Role of Cover Crops in Improving Water Quality and Other Environmental Benefits. Ranjith Udawatta

Transcription

1 Role of Cover Crops in Improving Water Quality and Other Environmental Benefits Ranjith Udawatta

2 Partnership MU USDA-ARS NRCS Chariton County Missouri Department of Natural Resources Chariton County SWCD Associated Electric Cooperative Inc. Missouri Department of Conservation Cover Crop Solutions, Garst, Pioneer Landowners, Farmers, Private Businesses

3 Water Quality: Water Body Total size Assessed (% of total) Impaired (% of assessed) Rivers 3,533,205 miles 16% 44% Lakes 41.7 million acres 39% 64% Estuaries 87,791 square miles 29% 30% USEPA, 2013

4 N and P loss from Agricultural Watersheds in North Missouri P Loss: Range 0.29 to 3.59 kg ha -1 yr -1 Mean 1.36 kg ha -1 yr -1 48% or more of the annual loss occurred during crop free period Runoff volume and sediment loss were highly correlated with P loss Udawatta et al., 2004 N Loss: Range 13 to 19 kg ha -1 yr -1 Mean 16 kg ha -1 yr -1 57% of the annual loss occurred during crop free period Udawatta et al., 2006

5 6-8 MONTHS

6 Major Soils: 49% Armstrong loam, 5 to 9 % slopes, 40% Grundy silt loam, 2 to 5 % slopes, 10% Bevier silty clay loam, 2 to 5 % slopes Long-term ppt 986 mm 63% in April through Sept. Mean temp in July 30 C Mean temp in Feb -6 C. (

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8 Control Cover crop Control Cover crop Runoff m 3 ha -1 Sediment kg ha Control Cover crop Total Nitrogen kg ha -1

9 Changes in Soil Nutrient Status, physical and chemical properties

10 Soil Sampling for Soil Quality: (1) Before treatments (2) Annually Table 2. Standard Soil Quality Analysis Methods Parameter Reference Water stable aggregates Angers et al., 2007 β-glucosidase Dick et al., 1996 glucosaminadase Parham and Deng, 2000 fluorescein diacetate Dick et al., 1996 dehydrogenase Pepper et al., 1995 Microbial diversity Bottomley, 2005 Nematodes Coleman et al., 2004 Mycorrhizal Fungi Sylvia, 1994 Soil DNA Marstorp et al., 2000 Root biology (exudates) Neumann, 2006 Plant growth regulators Sarwar and Kremer, 1995 Glomalin Wright and Upadhyaya, 1998 Bulk density Grossman and Reinsch, 2002 Available water content Udawatta and Henderson, 2003 Cations, CEC, ph, C and Soil Survey Staff, 1984 forms

11 Biofumigants Pesticide Use 1. Natural chemicals are more accepted than synthetic 2. Mainly Mustard family, produces biofumigants and about 15 plant families 3. Cell break: Myosinase enzyme, glucosinolates 4. Isothiocyanate: effective in controlling diseases, insects, nematodes, and weeds. 5. More biomass, break plant material, and mix with soils 6. Reduced use of synthetic chemicals

12 Diseases, Insects, Nematodes, and Weeds

13 Ngouajio et al., 2007

14 Below Ground Corn Soybean Grass Turnip Radish Roots 1. Depth 2. Volume 3. Structure 4. Carbon form (recalcitrant) 5. Root exudates (leaching) 6. Root Turnover (33% NPP fine root) 7. Associated microbial communities, C, exudates, turnover

15 Future Direction 1. Modeling to predict long-term effects of conservation practices by simulating data driven (empirical) and physically based models 2. Scaling up to understand effects of conservation practices on larger watersheds with mixed management 3. Cyber structure for remote monitoring and realtime data/updates on the web 4. Online decision support user friendly tools for agency, farmer, landowner, and general public to evaluate of environmental benefits various conservation practices with cover crops

16 Topography Soil Data MODEL SIMULATION APEX Measured Data Management Precipitation

17 Scaling Up for Larger Watersheds with Mixed Management Practices Gassman et al., 2009 APEX & SWAT

18 Cyber structure N

19 Cover Crops for Sustainable Ag Production and Ecosystem Services