Fertilizing and No Till Gardening

Fertilizing and No-Till

Abandoning old and deep habits is not one of our species’ strong points in my observation. In most cases there must be compelling reasons to change. So what could compel gardeners and farmers to switch from till to no-till?

It doesn’t seem likely that chemical agriculture will ever switch – finding it so difficult to change to eminently more sensible organic agriculture –until the cost of phosphorus can no longer be passed on to the food consumer, at which point it will die a natural death. Considering the dwindling supply of mined phosphorus in the world this is not too far in the future.

What might compel organic gardeners and farmers to tweak their practices to no-till? Increased cost effectiveness of no-till would certainly be a compelling reason considering our mercenary tendencies, but it is yet not decisively proven to be true. The fact that no-till is much friendlier to the planet – less CO2 outgassing, less water pollution, and so forth – is compelling only to a few.

For me the most compelling reason was a deepening trust, over decades, in Nature’s way – that by an invisible hand Nature is self-organizing and self-correcting, provided she is not interfered with. Through the study of soil I saw that tilling was such an interference.

Employing Nightcrawlers (Lumbricus Terristoris)

There will always be those who during economic hard times, and particularly economic meltdowns, prefer to take personal responsibility for food security rather than join angry protesters. Of course access to land will be necessary and in many cases there may not be enough land to feed oneself and perhaps dependents. It is recommended by some that very close spacing is a good way to maximize production, but I am not one of them. Though close spacing economizes space above ground, the roots below are cramped which would tempt the gardener to resort to costly soil additives of many kinds. A better practice would be to increase topsoil depth. In this regard nightcrawlers should be employed as nightcrawlers are Nature’s premier topsoil builders.

Rather than ingesting organic matter that is already in the soil they prefer organic matter at the surface and bring it down deep through vertical tunnels, mixing it with subsoil which provides the grit for shredding the organic matter. Like other earthworms they prefer partially decomposed organic matter that provides them with digesting microorganisms. These tunnels also transport oxygen and water, essential for the survival of both worms’ and plants. Surface mulch, therefore, is needed to keep the worms constantly fed. Even cover crops would need to be mulched, otherwise the earthworms may spend too much time hibernating at the bottom of their tunnels.

Feeding the World

It’s reported that half the planet’s life-sustaining topsoil now resides under water in rivers and the oceans, not ever to be retrieved. Even the remaining half is not actual topsoil, or at least does not have the full complement of fertility and tilth that characterized the soil that was lost.

Fortunately the lower quality topsoil that remains can be upgraded quickly, but not by turning under large quantities of organic matter, as such tilling depletes the key ingredient of inherently fertile soils – stable humus. Through the decomposition of cover crop roots subsoil will also become part of the topsoil complex. In this manner the original depth of topsoil can eventually be achieved. Food can be produced during this soil building process, using high nitrogen mulch.. Applying natural fertilizers and amendments (surface application) can assist the production of food while such supplements are still affordable and/or available.

The First True Revolution in Agriculture

When we speak of agriculture we naturally think of tilling the soil, yet we have known for a long time that tilling results in soil loss and therefore is not a sustainable form of agriculture. Though organic agriculture is purposed towards sustainability it is mired in the futile attempt to prevent soil loss while still tilling the soil. Agriculture without tilling is now being looked at but surface tilling (cultivation) is deemed necessary for weed control. This is not true. Cultivation keeps a constant supply of weed seeds close to the light needed for sprouting. In my garden beds where I have avoided disturbing even the surface of the soil for several years the weed situation has become quite manageable, though there continues to be the encroachment of grass from the grass paths. This “problem” could be exploited by permitting the narrowing of the garden beds and a widening of the paths for a time, since the encroaching grass adds root organic matter.

Just Dirt?

Just Dirt?

There is a recent study that puts together statistics on soil erosion from more than 125 sources. It says “the US is losing soil ten times faster than the natural replenishment rate while China and India are losing soil 30-40 times faster than the natural replenishment rate”. The study goes on to say “worldwide, as a result of wind and water erosion in the past 40 years 30% of the world’s arable land has become unproductive”. The study also says that the soil that is washed away harms other ecosystems, including our oceans and atmosphere. Obviously a food crunch is on the horizon.

Proper Stewardship of our Renewable Resources

It was assumed that by adding free trade to the global markets hunger and starvation would be greatly alleviated, if not yesterday’s problem. Hindsight has shown otherwise. Free trade simply opened the door for the exploitation of weaker nations by stronger nations, particularly, though not exclusively, in regard to the appropriation of natural resources. In a better world each nation would take care of all of its people first, with any excess of resources applied to the trade balance. Failing that we must rely on emergency relief, which is never adequate and may not even be available in the future. At the present time we are faced with an equally dire situation, if not more so -  we are fast running out of non-renewable resources. As a consequence future generations will become ever more dependent on renewable resources.

This brings up the matter of the stewardship of the basic renewable resources – soil, air and water. Although in my articles my focus has been on soils, these three resources cannot be effectively addressed apart from each other. Degraded soils (loss of carbon) result in degraded air (excess carbon) which in turn degrade our oceans – warming and acidifying them, causing climate aberrations worldwide. It is important to notice that the degradation of soils came first, so the secret to restoring balance in the atmosphere and oceans lies not only in reducing fossil fuel emissions but also in sequestering carbon in our agricultural soils where it is critically needed, and not in underground or under water pools where it is concentrated and made highly toxic.

Making a Lighter Carbon Footprint as we Garden

Understanding how the Biosphere functions can provide useful information on how best to garden. The biosphere seeks equilibrium between photosynthesis (capturing CO2 from the atmosphere) and respiration (releasing CO2 to the atmosphere). We humans have affected this equilibrium even from the early hunter/gatherer culture, as I read. However it was not until the industrial and chemical age that this equilibrium became seriously out of balance (respiration/photosynthesis ratio skewed in favor of respiration). Warming the atmosphere is one consequence which warms both the ocean and the soil. Such warming then feeds on itself, leading to dire consequences. Other than cooling the atmosphere we don’t have a way of cooling the ocean, but we can cool the land by shading. Nature herself is adamant about keeping the soil covered, or shaded, (click on to grass:the forgiveness of nature for a beautifully written example of this) Little attention has been paid to shading the soil as a way to sequester carbon but recent research points this out. It was found that 50% crop residue removal is the point where carbon sequestration stops and carbon loss begins. Maximum sequestration occurs when 100% residue is retained. These studies were done under no-till conditions. When plant residue is incorporated carbon loss continues, even with 100% of the residue incorporated. How much carbon sequestration occurred simply by the shading was not determined but since mulch provides little carbon-sequestering humus it would seem to be a considerable amount.

Mitigating the Effects of Fossil Fuel Burning

I’ve mentioned the contribution till agriculture makes to global warming but I feel it could use more emphasis. We have lost a great deal of soil carbon to the air in the past but there still remains more carbon in the top 6″ of soil than in the air above. However, through continued tilling this carbon is going fast. Though organic gardening adds carbon to the soil, in the process of incorporation of this organic matter the more stable forms of humus are oxidized – the humus that actually sequesters carbon (nitrogen also, a greenhouse gas). If till agriculture was replaced by no-till agriculture world-wide much of the carbon released by the burning of fossil fuels would be mitigated. It would certainly still be necessary to greatly reduce fossil fuel burning but nonetheless fossil fuels will  continue to be our major fuel source for a long time.  Even renewable energy requires fossil fuels in the manufacture of their equipment, including the infrastructure to distribute this energy. Also renewable energy other than wood will become phased out, not that long after they are phased in, due to the exhaustion of critical materials needed in their production.  Fortunately the burning of wood is a simple process and the technology now exists to virtually eliminate emissions from it. This means that planting trees should  take priority right alongside humus building. As wood will be the primary resource in the future, for both our energy and shelter needs, we need to start planting more trees now, since by the time the trees are ready for harvesting they will be in critical demand.

More on Humus Building

We gardeners/ecologists look to Nature as our model for sustainable gardening, and rightly so.  But Nature doesn’t “model” a permanent, or climax monoculture of annuals, typical in our garden beds, and hasn’t needed to before we came along. All non-humans are perfectly satisfied with food produced by perennials and, since perennials are our humus builders, the sustainability of our soils was ensured. That doesn’t mean, however, that in growing annual vegetables we must operate outside Nature. That approach has failed and it is obvious that it always will. It is time we operated inside Nature, building on her vast experience of sustaining soils, the basic features of which are:

1)    Do not disturb the soil by tilling

2)    Recycle via mulch a minimum of one-third of organic matter produced.

3)    Never leave the soil bare

4)    No concentrated fertilizer amendments

5)    Never leave the soil without living roots

This fifth point has not been given adequate emphasis and there is a way that we can use annuals to behave somewhat like perennials.

Feeding Plants the Proper Way

Fertilizers and amendments vs healthy humus for feeding your plants…

“Healthy soil produces healthy food.” Few would argue that fact. Nonetheless we can’t ignore economics and today’s cash crops often result from soil that is far short of being healthy by applying certain chemicals and/or soil amendments.

Let’s look at the downside of applying fertilizers in a concentrated form. Such fertilizers, which are costly, are commonly water soluble and taken up by the plant to meet its water needs. To keep up with transpiration plants must drink water ‘day and night, much like our breathing’, as one writer put it. So these plants with the nutrients dissolved and administered via water are constantly being fed.