In an effort to extend information on CASI's twenty-year conservation agriculture study that has been conducted at the University field station in Five Points, CA and that has been recently published in the journal, California Agriculture, Jeff Mitchell provided three radio interviews on the morning Ag Report that Don York produces for KMJ580 AM each morning out of Fresno.  The segments aired on May 23rd and on June 4^th and 6th, 2024 and are available below.  Mitchell shared findings of the long-term “NRI Project” that since 1998 has examined four production systems – standard tillage without cover crop, standard tillage with cover crop, no-till without cover crop, and no-till with cover crop. 

The NRI Project started as an effort to determine the potential of reduced disturbance tillage in terms of generating or producing less dust and in the early 2000s found that dust can be significantly reduced by as much as 80% with a variety of reduced tillage practices relative to standard tillage techniques that have been widely used in annual crop fields throughout the San Joaquin Valley since the early 1930s.   The recent findings from the unique long-term study have shown that several soil health indicators including aggregation, water infiltration, biodiversity, and surface carbon were improved through the long-term use of cover crops with reduced disturbance tillage. 

In the interviews, Mitchell points out that the systems that were evaluated and developed in the NRI Project were not at all easy to implement and required considerable trial-and-error effort to achieve.  Yields, for instance, of cotton in the early years under the high residue, no-till cover crop system lagged behind the standard tillage, however once effective planting techniques were learned to establish the cotton crop. There were no yield differences between the two tillage systems for the next several years. 

The results of this study that included 18 coauthors can be seen at  https://doi.org/10.3733/001c.94714

A unique - dare we say - "never before attempted in the region," effort to precede strip-tilled tomatoes with a mowed vigorous winter cover crop was conducted in one of the fieldsofWoolf Enterprises, a major tomato and other row crop farm just south of the small San Joaquin Valley town of Huron, CA in the spring of 2022. Several Woolf agronomists including Rick Blankenship and Shane Bickner, along with agronomy consultant,Cary Crum,of Agrotechnovation, oversaw the effort.  The cover crop was a short-season mix that ended up being largely dominated by triticale, was mowed by a flail mower that had been fitted with a horizontally mounted circular chopper to fill in a 'skip' area in the flails behind the center of the unit.  Then,an Orthman three-row 60" spacing strip-tiller followed the mowing ahead of tomato transplanting.  Two short video files are linked here that show the mower and the strip-tiller in action.  After this first year of trying the cover crop strip-till system, one agronomy manager at Woolf put it this way,

"There are a lot of extra management required, but worth the effort. The learning curve is steep and ridden with holes to fall into, but the soil changes behind the multispecies cover crops is impressive. I wouldn't recommend it to someone who doesn't tolerate some failure along the way. Less passes to get beautiful tomato beds behind it.

I'm not sure I've bought into the strip till on the flat tomato beds yet because of the necessary harvester adaptations or the strip till beds because of residue but I think with some more adaption we could make it work.

 I really like the multi species cover crop as a rotation partner when it's green chopped early."

More to come from this exciting, innovative work soon!