Off-campus UNL users: To download campus access dissertations, please use the following link to log into our proxy server with your NU ID and password. When you are done browsing please remember to return to this page and log out.
Non-UNL users: Please talk to your librarian about requesting this dissertation through interlibrary loan.
Relay surface-seeding of corn, sorghum and soybean into wheat
Abstract
Surface-seeding was tested as an alternative cropping system for Nebraska in a series of small plot experiments under irrigation in a normal (1987) and a hot, dry year (1988) at the Agricultural Research and Development Center near Mead. Corn, sorghum, and soybean were surface-seeded into wheat during grain filling and irrigated daily for 15 days. Variables tested included bare vs. residue-covered soil, primed vs. dry seed, cultivar, and corn seed size and shape. Experiments were also conducted on the effect of relative humidity (RH) on exposed radicals. Percent corn establishment response to residue vs. bare soil was nonsignificant in 1988 (9 vs 7%), but was four times higher in 1987 (72 vs. 18%). Percent sorghum establishment was 46% in residue vs 28% on bare soil in 1987 and 31% (residue) vs 19% (bare) in 1988. Percent soybean establishment in residue was 76% vs 26% on bare soil in 1987 and 38% (residue) vs 19% (bare) in 1988. Primed sorghum and soybean seed maintained 26 g kg$\sp{-1}$ higher moisture before and after germination only when seeded moist. Priming did not consistently improve percent establishment. Significant yield differences among soybean varieties occurred in 1987, when a freeze killed the soybeans: Hobbit and Group II varieties averaged 2.05 Mg ha$\sp{-1}$ while Williams 82 and Pella averaged 1.46 Mg ha$\sp{-1}$. Late-season lodging (degrees from vertical) in 1987 was 16$\sp\circ$ (Century 84) to 58$\sp\circ$ (Amcor) and 65$\sp\circ$ (Hobbit), but 2$\sp\circ$ or less in 1988, except Amcor (20$\sp\circ$). Corn seed shape did not consistently affect development or establishment. Large Pioneer 3475 seed produced more advanced plants than those from small seed. Imbibed seeds on the soil surface lost 19% of their water during mornings and 4% in afternoons. Seed water content increased again at night. When seedlings were held in jars between 12 and 92% RH, emergence after transplanting decreased as time in jars increased (to 6 days) and with lower RH levels. Corn tolerates RH blow 90% better than soybean and sorghum. RH in the seed zone of surface-seeded crops needs to remain over 90% or seeds must germinate and establish within several days. This research does not support surface-seeding as a reliable cropping system.
Subject Area
Agronomy
Recommended Citation
DeLoughery, Richard L, "Relay surface-seeding of corn, sorghum and soybean into wheat" (1994). ETD collection for University of Nebraska-Lincoln. AAI9425278.
https://digitalcommons.unl.edu/dissertations/AAI9425278