Battle for the Belt: Episode 14

Episode 14 of Battle for the Belt is now available:

In Episode 14, we have a conversation with Dr. Alex Lindsey about the effect of drought stress on corn and soybeans.

Up to last week (June 5 to June 11), most of Ohio has been in slight/moderate drought conditions, which can be a concern as plants are undergoing germination, emergence, and early vegetative growth. Planted seeds need to increase in moisture content before germination will occur (approximately double the internal moisture content of the planted seeds). Corn germination can occur once internal moisture content achieves 32%, though soybeans can start germinating at 20% moisture content. If drought occurs before germination, seeds are relatively unaffected. If seeds have germinated but have not emerged, drought conditions can reduce survival and realized emergence (fewer plants out of the ground). Once emerged, plants will exhibit rolled leaves and have a blueish color in response to water deficit. Plants can work to produce more root biomass, though hot dry soil can limit corn root development and lead to floppy corn (Figure 1).  The change in leaf angle (or rolling leaves) helps plants retain moisture and reduce direct light interception (less light = less heat). If the water deficit persists, plants will overall be shorter, have smaller leaves, and develop thicker waxy cuticles. Once drought conditions improve, conducting a stand count will be important to assess the condition and distribution of surviving plants.

The water deficit effect is more detrimental to yield during flowering and grain fill, but the early-season drought will affect how plants look to some degree as well as how well they can capture light and photosynthesize. Altered growth during vegetative stages does not necessarily translate to a severe yield penalty. The seasonal conditions will continue to be monitored, and future updates will be supplied in relation to anticipated plant responses and potential yield effects.

Battle For the Belt Location Updates

The drought conditions persisted throughout all locations of the study last week until the majority of the state received rain on Sunday. Finally! The Wooster, Western, and Northwest research stations were all at similar moisture levels. One may expect to see symptoms of drought stress, however, both the corn and soybeans have been resilient with little reaction to the dry environments for the most part. The lack of moisture caused both crops to slow down crop growth & development. During hot/dry weather corn and soybeans can have the ability to grow up to two stages in one week. Comparatively, each location may have increased a singular growth stage or completely stagnated. Soil samples were taken to observe moisture at all three locations, and all were similar (Figure 3). The soil still had moisture at two inches of depth and in the root zone (a good thing!) (Figure 4). At the Wooster location planting date one, two, three, and four were V2, V2, V1, and VE for soybeans and V5, V4, V3, and VE for corn. At the Western location, soybeans were staged at V3, V2, V1, and VC and corn was at V7, V5, V4, and V2. The Northwest location’s soybeans were at V2, V2, V1, and VC and corn was at V6, V5, V4, and V1. Some locations have applied side-dress nitrogen and herbicide.

As a recap, this research project includes five planting date windows, 1) Ultra early = late March to early April; 2) Early = mid to late April; 3) Normal = early to mid-May; 4) Late = late May-first week of June; and 5) Very late = mid to late June. Weather permitting, the last planting date (very late) is scheduled for mid to late June. More updates on the last planting date coming soon.

Keep following the ‘Battle for the Belt’ this growing season to learn more and get further updates! You can find the full video playlist of Battle for the Belt on the Ohio State Agronomy YouTube channel.

References:

Kim, S.H. and Jeon, Y.S. (2009). Critical seed moisture content for germination in crop species. The Journal of the Korean Society of International Agriculture 21:159-164.

Senaratna, T., and McKersie, B.D. (1983). Dehydration injury in germinating soybean (Glycine max [L.] Merr.) seeds. Plant Physiology 72:620-624.