Starch content in corn grain and bioethanol yield depending on vegetation conditions and factors of cultivation technology

Abstract

Objective: to study the influence of climatic conditionsand elements of technology on productivity, grain qualityand bioethanol yield in maize hybrids of different maturitygroups. Field and laboratory methods of studying hybridmaterial of corn were used in the research. Determinationof starch content was performed using a polarimeter.Results. The starch content in the grain depended not onlyon the ripeness group of hybrids, but also on the timingof their sowing. At the early sowing period, the loweststarch content was noted, and at the late sowing period, it was noted the highest one. Early sowing, due tothe high yield, contributed to the maximum starch yield(7.372 t/ha) compared to the average (6.714 t/ha) and late(5.953 t/ha) sowing periods. That is, the use of late sowsperiods contributed to an increase in the starch contentand yield by 1.57–1.97% and 1.181–1.567 t/ha relativeto the early sowing period. The starch content canvary significantly depending on the type of corn. Thus,at the early sowing period, the starch content was 71.56%in the siliceous-tooth – like subspecies, 73.13%; the starchcontent was in the tooth – like subspecies, 72.44 and 74.21%in the average sowing period; and the starch content was73.33 and 75.06% in the late sowing period. Conclusions.The highest starch content and its yield per unit area wereprovided by double foliar top dressing of all hybrids withEcolist Mono zinc microfertilizer. The highest starch yield(0.6-1.9 t/ha) was determined by double foliar top dressingwith microfertilizers Ecolist Mono Zinc and Sprout corn.The use of shallow (4–5 cm) grain embedding depthprovided starch content and yield of 72.08 up to 75.23%and 5.9 up to 7.49 t/ha, or an average of 6.75 t/ha, average7–8 cm; the starch content and yield was 72.19 up to76.02%and 5.85 up to 7.71 t/ha, or an average of 6.78 t/ha; deep10–11 cm the starch content and yield was 72.04 up to75.58% and 5.68–7.62 t/ha, or an average of 6.66 t/ha.Accordingly, the highest starch content in grain, on averagefor three years, was 74.31% at a depth of 7–8 cm, whileit was 73.8% at a depth of 4–5 cm, and it was 74.11%at a depth of 10–11 cm. The delay in sowing cornhybrids led to a decrease in the yield of bioethanol by0.640–0.847 thousand liters/ha compared to the earlysowing period. The increase in bioethanol yield with a singlefoliar top dressing was 0.10–0.65 thousand l/ha, and witha double foliar top dressing it was 0.30–1.04 thousand l/hacompared to the control such as water top dressing.The estimated bioethanol yield was affected by the seedfraction. In particular, the yield of bioethanol for sowing seedsof small fraction, ranged from 2.94–3.78 thousand l/ha,or on average for the fraction of 3.41 thousand l/ha, forsowing seeds of medium fraction it was 3.28–4.36 thousandl/ha or on average for the fraction of 3.81, and for sowingseeds of large fraction it was 3.33–4.31 thousand l/ha or onaverage for the fraction of 3.84 thousand l/ha. The depthof embedding of corn seeds had an ambiguous effect onthe yield of bioethanol from grain. Thus, the use of nondeep(4–5 cm) seed embedding contributed to the yieldof bioethanol in the range of 3.23 up to 4.11 thousand l/ha, oron average for this depth of 3.697 thousand l/ha, for the useof an average (7–8 cm) depth of embedding it was 3.21 upto 4.23 thousand l/ha, or on average as 3.713 thousand l/ha,and for the use of deep (10–11 cm) embedding it was3.11–4.17 thousand. l/ha, or an average of 3.648 thousandl/ha. That is, an increase in the depth of seed embedding ledto a decrease in the yield of bioethanol per unit of sowing.