Millet forage yield and silage quality as affected by water and nitrogen application at different sowing dates

This experiment was conducted to evaluate the effects of two irrigation regimes (control and water stress) and two nitrogen (N) levels (0 and 112.5 kg/ha) on forage yield and silage quality in millet. Bastan (Setaria italica (L.) P. Beauv) and Pishahang (Panicum miliaceum) were sown at two different dates during 2015 and 2016. Both cultivars exhibited reduced dry-matter (DM) yields (45% and 51% in Bastan and Pishahang respectively) due to drought stress. Proline and phenolic contents increased as a result of drought and were significantly and negatively correlated with DM yield and digestibility. Moreover, Pishahang had a reduced acid detergent fibre (ADF) content but improved leaf/stem ratio, digestible dry matter (DDM), relative feed value (RFV), net energy for lactation (NE_L), digestibility and silage quality as a result of drought stress, while no significant effects on these traits were observed in Bastan. Silage quality was greatly cultivar-dependent. Both cultivars had higher levels of DDM, RFV and NE_L at early sowing dates. Nitrogen supply had greater positive effects on increasing ash, crude protein (CP) content and DM yield under normal irrigation than under water-stress conditions. In summary, given the importance of the energy received per unit of forage from an animal husbandry viewpoint and the significance of DM yield per unit area from an agricultural viewpoint, the obtained results might help farmers in choosing not only the best sowing dates but also proper irrigation and N management practices to achieve their quantitative and qualitative objectives in forage production.