‘Snow is the poor man’s mulch’
One of my friends who read my last post about Winter predictions, commented that he was looking forward to Winter. He mentioned the benefits of snow and freezing temperatures, and wrote that “...snow is the poor man’s mulch!” I had never heard this saying before and looked into it. Of course, he was right!
Every gardener uses mulch to protect and fertilize his/her plants. When the ground is frozen, a couple of inches of snow are like a layer of protective mulch. (Mulch is a protective layer of organic matter like decaying leaves, bark and other organic matter that protects the soil and decays, returning its nutrients to the soil). Like mulch, the snow protects the soil and the plants from the wind and freezing temperatures. It insulates the plants, as they might heave and expose their roots to freezes and thaws during winter weather- much like the way new rocks appear in our gardens each Spring, as we described in our post in September 2016.
Every gardener uses mulch to protect and fertilize his/her plants. When the ground is frozen, a couple of inches of snow are like a layer of protective mulch. (Mulch is a protective layer of organic matter like decaying leaves, bark and other organic matter that protects the soil and decays, returning its nutrients to the soil). Like mulch, the snow protects the soil and the plants from the wind and freezing temperatures. It insulates the plants, as they might heave and expose their roots to freezes and thaws during winter weather- much like the way new rocks appear in our gardens each Spring, as we described in our post in September 2016.
But snow does even more! I always believed it was only distilled (pure) water. Nothing else. But it also brings a load of essential nitrogen down to earth! This is an important fertilizing element for all plants and plays a crucial role in metabolism. It is critical for our metabolic functioning. We humans get this nitrogen from eating plants, and animals that eat plants.
Daniel Rutherford discovered nitrogen in 1772, when he removed oxygen and carbon dioxide from the air. In combination with other elements, nitrogen is found in all living organisms. It is for example, part of chlorophyll pigment, which allows plants to change sunlight into energy. Nitrogen is present in their roots, leaves and grains. Its various forms are required in proteins and nucleic acids for our cells. It is part of the fundamental building blocks of our metabolism. It is basic to our survival.
Nitrogen (N2) is an essential element for plant growth. It makes up about 78% of our air, but in it’s atmospheric form is very inert (non-reactive) and needs to be ‘fixed’ to be usable by plants. What does this mean? It means it has to be ‘fixed’ (changed) into different molecules for plants to use.
This requires an enormous amount of energy! Usually ‘fixed’ nitrogen enters the environment by three routes: lightening (which delivers the energetic jolt to combine nitrogen with atmospheric oxygen to create about 5-8% of usable nitrogen oxides, which attach to rain and snow and fall to earth), biological processes (more on this later) and industrial manufacturing (which also requires tremendous energy expenditures to create our commercial fertilizers).
Nitrogen (N2) is an essential element for plant growth. It makes up about 78% of our air, but in it’s atmospheric form is very inert (non-reactive) and needs to be ‘fixed’ to be usable by plants. What does this mean? It means it has to be ‘fixed’ (changed) into different molecules for plants to use.
This requires an enormous amount of energy! Usually ‘fixed’ nitrogen enters the environment by three routes: lightening (which delivers the energetic jolt to combine nitrogen with atmospheric oxygen to create about 5-8% of usable nitrogen oxides, which attach to rain and snow and fall to earth), biological processes (more on this later) and industrial manufacturing (which also requires tremendous energy expenditures to create our commercial fertilizers).
When snow is falling, ‘fixed’ nitrogen attaches to snowflakes and they land on the ground. One thing that makes snow so beneficial to the soil, is the fact that it gives the nitrogen, together with moisture, into the soil at a slower and even rate. It is like a mild, slow release fertilizer. Snow also enhances and retains soil moisture, shielding it from drying winds. This preservation of soil moisture is also key to adding more ‘fixed’ nitrogen into the earth for plants to use.
This is the second great benefit of snow in fertilizing the soil! Biological processes rely on moist soils for bacteria (genus Rhizobium)- which have evolved a symbiotic relationship with certain plants, to create more usable ‘fixed’ nitrogen molecules in the soil for other plants to absorb. These plants include legumes (e.g.- soybeans, alfalfa), and others such as clover and alders. This is one of the primary reasons farmers rotate crops and plant legumes in fields meant to be fallow, to restore ‘fixed’ nitrogen. According to the South Dakota State University Extension (www.iGrow.org), annual snowfall deposits between 5- 12 Lbs/acre of nitrogen in their corn belt.
This is the second great benefit of snow in fertilizing the soil! Biological processes rely on moist soils for bacteria (genus Rhizobium)- which have evolved a symbiotic relationship with certain plants, to create more usable ‘fixed’ nitrogen molecules in the soil for other plants to absorb. These plants include legumes (e.g.- soybeans, alfalfa), and others such as clover and alders. This is one of the primary reasons farmers rotate crops and plant legumes in fields meant to be fallow, to restore ‘fixed’ nitrogen. According to the South Dakota State University Extension (www.iGrow.org), annual snowfall deposits between 5- 12 Lbs/acre of nitrogen in their corn belt.
Even other strains of bacteria have developed symbiotic (mutually beneficial relationships) with animals, like termites and ship-worms, to ‘fix’ nitrogen molecules in the soil. Cyanobacteria function similarly in semi-aquatic environments like rice paddies. All these mechanisms for ‘fixing’ various forms of nitrogen molecules into the soil, are essential for all our life functions.
As mentioned, snow not only provides a protective insulating blanket, but plays a role in blossom formation in bulbs like crocuses and daffodils. It is believed that harsh winters and adequate snow also leads to more fruit setting in apples and pears for example.
As mentioned, snow not only provides a protective insulating blanket, but plays a role in blossom formation in bulbs like crocuses and daffodils. It is believed that harsh winters and adequate snow also leads to more fruit setting in apples and pears for example.
Snow - the Poor Man's Fertilizer Of course pest control is also a benefit. Cold temperatures can kill off large portions of harmful bug populations, giving the victimized plants a better chance to rebound next year. As invasive species such as the Emerald Ash Borer advance north in North America, there is a slim hope that they will be slowed down enough for us to find a solution. Warmer winters don’t help.
Although snow does not deliver much nitrogen, in the grand scheme of the environment, it helps. Its protective layer and moisture retention in the soil which promotes and preserves bacterial nitrogen formation, is probably much more important.
People use nitrogen in fertilizers to make crops grow faster and bigger. But by using those fertilizers in high doses, they have negative consequences for human health and the environment. It takes a tremendous amount of pressure and energy (burning fossil fuels at 600 degrees Celsius), to convert raw materials into nitrogen rich fertilizers.
Although snow does not deliver much nitrogen, in the grand scheme of the environment, it helps. Its protective layer and moisture retention in the soil which promotes and preserves bacterial nitrogen formation, is probably much more important.
People use nitrogen in fertilizers to make crops grow faster and bigger. But by using those fertilizers in high doses, they have negative consequences for human health and the environment. It takes a tremendous amount of pressure and energy (burning fossil fuels at 600 degrees Celsius), to convert raw materials into nitrogen rich fertilizers.
Algae Bloom on Lake Erie (Ironically, some of these emissions are nitrogen oxides that become nitrogen ions, which actually are picked up by the snow and raise snowfall nitrogen levels to pre-industrial levels- seemingly a good thing (and would have been in the old school).
Overall, they are blamed for the pollution of groundwater and surface waters, and other forms of toxic air and water pollution (think green toxic water blooms and mass fish die offs from lack of oxygen you see in the news). In general, agricultural use of nitrogen fertilizers to feed world-wide human food demand (plant and animal), are unbalancing the natural cycles of nitrogen compounds in the environment. This is what is leading to the problems we see in the news.
Overall, they are blamed for the pollution of groundwater and surface waters, and other forms of toxic air and water pollution (think green toxic water blooms and mass fish die offs from lack of oxygen you see in the news). In general, agricultural use of nitrogen fertilizers to feed world-wide human food demand (plant and animal), are unbalancing the natural cycles of nitrogen compounds in the environment. This is what is leading to the problems we see in the news.
But we digress here! These are larger matters. These are systemic issues which fall outside of our original observation- that snow is beneficial! But it is important to understand the natural cycle. Let’s not lose sight of the natural benefits of a good snowfall. Snow shelters and nourishes our landscape, our plants, our animals and ourselves. It can be a very good thing.
Perhaps one should pause the next time one groans at ‘too much’ snow. Snow helps to temper the fierce effects of Winter on our plants and sustains the reservoirs of nitrogen, so necessary to plant, animal and human metabolisms. At this time of the year, we are the “poor man”, and we are using a bit of snow as mulch. That is a good thing!
Perhaps one should pause the next time one groans at ‘too much’ snow. Snow helps to temper the fierce effects of Winter on our plants and sustains the reservoirs of nitrogen, so necessary to plant, animal and human metabolisms. At this time of the year, we are the “poor man”, and we are using a bit of snow as mulch. That is a good thing!
Nitrogen dioxide pollution map by Phys.org
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