UCCE and UC Davis research efforts to understand the opportunities and challenges for industrial hemp production in California are growing.

As a crop relatively new to California growers and researchers, there is still much to learn about variety choices, how varieties and crop responses differ across regions with different soils and climates, best practices for nutrient management, and pest and disease issues.
Industrial hemp field research efforts began at the University in 2019 after the previous year’s Farm Bill declared the crop should no longer be considered a controlled substance, but rather an agricultural commodity. Hemp is valued for its fiber and edible seeds; however, in California, producing hemp primarily for essential oils, including medicinal cannabidiol (CBD), is thought to offer the best economic outlook. U.S. and California hemp acreage surged in 2019, but fell in 2020.

Hemp Water-Use Study Expands

In a study coordinated by Jeff Steiner of Oregon State University’s (OSU) Global Hemp Innovation Center, drip irrigation trials are underway in California, Oregon and Colorado. Research was conducted in 2020 at the UC West Side Research and Extension Center in Five Points and at the UC Davis campus in addition to three sites in Oregon, with an additional site in Colorado added in 2021. These studies were set up to determine water use of industrial hemp for CBD production under irrigation regimes ranging from about 40% to 100% of estimated crop water requirements, with comparisons of responses observed across the five sites with different soils, climate and other environmental conditions.

The study, funded by USDA and OSU, includes photoperiod-sensitive cultivars, where the flowering response is triggered by shortening day lengths in mid- to late summer in central California, and auto-flower varieties that do not require shortening day length to flower.
Some of the irrigation treatments impose moderate to more severe deficit irrigation to help assess the crop responses to water stress. Deficit irrigation is a method of conserving water by applying less than what might be considered optimum for maintaining rapid growth.
“This plant appears to be quite tough under deficit irrigation,” said UCCE Specialist Bob Hutmacher at the UC WSREC.

“We need to learn more about benefits and drawbacks to stressing the plants,” Hutmacher said.

The auto-flower cultivars tested tend to use less water than the photoperiod-sensitive cultivars because they can be grown in a shorter season. In the San Joaquin Valley, auto-flower cultivars in these studies were ready for harvest in 75 to 90 days after seeding.

“Water use is very variety-specific” Hutmacher said. “Auto-flower varieties may have potential to be grown in the spring and harvested by early summer, or planted in late summer and harvested before winter. With a short-season crop, and with a decent water supply, farmers could consider double-cropping with such varieties, potentially increasing profits.”

Yields were variable, but showed promise for auto-flower varieties.

“In our studies, the highest-yielding auto-flower cultivars have produced 80% to 90% of yields of the much larger full-season, photoperiod-sensitive plants, and some varieties may be equal,” he said.

Hemp Planting Density Studies

In cooperation with Kayagene Company of Salinas, Dan Putnam, UCCE forage crops specialist at UC Davis, and Hutmacher have conducted studies in 2019 and 2020 with two auto-flower varieties to determine the effect of plant density on crop growth, yield and chemical concentrations. Since some of the auto-flower varieties are smaller and earlier maturing than many photoperiod-sensitive cultivars, data in these studies will help determine the tradeoff between higher densities needed to increase yields versus increases in the cost of higher seeding rates.

A key concern for growers is producing a crop with economic levels of CBD or other compounds of commercial interest, while staying within regulatory limits for THC (tetrahydrocannabinol), the psychoactive compound found in marijuana, a related plant. According to CDFA, an industrial hemp crop grown in the state may have no more than 0.3% THC when plant samples are analyzed.

“This is a challenge for growers. You don’t want to risk too high a THC level,” Hutmacher said. “Farmers must test to make sure THC is at a level to meet regulations. If it’s too high, CDFA regulations would require the crop be destroyed.”

The studies provide opportunities for the scientists to assess plant-to-plant variation and impacts of flower bud position on THC and CBD concentrations. The data collected across a range of cultivars differing in plant growth habit may help better inform both researchers and regulatory groups in decisions regarding how to monitor plant chemical composition.
Hutmacher and Putnam are also working with commercial companies to test lines in the field, including Arcadia Biosciences in Davis, Phylos Biosciences in Portland and Front Range Biosciences in Salinas.

“There are a lot of challenges when it comes to estimating maturity with these varieties,” Putnam said. “Each variety will mature at different times, and deciding when is the best time is a key decision. We’re still learning about this issue.”

In 2021, in variety trials also coordinated by OSU’s Global Hemp Initiative Center, data will be collected from studies at up to 12 locations ranging from Oregon, Washington and California in the West to New York, Vermont and Kentucky in the eastern U.S. to compare varieties grown for CBD and other essential oils.

“Our participation in these multi-site trials is important in efforts to identify across very diverse environments and latitudes the plant response in terms of attained levels of CBD and THC,” Hutmacher said.

Launch of Hemp Fertilizer Project in 2021

As a new crop in California, little is known about crop nitrogen needs and application optimization to prevent environmental problems related to overuse. In 2021, a team of UC Davis researchers are launching a three-year nitrogen management trial supported by the CDFA Fertilizer Research Education Program (FREP). An important part of the project is THC and CBD analysis, a costly enterprise.

Three companies are providing seeds or clones for the project: Cultivaris Hemp of Encinitas, Kayagene of Salinas and Phylos Biosciences of Portland. Alkemist Labs of Garden Grove is donating services for analyzing crop samples.

“These are incredibly valuable donations to assist with this project, certainly in excess of $50,000 in donated materials and services from each of those companies,” Hutmacher said. The collaboration with the donors makes the development of environmentally sound nitrogen optimization information for growers possible together with the money provided by CDFA-FREP for the trials.

Agricultural spray adjuvants are materials added to the spray tank when loading the sprayer. They include products classified as activator adjuvants and marketed as wetters/spreaders, stickers, humectants and/or penetrators. Activator adjuvants are marketed to improve the performance of pesticides and foliar fertilizers.

Activator adjuvants can have a place in tree and vine crop sprays, but matching the material to the job can be tricky. A bad match can lead to minor or major losses to the grower. Minor losses can result from excess spreading and pesticide runoff from the target plant. Phytotoxicity can cause major damage.

This article describes ingredients and functions of activator adjuvants commonly sprayed on tree and vine crops. Suggestions regarding activator adjuvant selection are offered. Growers must make their own activator adjuvant use decisions based on experience, particular needs and risk tolerance.

When to Use an Activator Adjuvant

Read and follow the specific instructions on the label. If the pesticide or foliar fertilizer label indicates the product should be used with a certain type or brand of adjuvant(s), that’s what you need to use. For example, the Bravo Weather stik® label cautions against using specific adjuvants and puts the responsibility on PCA or grower court regarding adjuvant use.

If the label includes phrases such as “use of an adjuvant may improve results” or “complete coverage is needed for best results,” then you may want to look into selecting and using an appropriate activator adjuvant.

Before proceeding with use of an activator adjuvant, first look at your existing spray program. Are you already doing the best spray job you can? Good spray coverage begins with proper sprayer calibration and setup. Is your sprayer calibration dialed in for different stages of canopy development? Optimum sprayer setup (gallons of spray per acre, ground speed, fan output and nozzle selection/arrangement) changes from dormant to bloom to early growing season to preharvest sprays. Adjusting your sprayer to best match orchard and vineyard conditions at each general stage in canopy development is the foundation of an effective, efficient spray program. An activator adjuvant will not make up for excessive tractor speed, poor nozzle arrangement and/or worn nozzles. Your money is best spent first dialing in your sprayer(s) for the whole season before considering an extra material in the tank that is not required on the label.

If you have your sprayer(s) dialed in for each orchard and stage of growth, now is the time to say, “OK, I want to think about a little extra boost to my spray job.”

Which Activator Adjuvant to Use

First, know the properties of the pesticide you will use. Does it work on the plant surface or inside the plant? This is a key point in selecting adjuvants. Here is a quick review of the main classifications and characteristics of activator adjuvants as they currently appear in the field. Note: Certain products can provide more than one adjuvant property; that can be beneficial in the field. For example, non-ionic surfactants can work as surfactants and penetrators, depending on use rate.

Wetters/Spreaders

These materials contain surfactants that decrease the contact angle and increase the spreading of the spray droplet on the target. High rates of wetters/spreaders may also increase penetration of pesticides into the target tissue (leaves or fruit), potentially causing phytotoxicity. Excessive spreading of pesticide spray solution and runoff from the target may result when using a new or higher rate of spreader, especially when using silicon “super-spreaders”. Test new combinations of spreader material(s) and spray volume before regular use. Spray volume per acre or adjuvant use rate will probably have to be reduced if a labeled rate of adjuvant provides excessive spreading.

To check for excessive spreading, place a length of black plastic sheeting under several trees or vines in a row. Secure the plastic with spikes, wire staples and/or weights. Spray the new adjuvant and pesticide combination using your current sprayer setup. Reenter the field right after spraying, wearing appropriate PPE, and evaluate coverage. If material is pooling at the lower portion of leaves and/or fruit, excessive spreading is occurring. Check to see if pooling is occurring only in a certain area(s) of the canopy or throughout the canopy. If more spray solution is landing on the black plastic tarp under the trees/vines than between them, then runoff is occurring. Some ground deposit should be expected from standard airblast sprayer use.

Compare the results of your adjuvant test with a similar application of your current pesticide/adjuvant combination on another portion of the row. If there is no pooling or runoff with the new adjuvant in the tank, you can use the adjuvant with confidence. A lack of pooling or run off with the new adjuvant also might mean that your old sprayer setup and tank mix didn’t deliver adequate coverage.

If the test with the new adjuvant showed pooling on leaves and/or runoff on the ground, you have several choices: 1) You can reduce spray volume per acre by replacing some or all nozzles with smaller nozzle sizes on the sprayer in an effort to reduce overspreading. If you saw overspreading on some portions of the canopy but not others, reduce nozzle size only on the part of the spray boom that targets the over-sprayed part of the canopy. Recheck spray coverage if nozzling changes were made. 2) Reduce the adjuvant rate and recheck coverage/spreading. 3) You can go back to your established program without the new adjuvant.

What’s the “best” course of action? That depends on your farming operation. Reducing spray volume per acre means more ground covered per full spray tank, a potential time and cost savings. If spraying is done during the heat of the day in hot, dry climate, spray water evaporation is a major issue, and it may be best to keep the higher spray volume and reduce the spreader rate or eliminate it entirely. Checking coverage and overspreading allows you to make the best decision possible; avoid damage and, hopefully, save money. All farming operations are different. Make the choice that best fits your farm.

Stickers

These adjuvants can increase the retention time of the pesticide on the leaf and reduce rain wash-off. They may limit movement of systemic pesticides into the plant and are probably most beneficial when used with protectant materials (cover sprays). Do you overhead irrigate? Is there rain on the horizon? If you answer yes to either one of these questions, you may benefit from using a sticker.

Humectants

Under low humidity conditions, humectants can help reduce spray droplet evaporation before and after deposition on the plant. This is especially valuable when small droplets and/or materials that must be absorbed into the plant (systemic pesticides, PGRs, nutrients, etc.) are used in the summer under high temperature and low relative humidity conditions.

Penetrators

Frequently used with herbicides, these products include oils (petroleum, vegetable or modified vegetable oils) and non-ionic surfactants used at higher rates. In crop sprays, penetrators can be used to increase absorption of systemic pesticides (e.g., oil with Agri-Mek) as well as translaminar materials. Penetrator adjuvants should be used with caution or avoided entirely with surface active pesticides such as cover sprays or else phytotoxicity may result. Finally, some penetrators can increase the rain-fastness of some pesticides.

Do Your Homework

Use a product intended for crop spraying. Many activator adjuvants were developed and intended for use with herbicides. Products that are advertised for use with plant growth regulators should have a higher chance of crop safety compared with those that don’t. This is still no guarantee of a phytotoxicity-free application.

If you choose to use an adjuvant that is not specifically listed on the pesticide or foliar fertilizer label, jar test the planned spray solution first. Use the same spray water source. Include all leaf feeds, other adjuvants and pesticide(s) that you plan to put in the spray tank. Do this before tank mixing these materials.

A lot of time and money rides on effective pesticide application. Do your homework before the spray tank is filled and you will be well on your way to solid results.

What are the Lodi Rules for Sustainable Winegrowing (LODI RULES), which entered its 16th year in 2021? It is a set of farming practices that result in higher quality winegrapes and wine according to grower and winemaker panelists on a recent webinar entitled ‘Boots on the Ground – A masterclass in sustainable viticulture & LODI RULES,’ a collaboration of the SommFoundation and the Lodi Winegrape Commission and hosted by Elaine Chukan Brown.
On a technical level, LODI RULES is California’s first third-party certified sustainable winegrape-growing program. It was initially developed for growers in Lodi’s Crush District #11 but made available to any California winegrape grower in 2008, expanded to Israel (Golan Heights Winery) in 2017 and Washington State winegrape growers in 2020. LODI RULES encompasses more than 120 farming practices, some of which will be discussed in this article, and is certified by Protected Harvest, a non-profit third-party certifier of sustainable farming programs.

Origins of LODI RULES

From 2003 to 2004, I led the team of 22 winegrape growers, Lodi Winegrape Commission staff, crop consultants, PCAs, UC Farm Advisors, a wildlife biologist and a winemaker to create the first edition of the LODI RULES farming standards. They were based on what the team considered to be the most sustainable farming practices in the Lodi Winegrowers Workbook (Ohmart and Matthiasson 2000.) They were then submitted to Protected Harvest for scientific peer review and endorsed in 2005. The LODI RULES farming standards have been updated twice since then. The program has grown from six growers and 1200 vineyard acres in 2005 to more than 130 growers and 68,000 acres participating in 2021. In 2008, one winery started paying bonuses for LODI RULES certified grapes, and since then, many others have followed suit. One estimate has the annual bonuses exceeding $2 million.

The LODI RULES is organized into six chapters: Business Management, Human Resources Management, Ecosystem Management, Soil Management, Water Management and Pest Management. Each farming practice standard is assigned a number of points based on its assessed level of importance in sustainable winegrowing. To achieve certification, a vineyard must be farmed using practices that score 50% or more of the total possible points in each chapter and 70% of the points in the six chapters combined. The purpose of this scoring is so that a vineyard does not obtain certification while performing poorly in one chapter but very high in all the others. Furthermore, pesticides used in the vineyard are run through a pesticide risk model that calculates risk points for each application. To achieve certification, the risk points from the year’s pesticide applications cannot exceed a rigorous risk points threshold.

Independent professional auditors are contracted by Protected Harvest to audit annually the practices being used in each participating vineyard. An on-site audit is done on any vineyard new to the program and at least every three years after that. A desk audit is done each year for every vineyard not visited on-site. And finally, a grower is chosen at random each year for an audit to be done with a 48-hour notice. This ensures all growers are up to date with their records and practices. The auditors submit their reports to Protected Harvest near harvest for final certification decisions.

I will now highlight a few of the practices in each of the LODI RULES chapters. I will remind you that there are more than 120 practice standards, so I am only able to touch on a few of them. For a complete copy of the LODI RULES farming standards, go to lodigrowers.com in the grower resources section. A farming practice standard is a description of a practice that is required to be done in order to qualify for the points awarded for doing the practice. It is very specific and is described in a way that enables an auditor to clearly verify the practice is being done during the onsite audit of the vineyard being certified.

Business Management

The very first farming practice standard in LODI RULES is the requirement that a grower attend a LODI RULES workshop sponsored by the Lodi Winegrape Commission where they learn how to develop a sustainable management vision plan for their farm. They then need to draft the plan that contains elements that they were introduced to in the workshop.
One might ask, ‘Why is having a sustainable management vision plan for the farm so important?’ I will answer this question by quoting one of my favorite Yogi Berra statements: “If you don’t know where you are going, you may end up some place else!” Sustainable winegrowing is a long-term commitment and needs long-term goals so one has a target to aim for.

Other important practices in the chapter are developing plans for leadership succession within the farming enterprise and business risk management as well as tracking fuel and electricity use following the adage if you can’t measure it, you can’t manage it.

Human Resources Management

The first practice standard in the chapter is to develop a human resources management plan for the farm. Other practice standards relate to team building, employee training and development, employee performance evaluation, employee orientation, providing health care and benefits, safety training and a safety rewards program.

Ecosystem Management

The farming practice standards for ecosystem management focus primarily on parts of the farm that are outside the vineyard. They start with an environmental survey to identify and document important environmental features such as swales, riparian areas, trees, woodlands or vernal pools whose presence would impact how the farming is done in the vineyard.

This is followed by the development of an Ecosystem Management plan for the farm. Then there is a series of detailed farming practice standards for managing important ecosystem elements from cover crops in the vineyard, vegetation adjacent to the vineyard, and, if present, managing woodlands, individual trees, seasonal wetlands or riparian habitat.
There are other practice standards focused on biodiversity and providing nesting boxes for owls, birds and bats. And finally, if a grower has grazing animals on the farming, a grazing management plan needs to be developed and implemented.

Soil Management

The soil management chapter starts with farming practice standards for developing and implementing a nutrient management plan based on vine needs over the season, a soil conservation plan to minimize erosion due to wind and water and a soil map confirmed by soil coring or a soil pit. No tillage and maintenance of a cover crop every vine row gets the most practice points because these practices promote soil health through better drainage, increased organic matter content, increased soil moisture holding capacity and better soil microbial activity.

Soil and vine tissue sampling is required to be done to monitor the nutrient availability and status in vine tissue so as to guide nutrient additions if they are determined to be necessary. Several farming practice standards address nitrogen management due to its importance in vine performance as well as its mobility in the soil, making it prone to leaching into the ground water during winter rains.

Water Management

Water management is a critical element of sustainable winegrowing because it is a precious resource in California as well as the recognized fact that irrigation management is one of the most important ways to influence winegrape quality and therefore wine quality. The chapter starts with a practice standard for the development and implementation of a water management plan that states goals and strategies, followed by a focus on soil water holding capacity, water intake rate and permeability, and irrigation system design and performance measuring and monitoring.

Due to the importance of a properly performing irrigation system, several standards focus on amount of water used, maintenance, distribution uniformity and pump efficiency, with practices specific to micro, sprinkler or flood systems. There are also practice standards for irrigation scheduling based on monitoring vine water demand, level of soil moisture and avoidance of offsite movement of irrigation water.

Pest Management

I have long felt that pest management is one of the most challenging areas of sustainable winegrowing to capture in a set of farming practice standards. That is because, ideally, pest problems in the vineyard are minimal due to the grower having implemented a whole range of preventative practices that preclude the development of pest problems. In other words, much is done to minimize the need for a pest control action. Many of these preventative practices are captured in farming practice standards in other LODI RULES chapters such as Water, Soil and Ecosystem Management.

The Pest Management chapter begins with a standard for development and implementation of an insect and mite management plan. It is followed by one for insect and mite population monitoring and data recording and another specifying economic thresholds for management actions against leafhoppers and mites.

There are several practice standards for disease management due to its importance in developing an economically acceptable yield, quality winegrapes and ensuring the maximum length of life for the vineyard. The first is the development and implementation of a Powdery Mildew management plan given the key role this disease plays in vineyard management. There are practice standards for when to initiate mildew treatments in the early stages of the growing season, the subsequent timing of treatments as the season develops as well as one for managing fungicide resistance. There are also practice standards for managing Botrytis and canker diseases.

Weed and vertebrate pest management are addressed through standards requiring the development and implementation of weed and vertebrate pest management plans followed by ones for monitoring and recording their respective populations.

When a pest problem needs an action, it is often in the form of spraying, whether it is due to an insect, mite, disease or weed. We all appreciate the importance of sprayer calibration and maintenance, but it is often challenging for many growers to do them in a timely manner. Therefore, there are practice standards that thoroughly address these two critical aspects of pest management.

Pest problems change through time and it is important that the LODI RULES keep up with them. New practice standards are periodically added when revisions to the program are made. For example, given the rapid rise in the importance of leaf roll and red blotch viruses and the vectoring of some of them by Vine Mealybug, new sustainable practice standards have been written to address this issue and will be added to the program in 2022.

Certification

I often hear growers say, ‘Of course I farm my vineyard sustainably, why do I need to be certified?’ One reason is that more and more wineries are requiring certification to obtain and maintain a winery contract. That, however, is a cost of doing business requirement, which is not something that is all that inspiring for a grower.

Two primary goals for the team that created the LODI RULES was that implementing them would result in higher-quality winegrapes and help a grower improve their farming operation. Based on the feedback from growers in the program and wineries that are paying bonuses for LODI RULES certified winegrapes, I think these goals have been met.
One can look at a grower farming according to the LODI RULES as doing something similar to what an airline pilot is required to do before flying their plane. They go through a checklist of all the different systems on the plane to ensure they are in working order. Many of the things are obvious, but there are so many that it is easy to overlook some of them in day-to-day flying. The checklist assures that does not happen. As passengers on the plane, we can appreciate the importance of going through this check list! The same can be said for sustainable viticulture.

There are so many practices involved in growing winegrapes sustainably. Many are obvious and are second nature to a grower. However, it is easy to overlook some in the day-to-day frenzy involved in farming. Certifying to the LODI RULES ensures this does not happen.

In the last 10 or more years, water quality regulations that address nitrate in groundwater have expanded dramatically. Starting in 2012, the regulatory agencies charged with protecting California’s water quality have increased their scrutiny of and demands on agriculture. So, it is essential for crop consultants to understand the regulations and how regulations affect their customers.

Regulatory History

The challenges associated with nitrate in groundwater and its sources have been recognized for at least a generation. In 1987, the California State Legislature directed the State Water Resources Control Board to prepare a report on nitrate contamination in drinking water. The convened expert panel reported that agriculture was likely an important contributor to nitrate in groundwater.

In 2012, however, the regulatory landscape changed dramatically. First, a major study of nitrate in California drinking water was published by UC Davis. This sprawling effort, titled Addressing Nitrate in California’s Drinking Water, focused on the Tulare Lake Basin and the Salinas Valley. The multi-volume report was produced by the UC Davis Center for Watershed Sciences. It showed that nitrate problems would likely worsen for the next several decades and that most nitrate currently in drinking water wells was applied to the surface decades earlier. An important conclusion of the report was that agricultural fertilizers and animal wastes applied to cropland are by far the largest regional sources of nitrate in groundwater. Thus, in the last decade, the State and Regional Water Boards have been more assertive in regulating agricultural contributions to groundwater nitrate.

The Central Valley Irrigated Lands Regulatory Program (ILRP) started in the first part of this century with a focus on pesticides in surface water. That focus expanded in 2012 when the ‘Waste Discharge Requirements for the Eastern San Joaquin River Watershed (ESJ) General Order’ was first adopted by the Central Valley Regional Water Quality Control Board (CVRWQCB). This order required grower reporting of nitrogen fertilizer applied to cropland and estimates of the nitrogen removed with harvested crops, so the efficiency of nitrogen fertilizer use could be calculated. Growers record this information in their Nitrogen Management Plans (NMPs) as specified by the CVRWQCB. The reporting of NMP data was carried out through the ESJ Water Quality Coalition, a grower-led intermediary that anonymized the data and provided statistical analysis on a township basis. A component of the statistical analysis is identification of outlier values (i.e., parcels where the nitrogen efficiency is low relative to others in township.) These outlier growers are then targeted for outreach and increasing reporting requirements. Growers in all regions of the Central Valley are represented by coalitions. Nitrogen reporting requirements are now in place for all Central Valley regions and crops with the exception of rice.

In 2018, the State Water Board stepped into the picture and revised the ESJ Order to include new provisions to be precedential to all regional boards. The precedents adopted include reporting of nitrogen application (A) to and removal (R) from cropland, reporting of irrigation water used, testing on-farm domestic wells for nitrate and reporting nitrate exceedances to the well users. With these new requirements, the NMPs became the Irrigation and Nitrogen Management Plans (INMPs). The regional boards were directed to use both A/R and A-R (the nitrogen efficiency ratio and the total excess nitrogen, respectively) to evaluate compliance. All regional boards are required to adopt these precedents into orders by February 2023. The CVRWQCB updated its ILRP orders in 2019.

Another major nitrate-related regulatory effort in the Central Valley is the Central Valley Salinity Alternatives for Long-Term Sustainability (CV-SALTS). This is a multi-stakeholder effort that seeks to manage the long-term loading of salts in the Central Valley. Of interest here is the focus on nitrate. The CVRWQCB adopted the regulations proposed by the CV-SALTS stakeholders in 2018. The goals of CV-SALTS regulations are “1) to ensure a safe drinking water supply; 2) to achieve balanced salt and nitrate loadings; and 3) to implement long-term and managed aquifer restoration programs where reasonable, feasible and practicable.”

While the CV-SALTS process affects all discharges in the Central Valley, each of the above goals represent challenges to growers in terms of costs of compliance and improving nitrogen fertilizer management. Fortunately for growers, the administration of regulatory requirements is handled by the coalitions that were established for the ILRP.

Looking again at 2012, the Central Coast Regional Water Quality Control Board (CCRWQCB) adopted its first order to require reporting of nitrogen applications. This information was reported directly to the Regional Water Board. Just this year, the CCRWQCB adopted the updated “Ag Order 4.0,” incorporating the ESJ precedents and setting long-term limits on excess nitrogen applied to crops. Farming operations must now submit information on nitrogen applied to and removed from cropland. The order includes a schedule of targets for excess nitrogen fertilizer roughly defined as A-R. After 2026, specific excess nitrogen targets are in place for all crops. Those targets rachet down from 300 lbs/ac in 2026 to just 50 lbs/ac in 2050. For reference, the CCRWQCB estimates that currently only approximately 6% of the acres of high-value crops meet the 2050 benchmark.

The situation in the Central Valley is different than in the Central Coast. The Central Valley coalitions have developed a methodology to determine what those targets should be on a township basis. The methodology, a sophisticated modelling effort for the entire Central Valley, has been approved by the CVRWQCB Executive Officer and is scheduled to produce target excess nitrogen values in 2023.

The Crop Adviser’s Role

California Certified Crop Advisers (CCAs) are an integral part of the nitrogen management compliance picture. The CVRWQCB determined that CCAs who received special training in nitrogen management are qualified to certify growers’ INMPs. There are now nearly 900 CCAs eligible to certify INMPs.

For several years, CCAs became eligible to certify Central Valley growers’ NMPs through training received via a day-and-a-half in-person conference given once a year and presented by UC faculty. Funded by the CDFA Fertilizer Research and Education Program (FREP), this successfully certified nearly 1,000 CCAs. On October 1, 2020, the certification program changed to a Nitrogen Management Specialty category managed by the International Certified Crop Adviser organization. All CCAs who had the nitrogen management certification were “grandfathered” into the new Nitrogen Management Specialty category. CCAs who had not yet been certified now must take the Nitrogen Specialty category exam to be qualified to sign INMPs. UC staff developed online training modules to assist CCAs in passing the specialty exam. The training is available to any CCA and provides 16 continuing education units (CEUs) for a cost of $120. More information regarding the online training and the specialty exam can be found at certifiedcropadvisor.org/ca-nsp/. CCAs who have the California Nitrogen Management Specialty (CA-NSP) category must obtain eight CEUs in nutrient management and seven CEUs in soil and water management over two years but are still only required to obtain 40 total CEUs to maintain their certification. There is an additional fee required to maintain the CA-NSP.

CCAs may find that certifying INMPs, especially the irrigation portions of the forms, moves them out of the nutrient management comfort zones. Because we all recognize the importance of irrigation management in nitrogen management, we can also realize that it’s a crucial area for CCAs to step into. Information regarding anticipated crop evapotranspiration (ETc) and irrigation water to be applied is required in the INMPs.

Instructions provided with the plans suggest that the UC or coalition may provide the information to complete the ETc question, but the data are not readily available. To resolve the conflicts involving ETc determination, a statewide project was funded to create an accepted clearinghouse of coefficient values for the major crops in California. The project is nearing completion and should go a long way to helping CCAs provide accurate answers for the ETc questions in the INMP. Alternatively, this year, a project involving the National Aeronautics and Space Administration (NASA), the Environmental Defense Fund and a host of other partners will make ETc data available through interactive maps on the web. The project is called OpenET and is set to be released by the end of the year.

FREP is holding its annual conference this year in San Luis Obispo from October 26-28. There will be sessions on OpenET, ILRP water quality coalitions and other nutrient and irrigation management topics. For more information, see cdfa.ca.gov/is/ffldrs/frep/FREPConference.html.

Mark Cady is currently supervisor of the CDFA FREP. His understanding of water quality regulation comes from four years as an environmental scientist with the CVRWQCB. FREP’s role is to fund and facilitate research and education to advance the environmentally safe and agronomically sound use and handling of fertilizing materials. Please visit cdfa.ca.gov/is/ffldrs/frep for more information.