Providing an adequate supply of essential plant nutrients has a major impact on crop yields and is one crop production factor that can be readily managed. The purpose of this guide is to provide an overview of soil fertility practices in Manitoba and general fertilizer use considerations. Producers are encouraged to use this information in conjunction with reliable soil tests, their own experience and, when required, the assistance of a professional agronomist to develop effective, environmentally sound and economically viable fertilizer management practices. Five key practices must be implemented to achieve this goal: ■ apply only those nutrients that will result in economic yield increases ■ apply appropriate nutrient rates ■ apply appropriate sources of fertilizer nutrients ■ apply nutrients at appropriate timing ■ apply using the most effective and practical application techniques Practices that are economically effective and practical will serve to minimize potential adverse effects on the quality of soil and water resources.
Key insight
Manitoba soils are generally well-supplied with micronutrients, but specific soil conditions — high pH, organic soils, over-limed fields, coarse sandy textures, and poor drainage — consistently elevate deficiency risk. Soybean iron deficiency chlorosis (IDC) on calcareous soils is the most economically significant micronutrient problem identified, particularly in fields with soil pH above 7.5 and high bicarbonate levels. Molybdenum requirements for soybean are closely tied to nitrogen fixation efficiency and become limiting below pH 6.0.
Limitations
Government web guidance document without primary experimental data — critical thresholds and recommendations are based on Manitoba-calibrated soil test interpretations that may differ from Ontario OMAFRA recommendations. No yield response data, economic analysis, or statistical confidence intervals are provided. Boron guidance is primarily directed at canola rather than corn and soybean. Chloride response data is limited to small grains. The page lacks a formal publication date and may not reflect the most current Manitoba Soil Fertility Guide edition.
