fbpx

Terminating cover crops with glyphosate

For those who are yet undecided,

Evidence continues to accumulate regarding the pronounced negative effect of glyphosate on soil health, and how it leads to disease enhancing soils.

A new paper recently published describes how using glyphosate to terminate an oats cover crop alters the soil microbial profile as compared to a cover crop that is mowed1.

The conclusion? Glyphosate alters the microbial community dynamics, some species become more dominant, while others are suppressed. Not a surprise. We know from prior work by Huber et. al. that glyphosate applications shift the microbial population in the direction of a disease enhancing environment.

A second recent publication describes how minerals are lost from cover crops sprayed with glyphosate and don’t seem to remain plant available in the soil profile.2

If you want to develop disease suppressive soil that prevents possible infections of soil-borne bacteria or fungi, there doesn’t seem to be a place for glyphosate in the toolbox.

1. Allegrini, M., Gomez, E. D. V., Smalla, K. & Zabaloy, M. C. Suppression treatment differentially influences the microbial community and the occurrence of broad host range plasmids in the rhizosphere of the model cover crop Avena sativa L. PLoS One 14, e0223600 (2019)..

2. da Costa, J. V. T. et al. DECOMPOSITION AND NUTRIENT RELEASE FROM CROTALARIA SPECTABILIS WITH GLYPHOSATE APPLICATION.

2020-03-16T13:49:21-05:00January 3rd, 2020|Tags: , , , |

Spring applied planter solution products influence end of season cover crops

This is a field in Pennsylvania in December 2019.

It appears the section on the left has less residue, and possibly more cover crop growth.

The only difference is that the planter solution used for planting the corn crop in the spring was a product blend (AEA) that enhanced biology (left), as compared to a ‘conventional’ ionic planter solution that suppresses soil biology (right).

2020-03-16T13:48:25-05:00January 2nd, 2020|Tags: , |

The bulls-eye of the wrong target

We have become masterful at hitting the bull’s eye of the wrong target.

A colleague sent me a recent article1 describing the discovery of a master gene that regulates iron absorption in plants. You can read a journalist’s popularized version here.

Just so we are clear, iron absorption is not a genetics problem. This is a soil redox and microbial problem.

There is abundant iron in the earth’s crust and in our soils, around 4% or so. Most soil analysis results report excessive iron.

The iron that is in our soils, and that is measured on our soil analysis is often not physiologically active in plants because it is in the oxidized form that is unavailable for absorption. 

It is largely in the oxidized form because of how our soils have been mismanaged. We have shifted the microbial population and the general soil environment in the direction of excessive oxidation, and inadequate reduction. 

It is the function of beneficial microbial populations in the soil to convert iron and other elements from the oxidized to the reduced form and improve their plant availability. This only happens when we have a soil environment that can support the right biology and allow this transition to occur. 

When you change soil biology and redox status, crops will have an abundant supply of iron. And manganese. And cobalt. And copper.

Changing plant genetics to improve absorption of the wrong form of an abundant mineral completely misses the obvious.

Kim, S. A., LaCroix, I. S., Gerber, S. A. & Guerinot, M. L. The iron deficiency response in Arabidopsis thaliana requires the phosphorylated transcription factor URI. Proc. Natl. Acad. Sci. U. S. A. 116, 24933–24942 (2019).

2020-03-16T13:48:05-05:00December 31st, 2019|Tags: , , |

Redox as a driver of soil/plant/microorganism systems

Contemporary mechanistic agriculture has been based largely on the development of genetics and chemistry. 

The regenerative agriculture systems emphasize the development of biology and biophysics.

All the evidence points to an emerging agricultural revolution that will supersede the so-called “green revolution”, and exceed it in terms of crop quality and yield and economic returns to the producer. 

Since I first started working in this space I have been fascinated by the volume and integrity of high-quality science in the biophysics space that has not been utilized by mainstream agriculture, yet holds so much promise. 

One such topic is the role of soil redox in developing disease suppressive soils and regulating nutrient availability. Redox has at least as big an impact on nutrient availability as pH does.

Here is an important and foundational review paper1 that will get you started on this important topic.  Look for a more on this in the coming months. 

  1. Husson, O. Redox potential (Eh) and pH as drivers of soil/plant/microorganism systems: a transdisciplinary overview pointing to integrative opportunities for agronomy. Plant Soil 362, 389–417 (2013).

 

2020-05-05T08:57:27-05:00December 30th, 2019|Tags: , , , , |

Nutrient Application Timing

The best way to reduce our nutrient applications by 30% – 40% or more is to time application so the product release curve matches the crop demand curve.

We know that many crops will have a  nitrogen and potassium demand peak during fruit or seed fill.

A peak calcium demand generally occurs during the cell division stage in the weeks immediately after blossoming and pollination.

If you have a crop with a high calcium demand, consider using gypsum as a calcium fertilizer, not simply as a calcium soil amendment. The difference between the two uses is application quantity and timing. (and intent)

Using gypsum as a calcium fertilizer you might apply 100-200 lb per acre of a pelletized gypsum 30-45 days ahead of calcium demand peak. You would choose this timing because the calcium release curve of gypsum begins peaking in this time frame and then begins dropping off about 90 days after application.

Applied products don’t all release on the same curve. While there are variations because of particle size, temperature, and soil moisture, you can find general guidelines of when a product begins supplying nutrients.

For tree fruit crops, which bloom right after breaking dormancy, a gypsum application would need to be applied late winter or early spring so the calcium peak occurs during and just after pollination.

For a crop such as sunflowers or millet that blooms in late summer, a fall application of gypsum delivers just a fraction of the crop benefit as a spring application because the calcium release peak occurs before the crop demand.

Different potassium and phosphorus fertilizers all have different release curves.

We observe significant economic gains from managing nutrient application timing. This seems like an obvious point and is one of the best ways to get a bigger crop response with smaller nutrient applications.

It is also a single entry on the long list of reasons why nitrogen applications in the fall for the following years crop are a thoughtless and ill-informed choice.

2020-03-16T13:43:40-05:00December 28th, 2019|Tags: |

Manage-able data for soil nutrients

Data collection is only useful if you can use it to make management decisions. ‘Manage-able’ data in other words.

Soil analysis is still somewhat of an imprecise science. If you disagree, split a soil sample, send it to different labs and observe the results. This doesn’t mean we shouldn’t conduct soil analysis. It does mean we should understand what we are getting, and know the difference between the various extraction methods. 

I credit much of our success in our agronomy work at Advancing Eco Agriculture to the fact that we avoid guessing about anything we have the capacity to measure. We look at soil nutritional profiles, irrigation water quality where that is relevant, and actual plant absorbed nutrients through sap analysis. 

Our approach to soil analysis has continued to evolve. A decade ago, we would run an ammonium acetate extraction in early fall, August – September time frame, and saturated paste extraction every two weeks during the crop production season. You get an education really quickly about fertilizer performance when you measure what is happening in the soil with plant available nutrients every two weeks. 

After the development of reliable plant sap analysis in the lab, we replaced the biweekly saturated paste samples with biweekly sap analysis. After all, the plant is the final report card, and it can tell us precisely what it is finding abundant or missing, regardless of the soil levels. 

Sap analysis informed us rapidly that there is very little correlation between the presence of nutrients in the soil and actual absorption by the crop. In fact, in the case of some nutrients such as iron and manganese, there is zero correlation. (for reasons of soil redox, dysfunctional biology, and more.)

As a result of constantly learning and improving our understanding of what is happening with the soil’s nutritional profile, I would suggest that growers should collect at least three different types of soil samples to understand what is happening with soil nutrients.

  1. A ‘geochemical assay’ type soil analysis that measures the total mineral content within the profile. This will be the assay that shows in black and white the tens of thousands of pounds of phosphorus and potassium, and the hundreds of pounds of manganese and other trace minerals contained within many soils. Minerals that biology can tap into over time. Several samples should be pulled at different depths. One sample should be as deep as the A horizon, the topsoil layer, or as deep as the upper mass of roots generally reach. Usually somewhere in the neighborhood of 6-12 inches. A second sample should be collected immediately below the first, down to a depth of 24-36 inches, the B horizon. These samples only need to be collected once, to give us evidence of what reserves we have to work with, or not. If there is no molybdenum, selenium, cobalt, vanadium, or some of the other ultra trace elements showing up, crops will benefit from adding some. This type of sample can be run through AGAT Labs, and possibly others.
  2. A more familiar ‘CEC’ analysis with ammonium acetate or Mehlich III extraction. Mehlich III or Olsen extraction are preferred for phosphorus, Bray extraction can be unreliable in some soil types. We typically use a Mehlich III extraction for all the nutrients across the board. With this analysis it is also valuable, I would suggest necessary, to measure cobalt, selenium, molybdenum, and nickel as a standard, at least on some fields. We typically conduct this analysis in late summer/early fall, every year on high value crops, and every few years on broad acre commodity crops. 
  3. An organic acid, ‘H3A’ or Haney analysis to identify the nutrients the soil is capable of releasing in the coming growing season. We have just begun including this test as a standard, and are still learning it’s ins and outs. We are experimenting with both spring and fall samples, but it makes sense to me to collect these samples in the spring to most accurately identify what is happening closest to the crop season. 

When you collect all three of these samples, you can form an accurate perception of what is really going on with your soils mineral profile, and the resources you have available to work with. Now you can make informed decisions about nutrients actually need to be applied, and what you can tap into from the soil reserves. 

Saturated paste tests are still a very useful tool for special situations. Very sandy soil, a fast-growing crop such as spinach, muck soils, and in artificial media are all places where saturated paste tests give us valuable information. They are not the right decision-making tool to determine soil amendments though. Their biggest strength is also their biggest weakness. Their strength is they show you what is available the next few weeks. Their weakness is that they only show you what is available the next few weeks. 

I am still looking for a microbial assay that gives us ‘manage-able’ data. This is a bit of a challenge, because we need an assay that both identifies the presence of a species or group, AND the degree of presence. It is not enough to know that we have both pseudomonas and fusarium species. We need to know that we have enough of the right pseudomonads to suppress possibly infectious fusarium.

PFLA tests are ‘interesting’ but we haven’t figured out yet how to make the data manage-able. Non-actionable means we don’t run them very often. 

A topic for another post is the importance and usefulness of qualitative in field soil analysis such as water infiltration and agreggate stability tests.

 

2020-03-16T13:44:36-05:00December 27th, 2019|Tags: , , |

Value subtracted food and farming

I have added a new book to my recommended reading list. Grain by Grain by Robert Quinn and Liz Carlisle is an exceptional read on how our food and farming system has gone askew, and one farmer’s path to reversing the trend on a local level. You can find the entire reading list here.

Enter Bob Quinn ~

If farmers were shafted by such a system, I began to realize, eaters were not much better off. On the supermarket shelves of their local grocery stores, they had little choice outside of standardized commodity wheat, crushed between colossal steel rollers to strip it of its nutrient-dense bran and germ. Processors did their best to package this white flour into creative forms, giving the appearance of an abundance of culinary options: vitamin-fortified white bread, fiber-added breakfast cereal, omega-3 enriched energy bars – all packed with sugar and a host of unpronounceable ingredients meant to increase shelf life and make the stuff taste like food. The processors even had the audacity to call such concoctions “value-added products.”

To me, this definition of value-added is completely backward. Many things have been added to our commodity wheat, but value is not one of them. We would never have needed nutrient fortification in the first place if we had removed so many nutrients in the course of industrial breeding, production, and processing. When we look at the net movement of value in the commodity system, it’s pretty clear that it has been moving steadily away from our food. What we have now is essentially value-subtracted wheat. Not only has much of the embedded value been literally stripped away – no bran, no germ, no soil health, often no net profit to the farmer – the ability to even assess value in such terms has been removed too. The purveyors of value-subtracted products deliberately concealed the nature of their production and processing: as the saying goes no one wants to know how the sausage is made.

In contemporary American society, we see many such value-subtracted products. Commodity wheat, corn, and soy, aggressively refined and transformed into soda and burgers and cookies, greet you in nearly every aisle at the supermarket. The car you probably drove to get there runs on value-subtracted energy: commodity petroleum. The clothes you’re wearing? Value-subtracted fiber or commodity cotton, or perhaps a blend of synthetics.

Back to John ~

A lot to contemplate here. The foundational question that comes to mind is: Are my activities adding value or subtracting value from the crops we are growing?

 

 

2020-03-16T13:42:36-05:00December 23rd, 2019|Tags: |

Nutrient density is about freshness

Update and edit 12-21-19

After sending this post I was reminded there is still much we don’t know about the research described in the podcast interview I highlighted in this post, and asked to offer some context. A few points:

  • “Nutrition” is much more than Vitamin C and some compounds which may oxidize readily in a few days.
  • It is very probable that healthy plants with elevated levels of antioxidants will not lose even oxidizable nutrients as quickly as described.
  • How crops were grown was not evaluated, but experience pointed out large variation from season to season. We should expect to find significant variation based on agronomic factors.

I recall a conversation where Bruce Tainio described working with an apple grower who produced such high quality apples they did not ozidize when cut open. They stayed white, and did not brown when left exposed to the air. Patients with diabetes could consume them with no blood sugar or insulin response. This occurs when you have very high levels of antioxidants and complex carbohydarates. This is the quality of fruit we are striving for.

Back to the original post

–

Spinach loses much of its nutritional value within seven days of being harvested. No matter how you store it.  The spinach at Wal-mart may be better than that at Whole Foods, if it got there faster because of higher volume turnover.

Apples lose all their vitamin C within a few weeks of harvest, even when stored in cold storage or frozen. 

The foods on the grocery story shelf with the highest nutritional value are usually the ones that arrived there in the fewest hours from being harvested by the grower.

Stored fruits and vegetables have lost their nutritional value, and are little more than sugar bombs within weeks of being harvested. (Seasonal eating just escalated in importance.)

Most importantly,  buyers at the wholesale and retail level will be able to assess the nutritional quality of the crops they are buying in January of 2020.

These are a few of the highlights from an incredible podcast interview between Koen van Seijen, host of Investing in Regenerative Agriculture podcast, and Greg Shewmaker, co-founder of TeakOrigin. 

If you are even slightly interested in nutrient density,  how food quality will be assessed and farm products purchased differently  in the next few years, this podcast episode is a must-listen.  You are really missing out if you pass it up.

 

2020-03-16T13:42:18-05:00December 21st, 2019|Tags: , |

Foliar feeding of plant nutrients

I have long been an advocate of foliar feeding nutrients as one of the most financially rewarding applications that can be made to a crop, and the practice has become mainstream in many regions. 

Thus, it comes as a surprise that in some areas growers still consider foliars to be an ineffective tool. I would suggest they are ineffective only when they are not properly designed and applied. 

Some of the first published papers on foliar feeding I have read were based on research conducted for the Atomic Energy Commission by Sylvan H Wittwer and Harold B Tukey in the late ‘40s and ‘50s. Their congressional testimony is as relevant and exciting today as when it was first published. (Approximately 1952?)

I cleaned up the document and made some slight edits to make it more readable, but kept all the underlining in the original report. You can read the 24 page report (and bibliography) here. You will find valuable and intriguing information. Here are some excerpts:

  • not only can plants absorb nutrients through the roots, but also through the foliage, the fruit, the twigs, the trunk, and even the flowers.
  • the most exciting news is the foliage feeding of plant—that plants can take up nutrients through the foliage. Here is a case where the farmer has really gotten ahead of the scientist as so often happens. He has learned that foliage feeding is helpful and he has adopted the practice. 
  • The first point I should like to make is that the materials do enter the leaves rather easily.
  • In the final analysis, we find that a leaf is a very efficient organ of absorption. We find that the materials move into the upper surface of the leaf as well as the lower surface. We find that it enters at night and during the daytime. Further, we find the leaf surface of a 12-year-old apple tree in Washington State to be equivalent to one-tenth of an acre, even though that tree only occupies about one-hundredth of an acre. So there is a large feeding area.
  • Not only do these materials enter rather easily—and this is interesting, too, because all the textbooks used to tell how the plant was covered by an impervious cuticle—now we find textbooks are re-written and the leaf is reported as a beautiful mechanism for absorption. 
  • If we apply it to the leaf we find it moves downward through the plant—at the rate of a foot an hour. It is very interesting that it moves so freely. If we apply it to a middle leaf it moves both ways very effectively.
  • We have seen that materials are absorbed by the plant and move rather freely in the plant. The amounts may at first seem relatively small, but to off set this handicap, the efficiency is high. In fact, this is the most efficient method of applying fertilizer to plants that we have yet discovered. If we apply these materials to the leaves in soluble forms, as much as 95 percent of what is applied may be used by the plant. If we apply a similar amount to the soil, we find about 10 percent of it to be used. 
  • For example, the soil may be cool and low in phosphorus at just the time it is needed by a transparent vegetable or strawberry plant. Or there are cases where the soil locks up certain materials that are applied, like potash and magnesium. Under such conditions we find leaf application very significant and very effective.
  • But now we are highly suspicious that here may be a case where materials are actually being leached out of the leaves maybe by overhead irrigation, maybe by rain, and having a profound effect upon the crop.  

 


2020-03-16T13:44:48-05:00December 20th, 2019|Tags: , , |

The Only Right Way

This post is a challenge to dogma. The presence of dogma in our thinking blocks us from being open to new possibilities and new ideas. 

It is easy to observe dogma in other people’s positions.

It is common to hear emphatic declarations that a certain practice or management technique is imperative to a healthy agriculture ecosystem.

There is no ‘rule’ of ecological agriculture that has not been successfully broken by someone, somewhere.

Examples:

  • Biodynamics can only be practiced with these prescribed steps and in no other way.
  • Tillage is universally a negative tool and always has a negative impact. 
  • Ionic salt fertilizers always have a negative impact on soil biology. 

You can think of others you have heard or observed.

Very often, in agriculture systems, there is more than one right way to do something and a multitude of wrong ways.

The greatest obstacle to discovery is not ignorance – it is the illusion of knowledge. ~ Daniel J Boorstin

Read books and study nature. When the two don’t agree, throw out the books. ~ William Albrecht

It is not what you don’t know that is dangerous. It is what you think you know that isn’t so. 

What dogmatic positions have you observed? (besides tractor color)

 

2020-03-16T13:40:53-05:00December 19th, 2019|Tags: |
BLOG INDEX
Go to Top