Cold temperature and water effect on soybean (Glycine max [L.] Merr.) emergence

Abstract Rationale Early planted soybeans are at risk of cold injury because of low soil temperatures and increased chances of cold precipitation shortly after planting. Severity of injury may be affected by management decisions. Aim This research aimed to quantify how planting depth, cultivar, initial soil moisture content, air and applied water temperature after planting affected soybean emergence and biomass. Methods A controlled environment experiment was conducted using split-split-split plot randomized complete block design. Main plot factor was the soil available water content (AWC) at planting (20% and 60%). The sub plot factor included six treatments with varied water applications and temperatures (1.27 cm precipitation depth equivalent of water applied as liquid (10 °C or 1.7 °C) as ice, or no water added 1 or 11 h after planting; air temperatures of 10 °C or 1.7 °C). The sub-sub plot factor included two planting depths (shallow and deeper) with two cultivars randomized within each depth. Daily emergence was measured through 11 days, and total biomass was quantified on day 11. Results Application of 1.7 °C water one hour after planting was most detrimental to daily emergence. Treatments receiving liquid water 1 h after planting had < 25% normal seedling emergence and reduced normal seedling biomass per plant compared to other treatments. Deeper planting at 20% AWC increased normal seedling biomass by 40% compared to both depths at 60% AWC. Conclusion Decisions regarding early planting should consider forecasted precipitation likelihood given its importance at influencing emergence.