Seeding rate in soybean according to the soil apparent electrical conductivity

Area of Science:

• Agronomy
• Soil Science
• Precision Agriculture

Background:

• Soil apparent electrical conductivity (ECa) mapping is a valuable tool for understanding soil variability.
• Optimizing soybean seeding rates based on soil properties can enhance crop performance and yield.
• Understanding the relationship between soil characteristics, plant phenology, and grain yield is crucial for effective crop management.

Purpose of the Study:

• To investigate the impact of different seeding rates on soybean, stratified by management zones defined by soil ECa.
• To analyze the relationship between ECa-defined management zones, plant phenology, and soybean grain yield.
• To evaluate the effectiveness of a variable seeding rate strategy based on ECa maps.

Main Methods:

• Field experiment with three seeding rates (311,000, 360,000, and 422,000 plants ha-1) in management zones identified by ECa.
• Application of a variable seeding rate strategy: +20% in low ECa zones, -20% in high ECa zones.
• Measurement of plant height, Normalized Difference Vegetation Index (NDVI) at 50, 66, and 92 days after emergence (DAE), one-hundred-grain weight, and grain yield (GY).

Main Results:

• ECa maps effectively guided soybean seeding rate decisions.
• The variable seeding rate strategy resulted in comparable grain yields across management zones, despite variations in soil resistance of penetration (RP).
• Grain yield variability was influenced by ECa (0-0.2 m), NDVI at 92 DAE, and RP (0.4-0.6 m soil layer).

Conclusions:

• Soil ECa mapping is a viable method for determining optimal soybean seeding rates.
• A precision seeding strategy, adjusting populations based on ECa, can maintain grain yield while optimizing resource allocation.
• ECa, NDVI, and soil RP are key factors influencing soybean yield variability.