Creating competitive galega and bromus cenoses

Abstract

Field experiments (2001–2005) were carried out to create optimal schemes for sowing mixtures of perennial grasses in the forest-steppe of Western Siberia. Objects of research were Krasnoobsky oats, Eastern galega Gorno-Altayskaya 87, awnless brome Antey. The soil of the plots was medium thick, medium loamy leached chernozem. The experiment was carried out in two layouts spread in time and in space. Grasses were sown under the cover of Krasnoobsky oats. Awnless brome was sown across galega in the first ten days of May. Seeding rate of awnless brome was 3.0; 4.5 and 6.0 million germinating seeds per hectare. Recordings of yield were made according to standard methods. The highest yield of galega dry mass was achieved when it was sown in rows with awnless brome planted with inter-row spacing of 15 cm (it was higher than with 30 cm inter-row spacing by 1.16 t/ ha and 0.63 t/ha, respectively). In the variant “three rows of galega + a row of awnless brome” (3 : 1), the yield of dry mass of the mixture in two cuttings was higher by 5.7 and 2.1% than when they were sown with every other row skipped. The total yield for two cuttings exceeded single-species crops of galega by 0.48–2.03, and awnless brome by 2.15–2.54 t/ha. A tendency towards a decrease in the yield of dry mass in single-species crops of galega with an increase in row spacing was noted. In mixtures sown at the same time according to the 3 : 1 scheme, the yield of dry mass was 5.14 t/ha in the first mowing and 4.05 t/ha in the second. This is higher than in the mixture sown according to the scheme “a row of galega + a row of awnless brome” (1 : 1) by 2.2–7.6, or 2.2–13.1%. Awnless brome in mixtures is more competitive than galega. An increase in the seeding rate of awnless brome from 3.0 to 6.0 million germinating seeds/ha in the herbage of galega increased the yield by 0.9–1.37 t/ha. The yield of dry mass of mixtures sown at the same time was higher than mixtures with awnless brome planted between rows of galega with spacing of 15 cm by 2%, and with row spacing of 30 cm by 10%.