Winter rye as a renewable energy source

Abstract

Purpose and objectives. To determine the yield of green mass, the theoretical output of biogas from winter rye varieties and hybrids sown at various rates, to evaluate the influence of weather conditions during vegetation on the biomass yield.

Materials and methods. Winter rye varieties and hybrids bred at the Plant Production Institute named after V.Ya. Yuriev of NAAS were studied: Pamiat Khudoierko, Dikhar, Khamarka, Stoir, Yupiter _F1, Saturn F₁, Kharley F₁, and Slobozhanets F₁. They were sown with a seeding rate of 4, 5, and 6 million germinable grains per hectar. The yield of green mass, dry matter and ash contents were determined during two stages: stem elongation and onset of grain filling.

Results and discussion. The yield of green mass depends on the genotype, phase of the plant development and seeding rate. On average across four years, the varieties had an advantage over the hybrids. Stable high yields of green mass were given by varieties Khamarka, Stoir and Dikhar. In the grain filling phase, the four-year average yield of green mass varied from 24.7 t/ha to 35.2 t/ha. To obtain high yields of green mass from winter rye, it is better to use rye varieties Khamarka, Stoir and Dikhar.

The amount of dry matter differed in the development phases by 1.8 times. The amount of dry matter was greater in the grain filling phase than in the stem elongation phase. There were significant differences in the amount of dry matter between the genotypes during the stem elongation and grain filling.

The ash content was proved to be much higher in the stem elongation phase than in the grain filling phase. This parameter differed 2.1 times between the phases. The average ash content was 8.14–8.49% and 3.75–3.88% in the stem elongation phase and in the grain filling phase, respectively. The higher the dry matter amount in rye plants was, the lower the ash content became.

The theoretical output of biogas from winter rye varieties and hybrids depended on the phases of plant development and the plant genotype. The biogas output decreased with an increase in the seeding rate for hybrids Yupiter and Saturn in the both phases. Correlations between the theoretical output of biogas and the constituent traits were estimated.

There was a strong positive correlation between the biogas output and the ash content in the dry matter in the stem elongation phase for hybrids Saturn F₁, Kharley F₁ and Slobozhanets F₁ as well as for varieties Pamiat Khudoierko, Dikhar, Stoir, and Khamarka (r = 0.99). The correlation between the biogas output and the ash content was strong and positive (r = 0.76–0.99); the ash content had a little effect on the biogas output only in variety Stoir (r = 0.19).

The seeding rate significantly affects the biogas output. Thus, with a seeding rate of 6 million germinable seeds per hectare the average output of biogas is by 5,000-7,000 m³ higher in the both phases of the rye plant development. A significantly larger amount of biogas was obtained during stem elongation. The biogas output is heavily depends on the selection of a variety (hybrid).

There was a strong positive correlation (r = 1) between the grain yield and alcohol output per unit area. At the same time, the alcohol output did not depend on the starch content (r = 0.09).

Conclusions. To develop energy varieties and hybrids of winter rye, it is necessary to select genotypes with high yields of green mass and amounts of dry matter.

The multiformity of relationships between the constituent traits indicates a more significant role of the genetic component for the biogas output than that of agrotechnical methods.