Plants need only a small quantity of micronutrients, but they are essential for vital cell functions. Critical micronutrients for plant growth and development include iron (Fe), boron (B), manganese (Mn), zinc (Zn), copper (Cu), molybdenum (Mo), chlorine (Cl), and nickel (Ni). The deficiency of one or more micronutrients can greatly affect plant production and quality. To explore the potential for using micronutrients, we reviewed the literature evaluating the effect of micronutrients on soybean production in the U.S. Midwest and beyond. Soil and foliar applications were the major micronutrient application methods. Overall, studies indicated the positive yield response of soybean to micronutrients. However, soybean yield response to micronutrients was not consistent among studies, mainly because of different environmental conditions such as soil type, soil organic matter (SOM), moisture, and temperature. Despite this inconsistency, there has been increased pressure for growers to apply micronutrients to soybeans due to a fact that deficiencies have increased with the increased use of high-yielding cultivars. Further studies on quantification and variable rate application of micronutrients under different soil and environmental conditions are warranted to acquire more knowledge and improve the micronutrient management strategies in soybean. Since the SOM could meet the micronutrient need of many crops, management strategies that increase SOM should be encouraged to ensure nutrient availability and improve soil fertility and health for sustainable soybean production.

Uniform or evenly spaced planting (ESP) geometry is practiced when resources, such as water, are nonlimiting for growing crops, but under resource-limited environments, nonuniform treatment of the land can be an advantage. Corn (Zea mays L.) field studies were conducted in Gruver (Gruver field study, GFS) and Bushland (Bushland field study, BFS), Texas to compare plant canopy temperature, within-canopy vapor pressure deficit (VPD), grain yield, and yield components for clump (3 plants clustered) and ESP geometries with the same plant populations. At different growth stages for both studies, thermal images were taken for calculating canopy temperature (CT), and temperature and relative humidity (RH) within the plant canopy were measured. Overall, CTs were significantly lower for clumps compared with ESPs, and mean VPDs within the clumps were consistently lower than those for ESPs, indicating that clumps improved the microclimate. Compared with ESPs, clumps produced similar or higher grain yields, and harvest index (HI) was significantly higher for clumps than that for ESPs in both studies (0.56 vs. 0.54 in GFS and 0.48 vs. 0.45 in BFS). In GFS, plants were grown under three water levels (high, medium, and low). With decreasing irrigation level, canopy temperature and VPD increased and aboveground biomass, grain yield, and HI decreased. Results suggested that growing corn in clumps might be a useful strategy under semi-arid climatic conditions because they reduced CT, improved microclimate, decreased number of tillers, and increased HI with comparable grain yield compared with conventional ESPs.