Crop Growth Stages are Behind 2008

During my travels this week, I got a good chance to observe crop growth stages. In 2008, this first week of August was also an observation point, so a comparison can be made between 2008 & 2009 growth stages for both soybeans (Table 1) and corn(Table 3) . The majority of the soybean crop is in the R3 stage which is beginning pod. Most of the corn crop is R1-R2 which is silking to blister.

You can see the GDD accumulation chart matches (Table 4) the expected growth stages for corn based off GDD accumulations. So as we progress through the season we can watch the GDD accumulation and predict corn development. Table 5 shows accumulation at OARDC NW Agricultural Research Station from April 1 and May 15 to August 4. We seem to be about 10 days to 2 weeks behind the 2008 growing season in crop development.

Table 1. Comparison of Soybean Stages for Fulton County in 2009 and 2008 During First Week of August (Numbers Represent Number of Fields at this growth stage).

Year	R1	R2	R3	R4	R5	R6
2009	0	9	28	8	4	0
2008	0	1	5	11	15	10

Table 2. Soybean Reproductive Stages.

Stage		Description
R1	Beginning Bloom	One open flower at any node on the main stem.
R2	Full bloom	Open flower at one of the two uppermost nodes on the main stem with a fully developed leaf.
R3	Beginning Pod	Pod 3/16 inch (5 mm) long at one of four uppermost nodes on the main stem with a fully developed leaf.
R4	Full pod	Pod 3/4 inch (2 cm) long at one of the four uppermost nodes on the main stem with a fully developed leaf
R5	Beginning Seed	Seed 1/8 inch (3 mm) long in a pod at one of the four uppermost nodes on the main stem with a fully developed leaf.
R6	Full seed	Pod containing a green seed that fills the pod cavity at one of the four uppermost nodes on the main stem with a fully developed leaf.
R7	Beginning Maturity	One normal pod on the main stem that has reached its mature pod color.
R8	Full Maturity	Ninety-five percent of the pods that have reached their mature pod color. Five to 10 days away from 15% moisture.

Table 3. Comparison of Corn Stages for Fulton County in 2009 and 2008 During First Week of August ( Number Represent Number of Fields at that growth stage).

Year	RT	R1	R2	R3	R4	R5
2009	1	21	17	2	0	0
2008	0	1	6	21	7	1

Table 4. Corn Reproductive Stages.

Growth Stage	Description	Approx. GDDs	Cum.GDDs	Typical Calendar Date
VT	Tassel	60	1300	Jul 13
R1	Silking	60	1360	Jul 15
R2	Blister	300	1660	Jul 27
R3	Milk	200	1860	Aug 5
R4	Dough	140	2000	Aug 11
R5	Dent	300	2300	Aug 25
	1/2 Milkline	220	2520	Sep 5
R6	Black Layer	200	2720	Sep 17

Table 5. GDD Accumulations from April 1 or May 15 to August 4 of 2007, 2008 and 2009 at Northwest Agricultural Research Station, Custer, OH.

Time Period	2009	2008	2007
April 1-August 4	1921	1939	1968
May 15-August 4	1646	1691	1709