Photosynthesis Characteristics of xFestulolium and LoliumxBoucheanum Sward.

The productivity of grasslands and pastures mostly depends on cultivated grass varieties. Festulolium (xFestulolium Asch. & Graebn.) is among the most persistent and productive grasses used in many European countries, especially in adverse environments. The aim of the present research was to study photosynthesis activity and crop yield of local and foreign varieties of festulolium and hybrid ryegrass (Loliumxboucheanum Kunth.) under agro-ecological conditions of Latvia. The most significant indices of photosynthetic activity -- leaf area index (LAI) and net photosynthesis productivity (NPP) -- during growth period till first cut were investigated. Field trials were established on sod-gleyic soil (Luvic Epigleyic Phaeozem (Calcaric) -- WRB 2006), fine sandy loam; fertilizers -- 120 kg ha-1 of N, 78 kg ha-1 of P2O5, and 90 kg ha-1 of K2O. The average NPP for festulolium, hybrid ryegrass and perennial ryegrass varieties varied from 5.63 to 8.29 g m-2 day-1. No positive correlation between NPP and dry matter (DM) yield was established. The average LAI was within the range of 1.94-2.91, and a relationship between LAI and DM was found. [ABSTRACT FROM AUTHOR]