Overwintered Crops – Harvest or Leave?

Farmers sometimes have to harvest grain crops in the spring if the autumn harvest campaign was hindered by adverse weather conditions (prolonged rains, early frosts, snowfalls). Such crops are called overwintered grain, and their harvesting has specific characteristics.

Spring grain harvesting is a forced measure and is always associated with economic losses. However, sometimes it is the only way to preserve at least part of the crop.

Harvesting overwintered crops has several specific challenges, as the grain is exposed to moisture, frost, ice, and potential mold contamination. When deciding whether to proceed with spring harvesting, it is essential to consider the following factors.

Harvesting Overwintered Crops: Key Factors for Making the Right Decision.

1. Type of harvested crop.

• Grain crops (wheat barley, oats, corn). If left in the field over winter, the grain quality is likely to deteriorate due to temperature fluctuations, precipitation, and potential fungal infections. In spring, the grain may sprout or rot, making it unsuitable for food or feed purposes. However, if the winter was mild and snowy, some of the crop may still be salvageable, albeit with significant losses.
• Oilseed crops (flax, sunflower, rapeseed): These crops fare worse over winter, as moisture and frost damage the seeds, making them unsuitable for processing. While some harvest may still be possible in spring, the oil quality will be poor.

2. Condition of the crop.

•  Field assessment: Before harvesting, it is crucial to analyze the field to determine how much of the crop has been preserved. The grain may be sprouted, moldy, or have excessively high moisture content.
• Grain moisture content: Overwintered grain absorbs significant moisture in spring, often reaching 30–40%. Immediate drying to 13–14% is necessary for storage.
• Grain quality: A high proportion of broken, shriveled, or sprouted grains is expected. It may still be usable for feed but not for food production. The risk of fungal toxins (e.g., Fusarium) is high, so laboratory testing is recommended.

3. Harvesting techniques:

• Harvesters must operate at lower speeds with adjusted cleaning systems since the grain is weakened.
• Harvesting should take place in dry weather to prevent further moisture absorption.
• If the field is overgrown with weeds, pre-mowing may be required.
• Using a stripper header is the most effective method for harvesting overwintered grain, as it minimizes losses and improves collection efficiency. The header removes only the grain or heads, leaving the stalks in the field.

4. Post-harvest processing. Overwintered crops require rapid drying and sorting.If the grain is unsuitable for animal feed due to mold, it can be repurposed as organic fertilizer or biofuel.

Conclusions:

1. Overwintered crops are rarely of high quality; they are mostly suitable for use as fodder or may even be written off entirely. Harvesting should be done with caution, taking economic feasibility into account.
2. Due to excess moisture and temperature fluctuations during the autumn-winter period, grain quality can deteriorate, and there is a risk of contamination. To accurately assess grain quality, laboratory testing should be carried out before harvesting. This involves collecting representative grain samples from different parts of the batch and sending them to an accredited laboratory specializing in mycotoxin analysis.
3. Using a Slavyanka UAS two-rotor stripper header is the best option for harvesting overwintered grain, as it reduces losses, lowers grain moisture, and minimizes contamination. This is especially important under challenging spring conditions.

Our expert: Ph.D., Associate Professor of the Department of Optimization of Technological Systems at GBU, mr. Pakhuchiy.