Includes:
Weather Summary
Insect Pests
Plant Disease
Crop Yield and Qualit

Roush, Wayne B.

Vagts, Todd

English

Includes:
Weather Summary
Insect Pests
Plant Disease
Crop Yield and Quality</p

Roush, Wayne

Digital Repository @ Iowa State University (ISU)

Iowa State University, Western Research and Demonstration Farm                                                                           ISRF03-10Weather and Growing Season Summary, 2003Todd Vagts, crop specialistISU ExtensionWayne Roush, superintendentWeather summary. The 2003 growing seasonwas cooler and drier than normal through mostof the year, with the yearly and growing seasonrainfall totals ending up much less than normal.All months for the year were dryer than normal(except July) and cooler than normal (exceptAugust). The January through November periodyielded only 67% of the normal amount ofrainfall.Only three rainfall events (April–September)exceeded one inch in a 24-hour period. TheAugust precipitation total (0.67 in.) was thesecond lowest accumulation (August 2000 =0.58 in.) in the last 13 years. The only(extended) period of normal and above normaldegree-day (base 50) accumulation occurredfrom August 1–30.The spring planting season started in late Aprilwith good moisture and soil temperatureconditions, but then a three-week period of wetand cool conditions beginning May 1 delayedsome corn and most of the soybean planting.Most of June and early July experienced nearnormal precipitation, but degree-dayaccumulations were 10% below normal fromearly May through late July. Crop developmentduring this period was excellent, setting up veryhigh yield potentials in both corn and soybeans.August was a very stressful month to cropsbecause very little precipitation was receivedand degree-day accumulations were much abovenormal. Subsoil moisture was sufficient to allowthe corn crop to finish filling grain, butsoybeans suffered dramatically during pod fillunder the August conditions.September and October remained dry butcooler. Subsoil moisture reserves were nearlydepleted during the fall soil-moisture samplingperiod. The area received some fall and earlywinter precipitation to help recharge the soilsfor the next season, yet soil moisture reservesremain very low.Insect pests. The soybean aphid was the majorpest of the year, dramatically reducing soybeanyields across much of Iowa. Bean leaf beetlenumbers were way down, but grasshopperscontinued to be a problem across much of theregion. Potato leaf hoppers plagued alfalfa formost of the season. Western bean cutworms,although present, did not seem to be much of aproblem compared with previous years.Plant disease. Most of the season was relativelyfree of plant disease, although charcoal rot ofsoybeans showed up in some areas of soybeanfields. Some early season seedling disease was aproblem in scattered fields.Crop yield and quality. Remarkably good cornyields were seen across much of the region. Agood soil moisture profile in combination withmild temperatures through most of July allowedfor excellent corn growth, development,pollination, and early grain fill. Late season hightemperatures and low soil moistures robbedsome yield potential from area cornfields. Thesoybean crop came in very short because theAugust heat and moisture stress dramaticallyreduced pod-fill potential. Soybean yields were30–50% less than the previous season. Smallgrain yields were reported to be good toexcellent. Pasture and alfalfa yielded wellthrough July but then went dormant in earlyAugust.Iowa State University, Western Research and Demonstration Farm                                                                           ISRF03-10Table 1. Monthly precipitation, average temperatures and departures from normal for 2003.Precipitation (in) Temperature (°F)Total*Departurefrom normalDays 90°For above Mean*Departurefrom normalJanuary 0.3 -0.3 0 20 -0.3February 1.1 -0.7 0 20 -6.7March 0.9 -1.3 0 35 -3.1April 2.3 -1.0 0 51 0.1May 4.1 -0.1 0 58 -4.0June 3.1 -1.2 0 68 -3.3July 4.2 0.1 7 75 -0.2August 0.6 -3.0 9 75 1.8September 2.3 -0.9 0 60 -5.0October 0.7 -1.7 0 53 -0.1November 1.1 -0.4 0 35 -1.7December - 0 25 0.9Total 20.7 -10.5 16 - -*Deviation from 30-yr. averages recorded at the ISU Western Research Farm weather station.Precipitation Accumulation - Deviation from Normal-6.0-5.0-4.0-3.0-2.0-1.00.01.004/01/200304/15/200304/29/200305/13/200305/27/200306/10/200306/24/200307/08/200307/22/200308/05/200308/19/200309/02/200309/16/200309/30/2003DateInchesDegree-Day (base 50) Accumulation - Deviation from Normal-160-140-120-100-80-60-40-200204004/25/200305/02/200305/09/200305/16/200305/23/200305/30/200306/06/200306/13/200306/20/200306/27/200307/04/200307/11/200307/18/200307/25/200308/01/200308/08/200308/15/200308/22/200308/29/200309/05/200309/12/200309/19/200309/26/2003DateDegee-Days (base 50)Figure 2. Precipitation and degree-day accumulations.

Weather and Growing Season Summary, 2003

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Weather and Growing Season Summary, 2003

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