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LinkedInPosts Tagged: nutrient
AI and sustainable farming focus of May 7 workshop with UC, partners
On May 7, scientists from University of California, Riverside, UC Agriculture and Natural Resources, Colorado State University Extension, Kansas State University, University of Arizona, Central Arizona Project, and USDA-Agricultural Research Service will gather with growers in Palm Desert to discuss how artificial intelligence can be used in agriculture.
“Artificial intelligence can be used by farmers to save water, improve fertilizer efficiency and increase productivity,” said Khaled Bali, UC Cooperative Extension irrigation water management specialist and organizer of the workshop. “At this workshop, growers will hear about the latest research on AI technology for agriculture and about the experiences of growers who are already testing it in their fields.”
Speakers and topics will include:
- Raj Khosla, Kansas State University - AI for precision nitrogen and water management in row crops
- Michael Cahn, UC Cooperative Extension - CropManage decision support tool for irrigation and nutrient management
- Daniele Zaccaria, UC Cooperative Extension - Citrus crop water use and open ET in the low desert of California
- Nan Li, UC Riverside - Estimating soil moisture using remote-sensing and land surface parameters in the Central Valley of California.
- Ali Montazar, UC Cooperative Extension - Promises and pitfalls of drip irrigation in desert cropping systems
- Khaled Bali, UC Cooperative Extension - Deficit irrigation strategies for alfalfa in California
- Philip Waisen, UC Cooperative Extension - Environmentally conscious practices for managing soilborne diseases in low desert vegetable production
- Peter Moller, Rubicon Water - On-farm water conservation projects: surface irrigation
- Ronnie Leimgruber, Imperial Valley grower - On-farm water conservation projects: linear move, basin and subsurface drip irrigation
- Rick Benson, Imperial Valley grower - Alternative cropping systems for the low desert region of California: olives and other crops
The workshop will be held at the UCR Palm Desert Center at 75080 Frank Sinatra Drive in Palm Desertfrom 8 a.m. to 3 p.m. on May 7. It costs $30 per person and includes lunch. Register at https://bit.ly/AImay7.
UCCE advisor helps dairy operators strike a delicate balance to protect groundwater
Over the last 20 years, UC research has shown that dairies in the San Joaquin and Sacramento valleys are potentially major contributors of nitrate and salts in groundwater. To maintain the quality of this irreplaceable natural resource, the California Water Resources Control Board has ramped up regulations to ensure that diary manure and wastewater application isn't contaminating the aquifer.
UC Cooperative Extension advisor Nick Clark is helping farmers in Fresno, Kings and Tulare counties work through the process and continue producing crops sustainably now and in the future. He was hired in 2015 as the agronomy and nutrient management advisor, a title that reflects the importance of understanding the nutrient cycle and extending information to producers. Three other UCCE advisors are also focused on nutrient management.
Clark is working with dairy farmers who are producing crops to feed their herds, as well as farmers who are producing agronomic crops – such as silage corn, forage sorghum, wheat, triticale, alfalfa, rye and oats – to sell to dairies.
“These farmers operate under the microscope of several agencies for complying with environmental regulations and ordinances,” Clark said. Clark informs growers about the fate of nutrients in plants and soil and rules in place to protect water quality, helping them stay in compliance with government regulations. “Water quality regulations are becoming more strict, more complex and more specific.”
At the same time, some of the finer details about nutrient availability are not yet well understood.
Working closely with Luhdorff and Scalmanini Consulting Engineers, a groundwater engineering and consulting firm, Clark and colleagues have set up research trials on four commercial dairies in the San Joaquin Valley and one semi-research dairy farm to replicate a variety of treatments.
“The idea is to take a much closer look at nitrogen cycling in soil and plants to develop precise data about when plant development allows the crop to take up nitrogen,” Clark said. “The nitrogen application needs to be made so it is in the form plants need when the plants can use it. Otherwise, there is an increased chance it can percolate below the root zone and, eventually, into groundwater.”
Nutrient cycling involves advanced science. The majority of nitrogen content of manure is bound up in an organic molecule, which is not plant available. Plants only take up mineral forms of nitrogen – ammonium or nitrate. When the manure is in the soil, its chemistry changes. Timing by which this happens, Clark said, is extremely variable. Composition of manure, air and soil temperature, soil moisture, and soil microbiota all come into play.
“The research is trying to elicit information for Central Valley dairy farmers as to the best time, best rate and methods of application in order to fertilize crops without losing nitrogen to the groundwater,” Clark said.
Another factor that dairy farmers will have to consider is the implementation of the Sustainable Groundwater Management Act. The law, passed by the California Legislature during the 2011-2016 drought, creates local agencies to monitor groundwater extraction and bring that into balance with groundwater replenishment.
Diary operators are facing these new groundwater quality and quantity regulations at the same time new pressures from climate change are impacting their operations. Clark and his colleagues are also addressing climate change mitigation, adaption and resilience.
“We are looking into alternative feed crops for dairies that might help reduce the amount of irrigation water required to grow crops without sacrificing animal nutrition and milk yield,” Clark said.
One promising option is sorghum. UC Cooperative Extension scientists Jennifer Heguy, Jeffery Dahlberg and Deanne Meyer have been collecting data for a number of years on the crop's nutritional value and impact on milk yield. Another potential feed crop is climate-resilient sugar beets.
“Sugar beets have been used in other parts of the United States and the world as cattle feed, but not as much in the San Joaquin Valley,” Clark said.
He is working with UC Cooperative Extension agronomy specialist Steven Kaffka and UCCE animal science specialist Peter Robinson to refine knowledge about sugar beet production under Central California conditions.
“Sugar beets grow readily in the winter in California, so we can take advantage of winter rainfall and a low irrigation requirement. That may help mitigate climate change impacts,” Clark said.
Climate change mitigation may also be achieved on dairy farms by modifying manure application timing and procedure. Applications of manure to cropland has an impact on emission of nitrous oxide, a greenhouse gas 300 times more potent than carbon dioxide. Reducing the amount of manure applications on cropland and incorporating manure solids into the soil may be ways for dairy farmers to reduce their facilities' greenhouse gas emissions.
“We need to know a whole lot more to help farmers to stay in compliance and to deal with farming under new constraints,” Clark said. “Our research objectives are never static, because everything is shifting so quickly.”
Favorable Soil pH: Does It Really Increase Nutrient Use Efficiency?
Nice, very short article - doesn't take more than 5 minutes to read - addressing the general question of soil acidity and nutrient availability for plants. As many of you know, I am a big fan of soil acidity for plant culture but as the article clarifies, acidity is only beneficial down to a point, below which the availability of N, P, Ca, Mg and K drops off too much apparently.
Key here is that favorable pH for plants is in a RANGE from 5.9 to 7.0. Still, if you peruse the included graph closely you get the strong sense that optimum availability of most nutrients is at 5.9, especially the micronutrients iron, copper, manganese and zinc.
Many of our soils for berries in Salinas and Watsonville range from 6.5 to 7.5, so there are many above optimum (for many reasons, I know that). It would be an interesting avenue of research to pursue a soil that is at 5.9 and see how well a crop of berries does there.
Modifying the Nutritional Guidelines for Nitrogen for the Strawberry Variety ‘Monterey'
The question has come up more than a few times from industry participants on how to adjust nitrogen (N) inputs for strawberry varieties more productive and of larger plant size than Albion for which the original DRIS study was done.
Simple math says one could just increase simply N uptake estimate to cover the added fruit and bigger plant, so if Monterey produces 20% more fruit, and is that much larger a plant, one just adds 20% more nitrogen to the standard annual fertility program to make up the difference. However, as simple as this math may seem, it could quite possibly be incorrect, since it is not at all unknown that different strawberry varieties have variations in N content in the fruit and leaves.
The work to determine N content of Monterey compared to that of Albion was done over two samplings (one in early May, the other mid-July) of five fields of Albion and five fields of Monterey. We found that Monterey had marginally higher N concentrations in both the leaves (Table 1) and the fruit (Table 2) on both sample dates. An evaluation of plant size, without fruit, found that Monterey also ran about 20% larger than Albion from the five fields sampled.
From this information, we can say that N uptake is at least as high in Monterey as in Albion per unit of plant growth. That is to say, if a grower expects and has experienced 20-25% increases in fruit yield with Monterey over that of Albion, then the amount of N uptake to support that level of productivity will also be 20-25% higher than for Albion.
We need to be careful here however. This is not a call for growers of Monterey to automatically increase their N fertilizer additions by 25%. If a grower is finding his or her seasonal practices in the lower half of typical grower practice, then an increase in nitrogen application could be tested, but if a grower is already using a lot of N, say above 250 lbs per acre, then that might be enough to absorb the higher N requirement of Monterey.
Table 1: Nitrogen (N) concentrations in dry leaves
|
Variety |
4-5 May |
12-15 July |
|
Monterey |
3.02 % |
2.71 % |
|
Albion |
2.81 % |
2.44 % |
Table 2: Nitrogen (N) concentrations in dried fruit
|
Variety |
4-5 May |
12-15 July |
|
Monterey |
1.28 % |
1.06 % |
|
Albion |
1.22 % |
0.93 % |
Many thanks to the growers who participated in this study, and generously allowed me to tear plants out of their fields for the plant size sampling.
On the topic of vineyard nutrient management, farmers want to know about sheep
The UC Sustainable Agriculture Research and Education Program is working to build an online community for growers facing challenges and trying innovative approaches to how they manage nutrients on the farm. With the help of FarmsReach and Sustainable Conservation, we've been working to build up an online group based on nutrient management to discuss a wide array of practices. For two weeks in January, we hosted a discussion on nutrient management for vineyards, particularly in times of drought.
In a recent Capital Public Radio story on winemakers struggling with groundwater shortages this year, winemaker Chris Leamy said “the drought has helped to spur change and innovation.” When business as usual is not an option, farmers get creative. Through discussion, informational videos, and a tool kit of resources, farmers and UC advisors shared some of the creative ways that growers are adapting to water limitations and building healthy soil in their vineyards.
One discussion to rise to the surface throughout was the use of animals in vineyard systems. Farmers with experience running animals through their vineyards chimed in with valuable insights.
Some thoughts repeated by several growers were:
- Short breeds like babydoll sheep and tall cordons on vines make sheep less able to graze on the canopy. Some growers use electrified deterrents running parallel to the trellis to allow sheep to stay in the vineyard into the summer with no leaf damage. Growers who kept sheep in vineyards year round described eliminating mowing completely.
- Drip lines need to be tall enough to be out of reach from sheep.
- Move sheep frequently to prevent soil compaction.
- One grower runs chickens through the vineyard at the end of the season, but says to avoid the practice if shoot growth has been too vigorous — the added nutrients from the chickens may give vines an unwanted boost in the spring.
- Growers who use sheep in their vineyards describe significant nutrient inputs from sheep, some to the point of eliminating other fertilizers altogether.
You can follow more of the conversation here. The group of participants is growing (94 strong now!) and we'll be hosting future discussions on different topics. This project is hosted by UC SAREP as part of the Solution Center for Nutrient Management. You can join our mailing list to stay up-to-date with our activities, online discussions, and updates to our website.
