Estimating Pesticide Losses Within Indiana

 

November 5, 2001

 

Bernie Engel and Kyoung Jae Lim

Agricultural and Biological Engineering

Purdue University

 

The NAPRA (National Agricultural Pesticide Risk Analysis) model was enhanced. An overview of the most significant enhancements is provided below. A series of five workshops were held describing the NAPRA model and providing hands on training in its application. The NAPRA model can be accessed on the WWW at http://pasture.ecn.purdue.edu/~napra/.

 

The NAPRA WWW system was run for the three most widely used pesticides for corn, soybeans, and wheat within Indiana. The application rates of pesticides were set at the average application rate for each pesticide within Indiana as determined by the Indiana Agricultural Statistics Service. The STATSGO soil data were used to provide the soil properties for the model runs. The model was run only for areas that are cropped or potentially cropped based on the Indiana GAP land use map. Other model inputs are described in the sections below. The average annual pesticide losses estimated by NAPRA were mapped within GIS using the STATSGO soil layer. The maps for pesticide losses are contained in a section that follows. Electronic copies of the maps are also available at the NAPRA WWW site http://pasture.ecn.purdue.edu/~napra/.

 

 

Enhancement of the NAPRA WWW System

 

In the previous nutrient enabled NAPRA WWW, only one pesticide could be simulated at a time.  Since multiple pesticides are often applied to the field during the cropping season, the NAPRA WWW was modified to enable users to simulate multiple pesticide applications.   For practical purposes, up to 6 pesticide applications to a crop were enabled in the NAPRA WWW system.

 

The National Soil Information System (NASIS) (NRCS, http://nasis.nrcs.usda.gov/) data for 80 counties in Indiana were added to the ORACLE database to provide more specific soil information for the NAPRA WWW system.  It provides more detailed soil information than that of State Soil Geographic (STATSGO) (USDA, NRCS, 1994) soil data.  However, NASIS is not related with spatial location, and thus it is used only in the NAPRA WWW system when estimating pesticide losses for fields.

 

To estimate soil erosion in GLEAMS 3.0, a modified version of the Universal Soil Loss Equation (USLE) is used, and one of the factors is a C factor which accounts for cropping systems such as conservation tillage and crop rotation and gives consideration to prior land use, canopy cover, surface cover, and surface roughness.  To help users with NAPRA WWW input, 15 tillage operations with corresponding C factors were included in the NAPRA WWW, so the users need to select only a tillage system description rather than provide C values. 

 

Grassed waterways/ditches and grassed buffers are important components of a soil and water conservation program aimed at reducing erosion.  Waterways provide a nonerodible outlet for runoff.  Grassed waterways can be an effective practice to improve water quality.  To represent grassed waterways/ditches in Indiana, the “Overland-Channel-Channel” option in the erosion component of GLEAMS was used to represent the field (GLEAMS is the hydrologic/water quality model used within NAPRA).

 

 

NAPRA Input Information for Pesticide Loss Maps

 

Pesticides

1)      Continuous corn with three most commonly used pesticides:

-         Atrazine

-         Metolachlor

-         Acetochlor

2)      Continuous soybeans with three most commonly used pesticides:

-         Imazethapyr (Pursuit)

-         Chlorimuron-ethyl (Classic)

-         Glyphosate (Roundup)

3)      Continuous wheat with three most commonly used pesticides:

-         Dicamba (Banvel)

-         Thifensulfuron methyl (Harmony)

-         2-4,D

 

 

 

Planting, Maturity, and Harvest Date

            1) For continuous corn:

            - Plant on May 16

            - Mature on Sept. 22

            - Harvest on Oct 22

            - Assumed 30 % of surface is covered with vegetation (fall chisel)

            2) For continuous soybeans:

            - Plant on May 25

            - Mature on Sept. 18

            - Harvest on Oct 10

            - Assumed 70 % of surface is covered with vegetation (no tillage)

            3) For continuous wheat:

            - Plant on Oct. 5

            - Mature on June 15

            - Harvest on June 25

            - Assumed 70 % of surface is covered with vegetation (no tillage)

 

 

Pesticide Application Dates

1)      For continuous corn:

-         Atrazine: at the planting time

-         Metolachlor: at the planting time

-         Acetochlor: at the planting time

2)      For continuous soybeans:

-         Imazethapyr (Pursuit): at the planting time

-         Chlorimuron-ethyl (Classic): a month after planting

-         Glyphosate (Roundup): a month after planting

3)      For continuous wheat:

-         Dicamba (Banvel): applied on Nov. 1

-         Thifensulfuron methyl (Harmony): applied on March 15

-         2-4,D: applied on March 15

 

 

 

Glyphosate (Roundup): a month after planting

Pesticide Application Rate (Surface Application)

1)         For continuous corn:

-         Atrazine: 1.345 lb/ac

-         Metolachlor: 1.935 lb/ac

-         Acetochlor: 2.385 lb/ac

 

2) For continuous soybeans:

-         Imazethapyr (Pursuit): 0.050 lb/ac

-         Chlorimuron-ethyl (Classic): 0.020 lb/ac

-         Glyphosate (Roundup): 0.860 lb/ac

 

3) For continuous wheat:

-     Dicamba (Banvel): 0.057875 lb/ac

-         Thifensulfuron methyl (Harmony): 0.01875 lb/ac

-         2-4,D: 1 lb/ac

 

 

 

 

 

 

 

 

 

 

 

 

 

Pesticide Properties Used by NAPRA


Water Solubility (mg/L)

T1/2 in

Soil (days)

T1/2 in Foliar (days)

Sorption Coeff.

Koc  (ml/g)

Human Toxicity (ppb)

Fish Toxicity (ppb)

Atrazine

33

60

5.0

100

3.0

658.5

Metolachlor

530

90

5.0

200

70.0

562.6

Acetochlor

223

14

0.0

150

N/A

N/A

 

 

 

 

 

 

 

Imazethapyr

200000

90

30

10

1750

52267.6

Chlorimuron-ethyl

1200

40

15

110

140

1308.8

Glyphosate

12000

47

3

24000

700

168

 

 

 

 

 

 

 

Dicamba (Banvel)

400000

14

9

2

200 

4919

Thifensulfuron methyl (Harmony)

2400

12

3

45

91

19952.6

2-4,D

890

10

5

20

70

4247

 

 

Figure 1.  Crop Land from GAP Land Use. Pesticide Losses Were Estimated for Cropped Areas.


Figure 2.  Eight Digit Hydrologic Unit Boundaries


Figure 3.  Subsurface Drainage System Percentage in 1974. The Subsurface Drainage Percentage Was Used to Estimate the Portion of Pesticides Estimated to Leach Below the Rootzone Delivered to Surface Water.


·    Continuous Corn

 

Figure 4.  Annual Average Runoff for Continuous Corn in Crop Land

Figure 5.  Annual Average Percolation for Continuous Corn in Cropped Areas.

Figure 6.  Annual Average Atrazine Loading in Runoff for Continuous Corn in Cropped Areas.

 

Figure 7.  Annual Average Atrazine Loading in Sediment for Continuous Corn in Cropped Areas.

 

Figure 8.  Annual Average Atrazine Loading in Percolation for Continuous Corn in Cropped Areas.

 

Figure 9.  Annual Average Atrazine Concentration in Runoff for Continuous Corn in Cropped Areas.

 

Figure 10.  Annual Average Atrazine Concentration in Percolation for Continuous Corn in Cropped Areas.

 

 


Figure 11.  Annual Average Metolachlor Loading in Runoff for Continuous Corn in Cropped Areas.

 

 

Figure 12.  Annual Average Metolachlor Loading in Sediment for Continuous Corn in Cropped Areas.

 

 

Figure 13.  Annual Average Metolachlor Loading in Percolation for Continuous Corn in Cropped Areas.

 


Figure 14.  Annual Average Metolachlor Concentration in Runoff for Continuous Corn in Cropped Areas.

 

Figure 15.  Annual Average Metolachlor Concentration in Percolation for Continuous Corn in Cropped Areas.


Figure 16.  Annual Average Acetochlor Loading in Runoff for Continuous Corn in Cropped Areas.

 

Figure 17.  Annual Average Acetochlor Loading in Sediment for Continuous Corn in Cropped Areas.

 

 

Figure 18.  Annual Average Acetochlor Loading in Percolation for Continuous Corn in Cropped Areas.

 

Figure 19.  Annual Average Acetochlor Concentration in Runoff for Continuous Corn in Cropped Areas.

 

Figure 20.  Annual Average Acetochlor Concentration in Percolation for Continuous Corn in Cropped Areas.


·    Continuous Soybeans

 

Figure 21.  Annual Average Runoff for Continuous Soybeans in Cropped Areas.

 

Figure 22.  Annual Average Percolation for Continuous Soybeans in Cropped Areas.

 

Figure 23.  Annual Average Imazethapyr Loading in Runoff for Continuous Soybeans in Cropped Areas.

 

Figure 24.  Annual Average Imazethapyr Loading in Sediment for Continuous Soybeans in Cropped Areas.

 

 

Figure 25.  Annual Average Imazethapyr Loading in Percolation for Continuous Soybeans in Cropped Areas.

 

Figure 26.  Annual Average Imazethapyr Concentration in Runoff for Continuous Soybeans in Cropped Areas.

 

 

 

Figure 27.  Annual Average Imazethapyr Concentration in Percolation for Continuous Soybeans in Cropped Areas.

 

 

Figure 28.  Annual Average Chlorimuron-ethyl Loading in Runoff for Continuous Soybeans in Cropped Areas.

 

 

Figure 29.  Annual Average Chlorimuron-ethyl Loading in Sediment for Continuous Soybeans in Cropped Areas.

Figure 30.  Annual Average Chlorimuron-ethyl Loading in Percolation for Continuous Soybeans in Cropped Areas.

Figure 31.  Annual Average Chlorimuron-ethyl Concentration in Runoff for Continuous Soybeans in Cropped Areas.

 

 

Figure 32.  Annual Average Chlorimuron-ethyl Concentration in Percolation for Continuous Soybeans in Cropped Areas.

 

Figure 33.  Annual Average Glyphosate Loading in Runoff for Continuous Soybeans in Cropped Areas.

Figure 34.  Annual Average Glyphosate Loading in Sediment for Continuous Soybeans in Cropped Areas.

 

Figure 35.  Annual Average Glyphosate Loading in Percolation for Continuous Soybeans in Cropped Areas.

 

Figure 36.  Annual Average Glyphosate Concentration in Runoff for Continuous Soybeans in Cropped Areas.

Figure 37.  Annual Average Glyphosate Concentration in Percolation for Continuous Soybeans in Cropped Areas.


·    Continuous Wheat

 

 

Figure 38.  Annual Average Runoff for Continuous Wheat in Cropped Areas.

 

Figure 39.  Annual Average Percolation for Continuous Wheat in Cropped Areas.

 

Figure 40.  Annual Average Dicamba Loading in Runoff for Continuous Wheat in Cropped Areas.

 

Figure 41.  Annual Average Dicamba Loading in Sediment for Continuous Wheat in Cropped Areas.

 

 

Figure 42.  Annual Average Dicamba Loading in Percolation for Continuous Wheat in Cropped Areas.

 

Figure 43.  Annual Average Dicamba Concentration in Runoff for Continuous Wheat in Cropped Areas.

 

 

 

Figure 44.  Annual Average Dicamba Concentration in Percolation for Continuous Wheat in Cropped Areas.

 

 

Figure 45.  Annual Average Thifensulfuron methyl Loading in Runoff for Continuous Wheat in Cropped Areas.

 

 

Figure 46.  Annual Average Thifensulfuron methyl Loading in Sediment for Continuous Wheat in Cropped Areas.

 

Figure 47.  Annual Average Thifensulfuron methyl Loading in Percolation for Continuous Wheat in Cropped Areas.

Figure 48.  Annual Average Thifensulfuron methyl Concentration in Runoff for Continuous Wheat in Cropped Areas.

 

 

Figure 49.  Annual Average Thifensulfuron methyl Concentration in Percolation for Continuous Wheat in Cropped Areas.

 

Figure 50.  Annual Average 2,4-D Loading in Runoff for Continuous Wheat in Cropped Areas.

 

Figure 51.  Annual Average 2,4-D Loading in Sediment for Continuous Wheat in Cropped Areas.

 

Figure 52.  Annual Average 2,4-D Loading in Percolation for Continuous Wheat in Cropped Areas.

 

Figure 53.  Annual Average 2,4-D Concentration in Runoff for Continuous Wheat in Cropped Areas.

 

Figure 54.  Annual Average 2,4-D Concentration in Percolation for Continuous Wheat in Cropped Areas.