In 2020, we established a trial to evaluate soil properties and kidney bean yield following whole orchard recycling of a walnut orchard. Whole Orchard Recycling (WOR) occurs after the productive life of an orchard and is the process of grinding or chipping trees, spreading the wood chips evenly over the soil surface, and then incorporating the biomass into the soil. WOR has become more common in recent years because air quality regulations restrict growers' ability to manage biomass by burning. Additionally, half of California's biomass power generation plants have closed, and those that still operate are no longer paying for wood chips.

While the process of WOR came about due to biomass management restrictions, researchers have been evaluating its potential benefits for soil health and water management. This is because the practice incorporates large quantities of organic carbon (C) into the soil, and soil C influences other soil properties. The California Department of Food and Agriculture (CDFA) Healthy Soils Program (HSP) now recognizes the practice in their incentives program and provides growers with up to $800 per acre for WOR. The San Joaquin Valley Air Pollution Control District also supports growers who recycle orchards with up to $600 per acre.

While there are benefits associated with incorporating large quantities of C into the soil, there are also tradeoffs. The woody biomass of the trees has a high carbon to nitrogen (C:N) ratio. The C:N ratio is the mass of C relative to the mass of N. It is an important characteristic of soil amendments because it influences soil biological activity. When the C:N is high, as it would be with woody biomass, the N is primarily used for microbial energy and maintenance. In other words, the N is ‘tied up' by the microbes and not available for plants.

Our understanding of nutrient cycling and availability is most advanced in almond WOR sites replanted back to almond. Previous research at WOR sites that were replanted back to almond found that doubling the N fertilizer recommendation in the first year could help to avoid reduced growth of the new orchard. We established this trial because more research is needed on WOR in other orchard systems, and when annual crops are subsequently planted rather than orchards. Our objectives were to evaluate soil properties and bean yield following WOR compared to a non-WOR control, and to evaluate two N fertilizer rates. We hypothesized that bean yield might be compromised following WOR due to N immobilization but that a higher rate of N fertilizer might overcome the yield gap.

The trial took place on an approximately 35-acre site near Linden, following the June 2019 walnut orchard recycling that incorporated approximately 70 tons of wood chips per acre (Figure 1). At that time, three approximately 0.5-acre plots were kept without wood chips, as ‘untreated controls'. We then identified three 0.5-acre WOR plots adjacent to each control plot.

Figure 1. Recycled orchard site showing wood chips spread over the field and the depth of wood chips applied.

More information about our procedures can be found in the full report, available from https://ucanr.edu/sites/deltacrops/files/352144.pdf. Soils were sampled three times during the season to inform our fertilizer rates and understand C and N cycling. The UC production manual for dry beans indicates that a bean crop that yields 2000 lb/acre needs approximately 80-120 lb of N to grow the crop. While beans are a legume and can fix atmospheric N and turn it into plant-available N, they do not fix enough to satisfy their own N requirement. They fix about 20-40 percent of their need. Nitrogen inputs for the trial are listed in Table 1. The beans were planted on July 10^th and harvested on October 19^th.

Table 1. Nitrogen inputs in 2020 trial.

Soil samples were evaluated for organic C, total N, and nitrate-N. With the pre-plant samples collected in June, there were no differences in organic C, total N, or nitrate-N between the WOR treatment and control. Total organic C averaged 1.2 percent across all plots, total N averaged 1052 ppm, and nitrate-N averaged 2.78 ppm. In August, prior to sidedress N application, we observed differences in plant size, with plants in the WOR treatments being smaller than those in the control plots (Figure 2).

Figure 2. Bean plants in August 2020, prior to sidedress N application, where plants in the WOR treatment were observably stunted compare to those in the control plots where no wood chips were previously incorporated. A) Plants to the right of the pink flag in the foreground are in a control plot. B) Bean plants in the foreground near the pink flag are in a control plot.

By October, soil organic C, total N, and nitrate-N differed among treatments. (See full report for graphed data.) Organic C and total N were significantly higher in the WOR treatment compared to the control, and neither had differences between the N fertilizer treatments. Nitrate-N, however, had an opposite result. It was significantly higher in the control compared to the WOR treatment, and there were differences between fertilizer rates, with the lowest nitrate being in the grower N rate plots of the WOR treatment. The soil results suggest that, by October, the wood chips were decomposing and contributing to the soil organic C and N pools. The organic N, however, was not yet mineralizing to nitrate. Nitrate was limited in the WOR treatment, where it was possibly tied up by soil microbes, unless boosted by the doubled sidedress fertilizer rate.

Whole orchard recycling and nitrogen fertilizer rate impacted yield in this trial. Yield was statistically higher in the control plots, averaging 2652 lb/ac across replicates, compared to the WOR plots where the average was 1820 lb/ac (Figure 3A). There were also differences in yield among N fertilizer rates (Figure 3B). In the control, the grower N rate and the doubled N rate performed statistically similar. In other words, there was no benefit to applying the doubled sidedress rate in the control. Additionally, the grower rate in the control performed statistically similar to the doubled rate in the WOR treatment. This indicates that while WOR may tie up N – limiting its availability for plant growth and yield – doubling the recommended N rate overcame the yield penalty imposed by WOR. Thus, when coupled with additional N fertilizer, WOR can augment soil health properties, like organic C and N, without penalty to yield.

Figure 3. Bean yield in October 2020 averaged across three replicated blocks. A) Bean yield between WOR treatment and the control were statistically different. B) Bean yield for N fertilizer rates were also statistically different. Bean moisture averaged 10.5 percent across all treatments.

Summary:

This project evaluated soil properties and kidney bean yield following walnut WOR. By incorporating a large quantity of organic C into the soil, WOR has the potential to improve soil health properties, but a tradeoff may be that N becomes limited for subsequent crops. We found organic C and N to increase with WOR from the beginning of the bean season to the end, but plant-available nitrate was limited by WOR. Bean yield suffered as a result of WOR, but doubling the fertilizer N recommendation mitigated the yield penalty. Under the circumstances of this trial, a total N rate of just over 200 lb/ac maintained bean yield where WOR had been implemented compared to the control plots with no wood chips. It does appear, however, that the yield in the WOR treatment might have benefitted from an even higher rate of N. To our knowledge, this trial was the first of its kind and more research will be needed to develop N fertility guidelines in dry beans following WOR. Other tree and annual crops should also be studied. We will continue this trial in 2021 to evaluate whether the impacts of WOR continue in the second season after recycling.

How my training as a UC Master Food Preserver helped me become healthy after a heart attack.

Canned garden produce in jars.

Recently there has been increasing interest and desire to grow and preserve our own produce. In addition, there has been an increase of health-conscious families turning to WFPB lifestyles. This UC Davis article explains the differences between vegan and WFPB diets.

Home food preservation is a natural accompaniment to this lifestyle, however, misconceptions about the benefits of home canning are often overlooked for the WFBP lifestyle and therefore not utilized. There is a misconception that preserved canned fruits are loaded with sugar. Unlike vegan diets, WFPB diets do not include sugar, however, WFPB diets do include raw honey if sweeteners are desired. The UC Davis Integrative Medicine article, The real truth about sugar, supports the choice to preserve fruits without the addition of sugar. And, although unprocessed foods are encouraged, minimally processed foods like home preserving, is acceptable. Here is a great article from UC Davis Integrative Medicine - What about processed foods?

Fresh plums ready for canning

Beans are a protein staple for the WFPB lifestyle. A UC Davis Integrative Medicine article explains Why beans are best and are a healthful choice for a meal or a snack. Home canning beans saves time and money. This UCCE video by Dustin Blakey is an excellent demonstration for pressure canning beans. By following the recipe in the book So Easy to Preserve, for pressure canning beans, my beans always come out safe and perfect. Before serving, I bring the beans to a boil for 10 minutes and season for my desired taste.

So Easy to Preserve recipe book, pressure canner, and finished jar of canned pinto beans

Being a certified UC Master Gardener provided me the skills and knowledge to successfully grow my own produce. I often referr to my garden as “My Victory Garden for Health.” All the produce that is not eaten fresh is either canned, dehydrated or frozen using skills I learned as a UC Master Food Preserver.

We grew a large 4' x 16' bed of onions. Some onions were dehydrated, which was a great advantage. Snap peas, bush beans, asparagus, beets for pickling, carrots, tomatoes, and sweet corn were either pressure canned, blanched or frozen. Vegetable soup was made and canned using the So Easy to Preserve instructions.

I am not advocating that this lifestyle is for everyone since after almost one year I found my way to a hybrid form of WFPB. However, I will continue to use my UC Master Food Preserver skills to home preserve produce that is sugar free and healthy, knowing that my home preserved food is safe since I have followed recipes and procedures tested for home food preservation.

For more information about the UC Master Food Preserver Program, including the Food Preservation Video Library, visit mfp.ucanr.edu.

I love green beans, but even better are wax beans. For some reason as a kid I thought the yellow color of wax beans was something special. Since then I've preferred them if given a choice, but I'm sure it's all in my head. Kids make food choices based on some illogical characteristics. This one stuck with me.

I've grown three different varieties of wax beans since I've lived in Owens Valley. I always grow bush-type beans since I'm too lazy to set up a trellis. This is the first year I've had enough to make more than a meal. 

My first two years I attempted to grow ‘Top Notch' wax beans. They are easy to find and cheap. I like cheap.

I brought my 'Top Notch' seeds from Arkansas, but I didn't have much luck with them in Bishop. My plants had serious problems with fruit set in the dry heat. The plants grew and flowered prolifically, but few pods formed in either year. The other green beans (‘Blue Lake Bush' and ‘Royal Burgundy') I planted those years did fine, so I think it's a case of a poor choice in our area. Or at least that garden.

Since then I moved to another house and didn't put in a garden, but like everyone else, the coronavirus inspired me to plant a garden. 

My current garden spot is even hotter than the last as it's nestled in between my house and a fence, in full sun all day. I figured I need to try a different kind of bean. By the time I decided to put in my garden, there wasn't much left for sale. I ended up growing ‘Borsalino', an Italian variety I frankly paid too much for in desperation for seeds.

‘Borsalino' was highly productive. Each plant yielded about ½ lb of beans. They were fair tasting and tender, but the pods were not very long. Most were 3-4" long. Few looked worthy of entering into the fair, but I can't complain about the yield. They also yielded almost their entire crop in one picking.

About a week after I planted those wax beans, I was given some French rocbrun seeds to plant. The mature seeds look like brown pebbles. Maybe that's what the name means. (This cultivar may actually be ‘Buerre de Rocquencourt' but rocbrun is easier for an Anglophone to say, if that's actually the case.)

My rocbruns were not as productive as ‘Borsalino', but the pods were much larger and generally more tender. I ate a few raw out of the garden. I was glad the pods were larger as that speeds up harvest; however it did take two passes about 5 days apart to get them all. I kept the first ones in the refrigerator until I had the rest harvested.

While they were excellent to eat, I wasn't so happy about cleaning them prior to canning. The pods were very sticky, and little bits of dirt and spent blossoms adhered a bit too well. I had to wash the beans twice to clean them of debris. They were good enough to eat that I plan to let some of the seeds mature and save them for next year.

The moral of the story is that in many cases, the reason something doesn't work could be as simple as the variety not being adapted to one's location. Wax beans definitely seem to grow here, as I would expect they would. 

New gardeners: keep in mind that if you don't succeed with something this year, maybe the solution is to try another variety next year.

Somehow we missed having this posted for June 20.  Catch up now!  Article for June 27 will be posted June 29.

By Pat Hitchcock, U. C. Master Gardener of Napa County

Plant some beans!

Warm settled weather found me planting beans in the garden. First in were some seeds from packets that had dates prior to 2018—in other words, old seed. These were a mix of bush types: Roc d'Or (yellow), Provider (green), Royalty Purple Pod (purple) and a tricolor mix.

All sprouted except the green ones. Since bush beans tend to be ready to eat earlier than pole beans, I'm anticipating that we will be eating these first.

Next I planted some Romano pole bean seeds that I saved from last year's Master Gardener field trial. I really liked the two climbing varieties called Helda and Golden Gate. Being fresh, these seeds had a 100 percent germination rate. By the beginning of June, they had climbed to the top of the six-foot-tall tuteur I set up for them.

In the garden, a tuteur is a tall support structure. I purchased two at a local nursery a few years ago, and I added extra strings to them for the beans to twine around. It worked great for these beans last year and is super easy: I just put it in the ground where the beans can reach it.

I don't consider the summer garden to be complete without beans for drying. A couple of years ago Leonardo Urena came to one of our Master Gardener seminars to talk about growing giant pumpkins. He brought with him some beans that he likes to grow every summer: Coco Blanco and Cranberry Bush.

I grew out a few seeds of these last year and wanted to give them another try. Both are bush types; these were the next to get planted. They germinated well and are growing sturdily in the garden. I have noticed that the Coco Blanco have suffered some scorch in the recent hot spells we've had, but the plants are still growing fast. These will be ready to harvest after they form full pods and start to dry at the end of the summer.

I also planted two pole beans for drying. One is Christmas Lima, which I planted from a one-pound package I bought from Rancho Gordo. The other is a bean I call Kosovo, which was distributed to Master Gardeners several years ago by another seminar speaker. They look an awful lot like Eye of the Goat beans to me. Both of these bean types are vigorous climbers, so I set some poles in the ground and set up strings for them to climb as I don't have any more tuteurs.

You'd think that would be enough beans for one family. In fact, it might be too much, but my bean planting was still not finished. Our Master Gardener field trials group decided to grow out some different Romano beans this year. So, finally, I planted ten seeds each of three kinds of Romano beans: Musica, Violet-Podded and Capitano.

I planted Musica around the second of my tuteurs. Violet-Podded got a repurposed umbrella skeleton and Capitano, being a bush type, has a short metal cage for support. All of these germinated well, although I've lost some plants to the heat.

Out of all the bean varieties I've planted, only the Musica are being chewed up by something. Sneaking out after dark in my pajamas with a flashlight, I discovered earwigs munching happily on them. The next day I put out some rolled-up newspaper in hopes of trapping the hungry critters. I expect the beans to outgrow the munching soon.

I love to grow beans. I find that they germinate readily, grow without too much fuss and provide quite a bit of food for the effort. I try to plant twice as many seeds as the number of plants I want to allow for germination issues, insect predation or other problems. I never bother to thin them if they all sprout, and I always get more beans than I can eat.

Here's a hint: June is not too late to plant beans in our climate. While there may not be enough time for dry beans to mature (one source I consulted said this would take about 100 days), bush beans for fresh eating are ready in 50 to 60 days according to Johnny's Seeds. Pole beans will take a week or two longer but then produce longer.

Be brave and plant a couple of different varieties: “green” beans come in yellow and purple as well as green, making your dinner table that much more interesting.

The UC Master Gardeners of Napa County are volunteers who provide University of California research-based information on home gardening. To find out more about home gardening or upcoming programs, visit the Master Gardener website (napamg.ucanr.edu). Our office is temporarily closed but we are answering questions remotely and by email. Send your gardening questions to mastergardeners@countyofnapa.org or leave a phone message at 707-253-4143 and a Master Gardener will respond shortly.  

Online searching for beans by name will provide photos of all the beans Pat Hitchcock names in this article.

 The University of California's Vegetable Research and Information Center is just packed with vegetable growing information.  Find it here:

https://vric.ucdavis.edu/main/veg_info.htm