Alternative Soil Fertility

I’ve been preparing for a presentation titled Unusual Edible Perennials and How to Use Them for Soil Health. Already, I have a problem with the title because I dislike using the term soil health. I would rather it be the title of this post. However, I realize it is not as pleasant sounding. It seems as if a large part of what I end up focusing on revolves around making things sound good to get likes, clicks, and follows. I will be the first to admit if you look at my social media, well, let’s say I might not be as social as I should be if those are my goals. I have come along way from posting about the tattoo on my foot though. I have also stated that those are not the reasons why I'm doing all of this either. It is just the nature of the beast I guess.

What preparing for this particular presentation has made me think about is

How I as an agronomist view -how and what farmers use to manage soil fertility. I know the obvious – cover crops, fertilizers, manures, and management. But, does it have to stop there?

What if you grew an alternative crop that had multiple markets, could be used to do what cover crops do and provided a sustainable source of soil fertility? That seems like money in the bank to me.

I will insert all my disclaimers now. I realize the ideas I’m talking about aren’t necessarily new, however, far too often we get in our set ways and don’t look beyond what we’re currently doing. I realize that most of what I’m suggesting is anecdotal at best. I also understand the scale at which these crops could be grown successfully will vary. Last, but maybe the most important, incorporating them comes with financial implications. However, in this era of agriculture, it seems to me that markets are opening up to be more receptive if not on the cusp of demanding we make some radical changes to our approach. Our approach to crop choices, fertilizer choices, and management choices.

In doing research, I’ve come to realize there is not a lot I could find about the subject. I found the typical article about favorite cover crops, what soil needs to be fertile, and what one can do to promote soil health. Beyond that standard research and information and looking at actually using plants to target soil fertility, information gets pretty obscure.

One article I came across was titled, Maximizing Soil Fertility with Soil Improving Plants.

https://www.regenerative.com/magazine/maximizing-soil-fertility-soil-improving-plants

I finally felt like I was on to something, and maybe I am, but I still want to take the subject further. Again, what if you grew an alternative crop that had multiple markets, could be used to do what cover crops do and provided a sustainable source of soil fertility?

What if we looked at using specific plants to go beyond cover cropping and used them to help meet even more specific soil fertility needs?

Even my husband who proclaims he has no idea even on an average day what I’m talking about when he reads my stuff, let me know I am pretty much-smoking something if I think farmers are going to be able to incorporate alternative crops successfully. But, why not start and look at things through a different lens if only for one presentation.

Next, I thought I should look at the primary reasons farmers use cover crops. What are the significant factors leading to the choice of cover crop and how could an alternative crop meet those reasons.

Most farmers choose cover crops based on the following-

1. Reduce fertilizer costs, mainly nitrogen

2. Reduce herbicide and pesticide use

3. Prevent soil erosion

4. Increase overall soil tilth

When planning my talk, I took those reasons and few others into consideration based on the crowd I’m going to speak to and the typical scale of the grower I work with.

I also took into consideration-

1. The fact I grow each one in my garden - hence the scale

2. They are edible in some form - multiple markets

3. They are all relatively easy to grow – ease of management

4. They are relatively common – attainability

5. If it could address at least one fertility need – a movement towards sustainability

So, the five plants or “crops” that I included are borage, comfrey, stinging nettle, Jerusalem artichoke, and rhubarb.

Borage-

It’s growth characteristics lend it to being a natural addition to add to any market garden.

It... tends to spread if happy

and does not like to be in wet soil,

but it

can tolerate some shade, and

self-seeds

What are the fertility benefits?

It... is a functional companion plant for strawberries, squash, and legumes.

and is said to be a sacrifice plant for tomatoes from hornworms.

But, what I’m most interested in is the fact it contains B vitamins and trace minerals.

Research has been done regarding the role B vitamins play in metabolic pathways and how it helps to make biochemical reactions in plants easier in regards to environmental stresses. Take a look at some work being done at the University of Florida at the following link

https://researchfeatures.com/2017/08/08/control-metabolism-changing-conditions/amp/

The part about containing trace minerals interests me because most soils lack them and often overlooked. However, trace minerals can be a limiting factor in soil fertility that can mean the difference in yield loss and more noticeably crop quality. For some growers, trace minerals can be expensive and harder to apply at appropriate levels without doing more harm than good. Using a plant to supply that need could, in fact, be a viable option while having several other benefits as well.

Comfrey

I can’t say enough about this one. It seems to be the overall work-horse of the plant world.

It...

grows anywhere, and will tolerant several growing conditions

I suggest in my presentation to consider planting the sterile variety. It is a firsthand lesson I had to learn.

It uses include...

it can be used as a mulch and dried as a soil conditioner

soil stabilizer due to is deep roots

high in calcium and potassium

hay and forage potential

The fact it is high in calcium is what caught my attention. I have come across several scenarios where soil needs calcium, but other more mainstream inputs are not always an option. Comfrey could be one alternative depending on the scale, that could be more sustainable than mined products.

Stinging Nettle

Nettles are quite fussy about the soil in which they will grow

Once established roots creep so it can be hard to control

Unfortunately, the entire plant is covered with stinging hairs

So, there are some definite disadvantages to stinging nettle. But, it’s contributions regarding soil fertility in my mind out way the painful reality of dealing with the plant.

It is high in iron, calcium, magnesium, nitrogen, sulfur, and silica

Aphids love nettles, which you can grow as 'sacrificial' plant

There have been several studies done regarding the benefits of silica and its relationship to nutrient retention and efficiency as well as the role it plays in overall plant health. What I want to find out more about is the calcium, magnesium, nitrogen, and sulfur potential stinging nettle may bring to the table.

Stinging Nettle Photo Courtesy of DB Impressions

Jerusalem artichoke

Plan when deciding the location

They are prolific and can become invasive unless managed properly

It goes without saying...

the plant is an excellent source of biomass to add organic matter

because they are a tuber, they may help mitigate some compaction issues

and they are rich in minerals like phosphorus and potassium

Jerusalem artichokes contribution from a fertility aspect would come from mainly its addition of organic matter. I don’t have an issue with that being the only one. You have to create conditions conducive for a soil being able to handle the nutrients needed to grow healthy plants.

Rhubarb

Is easy to establish and can be harvested continuously

Interesting note about rhubarb

It’s considered a vegetable but mostly used as a fruit.

I wonder if it has any conversations with a tomato?! Admit it; you wanted to laugh or google it to see why I said that

On a more serious note, it’s fertility benefits are, it...

contains Ca, K, Mg, Mn, and fiber

So,

My presentation is ready

I’ve stated my case as to the why I think farmers should consider some alternative crops

And,

My husband has brought me back to reality

Even if for only one presentation, this agronomist got to think outside the typical bag of seed, fertilizers, and manures and started to think about...

Alternatives to Soil Fertility