Evaluation of changes in dry matter and nutrient content during the growth dynamics of silage maize

The aim ofthis study was toidentify and quantify the relationships between the nutrient content and the DM (dry matter) content ofvarious maize hybrids (Zea mays L.) inthe dynamics ofvegetative maturity and various soil-climatic growing conditions. Over the course of7growing seasons (years), aset of1972 samples ofwhole silage maize plants consisting of206 different hybrids grown intwo contrasting regions (lowland and foothill areas) was analysed. The focus was onDMcontent and the content ofkey energy nutrients (WSC– water soluble carbohydrates, starch, NDF– neutral detergent fibre) and their interactions. Results show that the transformation ofWSC into starch has four key points: (i)it begins ataDM content of150g/kg; (ii)it peaks ataDM contentofapproximately 235g/kg; (iii)it begins todecrease significantly from aDM content of300g/kg; and (iv)itpractically stops rapidly after exceeding aDM content of350g/kg. Inthe dynamics ofvegetative development ofmaize plants, the DM content isvery closely related tothe WSC content (R²= 0.728) and the starch content (R²= 0.873). With the gradual increase invegetative maturity and DM content inmaize plants, the transformation ofWSC into starch dynamically increases. These characteristics, with small deviations, were also confirmed atdifferent levels ofevaluation (all analyses, regions, seasons and individual hybrids). These results show that aDM content of300g/kg to350g/kg can beconsidered the optimal harvesting window for maize ensiling and the optimal phase ofsilage maturity for whole maize plants, because once the DM content exceeds 350g/kg; the transformation of WSC into starch stops and the drying phase of plants begins.