- (Focus Area) Food
Ryan Williams joins the Nutrition Policy Institute at the University of California, Agriculture and Natural Resources on October 2, 2023 as a new project policy analyst. Ryan completed his dietetic internship program at UC San Francisco Health where he developed in-depth knowledge of medical nutrition therapy, assessment, nutrition interventions, and evaluation of nutrition care. Ryan is also experienced in food service, food production, and food service management. His primary interest is in improving the health and well-being of Americans and is interested in projects that broadly can inform nutrition policies in the US. As a dietetic intern, he worked with NPI on a project to assess the barriers to and recommendations for increasing breastfeeding in five counties in California, among those with the lowest breastfeeding rates. Ryan will be working on two National Institutes of Health projects: the Childcare Water project and the Milk-Tot study.
- Author: Michael Cahn
- Contributor: David Chambers
- Contributor: Tom Lockhart
- Contributor: Noe Cabrera
Minimizing suspended sediments in irrigation runoff is desirable for several reasons. For growers reusing tailwater for watering their crops, they must assure that the water has minimal food safety risks by testing it for generic E coli and/or treating it with chlorine. The concentration of free (or reactive) chlorine is reduced when tailwater contains a high concentration of suspended sediments. Treating a large volume of tailwater with chlorine can be a significant expense over a season so it is important to be able to remove as much of the suspended sediments as possible before treatment.
A second reason is that water quality regulations under Agriculture discharge Order 4.0 requires tailwater discharged into public water ways to not be toxic to aquatic organisms. Pesticides that strongly bind to soil, such as pyrethroids, are carried on the suspended sediments in runoff which can cause toxicity to aquatic organisms that live in creeks and rivers downstream from farms. Also, particulate forms of N and P which bind with the suspended sediments pose a water quality risk to receiving waterbodies such as the sloughs and wetlands along the coast. Both nutrients can spur algal blooms which reduces dissolved oxygen available to fish and other aquatic organisms.
In a previous article we discussed a new approach to using Polyacrylamide (PAM), an inexpensive polymer molecule for reducing soil erosion, to treat sprinkler water. This practice uses a specialized applicator (Fig. 1) to condition water flowing from a well with PAM. An advantage of this method is that the cartridges in the applicator release a small amount of PAM (1 to 2 ppm) into the irrigation water, which flocculates soil particles that could potentially become suspended and transported in runoff. Field tests using a prototype version of this applicator resulted in about 90% less suspended sediment in the tailwater when treated with PAM compared to untreated irrigation water.
Auger ditch applicator
A second approach we developed for reducing suspended sediment in runoff is to use a smart applicator that can automatically apply dry PAM to the runoff water flowing in farm ditches. This type of applicator is suspended on a platform above a ditch and uses a hopper filled with dry PAM and an auger system controlled by an electric motor and small computer to drop PAM down a tube into the flowing runoff (Fig. 2). A weir and float mechanism located upstream are used to monitor the flow rate of the runoff so that the computer can adjust the frequency that PAM is applied. A video at this link demonstrates how the auger applicator operates.
Field testing of the ditch applicator
A yearlong study at a commercial farm showed that the ditch applicator was effective in removing 98% of the suspended sediments transported in runoff (Table 1, Fig. 3). Based on the total runoff measured in a single drainage ditch during the 2022 season (21.5 acre-feet), an estimated 106 tons of sediment were removed (Fig. 4).
Turbidity in the runoff was reduced by more than 99%, and Total P and N were reduced on average by 89% and 60%, respectively, during the season (Table 1, Figs. 5 and 6). These reductions in nutrient load, suspended sediment, and turbidity could greatly improve water quality in water bodies downstream from farms that discharge irrigation runoff.
Table 1. Average concentration of N, P, and sediments carried in irrigation runoff before (upstream) and after (downstream) treatment with the PAM ditch applicator (April – October 2022). Average of 32 paired grab samples from 3 farm ditches. Downstream locations varied from 300 to 500 ft downstream from the PAM applicators.
Ditch applicator vs well applicator
Although more effective at reducing suspended sediment in runoff than the well applicator, the ditch applicator required more maintenance. PAM needed to be added to the hopper once or twice per week during the irrigation season, and sediment that settled in the ditches had to be cleaned out periodically using a backhoe. Also, removed sediment had to be spread back in the fields. The well applicator only required periodic refilling of the cartridges with PAM, and minimizes the amount of sediment that settles out in the drainage ditches.
PAM effects on chlorine requirement
To evaluate the effect of PAM on the quantity of chlorine needed to treat runoff, we performed a laboratory assay on samples of sprinkler runoff collected upstream and downstream of one of the ditch applicators. The turbidity of the upstream (untreated) and downstream samples (PAM treated) was 2276 and 9.5 NTU, respectively. The electrical conductivity of the runoff samples was 1.35 dS/m and the pH was 8.4 before adding chlorine. The main factors evaluated in the assay were sodium hypochlorite concentration and acidification with 10% sulfuric acid. Presumably, acidifying the runoff to a pH of 6.5 should increase the concentration of the more reactive form of chlorine, hypochlorous acid which is more effective as a microbial disinfectant. Residual free chlorine concentration of the treatments was evaluated 2 and 4 hours after adding 12.5% sodium hypochlorite at concentrations ranging 12.5 to 31.3 ul per liter of runoff (100 to 250 ul of 12.5% NaOCl per L of water).
The laboratory assay showed that reducing suspended sediment concentration using PAM increased the efficacy of chlorine treatment of runoff. The free chlorine concentration for PAM treated runoff was more than twice the concentration measured in the untreated runoff for all sodium hypochlorite concentrations evaluated after 2 hours and more than three times the concentration after 4 hours (Fig. 7). Free chlorine concentration in the PAM treated runoff was more than 2.5 ppm two hours after treatment at the lowest concentration of chlorine evaluated (12.5 ul/L) but was less than 0.5 ppm in the untreated runoff. To attain similar chlorine efficacy as PAM treated runoff, untreated runoff would require twice as much sodium hypochlorite (25 ul/L). These chlorine requirements would correspond to 26 and52 gallons of 12.5% sodium hypochlorite to treat and acre-foot of runoff with and without a PAM pretreatment, respectively.
Acidification of the runoff to a pH of 6.5 with sulfuric acid increased the free chlorine concentration in the PAM treated runoff at the highest concentration of sodium hypochlorite (31.3 ul/L) after 4 hours. Acidification did not have a significant effect on free chlorine concentration for the other treatments.
Summary
Both versions of the dry PAM applicators (well and ditch) show promise for greatly reducing soil erosion, as well as helping improve water quality and the efficacy of chlorine for treating tail water reused for irrigation. By considerably reducing the concentration of suspended sediment in irrigation runoff, chlorine can be more effective as a disinfection agent, and better control E. coli and other microbial pathogens that could potentially cause public health risks.
Acknowledgments: We greatly appreciate assistance in fabricating the prototype PAM applicators from RayFab. This project was funded by the California Leafy Green Research Board.
Further reading
Complementary feeding refers to the introduction of foods other than human milk or formula to a child's diet. In response to a request from the Centers for Disease Control and Prevention, the National Academies of Sciences, Engineering and Medicine's Health and Medicine Division convened the Committee on Complementary Feeding Interventions for Infants and Young Children under Age 2 to conduct a consensus study scoping review of peer-reviewed literature and other publicly available information on interventions addressing complementary feeding. The interventions studied took place in the US and other high-income country health care systems; early care and education settings; university cooperative extension programs; the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC); home visiting programs; and other settings. The resulting consensus study report, Complementary Feeding Interventions for Infants and Young Children under Age 2: Scoping of Promising Interventions to Implement at the Community or State Level (2023), summarizes evidence and provides information on interventions that could be scaled up or implemented at a community or state level. Lorrene Ritchie of the Nutrition Policy Institute at the University of California, Agriculture and Natural Resources, was a committee member and contributed to the development of the report.
A recent study finds that comprehensive school-based Supplemental Nutrition Assistance Program-Education, also known as SNAP-Ed, interventions focused on improving wellness policies and increasing physical activity opportunities are associated with better student fitness. Researchers identified predominant combinations of school-based, physical activity-focused SNAP-Ed interventions and then looked at how they affected student fitness. Study data included over 442,000 fifth and seventh-grade students attending nearly 4,300 public schools in California communities with low-income in 2016-2017. Students in schools with SNAP-Ed interventions combining policy changes and improved physical activity opportunities had better cardiorespiratory fitness, as measured by VO2 max. On average, these students had 1.17 mL/kg/min greater VO2max than students at schools without interventions. They also had greater VO2 max compared to students in schools with any other type of intervention combination. This study suggests that focusing on both wellness policy changes and increased physical activity opportunities may have a synergistic effect and may warrant prioritization in SNAP-Ed program planning and implementation. The study, published in Preventive Medicine, was conducted by Nutrition Policy Institute researchers Sridharshi Hewawitharana, Gail Woodward-Lopez, Hannah Thompson, and Wendi Gosliner; Arizona State University researchers Punam Ohri-Vachaspati and Francesco Acciai; and California Department of Public Health researcher John Pugliese.
- Author: Mike Hsu
Nutrition Policy Institute, Impact Justice, ChangeLab Solutions partner with California Department of Corrections and Rehabilitation
Serving slices of watermelon on the Fourth of July is a long-standing tradition at some facilities within the California Department of Corrections and Rehabilitation. But this July, there was something different about the watermelon offered to the approximately 8,000 residents at California State Prison Solano, California Medical Facility and Folsom State Prison.
It was juicy. It was sweet. It was “scrumdiddlyumptious,” according to one resident. And it was grown on a California family farm.
The three institutions are part of a “farm to corrections” project, Harvest of the Month, which aims to serve seasonal, locally grown produce to people who are incarcerated in California, while opening new opportunities for California farmers.
“We appreciate that someone cares enough to introduce this program that gives us something new,” said Jason Romero, a California State Prison Solano resident. “We look forward to what's coming in the future – California has the best stuff, right? – and hopefully we get other varieties of stuff.”
The program – bringing together the Nutrition Policy Institute, the nonprofit Impact Justice, and ChangeLab Solutions in collaboration with CDCR – was officially launched with the watermelon delivery in July. Pluots followed in August, and Bartlett pears were delivered in September.
“It's a ‘multiple wins' kind of an effort,” said Wendi Gosliner, the NPI principal investigator on the California Department of Food and Agriculture specialty crop block grant supporting the project. “The funding is available because the state is looking for state partners to purchase and expand the markets for California-grown fruits and vegetables. And we know that getting more of those fruits and vegetables on the plates of people who are incarcerated would be a huge bonus for them.”
California State Prison Solano resident Patrick Range said that, after tasting pluots for the first time through the program, the plum-apricot hybrid is now one of his favorites.
“I think I had five of them that day – and I'm waiting for them to have them again so I can get more; they were so good,” Range said. “It's something I'd never experienced, in the outside world or in prison.”
With rave reviews from residents and staff alike, CDCR – the State of California's biggest purchaser of food – is planning to roll out Harvest of the Month to all 33 of its adult facilities within the next two years.
“Food brings individuals together and introducing new products can give those in the care of CDCR something to talk about, as well as look forward to,” said Lance Eshelman, CDCR's departmental food administrator.
Improving conditions for people within correctional institutions is core to the mission of Impact Justice, which is working with partner organizations across the U.S. to bring fresher, more nutritious food to facilities, in support of residents' physical, mental and emotional health.
“We really want to prioritize the holistic well-being of an individual to help ensure that once they come home from incarceration, they are in a place where they are ready to actually contribute back to society,” said Heile Gantan, program associate with the Food in Prison project at Impact Justice.
Range said that enjoying the fresh produce – and learning more about its nutritional value – is helping him live a healthier, more energized, and hopefully longer life.
“I was a kid that didn't like vegetables; I didn't want nothing to do with vegetables…[but] as an adult, being 46 years of age, I want this for myself – I want to be able to tell someone else, to teach someone else about what I experienced when getting these fruits and vegetables that helped that nutritional factor,” he said.
In addition, Gosliner noted that early research suggests better food can benefit not only the well-being of residents but also of staff, with a calmer and safer work environment.
Partnership built on shared values, priorities
Gosliner and Ron Strochlic, academic coordinator at NPI, saw an opportunity to support “farm to corrections” work through a CDFA block grant, which aims to boost the purchase of California-grown specialty crops.
“CDCR is the state's largest single purchaser of food, so they're a natural place to consider ways to improve food systems,” said Gosliner, who was awarded the grant in 2020 to work with partners to research and develop pathways that encourage CDCR procurement of California produce, as well as nutrition programs for formerly incarcerated individuals. The project produced a report summarizing the opportunities and challenges in bringing more California-grown produce to the state's prison system.
The staff at Impact Justice appreciated that the NPI team brought not only research and evaluation acumen to the partnership but also an abiding concern for the people inside correctional facilities.
“Our grant funding was focused on simply increasing access to and consumption of California-grown specialty crops in CDCR prisons, but our team was very much in alignment around values and really focusing on the health and well-being of residents – highlighting and amplifying residents' experiences and voices,” said Leslie Soble, senior program manager of the Food in Prison Project.
Gantan echoed that sentiment, adding that NPI – which is under the University of California Agriculture and Natural Resources umbrella – also contributed its familiarity with regional food systems, particularly food hubs across the state.
According to the NPI team, engaging food hubs – organizations that aggregate, distribute and market food products from local producers – was a logical way to make a “farm to corrections” match.
“The majority of CDCR facilities are located in rural, agricultural regions, so to us, it was kind of a no-brainer to connect those facilities with the local communities and local farmers in the area,” Strochlic explained.
For the Harvest of the Month project, the partners teamed up with Spork, a Davis-based, mission-driven food hub that sources from growers across Northern California. Spork also aggregates the fresh produce from local farmers and delivers it to participating CDCR facilities each month.
“The farmers are very excited to see the change in the systems at CDCR in food and nutrition and what they're offering to the residents – and they're excited for the potential that this has for a larger, more consistent market,” said Hope Sippola, co-owner of Spork, which emphasizes working with underserved farmers as part of its mission. “We really needed to dig deep to figure out how to successfully implement this change of CDCR purchasing from large distributors to a food hub who sources from local family farms.”
Carolyn Chelius, an NPI project policy analyst and project manager of NPI's Farm-to-Corrections work, said the team hopes, as Harvest of the Month scales up, that they will be able to make Spork's generous investment of time and resources pay off.
“Our ultimate goal is to be able to benefit Spork and help them with their business, but it's been really helpful to have them as champions – people who are really interested in the mission,” Chelius said. “I don't know if this project would have been possible otherwise.”
California produce purchasing requirement helped spur project
Of course, cultivating a strong working relationship with CDCR also was essential. On the heels of AB 822 (a policy requiring state agencies to buy California-produced food over other options if the price differential is 5% or less), another powerful impetus for CDCR was the passage of AB 778 in 2022. It requires that, by the end of 2025, at least 60% of food purchased by state-run institutions must be grown or produced in California.
Eshelman, the departmental food administrator, said the law has challenged CDCR to look closely at its statewide menus and identify items that could be sourced from California growers and producers. He said that, through this project, food service team members have gained new knowledge about food production in the state, such as variability due to regional differences and weather trends.
“The Harvest of the Month program provides an additional resource, and places CDCR in contact with subject matter experts such as food hubs and local growers who can provide valuable insight into what to expect in terms of California-grown or produced food items and their accessibility,” Eshelman explained, adding that NPI and Impact Justice also have been vital resources for CDCR.
Gosliner acknowledges the challenges in retooling processes and procedures across CDCR, the second-largest correctional system in the U.S. With nearly 100,000 incarcerated individuals in its care, CDCR purchases more than $163 million in food each year.
“It's a big ask of a major state institution to reconsider some of their systems for doing something that they do every day: providing food to the people who are incarcerated,” Gosliner said. “It's revolutionary for them to rethink who they're sourcing from, to rethink how much fresh produce they're serving, to rethink the variety of that produce – it's a big lift for CDCR.”
‘This is really the beginning'
As CDCR brings Harvest of the Month to more institutions across the state, the collaborators anticipate that the logistics will smooth out – and that more farmers will be willing to participate.
“If we can add some more facilities and increase the volume, we have a better chance of making it work for growers, so we're really hoping that we can continue with this food hub model,” Strochlic said. “For us it's really important to be able to source from small and medium growers as well.”
And while flyers describing the health benefits of each month's “Harvest” item are currently distributed at the participating facilities, the partners hope they can provide additional nutrition education opportunities for the residents – during their time inside and after incarceration (like in the workshops held across the state).
Soble and Gantan of Impact Justice also noted that all members of the project team have been learning together, exploring “new territory” in growing this innovative partnership.
“I know personally I've learned so much from the NPI folks just about policy related to food and nutrition in California and about different nutrition interventions,” Soble said. “To me, it's been a very valuable and positive partnership.”
Gosliner said that building on those relationships will be crucial, as the movement to improve the services provided to incarcerated individuals continues to gain momentum in the state.
“This is really the beginning of California's work,” she said. “Even though we grow so much of the food here, there are other states in the country that are further along than we are in California. This is really the launch.”
Funding for this project was made possible by the U.S. Department of Agriculture's (USDA) Agricultural Marketing Service through grant AM200100XXXXG032. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the USDA.
