in-crop-weather State Indiana Crop Weather Week Ending Date July 25, 2004 Issue IN-CW3004 Agricultural Summary Crop reporters indicate conditions have been mostly favorable for pollination of corn this season, according to Indiana Agricultural Statistics. Cooler temperatures and timely precipitation have helped. Soybean plants are improving and also making good progress as pods are forming on many of the early planted fields. Much needed rain helped development of major crops and relieved dry soil conditions in most areas of the state last week. Many farmers were attending local county fairs. Field Crops Report There were 5.0 days suitable for fieldwork. Ninety-four percent of the corn acreage has silked compared to 54 percent last year and 76 percent for the average. Twenty-four percent of the corn acreage has reached the dough stage compared with 6 percent last year and 13 percent for the average. Corn condition improved and is rated 77 percent good to excellent compared with 55 percent last year at this time. Seventy-seven percent of the soybean acreage is blooming compared with 50 percent last year and 72 percent for the average. Thirty-six percent of the soybean acreage is setting pods compared with 11 percent last year and 27 percent for the average. Soybean condition improved and is rated 72 percent good to excellent compared with 51 percent last year at this time. Virtually all of the winter wheat acreage has been harvested compared with 94 percent last year and 99 percent for the average. Second cutting of alfalfa hay is 85 percent complete compared with 70 percent last year and 88 percent for the average. Other activities during the week were repairing equipment, harvesting mint, scouting fields, mowing roads and pastures, moving grain to market, hauling manure and taking care of livestock. Livestock, Pasture and Range Report Pasture condition is rated 15 percent excellent, 59 percent good, 20 percent fair, 5 percent poor and 1 percent very poor. Livestock are in mostly good condition. Crop Progress Table ----------------------------------------------------- : This : Last : Last : 5-Year Crop : Week : Week : Year : Avg ----------------------------------------------------- Percent Corn Silked 94 82 54 76 Corn in Dough 24 10 6 13 Soybeans Blooming 77 67 50 72 Soybeans Podding 36 22 11 27 Alfalfa Second Cutting 85 68 70 88 Winter Wheat Harvested 100 99 94 99 Crop Condition Table ----------------------------------------------------------- : Very : : : : Excel- Crop : Poor : Poor : Fair : Good : lent ----------------------------------------------------------- Percent Corn 3 4 16 53 24 Soybean 3 5 20 52 20 Pasture 1 5 20 59 15 Soil Moisture & Days Suitable For Fieldwork Table --------------------------------------------------- : This : Last : Last : : Week : Week : Year : --------------------------------------------------- Percent Topsoil Very Short 2 1 1 Short 12 14 5 Adequate 79 76 65 Surplus 7 9 29 Subsoil Very Short 1 1 1 Short 12 15 7 Adequate 82 78 66 Surplus 5 6 26 Days Suitable 5.0 5.0 4.5 Contact information --Greg Preston, Director --Bud Bever, Agricultural Statistician E-Mail Address: nass-in@nass.usda.gov http://www.nass.usda.gov/in/index.htm Crop Progress Other Agricultural Comments And News ESTIMATING CORN GRAIN YIELD PRIOR TO HARVEST Fancy colored yield maps are fine for verifying grain yields at the end of the harvest season, but bragging rights for the highest corn yields are established earlier than that down at the Main Street Cafe, on the corner of 5th and Earl. Some patrons of the cafe begin "eyeballing" their yields as soon as their crops reach "roasting ear" stage. Some of the guys there are pretty good (or just plain lucky) at estimating yields prior to harvest, while the estimates by others are not even close to being within the proverbial ballpark. Interestingly, they all use the same procedure referred to as the Yield Component Method. Other pre-harvest yield prediction methods exist (Lauer, 2002; Thomison, 2003), but the Yield Component Method is probably the most popular because it can be used well ahead of harvest; as early as the so-called "roasting ear" or milk (R3) stage of kernel development. Under "normal" conditions, the kernel milk stage occurs about 18 to 22 days after pollination is complete (Nielsen, 2004a). Estimates made earlier in the kernel development period risk being overly optimistic if subsequent severe stresses cause unforeseen kernel abortion (Nielsen, 2004b). The Yield Component Method is based on the premise that one can estimate grain yield from estimates of the yield components that constitute grain yield. These yield components include number of ears per acre, number of kernel rows per ear, number of kernels per row, and weight per kernel. The first three yield components (ear number, kernel rows, kernels/row) are easily measured in the field. Final weight per kernel obviously cannot be measured until the grain is mature (kernel black layer) and, realistically, at harvest moisture. Consequently, an average value for kernel weight, expressed as 90,000 kernels per 56 lb bushel, is used as a proverbial "fudge factor" in the yield estimation equation. Crop uniformity greatly influences the accuracy of any yield estimation technique. The less uniform the field, the greater the number of samples that should be taken to estimate yield for the field. There is a fine line between fairly sampling disparate areas of the field and sampling randomly within a field so as not to unfairly bias the yield estimates up or down. 1. At each estimation site, measure off a length of row equal to 1/1000th acre. For 30-inch (2.5 feet) rows, this equals 17.4 feet. TIP: For other row spacings, divide 43,560 by the row spacing (in feet) and then divide that result by 1000 (e.g., [43,560/2.5]/1000 = 17.4 ft). 2. Count and record the number of ears on the plants in the 1/1000th acre of row that you deem to be harvestable. TIP: Do not count dropped ears or those on severely lodged plants unless you are confident that the combine header will be able to retrieve them. 3. For every fifth ear in the sample row, record the number of complete kernel rows per ear and average number of kernels per row. Then multiply each ear's row number by its number of kernels per row to calculate the total number of kernels for each ear. TIPS: Do not sample nubbins or obviously odd ears, unless they fairly represent the sample area. If row number changes from butt to tip (e.g., pinched ears due to stress), estimate an average row number for the ear. Don't count the extreme butt or tip kernels, but rather begin and end where you perceive there are complete "rings" of kernels around the cob. Do not count aborted kernels. If kernel numbers are uneven among the rows of an ear, estimate an average value for kernel number per row. 4. Calculate the average number of kernels per ear by summing the values for all the sampled ears and dividing by the number of ears. EXAMPLE: For five sample ears with 480, 500, 450, 600, and 525 kernels per ear, the average number of kernels per ear would be(480 + 500 + 450 + 600 + 525) divided by 5 = 511. 5. Estimate the yield for each site by multiplying the ear number by the average number of kernels per ear, then dividing that result by 90. The value of '90' represents the average number of kernels (90,000) in a bushel of corn. TIP: Use a lower value (e.g., 80) if grain fill conditions have been excellent (larger kernels, fewer per bushel) or a larger value (e.g., 100) if grain fill conditions have been stressful (smaller kernels, more per bushel). Remember that this method for estimating pre-harvest grain yield in corn indeed provides only an estimate. Since kernel size and weight will vary depending on hybrid and environment, this yield estimator should only be used to determine "ballpark" grain yields. Yield will be overestimated in a year with poor grain fill conditions (e.g., low kernel size and weight from a drought year) and underestimated in a year with excellent grain fill conditions (e.g., larger kernel size and weight from non-stress grain fill periods). You can try to improve the yield estimation for unusual grain fill conditions by adjusting the estimation formula . For example, if you believe that kernel weight will be lower due to stress during grain fill, you may elect to replace the value of "90" in the equation with "100" to reflect the potential for smaller and lighter kernels (i.e., more kernels per 56 lb. bushel). Conversely, in a good crop year, you may elect to replace the value of "90" in the equation with "80" to reflect the potential for larger and heavier kernels (i.e., fewer kernels per 56 lb. bushel). Recognize that the Yield Component Method for estimating corn grain yield is probably only accurate within plus or minus 30 bushels of the actual yield. Obviously, the more samples you measure within a field, the more accurately you will "capture" the variability of yield throughout the field. Use the yield estimates obtained by this method for general planning purposes only. ** Thanks to Emerson Nafziger, Univ. of Illinois, for suggested revisions to the kernel number calculations. Illinois Agronomy Handbook. 2004. Estimating Corn Yields. (An Online Calculator) Univ. of Illinois. Online at http://www.ag.uiuc.edu/iah/index.php?ch=ch2/est_corn_yield.htm l&m=CFAR. (URL verified 7/11/04, but temporarily off-line as of 7/18/04) Lauer, Joe. 2002. Methods for Calculating Corn Yield. Agronomy Advice, Univ. of Wisconsin-Madison. Online at http://corn.agronomy.wisc.edu/AAdvice/2002/A033.pdf. (URL verified 7/11/04) Nielsen, R.L. (Bob). 2004a. Grain Fill Stages in Corn. Corny News Network, Purdue Univ. Online at http://www.kingcorn.org/news/articles.04/GrainFill-0705.html. (URL verified 7/18/04) Nielsen, R.L. (Bob). 2004b. Yield Loss Potential During Grain Fill. Corny News Network, Purdue Univ. Online at http://www.kingcorn.org/news/articles.04/GrainFillStress-0705. html. (URL verified 7/18/04) Thomison, Peter. 2003. Estimating Corn Yields Prior to Harvest. C.O.R.N. Newsletter, Ohio State Univ. Online at http://corn.osu.edu/archive/2003/aug/03-28.html#linkc. (URL verified 7/11/04). Weather Information Table Week ending Sunday July 25, 2004 ------------------------------------------------------------- | Past Week Weather Summary Data |--------------------------------- Station | Air | | Avg | Temperature | Precip. |4 in. |---------------|------------|Soil |Hi |Lo |Avg|DFN|Total |Days |Temp ------------------------------------------------------------- Northwest (1) Chalmers_5W 93 55 73 -2 0.16 1 72 Valparaiso_AP_I 91 53 71 -3 1.12 2 Wanatah 91 51 71 -2 1.92 1 78 Wheatfield 91 55 72 -2 1.94 3 Winamac 90 56 71 -2 1.53 3 76 North Central (2) Plymouth 89 55 71 -4 1.83 2 South_Bend 88 55 72 -2 1.44 2 Young_America 89 56 72 -3 0.41 3 Northeast (3) Columbia_City 89 55 71 -2 2.21 4 75 Fort_Wayne 90 55 72 -3 2.52 3 West Central (4) Greencastle 88 55 72 -5 0.25 3 Perrysville 87 55 72 -3 0.55 3 79 Spencer_Ag 87 57 72 -4 1.89 3 Terre_Haute_AFB 91 58 74 -3 0.45 3 W_Lafayette_6NW 90 51 72 -3 0.41 2 82 Central (5) Eagle_Creek_AP 89 60 74 -3 2.22 2 Greenfield 91 57 73 -3 1.35 2 Indianapolis_AP 89 60 74 -2 3.58 2 Indianapolis_SE 89 57 73 -4 2.71 2 Tipton_Ag 90 55 71 -3 1.15 2 79 East Central (6) Farmland 89 54 70 -3 1.25 2 71 New_Castle 88 52 69 -5 1.32 2 Southwest (7) Evansville 91 63 77 -3 1.53 3 Freelandville 90 57 74 -4 0.90 3 Shoals 90 60 74 -2 2.04 3 Stendal 91 62 75 -3 0.69 3 Vincennes_5NE 91 57 76 -1 0.37 2 77 South Central (8) Leavenworth 89 62 74 -2 1.03 2 Oolitic 89 60 73 -2 1.55 2 78 Tell_City 90 65 77 -1 0.44 1 Southeast (9) Brookville 92 58 73 -2 0.96 2 Milan_5NE 90 58 73 -2 1.51 4 Scottsburg 89 59 73 -4 0.35 2 Weather Information Table Week ending Sunday July 25, 2004 ----------------|-------------------------------- | Accumulation |-------------------------------- | April 1, 2004 thru Station | July 25, 2004 |-------------------------------- | Precipitation |GDD Base 50oF |-------------------------------- | | | | | |Total | DFN |Days|Total| DFN ------------------------------------------------- Northwest (1) Chalmers_5W 20.54 +6.10 40 1744 -15 Valparaiso_AP_I 13.24 -2.08 45 1634 +57 Wanatah 13.13 -1.71 47 1543 +37 Wheatfield 25.62 +11.11 53 1613 +61 Winamac 17.08 +2.54 51 1671 +58 North Central (2) Plymouth 16.18 +0.94 49 1608 -74 South_Bend 15.56 +1.31 50 1701 +141 Young_America 18.04 +4.05 44 1775 +127 Northeast (3) Columbia_City 16.48 +2.15 54 1612 +123 Fort_Wayne 17.81 +4.61 49 1746 +108 West Central (4) Greencastle 17.73 +1.27 48 1780 -88 Perrysville 15.83 +0.06 40 1949 +200 Spencer_Ag 21.44 +4.59 53 1912 +162 Terre_Haute_AFB 13.91 -2.06 44 2073 +207 W_Lafayette_6NW 19.20 +4.70 36 1792 +143 Central (5) Eagle_Creek_AP 15.51 +0.68 48 1965 +118 Greenfield 16.71 +0.48 50 1870 +109 Indianapolis_AP 20.93 +6.10 46 2053 +206 Indianapolis_SE 17.21 +1.80 42 1887 +61 Tipton_Ag 15.30 +0.68 46 1717 +122 East Central (6) Farmland 15.71 +1.16 47 1756 +205 New_Castle 17.62 +1.67 39 1560 -25 Southwest (7) Evansville 19.05 +3.51 42 2349 +177 Freelandville 17.67 +1.59 44 2088 +158 Shoals 22.12 +4.75 48 2089 +234 Stendal 19.23 +2.00 45 2233 +203 Vincennes_5NE 18.37 +2.29 52 2179 +249 South Central (8) Leavenworth 25.85 +8.32 51 2105 +255 Oolitic 21.05 +4.60 52 1969 +203 Tell_City 23.84 +6.41 45 2371 +315 Southeast (9) Brookville 13.98 -1.83 41 1961 +299 Milan_5NE 20.17 +4.36 67 1944 +282 Scottsburg 28.82 +12.57 49 2051 +138 DFN = Departure From Normal (Using 1961-90 Normals Period). GDD = Growing Degree Days. Precipitation (Rainfall or melted snow/ice) and Pan Evap in inches. Precipitation Days = Days with precip of .01 inch or more. Air Temperatures in Degrees Fahrenheit. Copyright 2004: Agricultural Weather Information Service, Inc. All rights reserved. The above weather information is provided by AWIS, Inc. For detailed ag weather forecasts and data visit the AWIS home page at www.awis.com or call toll free at 1-888-798-9955.