Effects of Different Sowing Dates on Nutrient and Microbiological Quality of Maize (Zea mays L.)

The field experiment was conducted in 2016–2018 at the Department of Agronomy of the Poznań University of Life Sciences on the fields of the Research and Education Centre in Gorzyń, Złotniki branch. It was a single-factor experiment with six sowing dates of an ultra-early maize variety: A1—12 April, A2—26 April, A3—10 May, A4—24 May, A5—7 June, and A6—21 June. Seeds of the maize variety ‘Pyroxenia’ were used in the experiment. This variety is characterized by extremely early maturity (FAO 130), rapid initial development and elongation growth. Delaying the maize sowing date from A1 to A2 resulted in a 16.5% reduction in starch content in the silage dry matter, and a 14.6% increase in the ADF (Acid Detergent Fiber) fiber fraction. The difference in milk production per hectare between maize sown on date A1 and date A6 was 14,189.51 kg/ha, representing 97.1%. Delaying the maize sowing date led to an increase in the abundance of Clostridium spp. in silages, which are responsible for increased losses of dry matter, including starch. No butyric acid was detected in the silages as a final product of butyric fermentation. The low abundance of bacteria from the family Enterobacteriaceae in the silages indicated that they were well prepared. Silages prepared from maize sown at later dates were characterized by a higher abundance of undesirable mold fungi, which are responsible for dry matter losses, including starch. The coefficient of determination showed that 38.54% of the variation in silage starch content was explained by variation in mold abundance in the silage. According to the Flieg–Zimmer scale, all silages received a very good rating, regardless of maize sowing date.