Effects of bio-activators on yield and quality composition of triticale forage as an animal food resource

A field trial was conducted to study the response of fresh triticale (x Triticosecale, Wittmark) to different nitrogen (N) fertilization levels and inoculation with bio-activators (Mycorrhiza and Azospirillum). Therefore, the aim of this work was to quantify the effects of N supplies and plant inoculation on yield, N uptake, chemical composition, nutritive values and N fractions of triticale forage, harvested in different phenological stages, corresponding to different possible utilizations in animal feed. In a completely randomized block design with three replications, the following applications of bio-activators were compared: Mycorrhizal (M), Azospirillum (A) and Mycorrhizal plus Azospirillum (A+M) inoculation; control without the use of bio-activator (Test). These treatments were in factorial combination with three levels of N fertilization (0, 50, 100 kg ha -1 ). Green crops were harvested in three phenological stages: first node detectable, heading stage and milk-dough stage, corresponding to grazing, hay and silage utilization. The following parameters were determined for each cutting and elementary plot: dry matter percentage, dry matter yield, crude protein, ether extract, ash, crude fiber, neutral detergent fiber, acid detergent fiber, acid detergent lignin, total N content allowing the calculation of plant N uptake and protein yield. Furthermore, the nitrogen fractioning (A, B 1 , B 2 , B 3 , C) used by the Cornell Net Carbohydrate and Protein System was adopted. Finally, the nutritive values (PDIN, PDIE, Milk and Meat FU) were estimated utilizing INRA equations. N fertilization affected dry matter (content and yield), estimated protein and energy values, crude protein and crude fiber. The phenological stages at cutting influenced the nutritional values of fresh triticale and consequently its possible utilization. Furthermore, when considering the first cutting, protein yield was significantly higher with bio-activators (mean of A, M, and A+M) compared to the control in the highest fertilization level. Moreover, there were significant variations of protein fractions in the first phenological stage, confirming that the use of bio-activators is more important in the initial phases of plant development, when the environmental conditions are more restricted for growth. Significant correlations amongst N uptake and protein yield and organic matter were found, indicating that this parameter could influence the response of triticale plants. Furthermore, N uptake was positively correlated with chemical composition, proteinic parameters and non-protein N, whereas a negative correlation with true soluble protein-N was found. Therefore, the use of bio-activators could positively influence grass yield and quality, and consequently its utilization.