Corn and Soybean Stand Assessment

There are three common methods for taking stand counts. The 1/1000th acre method and wheel method are widely used for corn and wide-row soybeans. The hoop method is often used for drilled soybeans.
13;10;digital tool 1

1/1000th Acre Method

13;10;
Count the number of plants in a length of row equal to 1/1000th of an acre based on row width (Table 1). Multiply the number of plants by 1,000 to get plants per acre. Repeat the process in several locations in the field for an accurate estimate.
13;10;
 
13;10;




13;10;

 

13;10;

Wheel Method

13;10;
digital tool 1
Count 150 plants and measure the distance from start to finish with a measuring wheel.  Divide the number of feet traveled into the appropriate factor in Table 2 to determine plant population. For example, if you walked 94 feet while counting 150 plants in 30-inch rows, the population is 2,613,600 ÷ 94 = 27,804 plants per acre. You may repeat the count several times and average the results.  
13;10;

Hoop Method

13;10;
This method should be used for drilled soybeans. Measure the diameter of the hoop, toss it in the field, and count the number of plants inside the hoop. Do this in at least 5 locations in the field. Multiply the average number of plants by the appropriate factor listed in Table 3 to get the number of plants per acre.  Notice that having a diameter of 28 ¼65533;? allows you to simply multiply by 10,000 to obtain the number of plants per acre. This size of hoop can be made by cutting anhydrous tubing to 88 ¾65533;? and joining it to form a circle. 
digital tool 1
13;10;
 
13;10;
Check the root and mesocotyl health when assessing corn and soybean plant stands.  Wet, cool soil conditions (less than 50 to 55° F) predispose seedlings to infection by a number of fungi that may result in seedling death.  Uneven emergence and stunted seedlings may indicate seedling disease, insect feeding, or herbicide damage.
Corn seed rots, seedling blights and/or root rots are caused by Pythium, Fusarium, and Rhizoctonia diseases, which are common in soils.  Seedling susceptibility to infection increases the longer the seed is in the ground, and the more stress germinating corn undergoes.  Typical below ground symptoms associated with seedling disease include rotting seed and brown discoloration (rotting) of the mesocotyl and seminal roots.  Acceleron® Seed Treatment Products for corn provide excellent control of soil and seed borne diseases, including Fusarium, Rhizoctonia and Pythium and protection from early-season pests, such as wireworm, seedcorn maggot, white grub, and suppression of black cutworm.
13;10;
Soybean seedling health can be compromised by fungi causing seed rot, seedling death, and root decay.  Problems are usually associated with wet soils. Phytopthora, Pythium and Rhizoctonia are the most important pathogens. 
Other pathogens infecting soybean during the VE to V4 stage of growth are Fusarium, sudden death syndrome, and brown stem rot.  Acceleron®Seed Treatment Products for soybeans can help manage Rhizoctonia, Pythium, Fusarium, and Phytopthora and early season insects like bean leaf beetle and aphids.


Sources:
Robertson, A. 2010. Assess seedling health when doing corn stand counts. Iowa State University, Integrated Pest Management; Illinois agronomy handbook. 23rd Edition. University of Illinois Extension, pg 31; Corn and soybean field guide. 2007. Purdue University; Lee, D. A guide to corn production in Georgia 2013. University of Georgia;  Wiebold, W. and R. Massey. 2012. Corn and soybean replant decisions. University of Missouri. G4091.