Agricultral Research Service University of California Riverside US Salinity Laboratory Environmental Sciences Dept. Salt Affected Soil and Agricultural Production: Assessment and Management of Salinity by Elia Scudiero and D.L. Corwin Future of Water for Irrigation in California and Israel workshop Davis, California, 18 July 2018 Soil salinity + 2+ 2+ + - 2- - - 2- Salinity refers to the presence of Na , Mg , Ca , K , Cl , SO4 , HCO3 , NO3 , CO3 in the soil solution. -1 Usually measured as electrical conductivity of saturated soil extract (ECe, dS m ) Non-saline (0-2 dS m-1 ) Strongly saline (8-16 dS m-1) Slightly saline (2-4 dS m-1) Extremely saline (>16 dS m-1) Moderately saline (4-8 dS m-1) Salinity in the world •1 billion ha of land is salt-affected (ITPS, 2015) •20% of the ~300 million ha of irrigated farmland is estimated to be affected by salinity. • >50% found in four countries: China, India, Pakistan, and United States Spatial variability of salinity • Central Valley, CA, yield losses causes spatial variations of ca. 3.7 billion USD / year (Welle & Mauter, 2017) crop performance. Near Lemoore, CA 2/16 Guidlines and protocols for field-scale mapping and monitoring of soil salinity (& other soil properties) Corwin, D.L., and S.M. Lesch. Characterizing soil spatial variability with apparent soil electrical conductivity: I. Survey protocols. Computers and Electronics in Agriculture. 46(1-3):103-134. 2005. Corwin, D.L., S.M. Lesch, and D.B. Lobell. 2011. Chapter 10 - Laboratory and field measurements. In: Tanji, K.K. (ed.) Agricultural Salinity Assessment and Management, 2nd edition. ASCE Manuals and Reports on Engineering Practice No. 71. American Society Of Civil Engineers, New York, NY. Corwin and Scudiero (2016) “Field-scale Apparent Soil Electrical Conductivity” In: Methods of Soil Analysis – Vol. 1. Editor: SD Logsdon Soil Science Society of America, Madison, WI, USA 3/16 Field-scale soil apparent electrical conductivity (ECa) Electrical resistivity Electromagnetic induction Several depths of penetration: 0-30, 0-75 cm, 0-150 cm ECa complex measurement: - Salinity (ECe) ↑ - Water Content ↑ - Texture (Sand ↓; Clay ↑) - Gravel (↓) - …. 4/16 Field-scale soil salinity mapping 1. ECa survey 2. ECa-directed soil sampling scheme delineation 3. Soil sampling / lab. analyses 4. ECa-salinity calibration – Linear modeling 5. Appling the calibration at all surveyed locations 6. Spatial interpolation – Kriging – IDW Corwin and Scudiero (2016). SSSA’s Methods of Soil Analysis 5/16 Field-scale salinity monitoring Monitor 3D changes in salinity (or other transient soil properties) can be monitored when surveys are repeated over time. • Efficacy of leaching • Effects of short-term land use change • Example: 2002-2011 soil salinity changes with a Scudiero et al. (2017) Science of the Total Environment (INVITED) cross-section view • Google Earth 6/16 Field-scale maps as ground-truth dataset for regional-scale remote sensing of soil salinity Ground-truth dataset • 22 fields in 2013 (ca. 550 ha) • ~6000 ground-truth cells @ 30x30-m resolution MODEL: 0-1.2 m soil salinity as function of • Multi-year crop performance from remote sensing (Landsat 7) • Land-use • Crop-type • Multi-year climate variables • Soil type 7/16 Field-scale maps as ground-truth dataset for regional-scale remote sensing of soil salinity Read more at: • Scudiero et al., 2014. Geoderma Regional. 2014, 2-3:82-90. • Scudiero et al., 2015. Remote Sensing of Environment. 2015, 169C:335-343. • Scudiero et al., 2017. California Agriculture. 2017, 71(4): 231-238. 8/16 Managing saline soils: use of degraded waters Corwin et al. (2006), Geoderma, 132:369-387 Corwin (2012), J Environ Monit, 14:1576–1596 • 80-acre saline-sodic field (Lemoore, CA) • Shallow water table ~1.5 m • Bermuda grass (Cynodon dactylon L. Pers.) • MANAGEMENT. Drainage water varying in salinity (1.8–16.3 dS m-1) was applied from July 2000 to June 2010 After June 2010, the field was left un-irrigated, due to water shortage during the drought • MONITORING SOIL SALINITY Soil sampled at 40 representative sites (0.3-m increments. To 1.2 m.) at five time points: Aug 1999 Apr 2002 Nov 2004 Aug 2009 May 2011 9/16 Managing saline soils: use of degraded waters March 20, 2000 March 24, 2004 April 8, 2010 August 22, 2012 Drainage water reuse reclaimed non-productive saline-sodic soils Increasing yields over time Irrigation terminated in 2010/2011 because of water shortage (drought). MEAN The reclaimed field quickly returned (less than 2 years) to its original conditions due to shallow water table at 1.5 m Corwin (2012), J Environ Monit, 14:1576–1596 10/16 Managing saline soils: use of degraded waters Current breeding research aims to increase salt tolerance of major crops USDA ARS US Salinity Laboratory • Started with 1000 cultivars of alfalfa • Currently growing 5 varieties that Dr. Devinder Sandhu tolerate up to 18 dS/m irrigation water • Breeding target: 1 or 2 varieties with tolerance thresholds at 20-25 dS/m 11/16 Soil-plant directed site-specific management • Corwin et al. Identifying soil properties that influence cotton yield using soil sampling directed by apparent soil electrical conductivity. Agronomy Journal. 2003, 95:352-364 • Corwin, D. L., and S. M. Lesch. Chapter 6 - Delineating site-specific management units with proximal sensors. In: Oliver, M. (ed.) Geostatistical Applications in Precision Agriculture. Springer, New York, NY. p. 139-166. 2010. • Scudiero,..,Corwin et al. Delineation of site-specific management units in a saline region at the Venice Lagoon margin, Italy, using soil reflectance and apparent electrical conductivity. Computers and Electronics in Agriculture. 2013, 99:54-64 12/16 Soil-plant directed site-specific management Corwin et al. Agronomy Journal. 2003, 95:352-364 13/16 Soil-plant directed site-specific management Continued research … • Multiple soil sensors as covariates for soil properties • Multi-year crop information (yield map, remote sensing) • Unsupervised clustering (fuzzy-c) 14/16 Ongoing work: water & salinity management in micro-irrigated orchards (w/ TH Skaggs) High micro-scale heterogeneity Root-zone imaging of water/salts/nutrients using soil sensor measurements: apparent electrical conductivity, soil reflectance, gamma-ray, micro- elevation Developing sensor-based pedo-transfer functions for solute-transport modeling upscaling 15/16 Conclusions. Dig it – Map it! • Field scale ECa-salinity calibrations allow mapping and monitoring salinity with high accuracy • Marginal land can be used for salt-tolerant crops when low quality drainage water is available • Soil-plant based site-specific management zone can help identify agronomic needs at the sub-field scale 16/16 THANKS FOR YOUR ATTENTION Elia Scudiero, PhD UC Riverside, Environmental Sciences Department & USDA-ARS, U.S. Salinity Laboratory [email protected] 17/43.