1999 Iowa Turfgrass Research Report

In this study the effect of CGA #136872 (Beacon) on seed germination and establishment of Kentucky bluegrass and creeping bentgrass was evaluated. This study started in 1997 and concluded in 1998 at the Iowa State University Horticulture Research Station located north of Ames, IA. The experimental plot was a bare soil area that had been tilled, raked, and prepared for seeding. The soil in this plot was a Nicollet (fine-loamy, mixed, mesic Aquic Hapludoll) with an organic matter content of 3.9%, a pH of 7.0, 3 ppm P, and 76 ppm K.

Individual plot size was 5 x 6 ft. There were three replications with 3 ft barrier rows between replications. CGA #136872 (Beacon) was applied at 20 and 40 g product/acre. Applications were made eight, four, and two weeks, and one day before seeding. The liquid materials were applied at 30 psi using a carbon dioxide backpack sprayer equipped with Teejetâ #8006 flat fan nozzles. A methylated seed oil spreader (SCOIL MSO) was added at 0.25% V/V to all treatments except the control. CGA #136872 (Beacon) was mixed in 283 ml of water per plot which translates to an application rate of 3 gal/1000 ft².

Treatments were applied in 1997. The ‘eight weeks before seeding’ treatments were applied on July 14, the ‘four weeks before seeding’ on August 15, the ‘two weeks before seeding’ on August 28, and the ‘one day before seeding’ on September 11. Seeding took place on September 12, 1997.

There was a heavy infestation of weeds in the plots and border rows at the time of seeding. All weeds were cut off with a hoe and removed. The soil from individual plots was not mixed with adjacent plots. Light raking was performed to make shallow grooves in the soil for the seeds. The plots were split into two 5 x 3 ft subplots. One of these was seeded with ‘Penneagle’ creeping bentgrass at 1 lb/1000 ft² and the other with ‘Award’ Kentucky bluegrass at 1.5 lb/1000 ft². The seeding was done using a drop seeder. The plots were lightly raked following seeding to partially cover the seeds. Rainfall was sporadic during this period so the plot was irrigated daily.

Bentgrass seedlings were first observed on September 18, 1997. Kentucky bluegrass germination was noted on September 26. By October 2, differences in bentgrass cover were beginning to appear but the plants were so small that data were not taken. Germination was determined as the percentage of area per plot covered by each species. Percentage cover data were taken in 1997 on October 9, October 14, and November 11 (Table 1 and 2). Final 1997 data for this study were taken on November 11 because winter weather conditions had already set in. At this time, the bentgrass plants had matured but the bluegrass plants were still quite small.

Additional germination data were taken spring 1998. Percentage creeping bentgrass cover data were taken on April 22 and May 13, 1998 (Table 3). Data for Kentucky bluegrass were taken on May 13.

Data were analyzed with the Statistical Analysis System (SAS, version 6.12) and the Analysis of Variance (ANOVA) procedure. Means were compared with Fisher’s Least Significant Difference (LSD) test.

There were observable reductions in percentage cover of creeping bentgrass on October 9 and 14, 1997 even though the differences were not significant. The November 11 data show that the ‘one day before seeding’ treatment of CGA #136872 (Beacon) at 40 g product/A significantly reduced the percentage cover of bentgrass when compared with the untreated control. Although the ‘one day before seeding’ treatment of CGA #136872 (Beacon) at 20 g product/A did numerically reduce the bentgrass cover, the percentage cover was not significantly reduced from the untreated control (Table 1).

Because of the weather conditions in October 1997, the bluegrass did not mature. The plants were still quite small when the final data were taken. There were significant differences (P Ñ 0.06) in bluegrass cover on November 11. The percentage cover of bluegrass treated with 20.0 g product/A at eight weeks, two weeks, and one day before seeding was significantly reduced when compared with the untreated control. In addition, significant reductions were recorded for bluegrass treated 2 weeks before seeding at 40 g product/A (Table 2). These were unusual results for the Kentucky bluegrass and observations will be made Spring 1998 to confirm these results.

In 1998, there were no significant reductions in either creeping bentgrass or Kentucky bluegrass percentage cover but there were numerical differences in bentgrass cover on both dates (Table 3). Percentage bentgrass cover was 10.0% on April 22 and 13.3% on May 13 in plots treated with CGA #136872 1 day before seeding as compared to 40.0 and 43.3% in the untreated plots. Kentucky bluegrass cover was similar in all untreated and treated plots in May 1998.

Table 1. Percentage cover¹ of ‘Penneagle’ creeping bentgrass in the 1997 Carryover Seedling Study.

	Material2	Rate product/A.	Timing of application (before seeding)	October 9	October 14	November 11	Mean cover
				----------------------------- % ----------------------------
1	Untreated Control	NA	NA	32	35	55	41
2	CGA #136872	20.0 g	8 weeks	40	45	73	53
3	CGA #136872	20.0 g	4 weeks	43	43	75	54
4	CGA #136872	20.0 g	2 weeks	30	32	72	44
5	CGA #136872	20.0 g	1 day	22	27	40	29
6	CGA #136872	40.0 g	8 weeks	33	35	65	44
7	CGA #136872	40.0 g	4 weeks	20	20	45	28
8	CGA #136872	40.0 g	2 weeks	20	23	53	32
9	CGA #136872	40.0 g	1 day	5	5	12	7
	LSD0.05			NS	NS	38	NS

¹Percentage cover was estimated as the area per plot covered by creeping bentgrass.

²CGA #136872 was applied with SCOIL MSO at 0.25% V/V.

'Eight-weeks before seeding' materials were applied on July 14, '4-weeks' on August 15, '2-weeks' on August 28, and '1-day' on September 11, 1997. Seeding took place on September 12, 1997.

NS = means are not significantly different at the 0.05 level.

Table 2. Percentage cover¹ of ‘Award’ Kentucky bluegrass in the 1997 Carryover Seedling Study.

	Material2	Rate product/A.	Timing of application (before seeding)	October 9	October 14	November 11	Mean % cover
				----------------------------- % ----------------------------
1	Untreated Control	NA	NA	13	15	53	27
2	CGA #136872	20.0 g	8 weeks	12	17	32	20
3	CGA #136872	20.0 g	4 weeks	17	18	48	28
4	CGA #136872	20.0 g	2 weeks	12	15	25	17
5	CGA #136872	20.0 g	1 day	12	12	35	19
6	CGA #136872	40.0 g	8 weeks	15	17	50	27
7	CGA #136872	40.0 g	4 weeks	12	15	40	22
8	CGA #136872	40.0 g	2 weeks	12	15	35	21
9	CGA #136872	40.0 g	1 day	10	10	40	20
	LSD0.05			NS	NS	(p Ñ 0.06) 18	NS

¹Percentage cover was estimated as the area per plot covered by Kentucky bluegrass.

²CGA #136872 was applied with SCOIL MSO at 0.25% V/V.

'Eight-weeks before seeding' materials were applied on July 14, '4-weeks' on August 15, '2-weeks' on August 28, and '1-day' on September 11, 1997. Seeding took place on September 12, 1997.

NS = means are not significantly different at the 0.05 level.

Table 3. Spring 1998 percentage cover¹ of ‘Penneagle’ creeping bentgrass and ‘Award’ Kentucky bluegrass data for the 1997 Carryover Seedling Study.

				Creeping bentgrass				Kentucky bluegrass
	Material2	Rate product/A.	Timing of application (before seeding)	April 22	May 13	Mean cover		May 13
				----------------------------- % ----------------------------
1	Untreated Control	NA	NA	40.0	43.3	41.7		11.7
2	CGA #136872	20.0 g	8 weeks	53.3	53.3	53.3		11.7
3	CGA #136872	20.0 g	4 weeks	60.0	63.3	61.7		15.0
4	CGA #136872	20.0 g	2 weeks	53.3	60.0	56.7		11.7
5	CGA #136872	20.0 g	1 day	38.3	40.0	39.2		8.3
6	CGA #136872	40.0 g	8 weeks	53.3	53.3	53.3		6.7
7	CGA #136872	40.0 g	4 weeks	28.3	33.3	30.8		8.3
8	CGA #136872	40.0 g	2 weeks	40.0	36.7	38.3		8.3
9	CGA #136872	40.0 g	1 day	10.0	13.3	11.7		11.7
	LSD0.05			NS	NS	NS		NS

¹Percentage cover was estimated as the area per plot covered by either creeping bentgrass or Kentucky bluegrass.

²CGA #136872 was applied with SCOIL MSO at 0.25% V/V.

'Eight-weeks before seeding' materials were applied on July 14, '4-weeks' on August 15, '2-weeks' on August 28, and '1-day' on September 11, 1997. Seeding took place on September 12, 1997.

NS = means are not significantly different at the 0.05 level.

ISU Horticulture:Publications:1999 Turfgrass Report

College of Agriculture