Dairy and livestock industry drives the economy and food security through sustainable supply of dairy products and meat across the globe. Dairy farm operations produce a large quantity of manure, which is a cheap and abundant plant nutrient source. However, insufficient forage production with low quality matrix are the current challenges of dairy industry in boreal climate due to extreme weather conditions. To address these challenges, a field experiment was conducted for three years to determine the effects of organic (dairy manure-based phosphorus (DMP)) and inorganic phosphorus (P) amendments on forage yield and quality indices of silage-corn cultivated in boreal climate. Experimental treatments were: (i) DMP with high P concentration (DMP1); (ii) DMP with low P concentration (DMP2) and (iii) inorganic P, also designated as control; and five silage-corn genotypes (Fusion-RR, Yukon-R, A4177G3-RIB, DKC23-17RIB, DKC26-28RIB). Results revealed that DMP1 amendment produced significantly higher forage yield compared to inorganic P, whereas non-significant effects were shown on quality indices except P mineral, available and crude protein. Yukon-R and DKC26-28RIB showed superior agronomic performance and produced significantly higher forage yield, whereas A4177G3-RIB produced lowest forage yield but exhibited superior nutritional quality; higher minerals, protein, total digestible nutrients, net energy for gain, net energy for maintenance and calculated milk production compared to other genotypes. Yukon-R not only produced higher forage, but also displayed good forage quality indices which were very close to A4177G3-RIB genotype. Therefore, we conclude that Yukon-R cultivation following DMP as organic amendment could be a sustainable production practice to attain high forage yield with optimum nutritional quality to meet the forage needs of growing dairy industry in boreal climate.