Water Quality-Quantity Issues in Mid-South Rice Production

Transcription

1 Water Quality-Quantity Issues in Mid-South Rice Production USEPA Region 6 Agricultural Issues Seminar Series 26 May 2009 Joseph H. Massey, Ph.D. Associate Professor Department of Plant & Soil Sciences Mississippi State University

2 Why is this relevant?

3 Rice Production in the U.S. The majority of ~ 3 million rice acres grown each year in U.S. are grown in EPA Region 6, esp. along the Mississippi River Valley Alluvial Plain.

4 Why is rice important?

5 International Rice Research Institute (2005) By 2030, global rice yields will need to increase by ~ 40% to meet rising demand

6 World s Top 5 Rice-Exporting Countries in 2004 USDA (2005) Country Rice Export Volume (MT) Thailand 10,137,000 Vietnam 4,295,000 India 3,100,000 United States 3,097,000 Pakistan 1,900,000 ~ 40% of US rice crop is exported

7 International Rice Research Institute (2005) By 2030, global rice yields will need to increase by ~ 40% to meet rising demand while not affecting the natural resource base adversely.

8 Pesticide Use Intensity in Major U.S. Row Crops Wheat The majority of pesticides used are herbicides, often times applied to standing water. Soybean Crop Rice Cotton Also, ~ 170 kg N/ha applied per season. Corn Source: USDA NASS, Cumulative Pesticide Application Rate (kg a.i. /ha) NPS Runoff Potential

9 Rice herbicides accounted for majority of pesticide detections in rivers/streams draining agricultural regions of eastern Arkansas Mattice et al. (2004)

10 Typical Water Use in Mississippi Delta Crops YMD (2008) Crop Water Use (A-ft/A) Rice 3 Corn 0.8 Soybeans 0.7 Cotton 0.5 ~ One million gallons of fresh water per A of rice Yazoo Water Management District-Stoneville, MS

11 Declines in the Mississippi River Alluvial Aquifer Arkansas Mississippi

12 So what can be done?

13 Intermittent Rice Irrigation Flood Height (cm) wk flood holding period Drying Cycle 1 Drying Cycle Days After Initial Flood Continuous Flood Drying Cycle 3 Less-than-Full Flood

14 Intermittent Rice Irrigation Also reduces CH 4 emissions from rice paddies Increase Rainfall Capture Reduce Water & Energy Use Reduce NPS Runoff

15 Mississippi River Valley Alluvial Plain (The Mississippi Delta ) 6 states covering ~ 31,000 sq. miles Intensive agricultural production Sub-tropical climate 8 of 12 soil orders identified

16 20-yr Average In-Season Precipitation for the Mississippi River Valley Alluvial Plain Total ppt. averages 45 (north) to 60 (south) inches/yr. In-season rainfall averages ~14 to 18 inches. Data source: NOAA

17 Irrigated Harvested Cropland (% of total acres harvested) State Rank (2002) Irrigated Acres (millions) CA TX AR FL MS Map and ranking data source: USDA NASS ~ 90% of ag irrigation in this region derives from groundwater

18 Mississippi River Valley Alluvial Aquifer Shallow, unconsolidated sand and gravel aquifer with thickness ranging from ~ 50 to 150-ft. Used primarily for production of soy, corn, cotton, catfish, and rice. Map credit: US Geological Survey

19 Historical Water Concerns in the Mississippi Delta Flood Control, Levee Management, & Drainage Photo credits: USACE website Mississippi River Flood of 1927

20 More Recent Water Concerns in the Mississippi Delta Water Quality, Aquifer Overdraft, & Minimum Stream Flow Sunflower River YMD (2008)

21 Desoto Sunflower River Mississippi River Bolivar Coahoma Sunflower Tunica Quitman Tallahatchie Leflore Tate Panola Grenada Carroll Yazoo River Two Major River Systems in the Mississippi Delta Washington Sunflower River Humphreys Holmes Issaquena Sharkey Yazoo River Yazoo Warren Miles

22 F.E. Smith (1954) The Yazoo River: Jackson, Miss John James Audubon ( ) In 1821, Audubon described the Yazoo River, as "a beautiful stream of transparent water, covered by thousands of geese and ducks and filled with fish". Audubon image credit:

23 MS Department of Environmental Quality (2008) Today, 29 reaches of Yazoo River are on the MS 303(d) impaired water body list Impairments Sediment Low Dissolved O 2 Pathogens Nutrients Legacy Pesticides Source:

24 More Recent Water Concerns in the Mississippi Delta Water Quality, Aquifer Overdraft, & Minimum Stream Flow Sunflower River YMD (2008)

25 20-Yr Average Declines in the Mississippi River Valley Alluvial Aquifer Mississippi Entire MS delta: Estimated over-draft is ~300,000 Ac-ft/yr. Mississippi River Hill Country Legend Avg. Drop (ft/yr) In the ~300,000 Acre Red-Zone in Leflore and Sunflower Co: Estimated over-draft is ~150,000 Ac-ft/yr. YMD (2008)

26 Declines in the Alluvial Aquifer in Mississippi Mississippi Depth to Groundwater (YMD, 2007) Sunflower Co. (well F051) 100 Depth (ft) y = x R 2 = Aug-80 Aug-84 Aug-88 Aug-92 Aug-96 Aug-00 Aug-04

27 Water Use Permits in Mississippi Yazoo Water Management District (2009) Over 16,000 ground water permits (wells >6-in) in alluvial aquifer plus ~ 2,500 surface water permits in the Mississippi Delta. Cost of a 10-yr well permit: $25 Note: Each red dot represents a permitted ground water well.

28 Declines Alluvial Aquifer in Arkansas Arkansas USGS (2002) In portions of the Grand Prairie, water levels have fallen > 50-ft since Some upper portions of aquifer filled with air. Natural recharge is ~ 67% of current withdrawals.

29 Declines in the Alluvial Aquifer in Arkansas Arkansas Source: Arkansas Natural Resources Commission Ground Water Report (2007)

30 Water Use Permits in Arkansas ANRC (2008) Annual water use fee: $10 per well. Image credit: Arkansas Natural Resources Commission. Each dot represents a permitted site.

31 More Recent Water Concerns in the Mississippi Delta Water Quality, Aquifer Overdraft, & Minimum Stream Flow Sunflower River YMD (2008)

32 Sunflower River Bolivar Coahoma Tunica Quitman Tallahatchie Desoto Tate Panola Grenada Two Major River Systems in Mississippi Delta Sunflower Leflore Carroll Washington Issaquena Sharkey Sunflower River Humphreys Yazoo River Yazoo Holmes Yazoo River Warren Miles

33 Sunflower River (MS) Before 1975, 100 to 125 cubic feet per second (cfs) baseflow provided by aquifer to Sunflower River during dry periods. Riverdry wet Alluvial Aquifer prior to 1975 Base-flow 100 to 125 cfs

34 Sunflower River (MS) By 1990, lowering of alluvial aquifer reduced base flow to only ~ 10 to 20 cfs; this is insufficient to meet water quality standards required by MDEQ. This represents a convergence of water quantity and water quality issues in the Mississippi Delta. River wet Base-flow 10 to 20 cfs Alluvial Aquifer Today

35 Sunflower River Low Flow Project (YMD, 2008) 11 wells being used to augment flow in the Sunflower River during dry periods. Well Field in Cohoma Co. Sunflower River This is an example of why we need to reduce overdraft of the alluvial aquifer. Image credits: Yazoo Water Management District

36 Rice Irrigation Terminology Contour Levees Spill or levee gate Spacing of levees depends on existing slope of field.

37 Laser-Leveling Field to Improve Flood Depth Uniformity & Ease of Water Management Commonly grade to 0.1 to 0.15% slope across field allowing straight-levee rice irrigation.

38 Rice Irrigation Terminology Straight-Levee Rice Straight levees spaced every ~200 to 250 ft.

39 Water-Saving Rice Irrigation Systems (YMD, ) Irrigation System Avg. Water Use (A-ft/A) Avg. Water Savings (%) Contour Levee 3.7 ± Straight-Levee 3.2 ±

40 Rice Irrigation Terminology Multiple (Side) Inlet Irrigation

41 Rice Irrigation Terminology Graphics: P. Tacker, University of Arkansas

42 Water-Saving Rice Irrigation Systems (YMD, ) Irrigation System Avg. Water Use (A-ft/A) Avg. Water Savings (%) Contour Levee 3.7 ± Straight-Levee 3.2 ± Straight-Levee + Multiple-Inlet 2.6 ±

43 Laser-Leveling Field to Improve Flood Depth Uniformity & Ease of Water Management Zero-Grade Irrigation If level field to have no slope, this is called zero-grade rice irrigation.

44 Water-Saving Rice Irrigation Systems (YMD, ) Irrigation System Avg. Water Use (A-ft/A) Avg. Water Savings (%) Contour Levee 3.7 ± Straight-Levee 3.2 ± Straight-Levee + Multiple-Inlet 2.6 ± Zero-Grade 1.7 ±

45 Zero-Grade Rice Irrigation A major downside to Zero-Grade systems is water logging of rotational crops (e.g., soy) The lack of slope exacerbates drainage problems in the Mississippi Delta.

46 Continuous vs. Intermittent Flood Management Flood Height (cm) wk flood holding period Drying Cycle 1 Cycle Time ~ 7 to 10 d Drying Cycle Days After Initial Flood Continuous Flood Drying Cycle 3 Less-than-Full Flood Target = mud in upper paddy

47 Intermittent Rice Irrigation Concerns Asia U.S.?? Scalability Fertility Yield loss Grain quality Weed Control Field size 5 A Field size 40 to >100 A

48 Long History of Continuously Flooding Rice The flooding of rice has been traditionally used to reduce competition from weeds that can t grow under flooded conditions.

49 Scherder et al. (2003) Average of 3-yr Results Soil Saturation Level (%) BYG Control (%) University of Arkansas 20% (dry) 96 27% 97 34% 96 41% 95 48% 96 All six herbicide programs tested effectively controlled weeds under wide range of rice flood conditions in small plot trials. 51% (continuous flood) 96

50 Water-Saving Rice Irrigation Systems (2004 through 2008) Irrigation System Avg. Water Use (A-ft/A) Avg. Water Savings (%) Contour Levee 3.7 ± Straight-Levee 3.2 ± Straight-Levee + Multiple-Inlet 2.6 ± Straight Levee + Multiple Inlet + Intermittent Zero-Grade 1.7 ± ±

51 Water-Saving Rice Irrigation Systems (2004 through 2008) Irrigation System Avg. Water Use (A-ft/A) Avg. Water Savings (%) Contour Levee 3.7 ± Straight-Levee 3.2 ± Straight-Levee + Multiple-Inlet 2.6 ± Straight Levee + Multiple Inlet + Intermittent Zero-Grade 1.7 ± ±

52 Estimated Energy Requirements for Groundwater- Based Rice Irrigation in the Mid-South Bryant et al. (2001) estimates ~1 gal diesel used per A-in water pumped from Arkansas wells < 120-ft. [~139,000 Btu per A-in] Thomas (2006) estimates ~0.7 gal diesel per A-in water pumped in Mississippi. [~97,300 Btu per A-in]

53 Intermittent Rice Irrigation Increase Rainfall Capture Reduce Water & Energy Use Reduce NPS Runoff

54 Rice Water Quality Monitoring Study Sampling & Analytical Procedures Weekly water samples collected from the upper, middle, and lower paddies of each field. Stored at 4C until analyzed using C18 JT Baker Speedisks and GC-MSD (Senseman et al., 2003). Field and lab spikes prepared. Analytes were clomazone, propanil, malathion, pendimethalin, iprodione, lamda-cyhalothrin, propriconazole, cyhalofop-butyl, and azoxystrobin. Recoveries ranged from 65% (l-cyhalothrin) to 107% (iprodione).

55 Runoff Results for MS-01 Site Field Water Loss (m 3 /ha) Clomazone Loss (g/ha) Clomazone Loss (% of Applied) Conventional Flood Intermittent Flood 1953 (50% decrease ) 2 0.4

56 Predicted Long-Term Clomazone Runoff Losses as Function of Flood Treatment Estimated Runoff Loss (% applie Conv: 1.7 +/- 0.7% Int: 0.5 +/- 0.5% Conv Rice Flood Intermittent Rice Flood Year

57 Research Summary Multiple Inlet + Intermittent Irrigation Using intermittent rice irrigation extends the water savings of SL + MI by ~20%. Intermittent irrigation uses ~6% more than 0- grade without associated downsides. Water savings were observed even with partial adoption of intermittent irrigation regime.

58 Research Summary to Date Multiple Inlet + Intermittent Irrigation Rice yield and grain quality have been unaffected by intermittent irrigation (primarily studied Cocodrie variety grown on Sharkey clay soil). Current weed control programs appear able to provide adequate weed control.

59 Intermittent Rice Irrigation Increase Rainfall Capture May help to address water quality and quantity issues in Mid-South rice production. Herbicides are critical to success of intermittent irrigation. Reduce Water & Energy Use Reduce NPS Runoff

60 Additional Measures to Reduce Water Use Simple, low-cost depth gauges being distributed to assist producers in flood management Program optimizes hole size, number, and tubing size for furrow irrigated crops, providing water savings of 25% (Tacker, 2009)

61 Contemplating the decline The decline in the alluvial aquifer occurred in a region that Mississippi boarders one of the largest rivers in the world, and receives 50 inches of precipitation per yr. YMD (2008)