Do I 'Clean Cultivate', or 'Mulch', or 'Let It All Grow to Hell?'

    There are many schools of thought when it comes to agriculture….. and since it is one of the oldest professions with a history of some ten thousand years, you can be that almost every option has been tried at some time or another. 

   Oddly, in that ten thousand years, some of the greatest advances in ag have come about in the last few hundred years… the advent of the ‘Green Revolution’ was greatly heralded in the sixties. Yield-per-acre has been increased due to new varieties, new advances in technology and equipment…. and (I hate to say it as an organic grower) new advances in chemicals.   Sometimes philosophy and practicality rub shoulders, and sometimes they seem diametrically opposed…. but sometimes that latter is influenced by your preconceived notions and biases.

   “When you change the way you look at things,
the things you look at change”
Wayne Dyer

   So much of human thought is stuck in ruts…. agriculturalists are perhaps better at being in ruts than other people…. something that’s been done ‘such-and-such-a-way’ for thousands of years is hard to want to change. If a change can mean no food production, it makes one loath to commit full resources to change. It’s probably not by accident that most farmers and ranchers are conservative in thought process… even the organic ones. In fact, it is not a bit of a surprise that organic growers are conservative, they are carrying on traditions rooted in thousands of years of hard-won experience. Even when they abandon the synthetic farming of their parents, they are embracing the organic methods of their great-grandparents.

   Still, even organic growers that were raised on synthetics and went organic are going to have some pre-set biases that might require years of ‘working through’ to accept…

   Here’s my lay-down on the three main systems of ‘weed management/Ground Cover Issues’

   Clean Cultivation

   For much of the last few centuries the most common method of weed-cultivation was called ‘clean cultivation’.  This is nothing more than making sure there are no plants growing in the area other than the desired crop plant.  This method used to be accomplished by flame-weeding, or hand weeding with hoes or by hand, and sometimes with grazing animals such as fowl. With the advent of chemical herbicides these tasks were accomplished with much less labor, and the amount of land a farmer could manage increased.  But clean cultivation has many drawbacks. It is much more susceptible to soil erosion by both wind and rain. It can lead to dirty produce as raindrops and overhead irrigation might splash dirt upon the crop. And if a grower wishes to be organic, they are pretty-much relegated to hand or flame cultivation if they wish to have clean ground.

  Organic Mulch

   For growers wishing to be organic, an organic mulch is often recommended.  Such was our choice for a few decades.  Four inches of oak-leaf mulch on our soil makes the ground below moist several months into the dry season due to it’s shading effect. It also keeps most weeds from growing well…. most seeds below a thick mulch will be unable to grow through it. Most weed seeds that fall onto the surface will not grow a healthy root through four inches of packed mulch… those that do are VERY easy to pull up when you see they are growing.  An organic mulch is also great for the soil and the microbial population due to the decomposition that occurs.  The mulch will slowly break down over several years…. after a few years the layers nearest the soil will be very dark and starting to turn into humus. The actual process of creating humus can take decades….. we have had our humus levels tested at nearly 14% in some areas. This is due to the tons of ground trees we used to bring in as mulch material.  Just as there are drawbacks to clean-cultivation, so to with mulch inputs…. these thoughts operate on two levels… practical and philosophical. The practical thought process goes that one never really knows what substances were on the trees that produced the leaves…. so bringing them onto an organic farm is a bit of a risk. I can understand this train of thought and it is the main reason we have brought no mulch in now for three years. The philosophical argument says that since the world is a closed-loop, so too should each farm be. Each farm should use frequent ‘fallow-crop’ intervals such that the soil is constantly regenerating itself and replacing the nutrients lost due to harvest. This is a bit of a fatuous argument however… because while the earth is a closed-loop system, any particular portion of it is usually losing part of itself, or gaining something from somewhere else due to the usual ups-and-downs of the earth and all the associated system therein. And no farm should be seen as an entirely closed loop since you are continually (hopefully) selling your crop. Those nutrients sent out do need to be replaced….. but MUST it be solely from outside inputs?

 Living Mulch

  This brings us to the third system of weed management, the one that was probably pretty much in heavy use until a few-hundred years ago… that of a living mulch of plants.  This system works quite well under many plants that have some vertical space under the leaves, for instance an orchard. In this system a native or a planted crop will be grown between the rows of your cash crop, or perhaps underneath the very leaves of your cash crop. A field of corn might be planted also with a clover, the two plants will grow together, the clover able to survive under the corn leaves, covering the soil, and after the corn is harvested, the clover will die over the winter. Any corn material that returns to the soil will accompany the many pounds-per-acre of nitrogen the clover will give the soil, not to mention the extra bio-mass which will largely decompose into the soil, increasing that ever-precious humus level.  There are disadvantages with this system also… and they also split along both philosophical and practical concerns. The philosophical side accepts the age-old wisdom of ‘enterprise’ and ‘labor’….  having ‘weeds’ growing in your fields is a sign of sloth…. ‘weeds’ are often accused of ‘stealing’ both moisture and nutrients from the cash crop. They can act as a shelter for bad bugs, and they can act as a bridge or ladder for ants or other pests to easily access the structure of your plants.  All of these accusations are valid to various degrees, but they can also be ameliorated to some degree by some small planning and effort.  And this will ALL depend on your own circumstances. 

   This is Opuntia robusta, two year-old plants growing in the native grasses in California.
   This is at the beginning of the dry season, the annual grasses have all died.

   This is the same area after mowing. You can see the cut-down native grasses do a good job of shading the soil.
   The soil is also greatly protected from erosion…. and the grasses will eventually rot into the soil.

    For us for instance, the native grasses are allowed to grow between the large cactus plants.  They will take advantage of the winter rains just as in nature. Over the winter they will actually keep the soil from being too wet which would injure the cactus. Once springtime comes and the grasses set seed I mow between the rows, and use a weak weed wacker between the plants (a weak one so it won’t cut through the plants if I accidentally touch them).  The grasses will form a straw mulch over the ground, shading it and eventually decomposing into the soil the same way an imported mulch would have done.  So in this way I have put our own home-grown mulch onto the ground without having to bring in material from off the farm like before. I used to think I saved  a lot of time bringing in mulch… my thinking was each hour of mulching saved three hours of weeding, and put humus into the soil… well now, I don’t bother bringing in material, it grows in-situ and merely needs to be mowed down. This is a lot less labor than I had before.  One downside is that in the springtime, I have a lot of little spiky grass seeds in the cactus areas… these get caught in your clothes. But seriously, in the three years or so we’ve been doing these large plants that way, we’ve had no downside other than the stickers in the grass.

   For the small plants we still do a clean cultivation. The plants are very low to the ground, and we don’t want anything growing that will overwhelm the small plants. So in that instance, I’d prefer to have mulch. I may start collecting it from beneath our trees. For the short-lived perennials, one good thick mulching will last for a few years. 

That which you cannot change,
you must bear with
Mexican Proverb

 

   Someone asked me recently whether having to stop bringing in mulches to comply with the new Federal Organic Laws was a problem for us. My reply is this article…. so often in life we have to make adjustments based upon expectations of others.  When these things happen all we can do is find the best option to allow us to continue. Sometimes we are caught in ‘The Traditional Way’ to do things, other times we are hampered by a need for the approval of others…. for us, the hardest thing is getting used to ‘letting weeds grow’… but oddly, I’ve found that this method is actually very well suited to our large cactus plants. They grow just fine this way, and we don’t have to work hard driving a large truck into town to pick up mulch and bring it back, so our fuel costs are lowered (I only put 400 miles on the big truck last year).  So perhaps all-in-all, this will probably turn out to be a good thing.

   A closed mind can keep you from new opportunities,
yet you don’t want your mind so open that it falls out when you tie your shoes.