1997 Ornamentals Research Report - AUrora - Auburn University

50 ALABAMAAGRICULTURAL ExPERIMENT STATION
50
ALABAMA AGRICULTURAL EXPERIMENT STATION
These data concur with other work which indicated maximum Table I.Ability of Pine Bark-containing Filter to
isoxaben, oryzalin, and simazine runoff occurs during the first Cleanse Metolachlor Contaminated Runoff
irrigation events following herbicide application.
No rainfall occurred from day nine to 20, and daily
irrigation was applied at one acre-inch. Metolachlor levels in
Day Water received
Irrigation Rainfall
Metolachlor Metolachlor
initial runoff removed by filter
the runoff gradually declined from 19 to 14 micrograms per
cm cm ug/L pct.
liter from day 11 to 20, respectively. There was fluctuation in
the amount of metolachlor removed by the filter during this
time ranging from 0% to 33% from day 12 to 20, respectively.
No filtration trend was observed.
I
2
3
4
5
23
23
23
23
23
0
0
0
trace
0.8
24
25
23
23
24
31
54
42
44
13
From day 21 to 23, another rainfall event occurred. 6 23 14.9 18 8
During these three days, a negative response was detected as
metolachlor filtration dropped to less than -7%. However, the
amount of metolachlor recovered in the pre-filtered runoff
7
8
9
10
23
23
23
23
3.3
27.4
0
0
21
9
15
15
27
39
15
44
declined to less than 10 micrograms per liter for this same II 23 0 19 7
period. Desorption of metolachlor from the filter may have
occurred causing enrichment of the runoff.
Filtration from day one to 10 averaged 31.7% per
day. From day 11 to 20 filtration average declined to 15.5%
12
13
14
15
16
23
23
23
23
23
0
0
0
0
0
17
16
15
14
14
0
18
2
23
2
per day and -0.6% per day from day 21 to 25. There was a 17 23 0 16 21
general decline in metolachlor in the runoff up to day 23 and
during rainfall events.
While complete filtration of metolachlor in runoff
water was not achievable, the potential for use of filters and
18
19
20
21
22
23
23
23
23
23
0
0
0
13.9
5.2
16
I5
14
10
9
23
26
33
-7
-7
using readily available materials, such as peat and pine bark, 23 23 4.4 9 -8
to reduce off-site movement does exist. Container nursery
sites with no capability for retention basins may now consider
other alternatives for remediation of herbicide containing
runoff water. Further development and testing of filtering
systems that are easily constructed and maintained by
container nursery producers is achievable.
24
25
23
23
0
0
17
13
3
16
WLLLCL Wah II~~L iLLIIICVdlJIC. LIIC LnILCIILlal I~N UJC ~n 1IILClh aII1l LL L~
Cyclic Irrigation and Media:
Influence on Container
Leachate and
Ageratum G rowth
DONNA C. FARE, CHARLES H. GILLIAM, AND GARY J.
KEEVER,
Nurseries in the Southeast utilize large volumes of
water to meet irrigation demands of container-grown plants in
pine bark-based media. Environmental awareness has forced
nursery producers to look at production practices that will
reduce water use, reduce irrigation runoff, and improve water
quality of the runoff.
Overhead sprinkler irrigation is the most common
application method for producing container-grown plants. It has
been reported that about 2.6 million gallons of water are needed
to produce an acre of container-grown plants in a growing
season. Alternative irrigation systems, such as trickle, ebb and
flow, and capillary mat, are more efficient in water use than
overhead sprinkler irrigation. However, these are only feasible
when used to irrigate high-value greenhouse crops and largecontainer
nursery stock.
Though many growers are voluntarily conserving
water in response to drought and increasing water costs, wasteful
irrigation practices and excess runoff have been reported in some
nurseries. Milled pine bark is the primary component of
container media in the Southeast. Many amendments have been
evaluated for optimal porosity and water-holding capacity.