how to determine soybean yield

3 min read 30-01-2025

Soybean yield is a crucial factor for farmers, impacting profitability and resource management. Accurately predicting soybean yield before harvest allows for better planning, marketing decisions, and resource allocation. This comprehensive guide explores various methods for determining soybean yield, from simple estimations to more sophisticated techniques.

Estimating Soybean Yield: Pre-Harvest Methods

Before harvest, several methods can provide a reasonable estimate of your soybean yield. These methods are useful for planning and making informed decisions, but should not be considered definitive until post-harvest weighing.

1. The Plant Population Method

This method relies on counting the number of plants per unit area and estimating the number of pods per plant. It's a relatively quick method, ideal for early-season estimations.

Step 1: Count the Plants: Randomly select several areas within your field. Count the number of plants in a defined area (e.g., 1/1000th of an acre). Average these counts for a representative plant population per acre.
Step 2: Count the Pods: Select several representative plants from your sample areas. Count the number of pods per plant. Again, average these counts.
Step 3: Estimate Seeds per Pod: Soybeans typically have 2-3 seeds per pod. Use an average of 2.5 seeds per pod as a starting point, but adjust based on your observation of the plants.
Step 4: Calculate Yield: Use the following formula: (Plants/acre) x (Pods/plant) x (Seeds/pod) x (Seed weight/seed) / 60

Seed weight varies depending on the soybean variety and growing conditions. A common estimate is 250,000 seeds per bushel. Remember this is an estimate.

2. The Pod Count Method

This method focuses on counting the number of pods in a defined area. It’s simpler than the plant population method but might be less accurate.

Step 1: Define Your Sampling Area: Select several representative areas within your field.
Step 2: Count the Pods: Count the number of pods in your sampling area.
Step 3: Estimate Yield: Use the average pod count per unit area, factoring in seeds per pod and seed weight, similar to the calculation in the plant population method.

This method requires a good understanding of the average pod size and seed weight for your variety.

3. Using Technology for Yield Prediction

Modern technology offers sophisticated tools for yield prediction.

Remote Sensing: Aerial imagery and satellite data can analyze crop health and predict yield based on vegetation indices.
Yield Monitors: Combine harvesters with yield monitors provide real-time yield data during harvest. This is the most accurate method for determining final yield but doesn't help with pre-harvest estimations.
Software and Apps: Numerous software applications and mobile apps leverage various data points (weather, soil conditions, planting date, etc.) to predict soybean yields.

Determining Soybean Yield: Post-Harvest Methods

After harvest, the most accurate method for determining soybean yield is weighing the harvested soybeans.

1. Weighing Harvested Soybeans

Step 1: Weigh the Grain: Weigh the soybeans from a known area of your field (e.g., the entire field, a section, or individual bins).
Step 2: Calculate Bushels per Acre: Convert the weight of the harvested soybeans to bushels per acre using the conversion factor of 60 pounds of soybeans per bushel. Consider moisture content adjustments if necessary. This is your final, definitive yield.

Factors Affecting Soybean Yield

Several factors significantly influence soybean yield. Understanding these factors can help you improve your yield estimations and overall crop management.

Weather Conditions: Rainfall, temperature, and sunlight throughout the growing season play a vital role.
Soil Fertility: Nutrient availability impacts plant growth and pod development. Regular soil testing is crucial.
Pest and Disease Management: Timely identification and control of pests and diseases protect the crop's yield potential.
Soybean Variety Selection: Choosing a variety suitable to your soil type, climate, and management practices optimizes yields.
Planting Date and Density: Proper planting timing and plant spacing maximize yield potential.

Conclusion

Determining soybean yield involves a combination of pre-harvest estimations and post-harvest measurements. While pre-harvest methods offer valuable insights for planning and decision-making, post-harvest weighing provides the most accurate yield data. By understanding the various methods and factors influencing yield, farmers can effectively manage their soybean crops and optimize profitability. Remember to always calibrate your methods based on your specific field conditions and soybean variety.