Maize for biogas production

Maize grains and maize silage are two of the most commonly used raw materials for biogas production. Biogas is a renewable energy source produced by the anaerobic fermentation of organic matter such as maize grains and maize silage. The biogas produced can be used to generate electricity, heat or as fuel for vehicles.

Maize grains are the dried grains of the maize plant and are usually used as a raw material for ethanol production in the dry spinning process. However, they can also be used for biogas production, either alone or in combination with other raw materials. Corn silage, on the other hand, is produced from the entire corn plant, including the leaves, stalks and cobs. It is usually used as feed in livestock farming, but can also be used for biogas production.

Maize is a highly attractive crop for biogas production due to high biomass yields and methane yields between 7500 to 10,200 m3 ha (https://www.mdpi.com/2077-0472/8/11 ), which has not been achieved by any other crop used for biogas production so far. They are also relatively easy to grow and harvest, making them a cost-effective option for biogas producers. However, the quality of the feedstock can vary depending on the maize variety, growing conditions and harvesting and storage practices.

Advantages of maize grains and maize silage for biogas production

Maize grains and maize silage offer several advantages for biogas production. First, they have a high energy content, which makes them efficient feedstocks for biogas production. Secondly, maize grains and maize silage are readily available and widely grown, which ensures a constant and reliable supply. In addition, high biogas yields are achieved when maize is fermented in biogas production. In addition, the residues from the fermentation process can be used as a nutrient-rich fertiliser for agricultural purposes, which reduces costs and promotes sustainability. Overall, the use of maize grain and maize silage in biogas production provides a renewable energy source while utilising a versatile and abundant agricultural crop.

Factors affecting the quality of maize grain and maize silage for biogas production

Several factors can influence the quality of maize grain and maize silage for biogas production. Maize variety, growing conditions and harvesting and storage practices can affect the energy content and nutrient composition of the feedstock. The moisture content of the maize silage is also crucial, as it can influence the fermentation process and biogas yield. The presence of contaminants such as pesticides or mycotoxins can also have a negative impact on the quality of the feed. It is therefore important to carefully control these factors to ensure consistently high quality maize grain and silage for biogas production.

Best practices for growing and harvesting maize for biogas production

To ensure optimal growth and quality of maize for biogas production, several best practices should be followed. First, the selection of appropriate biogas maize varieties adapted to the farm requirements and location is crucial. Adequate soil preparation, including proper fertilisation and pH adjustment, promotes healthy plant growth. Timely sowing and regular monitoring for pests and diseases are essential. Harvesting at the right stage of maturity, when dry matter content is optimal, ensures maximum energy yield. Proper ensiling techniques such as compacting and sealing help maintain the quality of maize silage. Following these practices can increase the overall success of growing maize for biogas production.

Ensiling and fermentation of maize silage for biogas production

The ensiling and fermentation process of maize silage is crucial for biogas production. After harvesting, the maize plants are chopped into small pieces and packed tightly in silos or pits. During ensiling, oxygen is excluded to create anaerobic conditions that allow beneficial bacteria to ferment the plant material. This fermentation process breaks down the organic compounds in the maize and converts them into biogas, mainly methane. Proper compaction and sealing of the silage helps create an airtight environment that promotes efficient fermentation. Monitoring pH and temperature during fermentation is important to ensure optimal biogas production.

Maximising biogas yield from maize grains and maize silage

Several strategies can be used to maximise the biogas yield from maize grains and maize silage. First, selecting high-yielding maize varieties bred specifically for biogas production can increase the energy content of the feedstock. Proper agronomic practices, such as optimal fertilisation and irrigation, promote healthy plant growth and higher biomass production. Harvesting at the right stage of maturity, when energy content is highest, ensures maximum biogas yield. Effective ensiling techniques, including proper compaction and sealing, create favourable conditions for fermentation. Monitoring and adjusting moisture content, pH and temperature during fermentation can optimise biogas production from maize grains and silage.

Future trends and innovations in maize grains and maize silage for biogas production

Future trends and innovations in maize grains and maize silage for biogas production focus on increasing efficiency and sustainability. One trend is the development of genetically modified maize varieties with improved energy content and digestibility, leading to higher biogas yields. In precision agriculture, techniques such as remote sensing and data analysis are being used to optimise fertiliser and water use and reduce environmental impact. Innovations in ensiling technology, such as the use of additives or inoculants, are expected to improve fermentation efficiency and biogas production. Research is also being conducted on co-digestion, combining maize silage with other organic waste streams to improve biogas production and resource use.

Sources:

• Vanessa S. Schulz, Sebastian Munz, Kerstin Stolzenburg ,Jens Hartung ,Sebastian Weisenburger ,Klaus Mastel ,Kurt Möller ,Wilhelm Claupein and Simone Graeff-Hönninger, Biomass and Biogas Yield of Maize (Zea mays L.) Grown under Artificial Shading, Agriculture 2018, 8(11)
• Mazurkiewicz J, Marczuk A, Pochwatka P, Kujawa S. Maize Straw as a Valuable Energetic Material for Biogas Plant Feeding. Materials (Basel). 2019 Nov 22;12(23)
• Biogas Production from Maize Grains and Maize Silage. Polish Journal of Environmental Studies. 2010;19(2):323-329.