Grain Losses During Storage

 

1. Natural Losses

Moisture Evaporation:

Grain contains inherent moisture, which will gradually evaporate during storage, leading to weight reduction. Proper aeration helps maintain moisture within a safe range, but evaporation itself cannot be completely avoided.

Respiration:

Grain kernels are living organisms that undergo respiration, consuming oxygen and releasing carbon dioxide, water, and heat. Under safe moisture content and low temperature, respiration remains weak; however, under higher moisture and temperature, respiration becomes vigorous, consuming dry matter, causing weight loss, and reducing quality.

Loss of Dust and Impurities:

Even after cleaning, small amounts of dust and light impurities remain. During handling and aeration, these may be blown away or removed, causing minor losses. 

2. Losses Caused by Biological Factors

3. Physical and Mechanical Losses

Breakage:

During harvesting, transportation, loading/unloading, turning, and aeration, mechanical stress can cause grains to crack or break. Broken kernels are more prone to absorbing moisture, mold growth, and insect attack.

Spillage:

In transportation, handling, warehouse entry, or discharge, some grains may fall onto the ground or into crevices, resulting in direct losses.

1. Strict Control Before Storage

• Moisture Control:

Grain must meet safe moisture standards before storage. For example: paddy rice ≤13.5%, wheat ≤12.5%, maize ≤14%. If above, drying or aeration is required.

• Cleaning and Sorting:

Remove impurities, broken kernels, and imperfect grains to improve purity and enhance bulk aeration, reducing risks of mold and pests.

2. Improving Storage Facilities

• Modernized Warehouses:

Promote the use of steel silos, vertical bins, and shallow circular silos with excellent insulation, moisture-proof, airtightness, insect- and rodent-resistant features.

• Maintenance and Repair:

Regularly inspect and repair storage facilities to prevent leakage, dampness, and ensure tight sealing of doors and windows.

3. Applying Scientific Storage Technologies

1.Aeration Technology:

Use natural or mechanical aeration to reduce grain temperature and moisture, prevent condensation, and maintain uniform grain conditions.

2.Low-Temperature Storage:

Make use of natural cold air in winter or mechanical refrigeration to keep grain temperature below 15°C, effectively suppressing pests, molds, and respiration.

3.First-In, First-Out (FIFO):

Implement scientific grain rotation plans to prevent long-term storage and deterioration.

Grain storage losses result from the combined effects of natural, biological, and mechanical factors.

• Key control points: moisture and temperature
• Basic guarantee: sound storage facilities
• Management focus: scientific, precise, and smart grain management

By adopting green, ecological, and intelligent storage technologies (such as mechanical refrigeration, controlled atmosphere storage, and intelligent monitoring systems) along with fine-grained management, storage losses can be minimized. This is critical for safeguarding national food security, improving agricultural efficiency, and promoting sustainable development.