ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 105, No. 2 (2018), p. 133–140
Seed yield of tetraploid red clover as influenced by cover crop management
Ants BENDER, Sirje TAMM
Red clover for seed production is generally sown under cover crops. The warming climate raises a hypothesis that six-row barley cultivars might be replaced by intermediate cultivars of two-row barley as cover crops for establishing red clover seed production stands. The cover crop spring barley (Hordeum vulgare L.) cultivar ‘Maali’ was sown with four different cover crop treatments: 1) seeding rate 333 viable seeds per m², fertilisation rate 60 kg ha–1 N; 2) seeding rate 500 viable seeds per m², fertilisation rate 60 kg ha–1 N; 3) seeding rate 500 viable seeds per m², fertilisation rate 90 kg ha–1 N; 4) seeding rate 333 viable seeds per m², fertilisation rate 90 kg ha–1 N. The tetraploid red clover cultivars ‘Varte’ (early) and ‘Ilte’ (late) were sown at the rates of 2, 4, 6 and 8 kg ha-1 in four replicates using a randomised complete plot design. The height and density of generative tillers of barley, the grain yield and quality, the number of red clover plants per m² were measured in the sowing year. The seed yield and quality of red clover in the first harvest year were determined. Economic calculations were based on the prices valid in 2013–2014. The nitrogen rate and seeding rate had a significant effect on elongation of generative tillers, as well as increasing plant density, grain yield and protein content. Increased seed rate of the cover crop (500 viable seeds m²) and higher fertilization rate (90 kg ha–1 N) decreased red clover seed yield to 10 %. Increasing of only the seed rate of a cover crop, resulted in up to 4 % reduction in the red clover yield. The higher nitrogen rate (90 kg ha–1 N), when barely was sown at a rate of 500 viable seeds m² and at 300 viable seeds m², resulted in up to 5 % reduction in red clover seed yield. The study showed that it is practical to establish a seed production stand of red clover using a seeding rate of 4–6 kg ha-1.
It can be concluded that two-row barley cultivars are also recommendable cover crops besides the currently used six-row barley cultivars. Economic analysis indicated that it is practical to reduce both the seeding rate of the cover crop and nitrogen rate by one third.
Key words: barley, clover, cover crop, nitrogen and seeding rate, yield.
Full text: 105_2_str17.pdf