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The effectiveness of microbial inoculants in fixing nitrogen

Soil biology can ‘fix’ and supply more nitrogen, and faster, than they are often given credit for.

The wheat field section on the right received an October application of AEA’s soil primer, which includes bacterial inoculants and stimulants. By March the following year, soil analysis reported an additional 80 units of N available for the crop.

To achieve these results, the soil must have adequate microbially active carbon, good gas exchange, and good moisture levels.

Soil microbial populations can regenerate quickly when given the right environment and support. Regenerating soil health can be accelerated to a few years, it is not a process that needs to take decades to achieve a significant turn around.

2020-05-28T07:05:35-05:00May 28th, 2020|Tags: , , , |

Relay Cropping

How much can you increase farm profitability and economic performance by growing two crops on the same soil at the same time?

Different plants use moisture and sunlight differently. It is common for our first thought to be about how plants compete with each other, but what if the opposite is actually the case? Can we develop cropping systems where different plants actually complement each other?

One of the producers who has experimented with this idea extensively on grain crops is Jason Mauck from Indiana. Jason is always testing and trying new ideas, but he has moved past the experimental stage with relay cropping and is observing results more growers should be familiar with. For relay cropping to be successful, design matters. Defining optimal crop spacing for best sunlight utilization and weed suppression is critical.

I enjoyed a very interesting conversation with Jason on the podcast, you can find the episode here.

Here are some photos of Jason’s farm:

2020-03-16T14:09:36-05:00February 25th, 2020|Tags: , , , , |

Disease suppression of wheat take-all disease

The presence of soil-borne disease infection is not correlated to the presence of an infectious organism, but to the absence of suppressive microbes.

Here is an example from Paul Syltie1 on wheat take-all disease: 

It is well documented that the fungus responsible for the take all of wheat Gaeumannomyces graminis var. tritici is attacked by soil bacteria, in particular by the bacteria in what are called take-all suppressive soils. These soils are unique in that the severity of the disease becomes progressively less as the cropping season continues. In some cases the disease may not even express itself whatsoever despite being present.

It is concluded by soil microbiologists that most soils express some degree of natural pathogen suppression. This occurs generally in soils by the mass of beneficial organisms overwhelming the pathogens at a critical time in their life cycle, robbing critical nutrients from them. Specific suppression occurs when select species or groups of beneficial organisms antagonize the pathogen at some stage of its life cycle.

Take-all in wheat or barley becomes less and less of a problem if the crop is grown in consecutive years. Both fungi and bacteria, such as friendly saprophytic Fusarium species, reduce pathogen numbers by competing for food supplies, and at the same time specific antagonistic microbes like fluorescent pseudomonads attack the G. graminis. The pseudomonads are especially effective when ammonium rather than nitrate fertilizer is used, resulting in a lower rhizosphere pH. This suppression likely occurs mostly in the rhizosphere, but also throughout the soil mass.

1. Syltie, P. W. How Soils Work. (Xulon Press, 2002). Page 111

2020-03-16T13:50:36-05:00January 6th, 2020|Tags: , , , , , |
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