Key numbers for Assessing Wheat stands this spring.
Del Voight - Senior Extension Agent- Penn State Extension.
Wheat Stand Assessment by the numbers.
I have gotten some calls regarding some key numbers in wheat at this time. This article seeks to give one some numbers with which to base some decisions on. I have used the information obtained from the A Decision Guide for wheat from Kentucky Extension. The full document is found at this link. http://www.ca.uky.edu/agc/pubs/id/id125/03.pdf
Determining Plant Populations,Tiller, and Head Counts Plant Populations.
There are three methods to do the assessment.
The first one requires and yardstick or dowel rod 3ft in length.
Make spring stand counts before greenup of the plants occurs to determine if winter damage has reduced the initial plant population obtained in the fall. Count only whole plants, not tillers. Fields with stand counts below 15 plants per square foot have less than 75 percent yield potential (Table 3-4) and probably should not be kept but used instead for planting corn or soybeans. If stand counts are adequate to keep but somewhat reduced from optimum, consider an early nitrogen application.
To determine the number of plants per square foot:
Use a yardstick, or cut a dowel rod to a 3-foot length.
Place the measuring stick next to an average-looking row, and count all plants in the 3-foot length of the row.
Record the number.
Repeat the counting process in at least five other locations well spaced around the field. Record all numbers.
• Average all of the stand counts from the field.
Calculate plants per square foot with the following equation:
plant number =
(average plant count × 4)/row width in inches A second method to counting stands is to determine the length of row needed to equal one square foot (Table 3-5).
Mark the needed length on a dowel rod or stick and then count
the plants in a row. A third method is to count the plants, or tillers in 1, 2 or 3 feet of row and use Table 3-6 to determine stands. Tiller and Head Counts. Taking a tiller count which includes main shoot and tillers at Feekes 3 (roughly Zadoks 22 through 26) is the first step in all fields for determining nitrogen needs in late winter or early spring. To determine tiller numbers, count all stems with three or more leaves. Tiller counts below 70 per square foot indicate the need for nitrogen at Feekes 3. At recommended populations, many plants will have only three to four stems (main shoot plus two to three tillers, Zadoks 22 or 23). Thus, 70 to 100-plus tillers (stems) per square foot at Feekes 3 are considered adequate.