in soils with contrasting physio-chemical properties needs to be evaluated. The objectives of this study were to: (i) evaluate NIRS predictions of measured soil parameters (total N, organ...

Knowledge of the nitrogen (N) available to crops during the growing season is essential for improving fertilizer-use efficiency and minimizing the adverse impacts of N losses on the environment. In humid temperate regions, soil N supply is dominated by in-season N mineralization because plant-available N (NH4–N and NO3–N) is transformed to nonlabil...