I’m away this week for an out-of-state seminar and a little annual leave. Some of my favorite places to visit this time of year are the high deserts of California. Today we hiked to Horse Thief Creek, a relatively easy trail in the Santa Rosa Wilderness. It’s the perfect time of year to see the high desert in bloom, especially with last winter’s substantial rainfall.
In graduate school I became interested in environmental stress physiology, and I still am entranced by the plant kingdom’s ability to overcome nearly every environmental extreme on earth. Desert ecosystems are particularly harsh, as rainfall is limited to a short period of time, often in the winter or spring. While many perennials are able to tolerate the subsequent dry season, annual species cannot. In essence, they escape drought stress altogether by existing only in seed form for most of the year. Seeds contain relatively little water anyway, and are so protected against environmental extremes that they can remain viable for decades or even centuries.
But back to our desert. After the rainy season, seeds of annual plants go into overdrive, germinating, growing, setting seed, and dying back all the span of a few weeks. Thus, the lucky hiker can find an abundance of tiny, brilliant desert annuals when seasons and vacation schedules coincide.
Tomorrow it’s the Salton Sea. Not sure what we’ll see in terms of plant life, but we’re hoping to catch some of the migratory waterfowl on their journey north.
Just returned from a mega field trip across the state of Virginia with my Ornamental Plant Production & Marketing class. We toured major wholesale nurseries, greenhouses, and retail garden centers over the course of three days. The trip went well, I believe (university field trips are a considered a success if you return with the same number of students you left with).
One over-arching trend is, of course, that growers and retailers are going after the veg/fruit thing in a big way. Bonnie Plants has been one of the few vegetable transplant growers for the big box stores; now others are getting in on the act. Wholesale growers who traditionally supplied woodies and perennials to independent garden centers are including veg plants and herbs in their product mix.
Even the packaging is changing from the ubiquitous paper cup or poly 6-pack. Coconut fiber (coir) pots are a step up from peat pots – they hold up better for the grower and garden center but are still plantable or compostable.
I can’t decide whether these pre-planted bean cages are ridiculous or genius. The students rated them “very cool”. But how many beans can you get off of three plants?
Take some galvanized tomato cages, paint them bright colors, and charge three times the usual price. Who on earth would go for this? Oh wait, that would be me. Two. In orange. Cram ’em in the van, people.
Spring is off to a warm and fast start here in Michigan. March was unseasonably warm and the past week or so has seen temperature 20 degrees above average or more. Needless to say this is pushing all of our landscape trees and shrubs. Forsythia and saucer magnolia are in full bloom, at least two weeks ahead of schedule. The warm weather also has us scrambling to get some research projects in the ground as well. Today I was working with members of my lab to install a trial to look at the relationship between fertilization in the nursery and subsequent of shade trees in the landscape. For the past two years we’ve grown Acer miyabei (‘State street’ maple) and ‘Harvest gold’ Linden trees in 25 gallon containers as part of a trial on controlled release fertilizer. Interestingly, in the nursery we saw a significant increase in chlorophyll index and foliar nitrogen with fertilization (no surprise) but no difference in caliper or height growth (somewhat of a surprise). This indicates that in the nursery, fertilization induced ‘luxury consumption’ or an uptake of nutrients beyond what the trees need to meet their growth requirement. This observation provided the opportunity for our current, follow-up study. In the forest nurseries there is a growing interest in the practice of ‘nutrient loading’ seedling trees before they are lifted. Forest nursery managers deliberately induce luxury consumption by fertilizing late in the season. At this time seedlings have set a hard bud and won’t grow but can take up additional nutrients. Numerous studies, particularly by Dr, Vic Timmer and his associates at the University of Toronto have shown that nutrient loaded seedlings will outgrow standard seedlings when out-planted on reforestation sites; even though the seedlings are the same size when transplanted. How does this apply to large-caliper shade trees? We don’t know. There are certainly some underlying commonalities that are intriguing. Nutrient loaded forest seedlings have an advantage when planted on tough sites where follow-up culture is minimal – basically the seedling has to get by initially with its own energy reserves and resources. Shade trees planted as street trees often face the same hardship; once planted they may receive little or no after-care beyond an initial watering. Could nutrient loading provide a better internal nutrient reserve and jump start the re-establishment process for street trees like it does for the smaller forest cousins? We should gain some insights this summer and next.
I didn’t exactly cheat on this one…but it was a mean trick nevertheless.
This is a contorted cultivar of Larix (can’t remember the exact name and I’m out of town this week), hence the twisty needles. And indeed the tree is senescing. The newer growth (the second flush of the season) just wasn’t as prepared for fall as the older growth, which is yellowing naturally. So everything is just peachy with this tree.
Just goes to show you how important it is to know all the details when doing distance diagnosis!
Today I’ve attached a photo of a conifer displaying two symptoms: chlorosis of the older needles and a twisted appearance:
What do you think are the causes of these symptoms? Answers on Monday!
There are people who are fascinated by plants and people who are fascinated by the science of growing plants. While I love plants I must confess that I consider myself to reside more firmly in the latter group that the former. I do love to see the beautiful flowers on an apple tree in the spring, but I’m more fascinated by the nitrogen, phosphorus, potassium and other elements that the tree obtains from the soil. I like to contemplate the complex ecosystem that surrounds the tree, including the tree’s pests and the possible things that we can do to protect the tree from pests. I love to learn about insecticides, herbicides and fungicides, and I especially love to learn about alternatives like beneficial insects that may be used to control pests. Histories that cover fertilizers and pesticides are pleasure reading.
One of the most important things to ever happen to the world as we know it was the discovery of a process to take nitrogen from the air so that we could use it as a fertilizer. During the 1800s we discovered that applying nitrogen to our soils made plants grow really fast. Though this nitrogen could be supplied with manure we quickly learned that Peruvian Guano and Chilean nitrates had more concentrated nitrogen and so less needed to be added to fields to get bigger responses. Incidentally we could also use the nitrogen from these sources for bullets and bombs. Nitrogen is a cornerstone of most conventional explosives. Unfortunately these sources of nitrogen did have a drawback, they are not renewable resources. You may say — Hey, Guano’s renewable! — But you’d be stretching the truth. You see, guano is aged manure where the nitrogen has had a chance to become concentrated.
Anyway, by the time the 20th century rolled around we had used up much of the nitrogen available from South America and so we (and by we I mean the world in general) were hurting for nitrogen — particularly Germany. Germany had a feeling there was going to be a war and she needed a way to get nitrogen other than sailing all the way to Peru or Chile. So she put money into research. Pretty soon two researcher, Haber and Bosch, came up with a method to take nitrogen directly out of the air and make it into ammonia. Once present in ammonia it could then be used to make any number of other nitrogen based compounds, from fertilizers to bombs.
Coincidentally, Haber is also known as the father of chemical weapons. He led the German poison gas program and had a hand in developing such things as mustard gas. He was considered to be a patriot, but, born a Jew, the rise of Hitler wasn’t good for him and he was forced to leave in the early 1930s.
The story of Haber and Bosch is absolutely fascinating, not only because of the colorful characters, but because their discovery is, arguably, the most important factor in the increase of the worlds population over the last century. The best book that I know of on this topic is Enriching the Earth by Vacliv Smil. It’s a great book, but it does get a little technical. But my dad (he’s a chemist) showed me another book yesterday that is much more entertaining and readable than Smil’s book while retaining most of the pertinent science. It’s called The Alchemy of Air by Thomas Hager and, if your interested in fertilizers and the people who first developed them, then this is a must read.