Influence of Kaolin Clay Applications on Blueberry

Yields during Low-Chill Seasons in West-Central

FloridaBielinski M. Santos

Gulf Coast Research and Education CenterIFAS, University of Florida

Crop Protectants

Reduce transpiration and sun scalding.

Based on calcium carbonate, kaolin clay or wax.

Surround WP.

Degradable.

Previous Studies with Kaolin

a b b c a a b

Control 8 d + kaolin 6 d + kaolin 4 d + kaolin0

1

2

3

4

Early Fruit Weight (ton/acre)

a a a b

Why Surround and Blueberries?

Previous study: Kaolin clay application reduced bud temperatures.

What happens during low-chilling winters?

Would kaolin increase the number of chilling hours?

Objective

Determine effects of foliar application programs of kaolin clay on the marketable yield of southern highbush blueberries.

Materials and Methods

Two-year study: 2011-12 & 2012-13.

Gulf Coast REC, Balm, Florida.

3-year-old ‘Jewel’ (1500 plants/acre).

Pine bark beds.

No hydrogen cyanamide.

Materials and Methods

Surround (25 lb/acre).

Regular sprayer (100 gal/acre of water).

Non-treated, Weekly

applications,Biweekly

applications.

Materials and Methods

Application from Sept. 15 to Dec. 15.

Eight harvests starting in early March.

Early and total fruit weights.

160 h ≤45oF between Sept. 1 and March 1 of each season.

Bud Minimum Temp. 2011 (oF)

Treatment

OctoberNovemb

erDecemb

er

None 48 44 35

Weekly 42 39 33

Biweekly

47 43 35

Bud Minimum Temp. 2012 (oF)

Treatment

OctoberNovemb

erDecemb

er

None 45 40 36

Weekly 41 36 33

Biweekly

45 39 35

Treatment Early Totalton/acre

None 1.30 b 2.16Weekly 1.68 a 2.47

Biweekly 1.31 b 2.20Significanc

e * NS

Summary

Surround seems to decrease bud temperatures.

Weekly applications (6 to 8) of Surround improved early yield (+29%).

More research needed in large fields.

What about regular winters?

Thanks!bmsantos@ufl.

edu813-468-6322