Posts Tagged: nitrate

Rx for Flooded Strawberries

The recent flooding on the Central Coast has really put a lot of local strawberry growers in a bad position.  Some fields have been underwater several days to a week or more, which has deprived plants of oxygen and sunlight needed for respiration and growth.   As these plants try to recover, they will likely be severely set back for several weeks.  Other fields that were briefly flooded are silted over and  have completely saturated soils.

Looking beyond our current conditions of just too much water, we need think about what the plan of action is going to be going forward into the spring.  Since in many areas strawberry plants have been set back because they were in saturated, anaerobic soil, growers will need to turn their attention to jump starting growth in their fields once the ground dries out, and becomes aerobic again. 

It will be important at this time to think about nutrition.  It's a fair bet that even fields that received pre-plant fertilizer lost a significant amount of nitrogen from the soil during the flooding and unprecedented rains during the last few months.  We could be wrong about this, so the first thing growers and farm managers should do once they are back out in the fields is take a soil sample and check the mineral N levels, especially the concentration of nitrate, which is the form of nitrogen that strawberry readily take up.   Nitrate-N will also mineralize from the soil organic matter and any organic amendments that were previously incorporated in the soil as the soil becomes oxygenated again.  Soil samples should be collected from 8 to 12 locations in the field from the 0 to 12-inch depth in or near the plant row and composited together.  A subsample of the composited soil should be analyzed for mineral forms of nitrogen (nitrate and ammonium).  We recommend using the soil nitrate quick test to assess the soil nitrate status of your fields in a timely manner. Please refer to this previous article on the how to accurately measure soil nitrate using the quick test.  If you intend to send the soil to a laboratory that can quickly analyze the soil, we suggest shipping the soil sample with blue ice so that it stays cold to prevent mineralization of N in transit.  The laboratory should analyze the sample for both ammonium and nitrate, the two mineral forms of nitrogen that are in the soil.

If the soil nitrate values are below 10 ppm nitrate-N  then the plants will likely benefit from an addition of N fertilizer.  Fertilizers containing nitrate forms of N such as CAN-17, UAN32, or ammonium nitrate would be good to add so that the strawberry plants can immediately take up nitrogen, which should help jump start growth.  The urea and ammonium contained in fertilizer will also mineralize to nitrate, but due to the recent anaerobic conditions and cold soil temperatures, this process may be slower than normal. 

Since this might be the first time that you've run your irrigation system in a while, it'll be good to check before fertigating to ensure that everything is in good order.  Check for broken connections between drip lines and the submains (layflat, oval hose).  Check that valves and pipes are still connected and unbroken and that the pump is functioning well.  These will be all good items to check before putting this system to work after such a long hiatus. 

Photo showing green leaflets starting to push post flood. Photo courtesy Carlos Torres.

Strawberry covered with silt post flood. This plant will survive, albeit delayed. Photo courtesy Carlos Torres.

Changes to Soil Following Application of Mustard Seed Meal and Crab Meal

Below is a look at what happens to a soil following application of mustard seed meal (MSM) at 1.5 T per acre and mustard seed meal (again 1.5 T per acre) + crab meal (500# per acre) as separate treatments two weeks after fumigation with Ally 33  (67% AITC, 33% chloropicrin applied at 340# per acre on Oct 7).

Grower standard was methyl bromide/chloropicrin applied at 350# per acre. Planting took place Nov 3.

A soil sample taken on Nov 7 did not show differences in soil aspects analyzed between any of the treatments, although ammonium - N concentrations were surprisingly high (30 ppm and up) and nitrate - N numbers tended to be quite low (6 ppm and below).

Remarkably, look what has happened in the 4 weeks since that sample.  Bear in mind that the grower has since sprinkled overhead several times and we had a good amount of rain as well.  Commenting continues below the tables.

Unless otherwise indicated, units are in ppm of dry soil.

 Table 1A. Soil analysis from December 7, 2016

Sample	pH	EC (dS/m)	Nitrate – N	Ammonium – N
Methyl bromide grower standard	7.4	0.9	11.3	4.7
Mustard Seed Meal	7.1	1.7*	34*	20*
Mustard Seed Meal + Crab Meal	7*	1.8*	32*	12*

*Student's T-Test; different from grower standard at 5% level of significance.

Table 1B. Soil analysis from December 7, 2016 

Sample	(P)	(K)	(Ca)	(SO4)	(Mg)	(Mn)	Fe	Na in meq/L	Cl in meq/L
Methyl bromide grower standard	51	148	3100	278	178	8.9	18	1.9	3.2
Mustard Seed Meal	54	190*	2933	318	193	19.2*	16	1.5	1.9
Mustard Seed Meal + Crab Meal	60	185*	3100	589	150	20.1*	16	1.5	1.9

 

*Student's T-Test, different from grower standard at 5% level of significance.

 One sees immediately that the pH has fallen, even significantly, in plots treated with mustard seed meal and mustard seed meal + crab meal.  This is not surprising, since in the month's time since the initial sample on Nov 7, the ammonium has clearly nitrified (releasing 2 H⁺ ions per molecule, in turn acidifying the soil) creating a big pool of nitrates which have gone up significantly over the grower standard.

EC has gone up a bit due to the higher nitrates (NOT because of sodium or chloride), and interestingly levels of manganese (Mn) a mineral sensitive to acidification apparently, have soared in both MSM treated plots.  Levels of available potassium (K) have gone up significantly also in MSM treated plots.

Quite interesting on the whole.  By the way, a soil report like this makes for pretty good reading, and outside of the EC which is for the time being a little high in the MSM plots, all the other numbers are right where I like to see them.

Stay tuned on this one; we are following all of this trial through the season.

Backyard chicken post-mortem service boosts biosecurity

Backyard chickens are booming in California, but many owners don't know how to protect their flock from infectious disease. To help keep diseases from imperiling amateur and ultimately commercial operations, the California Animal Health and Food Safety (CAHFS) laboratories offer a free — but underused — post-mortem service for backyard poultry. New research tracks trends in poultry submissions, analyzes major causes of death and calls for raising awareness of this service.

Called the CAHFS Backyard Flock program, this service is funded by the California Department of Food and Agriculture as a biosecurity measure.

"Urban chicken owners generally aren't trained to recognize to recognize signs of illness, there are few if any chicken vets in the city, and online forums are not moderated by experts," says CAHFS researcher Sarah Stinson, lead author of the article.

The study showed that Backyard Flock submissions rose nearly fourfold between 2007 and 2012. Chickens accounted for 91 percent of submissions, and the greatest increases were in Santa Clara, Los Angeles and Sonoma counties. Diagnoses revealed that the birds' digestive and hemolymphatic systems were most commonly affected, and that the most common illness was Marek's disease, a highly contagious virus that can kill up to 80 percent of infected birds.

However, only an estimated 2 percent of amateur poultry keepers are aware of and have used the Backyard Flock program. To decrease the biosecurity risk of infectious diseases in backyard poultry, the researchers recommend advertising this disease testing service as well as reliable information about keeping backyard flocks healthy. For example, backyard chicken websites and online forums could be invited to add links to government websites, programs and information.

Besides keeping their flocks disease-free, people should keep hens in coops that protect them from cats and other urban predators, and give them specially formulated chicken feed from feed stores rather than chicken scratch or scraps. Moreover, even where chickens are legal, it's a good idea to talk to the neighbors before setting up a coop. Ways to earn goodwill include keeping hens in the coop until neighbors are awake, sharing eggs and, most of all, forgoing roosters, which can crow loudly day and night.

Link to full article: Popular Backyard Flock program reduces biosecurity risks of amateur production

Also in this issue of California Agriculture journal:

Testing protocol ensures the authenticity of organic fertilizers

After major "organic" fertilizer suppliers were found using cheaper inorganic compounds, the state gave the California Department of Food and Agriculture the authority to verify organic fertilizers starting in 2010. But there has been no good way to test whether fertilizers are actually organic. Now, UC researchers have developed an inexpensive method for distinguishing organic from synthetic fertilizers. This method assesses N¹⁵, an isotope of nitrogen that is relatively high in organic sources; ammonium, which is relatively low in most organic sources; and the ratio of carbon to nitrogen, which has a characteristic value for a given organic source.

Soil type, crop and irrigation all influence optimal nitrogen management

Groundwater can be contaminated by nitrate, and most of this contamination comes from fertilizer applied to crops. It makes intuitive sense to address this problem by managing nitrogen on farms, and this is the approach recommended by the California State Water Resources Control Board. However, new research shows that nitrate levels in groundwater are also affected by soil type and rainfall, which cannot be managed, as well as by irrigation and crop type, which can. Rather than focusing solely on nitrogen management, the researchers call for best management practices that also include irrigation management and that can be tailored individually to farms.

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These research articles and the entire October-December 2013 issue can be downloaded at: http://californiaagriculture.ucanr.edu.

California Agriculture is the University of California's peer-reviewed journal of research in agricultural, human and natural resources. For a free subscription, go to: http://californiaagriculture.ucanr.edu, or write to calag@ucanr.edu.

The University of California's Division of Agriculture and Natural Resources is the bridge between local issues and the power of UC research. UC ANR's advisors, specialists and faculty bring practical, science-based answers to Californians. Visit ucanr.edu to learn more.

WRITERS/EDITORS: To request a hard copy of the journal, e-mail crllopez@ucanr.edu

UC ANR to train crop advisers in nitrogen management

UC Agriculture and Natural Resources will offer nitrogen management training to certified crop advisers throughout the state.

UC ANR scientists are working with the California Department of Food and Agriculture to develop a curriculum and certification program to protect water quality, as recommended by the State Water Resources Control Board. The classes will begin in January 2014.

Last week (Feb. 20) the State Water Resources Control Board released its recommendations to the Legislature for addressing nitrate in groundwater.

The recommendations are based on a UC Davis study commissioned by the water board and released last March titled “Addressing Nitrate in California's Drinking Water,” which focused on the Tulare Lake Basin of the San Joaquin Valley and the Salinas Valley in Monterey County.

“While we know that farmers have already begun employing techniques to reduce the amount of nitrogen fertilizer that can ultimately end up in our groundwater, we also know that there are additional actions that can be taken,” said Doug Parker, director of UC’s California Institute for Water Resources and leader for the UC Agriculture and Natural Resources water strategic initiative.

“In our training for certified crop advisers, we will apply the latest UC research to refine their methods for helping farmers manage nitrogen more effectively.” Parker said. 

Plants need nitrogen to grow, but nutrients that are not used by the crop may move below the root zone. Nitrate, a byproduct of nitrogen, may infiltrate to groundwater used for drinking water.

For other examples of UC ANR research and extension projects under way to ensure that all Californians have access to safe drinking water and that the state’s farmers can grow enough food to help meet the world’s increasing demand, please visit http://ucanr.edu/News/Healthy_crops,_safe_water. 

Farmers and the environment profit from new UC website

UC Cooperative Extension is rolling out a new website for farmers that will help them save money and protect the environment. CropManage contains a wealth of UC research in a format that makes it easy for growers to apply to their farms.

Conceived by Michael Cahn, UCCE farm advisor in Monterey County, and programmed by the UC Agriculture and Natural Resources web team, the free website – ucanr.edu/cropmanage – allows farmers to quickly calculate the precise fertilizer and water needs of their crops.

“It’s great,” said Salvador Montes, ranch manager at Corey Ranch in the Salinas Valley, who pilot-tested the software last year on lettuce crops. “It’s very accurate in predicting the irrigation times and fertilizer (needs). It actually worked! We didn’t see any significant yield reduction using less water and fertilizer.”

By applying only the exact amount of water and fertilizer to optimize plant growth, the new website keeps farmers from using too much. Overfertilizing in the past has resulted in groundwater contamination with nitrate, a serious concern in the Salinas Valley and other farming regions. In coastal areas, overpumping wells can lead to sea water intrusion into the aquifer.

“Besides, fertilizer and water are expensive inputs,” Cahn said. “Applying more than the crop needs is like throwing money down the drain.”

On Feb. 26, Cahn will offer a mini CropManage workshop during the 2013 Irrigation and Nutrient Management Meeting at the Monterey County Agricultural Center, 1432 Abbott Street in Salinas. The meeting runs from 7:45 a.m. and concludes with a pizza lunch at 12 noon. Following lunch, the one-hour CropManage workshop begins. No reservations are required.

“Inspiration for this project,” Cahn said, “came from local growers who expressed a need for software to help them use the quick nitrate soil test and weather-based irrigation scheduling in their farming operations.”

Cahn and his colleagues, Tim Hartz, UCCE specialist in the Department of Plant Sciences at UC Davis, and Richard Smith, UCCE advisor in Monterey County, have been conducting trials for years to determine whether the combination of quick nitrogen testing and weather-based irrigation scheduling could reliably reduce the amount of nitrogen that lettuce growers apply.

“We demonstrated a 30-percent reduction in nitrogen fertilizer application,” Cahn said.

The excitement of such a significant result was tempered by the fact that implementing the research results on individual farms would require some serious math.

“When we introduced farmers to the quick nitrate test, some said they would have to hire someone to manage all the data, keep records and make decisions. I realized that we could make this a lot easier for them by programming software to do the work,” he said.

For example, farmers who wish to use weather data to schedule irrigation for lettuce must sign into CIMIS (California Irrigation Management Information Service) to request an email with reference evapo-traspiration for their locations. The data must be punched into an equation along with the irrigation coefficient for lettuce – a figure that represents how much water the lettuce needs – and the size of the lettuce canopy at the time of irrigation. This time-consuming data collection and manipulation is eliminated with CropManage.

“We’ve figured out how to facilitate all these calculations,” Cahn said.  

CropManage automatically downloads the CIMIS data. The website pulls soil, crop growth and water needs information from a UC research database. The farmer goes to a simple website, names his or her fields, adds the type of irrigation systems to be used and how much water they deliver per hour.  

“In effect, they set up a virtual ranch,” Cahn said.

When the farmer is ready to plant, the type of crop and results of a nitrogen quick test are added.

“The program recommends how long and when the irrigation should run and how much nitrogen, if any, should be added,” Cahn said. “The recommendations are updated automatically, taking into consideration the weather and the crop’s stage of growth.”

Throughout the growing season, farmers can monitor the progress of their farms by viewing online tables where irrigation, fertilization and growth are tracked. At any time, all the data can be downloaded as an Excel file the farmer can using for accounting or making reports.

Corey Ranch manager Montes said he accesses CropManage on a tablet computer.

“It’s very easy to use,” Montes said. “It’s easy to log on, input information and read from the tables. I love it. It’s a great tool and is definitely going to help us manage our water and fertilizer in a better way.”

Currently, CropManage contains information for production of romaine lettuce, iceberg lettuce and broccoli. Strawberries and caneberry data will be added to the system. Research is underway on leafy greens, such as spinach and baby leaf lettuce, so they also can be added.

“Everything we learn in research, we will add to CropManage,” Cahn said. “And by using it, growers can give us feedback on how accurate the system is. This is a fluid product. If growers find something that doesn’t work, we can change it.”

All the information uploaded to CropManage is held confidentially and secure on a UC server, protected with a private email address and password. The CropManage website’s privacy policy outlines setup options for users who wish to remain completely anonymous.

Development of the website was supported by a grant from the California Department of Agriculture Fertilizer Research and Education Program.

For more information about the 2013 Irrigation and Nutrient Management Meeting on Feb. 26 or about CropManage, contact Cahn at (831) 759-7377, mdcahn@ucanr.edu.

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