UUDISED

GOOD PROJECT EXAMPLE: The Nutritional Value, Quality of Fermentation and Biosafety of Maize Silage in Case of Different Tillage Methods

The problem to be solved

In Estonia, the cultivation of maize for producing silage has become increasingly popular. The introduction of the use of early maize varieties, as well as relatively favourable weather conditions over the past years, have contributed to this trend. Furthermore, the high yield of maize, the high energy value of the dry matter and moderate starch content are favourable attributes that enable replacing a considerable share of grain starch in the feed ration of cows. In addition, maize can be easily ensilaged, can be harvested in a single operation and grows well in hot and dry summer at the time when the growth and yield of grasses is modest. However, when climate and growth conditions are unfavourable, different species of Aspergillus may thrive and the crop may become infected with toxins produced by fungi belonging to the genus Fusarium. Plants get infected with the fungi producing mycotoxins both during the growth and harvesting period and contamination of feed with mycotoxins can lead to cows dropping out of the herd.

The aim of the project was to explore the impact of tillage methods on the nutritional value and biosafety of maize silage. It was investigated whether minimised tillage maize crops get contaminated with mycotoxins during the growth period more easily and whether the concentration of toxins in maize silage is higher in the case of reduced tillage or in case of greater tillage depth. 

"Despite the fact that maize can be easily ensiled, attention has to be paid to efficient storage of green maize to prevent the development of Aspergillus and decrease the generation of mycotoxins.” Andres Olt, the research partner of the project

Project outcomes

Neither the method of tillage nor the year of the use of the grassland influenced the content of toxins in green maize and grass to be ensiled as well as in maize and grass silage. ZEA and DON concentration of mycotoxins in harvested whole crop maize and grass to be ensiled was insignificant. However, ZEA and DON concentrations of mycotoxins increased in the storage during the fermentation process.

The reason for the intensive generation of mycotoxins in the storage could be related to the fact that oxygen was not removed from the storage quickly enough. The research carried out in the project demonstrated that Estonian agricultural producers had problems with the compaction of maize silage. In most cases the silage batches subject to research were not sufficiently compressed; therefore, the quality of silage was also affected.

Poorly compressed silage is extremely unstable at the time of feed-out. The air can enter from the feed-out phase of silage to the storage and cause subsequent fermentation, heating up and spoilage of silage. To avoid this, first the Fusarium fungi should be prevented from getting into the storage and second, an oxygen-free environment has to be ensured in the storage as quickly as possible.