Find It Here
Twitter update
Subscribe

Subscribe to Post Updates from Arkansas Row Crops


 

RSS AgNews
Quick Links
Agricultural Programs
04
May
2012
Arkansas Soybean Crop Update for the Week of April 30, 2012
Author: Jeremy Ross, Extension Agronomist - Soybeans

Weather:  The 10 Day Forecast predicts daily high temperatures in the upper 80’s to lower 90’s with daily low temperatures in the upper 60’s.  These average daily high temperatures will be 10 degrees above normal for this time of year.  There is very little chance of precipitation for the next 10 days.   Topsoil moisture supplies were 6% very short, 34% short, 58% adequate and 2% surplus.  Subsoil moisture supplies were 3% very short, 22% short, 73% adequate and 2 % surplus.

Crop:  As of April 30, 2012, producers had 45% of the soybean crop planted, 31% ahead of 2011 and 28% ahead of the five-year average.  Soybean emergence was at 26%, 18% ahead of 2011 and 19% ahead of the five-year average.

Percent of Soybean Progress (released April 30, 2012)

Soybean Stage

Current Wk.

Previous Wk.

2011

5-Year Avg.

  Planted

45

28

14

17

  Emerged

26

16

8

7

Optimum Planting Date for Soybean in Arkansas

Every year I get questions on when soybean producers should plant soybean to maximize yield.  The figure below was generated using data from the Soybean Research Verification Program and Rice Research Verification Program.  The data from 1983 to 2007 was analyzed to estimate grain yield by planting date.  Estimation results reveal the expected yield potential based on planting dates measured as ‘week of the year’ (WOY).   The data suggest that yield potential is maximized between the 17th WOY to the 23rd WOY for soybean.  The general trend is that earlier plantings for soybean result in higher grain yields.  The normalized yields indicates that the 18th WOY had the highest yield potential for soybean grown in Arkansas.  The week we are currently in (April 30, 2012 to May 6, 2012) calculates out to be the 18th WOY for 2012.  With the current planting progress at 45% planted this early in the year, and if we can catch a few rain showers during the summer, we could potentially have a record state wide average yield for soybean in 2012.

Fig. 1-Relative yield of rice and soybean by week of the year

Fig. 1-Relative yield of rice and soybean by week of the year

Soybean maturity group and planting date

I’ve been getting several calls from Extension agents and growers about planting Maturity Group (MG) 5 soybean in early-May.  The short answer to this question is there is no problem with planting MG 5 soybeans in early-May.  Comparing grain yield and plant height of several MG 5 varieties from the Early Planted and Full-Season Arkansas Soybean Performance Trials, average grain yields from both tests were similar and slightly shorter plant heights at the earlier planting date.   By planting a MG 5 variety three to four weeks earlier than normal may result in a plant being 1 to 6 inches shorter than at the normal planting date.  Another concern to keep in mind is that planting MG 5 soybean earlier will increase the number of days between planting to R8.  Data from Dr. Larry Heatherly in Mississippi showed the average number of days between planting to R8 for a MG 5 soybean planted in late-April and late-May increased as much as 20 days for the late-April planting versus the late-May planting.  The main reason for this increase in days to maturity for the earlier planting is the increase in vegetative growth prior to R1.  This difference in days to maturity for soybean and when other crops (corn, rice, cotton, etc.) will be harvested should be considered to maximize harvest efficiency.

 


«
»