A Vision For Sustainable Row Crop Farming

(Originally posted on Applied Mythology on 3 15/11)

It has been estimated that between increasing standards of

living and increasing population, there will be 1.5 to 2 times as

much demand for food as there is today by mid century.  To

meet that demand without adding more farmed land, the current

farms must achieve greater productivity per acre or hectare.

The challenge is to do that without increased, and hopefully

decreased, environmental impact.  As challenging as that

sounds, I actually believe that this is possible because of a

number of agricultural advances that have been made over the

past few decades.  I'm not saying it is obvious that we will get

there, just that it is possible.

These Are Not My Ideas

As part of my consulting business, I have had the privilege to

spend time reading hundreds of scholarly articles about

agricultural sustainability.  Over the past few decades there has

been an extensive research effort to quantify the environmental

problems/benefits of various farming practices.  I have not

conducted any of this research myself, but I have had the chance

to digest it and learn from all the hard work that was involved.

Many of the studies were based on field research over many

years, often 10 or more.  This academic research has also been

complimented by commercial innovation on the part of farm

equipment companies, agricultural chemical companies, seed

companies and other commercial entities.  The most important

aspect of this innovation cycle is that progressive farmers have

tested, integrated, and perfected the new farming options that

flow from the academic/commercial activity.

What emerges from all of this effort is a vision of the kind of

agriculture that could not only feed the world, but do it in an age

of climate change and with far less impact on the environment

than has been the case in the past.  Agriculture is a vast and

diverse industry, so I will limit my discussion here to the largest

segment: rain-fed row crops (wheat, soy, corn, cotton...).  For

these crops the five, quantifiably best, farming practices are as

follows:

No-till Crop following Wheat

1. Minimum Tillage

When soils are plowed or otherwise disturbed, the organic

matter content declines and with it the complex aggregate

structures and biological systems of the soil.  When soils are

farmed with "no-till" systems or related options, the soil organic

matter is preserved and soil "health" is enhanced.  This practice

also leads to less fuel use, far less erosion, and thus less off-site

movement of fertilizers or pesticides.  Minimum tillage systems

require specialized equipment.  They are aided by good seed

treatments and genetics, by either herbicide tolerance traits or

selective herbicides.  The transition to a minimum tillage regime

can take several years and during that time there are some risks

particularly during cold springs.  No-till systems have been in

commercial development since 1960.

A cover crop following Corn in Iowa

2. Cover Cropping

The land were most US, rain-fed crops are grown was once a

prairie biome.  That system had a mix of annual and mostly

perennial plant species.  The annual crops that are now planted

in this area are only growing, and thus feeding the soil, for a

part of the year.  A cover crop is planted to grow after the main

annual crop and before the next planting.  A cover crop after an

annual crop is the best substitute for the perennial systems that

preceded farming of the Midwest.  Cover crops can be used

either to tie up excess nutrients from the previous crop or to

generate more nutrients for the next crop (e.g. a legume).  They

further reduce erosion and contribute to the storage of carbon in

soils.  Most farmers recognize the benefits of cover cropping and

the main barrier to their use is the logistics of planting them

during the busy harvest season.  When minimum tillage and

cover cropping are combined, the development of soil health is

optimized.  Such soils are also more efficient at capturing

rainfall and at holding on to the moisture.  Over time the soils

become increasingly "drought proofed" which will be of great

value in an age of climate change.

Diagram of How Auto-steer or RTK

works

3. Controlled Wheel Traffic

One problem has discouraged many farmers from continuing in

no-till.  After some years without plowing, the soils can suffer

from compaction.  Growers describe them as feeling "tight," and

they often feel the need to break out the plow.  A more recent

technology can prevent this compaction issue.  It is called

"Controlled Wheel Traffic" and it uses enhanced GPS to guide

the tractors and far implements so accurately, that no wheel

ever rolls over most of the area of the field.  By preventing soil

compaction, this technology greatly reduces the production of

nitrous oxide during wet periods.  Nitrous oxide is more than

300 times as potent as Carbon dioxide as a greenhouse gas, and

is often the single largest contributor to the carbon footprint of

farming.

The sort of soil maps and yield maps used for variable rate

fertilization

4. Precision Fertilization

One of the greatest ecological challenges for farming is the

efficiency of fertilizer uptake.  The growing crop has a certain

pattern of uptake from the soil that changes throughout the

season.  There can be periods before or after the peak plant

demand when fertilizers can be lost to surface or ground water

or to the atmosphere.  In all those cases the lost fertilizer can

cause pollution and/or greenhouse gas problems. Farmers now

have the tools to minimize those losses as much as possible.

"Precision Fertilization" is really a combination of practices

through which the fertilizer is precisely placed where the plant

is likely to find it easily and applied at rates which differ across

the field.  Extensive data is collected through devices like a GPS

enabled "yield monitor", by soil sampling, and even by real-time

infra-red monitoring of the nutrient status of the crop.

Specialized fertilizer applicators then apply less fertilizer or

more fertilizer as needed for each spot in the field.   This not

only saves money by requiring less total fertilizer, it increases

yields by avoiding inadequate fertilization of some parts of the

field.   The addition of variable rate, precision fertilization,

combined with the improved soil characteristics from the three

practices above, can almost eliminate nitrate and phosphate

pollution issues.

5. Integrated Pest Management

To achieve the sort of yields that will be needed in the future, it

will be necessary to control the yield losses that can occur

because of weeds, insects and diseases.  This will by necessity

involve the use of pesticides, but by using Integrated Pest

Management (IPM), farmers can do this is a way that is safe for

humans and safe for the environment.  Over the last two

decades, there has been enormous progress in finding new

pesticide options which are intrinsically low in mammalian

toxicity and very soft on the environment.  They also tend to be

used at much lower rates.  That can be combined with only using

pesticides if needed and fostering any degree of natural

"biocontrol" that can occur.  The growers also have to be careful

to practice good "resistance management" strategies to preserve

the utility of these tools.  Insect resistance traits developed

through biotechnology also help to reduce the need for

insecticide sprays.

All five of these technologies/practices are being used on a very

significant scale in modern, conventional agriculture.  They are

not yet being used as widely as would be desirable, and I have

explained why not in another post.

Wheat field image from adarsh

No-till image from NRCS

Cover crop image from Iowa State University

RTK diagram from Ohio State University

Yield and soil maps from Vermont Extension

Contact: feedback.sdsavage@gmail.com