Received: January 27th, 2023 ; Accepted: May 22nd, 2023 ; Published: July 10th, 2023 ; Correspondence: [email protected], [email protected] aim of current research was to investigate forage yield and crude protein content
of legume-grass mixtures during four years of sward use, applying three nitrogen (N) fertilisation
rates: N0, N60, and N120. Three perennial legume species - red clover Trifolium pratense (Tp),
lucerne Medicago sativa (Ms) and fodder galega Galega orientalis (Go) were tested in mixtures
with grasses (G). Mixtures were composed of 50% of legumes and 50% of grasses. Lucerne and
fodder galega are introduced forage legume species in Latvia, and are raising an ever-growing
interest in Latvia. The studies of persistency, quality and yielding ability of these legume species
in Latvian agroclimatic condition in comparison with traditionally used red clover are actual.
Significant differences in dry matter (DM) yields were found between successive production
years, mixtures, and N fertilization rates. The highest average DM yield was found for the mixture
with lucerne (Ms+G). The decline in productivity between the first and fourth production years
was more expressed for red clover mixture, but a more stable productivity was demonstrated by
swards with galega (Go+G). The N rate increase contributed to a significant DM yield increase
for all mixtures. The positive effect of the increased N rates on DM yield increase was better
expressed for red clover mixture (Tp+G). Red clover mixture (Tp+G) had the lowest average
crude protein (CP) content. Mixture with galega had a higher CP content in the third and fourth
production years. The CP content of red clover mixtures increased by nitrogen rate
