- Author: Nicki Anderson
Community Education Specialist
A Fresh Soil Health Resource
In 2015, a group of graduate students at the University of California, Davis attended a hearing on California's Healthy Soils Initiative. They witnessed firsthand the power of storytelling to captivate an audience, as well as the challenges of communicating uncertainty and nuance regarding the dynamic nature of soil.
They started a seminar to discuss and develop science communication, which evolved into a campaign to raise awareness about the value and importance of soil, which caught the attention of the Natural Resource Conservation Service, and ultimately led to a collaboration to produce educational resources (links below).
Their mission is:
- To inspire the next generation of soil explorers for the benefit of all
- To educate that soils are living bodies that harbor a diversity of life, and support and sustain life as we know it
- To empower young power with solutions to some of our greatest global challenges; solutions that lie right beneath our feet!
After years of work, the Soil Life website has officially launched.
The site includes
1) An interactive, graphics-based introduction to soil science;
2) A media hub of soils-related content, and
3) Clear, actionable ways for people to 'get involved' protecting and promoting soils in their everyday lives.
They have also launched the first video in a 6-part series highlighting the connection between soil and life.
Check out their website,
Watch "The Story of Soil and Food," and
Share with your networks (especially the educators and young people in your lives!)
The website and videos were produced under a UC Davis/USDA-NRCS collaborative project and are part of a national campaign to raise awareness about the value and importance of soil.
- Author: Ben Faber
Topics in Subtropics Newsletter Volume 23 Spring 22
Topics in this issue:
- Phytophthora disease associated with citrus in California
- Is it root rot? Or? The 12 signs of ARR
- New avocado irrigation study
- GEM vs Hass?
- Area-Wide Treatment of ACP
And there are past Newsletters here and
there's a site where you can subscribe
for alerts to future Newsletters.
You can also subscribe to this blog - coming a few times a week
https://ucanr.edu/blogs/blogcore/subscribe.cfm
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- Author: Ben Faber
Why guess how much water to apply to reduce salt damage by going to a simple graphical interface with pull down menus and get a pretty good idea of how to use that water to improve tree performance. Most mature crops are listed, soils, water qualities, and irrigation systems. From UC Riverside - SALEACH Try it, you might like it.
Leaching is essential in irrigated croplands where natural precipitation is insufficient to control salinity buildup. Several useful models exist for salinity management; however, leaching requirement (LR) calculations are based on steady-state approaches that only consider salinity tolerance of crops and irrigation water salinity to estimate the LR. In this study, a web-based soil salinity leaching management model (SALEACH) was developed as an online tool to assist growers for better and easier management of soil salinity to sustain agricultural production in irrigated croplands. SALEACH employs the traditional steady-state approach to estimate LRs but improves outputs by not only considering irrigation water salinity (ECiw) and salinity tolerance of specific crops (ECt), but also root water uptake patterns to account for irrigation system differences, and soil types for differences in hydraulic characteristics, as well as water stress and rainfall input. The SALEACH model can calculate the required irrigation water depth by using the estimated LR or any user-specified leaching fraction (LF) values; it can predict the drainage water salinity and soil salinity in the rootzone based on the applied leaching; and it can estimate relative crop yield for a given LF. SALEACH-estimated LRs were assessed in different soil types and irrigation systems by comparing them with LRs, soil water and drainage water salinity values obtained from an existing steady-state model (WATSUIT) and a transient-state model (HYDRUS-1D). Statistical analyses showed that SALEACH-estimated LRs, soil salinity, and drainage water salinity were all in the acceptable ranges of the corresponding values derived from other models. Thus, we conclude SALEACH is reliable and can be employed by practitioners to produce satisfactory estimations of LRs and soil salinity by considering the soil, crop, water quality, and irrigation system. Adoption of the model can improve water use efficiency and reduce groundwater pollution.
- Author: Ben Faber
If you can sell your cowpeas, fava beans and barley, you can make money in Spain and apparently not use any more water than if just growing the mandarins. And coastal growers should look at the fresh market. Have you ever tasted a fresh green cowpea or fava bean? Pretty darn good and consumers think so, as well.
A Diverfarming project study compares the environmental footprint and the economic performance of traditional mandarin monocropping as opposed to growing mandarin intercropped with herbaceous crops and the use of deficit irrigation
The transformation towards intensive agriculture has led to agricultural practices in Europe that have centred on increasing the yield and reducing costs in recent decades, and which involve a major dependence on external sources of agrochemicals and energy. These intensive monocropping systems have generated biodiversity losses, water contamination, and high rates of greenhouse gas emissions, as well as degrading the soil and reducing the ecosystem services.
Faced with this situation, the European Diverfarming project has trialled the diversification of crops throughout the European Union, seeking the best practices to combine crops and focusing on reducing inputs to find the best options to preserve the sustainability of the systems and increase the resilience of the European agricultural sector. To do so, it is also necessary to know the impacts of these practices both at environmental as well as economic level.
With the aim of knowing the environmental footprint and the economic performance of the introduction of herbaceous crops among the alleys of the mandarin trees using controlled deficit irrigation in a mandarin grove located in the Region of Murcia, a team of researchers from the Universidad Politécnica de Cartagena have carried out a life-cycle assessment of the crop and an evaluation of the costs and income of the farm for the three years that the experiment in this case study was carried out.
Although the growing area increased with the introduction of the herbaceous crops (in this case purslane, cowpea, broad beans, and a barley-vetch mix), no detrimental effects occurred in terms of exhausting resources, acidification, or global warming. Therefore, the practice of intercropping did not cause additional contamination or other environmental impacts. This, in addition to the results of the increase in nitrogen and organic carbon content and in the soil and the reduction in erosion and run-off makes the introduction of herbaceous crops in the alleys of the mandarin trees a good sustainable environmental option to cope with the current challenges of the sector.
In economic terms, the financial security of the agricultural community also becomes a key element for successfully adopting diversified systems. This study highlights, through the economic assessment, that intercropping can lead to an increase in production costs, mostly related with a greater demand for labour in comparison with monocropping. However, the study also concludes that “the correct choice of intercropping practices can bring economic advantages”. The results showed that the mandarin crop with purslane and broad beans as intercrops could be profitable and reduce the risk for the grower against volatile prices in the main crop.
In this way, considering all the potential environmental and economic benefits of intercropping practices, these systems arise as a tool to move towards more sustainable and profitable agricultural systems. The valorisation of agricultural products that are more respectful to the environment on the part of consumers and the backing of public funding (e.g., direct help to growers who introduce intercropping) are key aspects to drive the adoption of these practices.
- Author: Sandipa Gautam
Citrus mealybug has been increasing issue in the San Joaquin Valley in last 3 years. It has been reported from Kern, Fresno, Tulare, and Madera counties in the past years. It is a hemipteran pest that feeds on plant sap, reducing tree vigor and affects yield. Mealybug excrete honeydew which gets on leaf and fruit surfaces where sooty mold grows.
Mealybugs are soft, oval flat, distinctly segmented insects covered with white mealy wax, giving it a dusted in flour appearance. Females lay eggs in egg sacs loosely held by white cottony flint. Crawlers when hatched are yellowish in color but soon develop waxy covering once they start feeding. Adult females are 3-5 mm long, wingless, with pinkinsh body covered in white mealy wax. Males are winged and take a longer time to develop then females.
Although seasonal phenology of citrus mealybug in the San Joaquin Valley is not well understood, we found actively producing live female populations (with some egg hatch) in first week January. This means that it is just not cold enough for these insects to trigger their overwintering habits. Mealybugs are know to have multiple overlapping generations per year. Females cannot fly and are dispersed either by crawling between trees, assisted transport by ants, birds, wind, machinery or labor.
With the weather warming up, this is a great time to start checking your orchards, especially if you had mealybug infestation last year. Sampling studies that we initiated this week (February 9, first sampling date) already showed crawler activity.
Where to look for crawlers and first instars?
When eggs first hatch, the crawlers are yellowish in color and found around areas where egg sac is. They soon start feeding and develop a dusty white mealy wax covering. Crawlers usually disperse to neighboring leaves and start feeding and are commonly found along the midrib.
- If you still have fruit on the tree, check the fruit. Mealybug likes clusters, check for any signs of mealybug infestation. Eggs can be present on navel end or the areas where fruit is touching, or where the fruit is joined to the twig.
- On leaves with signs of sooty mold - usually found in inside canopy of the tree.
- Between twigs inside canopy of the tree