At various times, heavy rains and flooding can spoil stored hay, leaving farmers with limited options to recover their investment.

Some of these options include using the bales to fill old gullies, spreading hay over paddocks to allow pasture to grow through, or composting the spoiled hay.

Of these, composting stands out as the most effective method to generate value from spoiled hay and improve farm productivity.

Aerobic Composting: Transforming Waste into Value

Aerobic composting is the rapid decomposition of organic materials, turning them into a humus-rich product that greatly benefits soil quality. During this process, high temperatures are naturally generated and pathogens that may be present in the raw organic materials. If your farm regularly produces sizable quantities of ‘waste’ materials like spoiled hay, silage, and manure, composting is a great way to recycle them and improve soil health.

What Makes Compost Valuable?

Compost is rich in humus, which provides long-lasting benefits to soil. Humus improves the soil’s physical, chemical, and biological conditions, making it more fertile and better able to support plant growth. The process of composting waste materials can extract extra value from what would otherwise be considered waste. As a result, composting is a key strategy for maximizing the utility of available organic resources.

Composting Methods: The Turned Windrow Technique

There are various composting methods available, but one of the most simple and cost-effective for farmers is the Turned Windrow Method. This technique involves piling organic materials into rows, maintaining proper moisture levels, and then turning the piles to accelerate decomposition. The windrow's dimensions will depend on the type of materials being composted, the space available, and the equipment being used.

In a manure-based operation, the windrow typically reaches a height of 1.5 meters, with the base spanning 2 to 3 meters wide. The length can vary, depending on available space.

Basic Requirements for Effective Composting

Oxygen

Composting microbes require a constant supply of oxygen to thrive. Fresh air contains 21% oxygen, but within the composting pile, oxygen is consumed by microbes as they break down organic matter. Maintaining an oxygen level of at least 10% within the pile is crucial for ensuring that aerobic microbes remain active and effectively decompose the materials.

To maintain oxygen levels, turn the pile regularly and ensure a mixture of small particles and larger, air-trapping ones like straw or wood chips. Wastes with high moisture content, such as manure, need to be properly mixed with structured materials to facilitate airflow.

Moisture

Dear Lykkers! Moisture is another essential factor in the composting process. Ideally, the compost should have a moisture content of around 50 to 60%. Compost should appear wet but should not release moisture when squeezed. If the compost is too dry, microbial activity will slow down, while excessive moisture can lead to anaerobic conditions, creating foul odors and hindering composting.

When working with dry materials like spoiled hay, it’s important to hydrate them before mixing with manures. Spread out the hay ahead of time and allow it to absorb rain or use a soaker hose to re-wet it.

Carbon to Nitrogen (C:N) Ratio and Nutrients

The carbon to nitrogen (C:N) ratio of your compost materials plays a major role in how quickly the compost breaks down. Nitrogen serves as fuel for microbes, enabling them to break down carbon. A proper balance between carbon and nitrogen is crucial. An ideal C:N ratio of about 30:1 promotes healthy microbial activity and effective decomposition.

Other nutrients like sulphur, phosphorus, and trace elements also play a role in the composting process. These nutrients are often abundant in manure, which makes it a valuable composting ingredient.

Temperature: Monitoring and Maintaining Heat

Microbes generate heat as they digest waste, which builds up in the pile, with the highest temperatures occurring at the center. The ideal composting temperature range is between 45˚C and 65˚C. Regularly monitor the temperature of the pile to prevent overheating and to ensure an efficient composting process. During the early stages, the temperature can rise quickly, and care must be taken to prevent it from exceeding 70˚C. Once the pile reaches around 65˚C, it should be turned to mix cooler material from the outside into the center.

Once the easily digestible materials are consumed, the pile will begin to cool, and fungal activity will increase. When the compost cools to ambient temperature, turning will no longer cause significant temperature changes, and the process is complete.

Mixing the Feedstock: Proper Integration for Effective Decomposition

To ensure a successful composting process, the materials must be thoroughly mixed. Proper mixing influences both the speed and the quality of the final compost. Well-mixed feedstocks ensure that all components are subjected to microbial decomposition and maintain even moisture levels.

Site Selection for Composting

The composting site plays a significant role in determining the success of the operation. Choose a level, compacted surface like concrete, crushed rock, gravel, or compacted soil. The composting site should be located at a reasonable distance from paddocks, access points for ingredients, and water sources. Consider wind direction and the potential for odor complaints when selecting the site.

Monitoring and Turning: Keeping the Process on Track

Monitor your compost pile regularly with a compost thermometer. This will provide valuable insights into the progress of the process. If temperatures fall below 45˚C during the first few weeks, turn the pile to replenish oxygen and ensure proper microbial activity. Turning also helps expose new material to decomposition and ensures that all material reaches high temperatures, effectively killing pathogens.

Keep Records for Future Success

Maintaining detailed records of the composting process—ingredients used, proportions, moisture levels, weather conditions, and temperature readings—can help you fine-tune your technique over time. By documenting these variables, you can identify patterns and continuously improve the composting process.