Yield of Chile Peppers Irrigated with Brackish Groundwater and Reverse Osmosis Concentrate Manoj K Shukla, Ph.D. Nakayama Chair and Professor of Soil Physics Department of Plant and Environmental Sciences New Mexico State University, Las Cruces, USA

Collaborators Gurjinder Singh Baath, Graduate student Alison Flores, Graduate student Omar Ozturk, Graduate student Manoj Shukla, Professor Paul Bosland, Professor Stephanie Walker, Associate Professor Randy Shaw, BGNDRF, Alamogordo

World Population Model Projections: 2 of 3 show growth Food Security ? UN Projections in 2010 Model Projections: 2 of 3 show growth Food Security ? Water for Irrigation ? Pest Problems, etc.?

Water Scarcity Across the World IWMI – International Water Management Institute – Annual Report 2007

Las Cruces, NM

Elephant Butt Reservoir T OR C, New Mexico ~2% capacity from 2.6 M acre-ft August 2016

Water Allotment to NM Farms by EBID * 36 acre-inches per acre is considered as full allotment. Less than adequate for most years

Surface Water Availability for Irrigation in NM is declining And will the situation improve???? How is our groundwater?

Depth to groundwater with total dissolved-solids concentration (TDS) greater than 1,000 milligrams per liter in the United States (modified from Feth and others, 1965)

Water Type TDS (mg/L) Fresh <500 Brackish 1000-10,000 Saline 10,000-35,000 Brine 35,000-200,000 Salt Saturated >250,000 Aquifer water salinity is variable Usually deeper aquifers are more saline

Total volume of water in aquifers in New Mexico = 20 billion acre-feet Not available everywhere 75% is too saline 25% < 2000 mg/L NMWRRI Trans-boundary Aquifer Assessment (Hawley and Kennedy, 2004)

Use of Brackish Groundwater: Treated and Untreated Using Untreated for Irrigation will Increase soil salinity Treating brackish water: GOOD for soil How to Treat brackish water?

What to do with the Concentrate? And other constituents? KBHD facility, El Paso, TX BGNDRF, Alamogordo, NM New plant will have 1 MGD, expandable to 6 MGD 27.5 million gallons of fresh water daily (MGD) Deep well injection Evaporation pond Agriculture What to do with the Concentrate? And other constituents? Is Desalination a viable option for cleaning saline water in NM?

Brackish groundwater and Reverse Osmosis (RO) concentrate was provided by Brackish Groundwater National Desalination Facility, Alamogordo, NM Water EC SAR Mg Ca Na K Cl SO4 mg/L Brackish Water 2000 2.77 113 268 216 220 419 848 Brackish water 3300 3.55 191 424 352 233 683 1561 RO Concentrate 5300 5.13 275 600 607 398 1210 2148

Objectives How will irrigation with brackish groundwater and reverse osmosis (RO) concentrate change chile pepper: seed germination? height at different stages? yields? Chile pepper varieties selected were: AZ 1904, NuMex Joe E. Parker, NuMex Sandia Select, LB25, 3441

5 Irrigation Salinity treatments: Tap water of EC 400 ppm (control), Brackish groundwater of EC 1300, 1700, 2000, 2600 ppm 4 seeds placed within 1-2 cm soil depth Irrigation treatments applied at 3-4 days interval Germination recorded every 2 days Healthy plants transferred into bigger plots for survival, growth, and yield Brackish groundwater of EC 2000, 3300 ppm RO concentrate of EC 5300 ppm

Mean Seed Germination 400 1300 1700 2000 2600 Mean Germination percentage did not change with irrigation water salinity Baath et al., 2015

Mean Germination Time (days)  Treatments (ppm) Mean Germination Time (days) 400 (control)  11.19 d 11.02 d 2000 12.15 c 11.95 c 3300 14.10 b 13.99 b 5300 14.95 a 14.88 a LSD (0.05) 0.69 0.52 But time to germination increased with increasing irrigation water salinity

On day 40, differences were observed Initially there were no differences in mean height of 6 chile pepper cultivars with increasing irrigation water salinity On day 40, differences were observed Subsequently differences started to become more pronounced 400 ppm 2000 ppm 3300 ppm 5300 ppm

Days to Flowering decreased with increasing irrigation water salinity Treatments Experiment 1 Days to flowering Experiment 2 400 (control)  113.35 a 112.70 a 2000 111.65 a 111.45 a 3300 106.25 b 105.80 b 5300 103.90 b 105.35 b LSD (0.05) 2.72 2.93

All chile peppers irrigated with the same type of water had similar biomass yields Yields became significantly lower with increasing irrigation water salinity

Early fruiting observed in brackish and RO water treatments 400 mg/L 2000 3300 5300 Yield decline observed for chile peppers irrigated with water > 2000 mg/L Early fruiting observed in brackish and RO water treatments

Photosynthetic rate, Stomatal conductance and transpiration rate decreased with increasing irrigation water salinity

What to do with RO concentrate? Irrigate Halophytes? Chile peepers show yield decline when irrigated with brackish groundwater and RO concentrate What to do with RO concentrate? Irrigate Halophytes? Potential forage crops?   Season 1 Season 2 Species Treatment (mg/L) Fresh Wt (g) ± SE H. Vulgare L. 530 20.67 ± 1.01 30.78 ± 1.46 a Barley 3300 20.53 ± 2.49 29.26 ± 1.37 a 5300 17.78 ± 1.88 24.05 ± 0.98 b 6700 20.03 ± 2.66 31.32 ± 0.80 a xTriticosecale 13.99 ± 0.53 c 14.03 ± 0.87 Triticale 15.04 ± 0.49 bc 13.08 ± 1.28 Wheat x Rye 16.71 ± 1.17 ba 10.93 ± 0.99 18.70 ± 0.99 a 12.64 ± 1.04 Flores et al., 2016; Ozturk et al., 2017

Summary For Chile Peppers, irrigation with increasing water salinity resulted in: Delayed Germination Early flowering Decrease in plant height after 40 days Decrease in total biomass Decrease in evapotranspiration Low photosynthetic rate, transpiration rate, and stomatal conductance Brackish groundwater should be treated prior to irrigation and the RO concentrate could be used to grow salt tolerant food or forage crops (halophytes) away from chile fields

Acknowledgement Grad and Undergrad students and postdoc (Flores, Sharma, Ozturk, Baath, Fernandez, Gonzalez) “John" Kaichiro and Tome Nakayama Professorship and Chair endowment Brackish Groundwater National Desalination Facility, Alamogordo NMSU Agricultural Experiment Station WRRI NMSU

Thanks