Joint sowing of corn and soybean in forest-steppe conditions of Western Siberia

Abstract

The paper presents the results of studies on the cultivation of maise in joint crops with soybean in the forest-steppe zone of Western Siberia in 2003-2005. The authors studied plant height and dynamics of green mass yield of maise and soybean. As a result of recording plant height, the authors observed that corn hybrid Ob 150 CB by 25-30 cm and corn hybrid Krasnodar 382 MB by 35-47 cm were higher in single-seeded crops by harvest than in joint crops, indicating the negative impact of soybeans on corn. The maise hybrid Krasnodarskiy 382 MB reacted more strongly to the depress- ing effect of soybean than the hybrid Obskiy 150 SV in terms of plant height. This comparison was especially noticeable when it was cultivated in joint crops with the early-ripening soybean variety SibNIIK-315. In the early stages of development, the height of soybean plants in single-species and different variants of common crops did not practically differ. However, starting from the phase of fruit formation, the authors observed a decrease in the height of soybean plants in the row with maise and its increase in the intercropping. By harvesting, the difference between the height of soybean plants of the variety October 70 in the row and across the row was on average 11-24 cm. At the same time, the soybean plants of the variety October 70 were lower in the row with maise and higher in the row spacing than in the single-seeded crop. The height of the plants proves not only the principle of competitiveness but also the effect of the high range of tiering, which forces the legume component to reach for the light. In a mixture with the late-ripening maise hybrid Krasnodarskiy 382 MB, the early-ripening soybean variety contributed to a more significant decrease in the green mass yield of maise than the late-ripening soybean variety October 70. Harvesting, conducted on 2-6 September, showed that joint crops of maise, regardless of early maturity, provided a green matter yield of 23.7-40.1 t/ha. This yield was 49% and 14% lower than in the single-species crops of early maturing hybrid maise Ob 150 CB and 2-3 times lower than the mid-season hybrid Krasnodar 382 MV. The nature of the interspecific relationships indicates a more significant negative impact of early maturing soybean variety SibNIIK-315 on the productivity of maise and especially the medium-maturing hybrid Krasnodarskiy 382 MV, where the differences with the single-species sowing showed the most significant value – 51 %.