[Crop Note] current corn stage (03 July 2023) at Champaign in IL, USA
On this very hot day, I took part in sampling greenhouse gas (GHG) emissions in a corn field. The corn plants are currently in a growth stage between V11 and V12. Today marks 68 days since the planting date.
Typically, after 6 weeks from emergence, corn is known to be in the V12 stage. However, variations can occur due to weather conditions, varieties, and other environmental factors. In this case, since the estimated emergence is expected within a maximum of 2 weeks from the planting date of April 26, 2023, the total time from planting to the current date would be 68 days. Considering that the initial estimate accounted for a maximum of 2 weeks for emergence and an additional 6 weeks for the V12 stage, it appears that the growth is slightly delayed. It’s important to note that this is a rough estimate and may vary depending on the specific conditions of the corn field.
The recent drought in Illinois could have had a negative impact on the corn’s growth. Drought conditions can result in limited water availability, which affects plant metabolism, nutrient uptake, and overall development. Corn plants may experience stunted growth, reduced leaf area, and delayed reproductive stages due to water stress.
Nitrogen is absorbed by the crops during their growth. However, nitrogen absorption accelerates at the V6 stage. It is said that 25% of the total nitrogen absorbed by the crops is taken up between the V6 and V12 stages. From V12 until tassel emergence at the VT stage, 45% of the total nitrogen absorbed by the crops is taken up. The remaining required nitrogen is absorbed from the VT stage until the R3 stage.
The girth (kernel row number) and number per row (length) of the ear are important yield components in corn. The determination of girth in the uppermost ear begins shortly after the ear shoot is initiated, typically around growth stages V5 to V6, and is generally considered complete by growth stage V12.
During the V12 stage, the corn plant has undergone significant vegetative growth and is transitioning into the reproductive phase. This is a critical period for determining corn yield because it is when the girth of the ear is established. The girth determination proceeds in an acropetal fashion, meaning it starts from the base of the ear and progresses towards the tip.
The total nitrogen absorbed by the crop is at its maximum around the V12 stage. Nitrogen plays a vital role in the development and growth of the corn ear, including the formation of kernels. Adequate nitrogen availability during this stage is crucial for achieving optimal kernel set and determining the final kernel number, which directly impacts yield potential.
After the V12 stage, the corn plant enters the reproductive phase, and the critical period for determining yield extends into the R1 stage, which is the silking stage. During this period, the plant undergoes pollination, fertilization, and kernel development. Adequate nitrogen availability during this phase is also important to support grain filling and maximize yield potential. Managing nitrogen appropriately during this critical period can significantly impact the final kernel number and ultimately the yield of the corn crop.
