When I was studying trees in school over a quarter century ago, I read every arboriculture book in print (in English). One particular fact that stuck with me is that the only nutrient most trees respond to in most soils is nitrogen (excluding water and oxygen). At that time I was an all organic grower because I hadn’t ventured to attempt growing fruit trees in the east coast yet.
My understanding was that nitrogen is nitrogen and whether it is derived from man-made sources of organic ones the plant responds the same, which is technically the truth. Because I used a lot of mellowed horse stable waste I assumed I was getting the best growth possible from my nursery trees without adding any other nitrogen.
However, in recent years I’ve switched to using a lot of sulfur coated urea in my nursery and anywhere that I’m establishing an orchard. What a huge difference it makes in most soils! An established tree doesn’t need tremendous vigor, and moderation is the key, but when you stick a whip in the ground, the sooner it is big enough to stand up to deer and disease and start holding real crop the better.
The trees in my nursery size up much quicker now, which makes that business more profitable. I think what may make the synthetic N. so effective is that it gives the trees what they need while the soil is still relatively cool while organic processes tend to require the warm soil of summer to reach maximum release. This inhibits total growth, and even for established trees it is the opposite of what is desired for timing.
For my own trees I still stick to organic fertilizer, but I only have enough urine for so many trees. It works as well as any synthetic N so I recommend that at least men make use of that particular resource if you don’t find it disgusting. If you water it in the smell disappears quickly.
As far as most trees only responding to N- I’m not suggesting that applies to trees in an orchard where you are taking out nutrients every time you harvest. For them it depends on whether you are mulching and what with and also what is in the soil in the first place.
I live in North Dakota and we need the acid here. Soil is super basic. I just bought 185lbs of ammonium sulfate (20-0-0) from a farm fertilizer place in bulk for $34 (.17/lb). Ive never seen sulfur coated urea here, but I can get 46n urea fairly cheap also. The AS has more soil acidifying power tho so I usually go with that.
It depends in part on species. Peaches seem to utilize the N best when I apply it in early spring at about first growth. The coated urea is designed to release over approximately 90 days, so a few days before growth might be ideal. Apples respond well if I apply it in very late summer (mid-Sept) which also is a good time to replace the K the crop may have removed. That said, Cornell recommends spring application for apples as well- for N not K.
I don’t worry about it just because it is so easy to raise pH with lime- actually, on my property I use a lot of firewood ashes but if you also mulch that could lead to excessive K.
If I use quick release I have to reapply it, but the 90 day pretty much gets me through the season for young, establishing trees. Quick release is generally better for established trees if you want to get some N to the spur leaves to serve fruit without inspiring excessive vegetative growth. .
Wish I had used more nitrogen when I first started planting my fruit trees. After recently applying nitrogen to my muscadines I can see a huge growth rate difference in my newer plantings. In my opinion Ison has produced a great video on how to fertilize and prune in order to get the vine up and down the wire as fast as possible using calcium nitrate. I’m currently working on settling the apple/pear trees down to producing fruit.
I use a hand broadcast spreader and spread it on top of my wood chip mulch and then water it in. Typically I try to put fertilizer down before a rain, less work for me.
@alan being as Urea I would think is kinda a hot dose of nitorgen, I was kicking around the idea of getting a bag from my coop to put around my trees. I know you’d want to dust it out when its just about to rain or you lose some from blow.
However how do you measure how much to use for each tree, depends on caliper size? Keep it about a foot off the trunk if possible?
Honestly, I’m not all that precise. With Urea you are talking bout a very concentrated fertilizer with more chance of causing damage than with something that releases N more slowly. For a very young tree a couple of TBS watered in is sufficient. For something over 2" caliber, maybe a third cup this time of year.
I do same. Over my straw much surround. I try to aim for about six inches or so past current root zone. Keep building soil outwards to draw out feeder roots.
I have read that available N volatilizes significantly and is lost when placed against raw organic matter. When I put Urea on mulch, I break up the mulch with a fork so some of it rests against the soil and then water. I don’t know how helpful this is, but we all come up with our own gardening recipes. Research only takes us so far, thank God- following recipes from a book is boring. It’s nice to use one’s own brain to modify methods- even if it turns out not always to be the most efficient method.
It’s ironic that Fritz Haber is responsible for the lives of half the population in the world today. You and I likely wouldn’t be alive if not for him and yet most people have never heard his name. The world was experiencing a nitrogen shortage when he figured out how to extract nitrogen from air . As your all aware the atmosphere is roughly 78% nitrogen. Fritz Haber also had a dark side and killed many using chemical warfare in WWI. Read the articles I’ve known this story many years and it’s a lot to think about. From my perspective nitrogen = food since I grew up in the bread basket we see it every year produce the worlds grains which make the breads that feeds everyone
I do wonder who will be the next fritz haber and create terraforming in future planet/atmospheric creation or something better. People need to focus less on population control and more on dedicating the resources to the new population . They will be the scientist who will make the next synthetic nitrogen process so to speak. Let’s face it 70%+ of our atmosphere is just that.
I have heard of folks peeing in watering cans, etc. and saving it, watered down, my guess is that’s extremely sound practice even if it isn’t overly appealing.
