In our previous video we saw that by the end of the season, there is no difference in the number of heat units and temperature as seen by a conventional versus a no-till soil. In fact any differences in cumulative heat units between the two systems disappears by the first week of July. In this video, SDSU’s Anthony Bly explains how that happens by examining the side-by-side temperature comparisons between a no-till, and conventional till system near Vermillion, South Dakota. In the latter part of the season (after July 1), we also see that in no-till soils maximum temperatures are consistently cooler and minimum temperatures are consistently warmer than conventional till soils. The NRCS’s Eric Barsness discusses this and tells us why it’s a good thing.
In this video, the USDA-NRCS’s (Brookings, SD) Eric Barsness and SDSU’s Anthony Bly discusses and experiment the NRCS conducted in Vermillion SD on a conventionally tilled and a long-term no-tilled field. Eric buried two temperature probes at 2” and the probes were able to record temperatures every 15 minutes over the entire growing season of 2016. This test is a nice example of how no-till and conventional till fields perform side by side and also show that, while there may be differences in the heat units (or growing degree days) at the beginning of the growing season, by the end of the season each crop received the same number of heat units.
In this, the final video on weeds, we spent a little time with no-tillers Matt Bainbridge, Al Miron and Ralph Holzwarth and got them to tell their stories about how their no-till, diverse rotation systems were doing with weeds, and how this affected some of their costs to cope with weeds. The message we received from them is consistent with our previous videos namely that with low-disturbance (i.e., no-till) systems, especially when combined with diverse rotations, weed control can actually improve and costs for weed control can be lower than in conventional tillage systems.
Crop rotations for weed management? At first glance, it doesn’t seem possible. We know, however that in our previous videos, Dr. Anderson showed us how (1) no-till reduces weed prevalence and (2) how he verified this idea experimentally. In this third video, Dr. Anderson discusses why rotating cool season crops into our warm season rotations are so beneficial to weed control. Dr. Anderson demonstrates how through the synergistic effects of no-till combined with diverse rotations, one can reduce weed pressure by a factor of eight before the first drop of herbicide is used. We recommend you view the first two videos (“Fate of the Weed Seed in Conventional and No-Till Soil” and “Seedling Emergence in Conventional and No-Till Fields” with Dr. Anderson.
In our previous video, Dr. Randy Anderson walked us through the various fates of the weed seed in conventional and no-till fields. In this video, the theory comes alive as he discusses the results of a three year study he did in comparing conventional and no-till weed seedling emergence.
In a world where technology offers a quick fix to our weed problems, but inevitably leaves us with unintended consequences, the USDA Agricultural Research Service (ARS), Brookings, SD, Dr. Randy Anderson offers an approach to weed science that says “wait a minute”, what are we doing? In our systems to encourage or reduce weed proliferation before we consider which herbicide to use? To begin to grapple with this question, we have to understand the fate of the weed seed. Dr. Anderson considers weed seed when on the surface of the soil and when buried. Join us in this, the first of three discussions as Dr. Anderson shows us how we can use natural systems to reduce weed populations and save on herbicides.
As Dr. Anderson says, “A key point is when you leave the weed seeds on the soil surface you enhance these fates [predation, environmental exposure, natural death]. In other words, predation is much greater if insects can reach the seeds – if they are buried in the soil, the insects do not process the soil looking for weed seeds so therefore tillage actually protects seeds. Almost all studies with weeds seeds have shown that when you bury them in soil the weed seeds live longer and survive longer.”
We introduce the idea of weeds, and touch on how the production agricultural model views weeds. As the first in the Merit or Myth series on weeds, we’d like to introduce an alternative way of viewing weeds namely, to understand their ecological role as the “scabs” or “ambulance workers” of the land. The natural job of a weed is to cover disturbed soils and through tillage and monocultures, we create ideal environments for weeds. With the ecological way of thinking of weeds and by using a systems approach to our farming systems we can, according to Dr. Dwayne Beck, outsmart them. Rather than wage a full-on chemical warfare with weeds (and do everything the same) we can use natural systems to perform a little ecological ju-jitsu on weeds and not only reduce their populations but save on herbicide costs. Take a peek at this 2 minute video that sets us up for a three part series with the ARS’s (Brookings, SD) Dr. Randy Anderson.
While research showing that tillage actually reduces infiltration into the soil, and that cover crops actually enhance infiltration is proven, the refrain of “it won’t work here” is nevertheless often heard when it comes to applying soil health principles. This is not unique to South Dakota, soil health, nor to farming, but this phenomenon is common. In Merit or Myth’s final video on soil water movement, we are giving a perspective from three producers, one from way East River, one from the center of the state and one from way West River. Our point is: these principles work across landscapes and indeed across the state of South Dakota. As Doug Sieck says in the video, “we need to stop making excuses for why it won’t work here” and rather say “how can we make it work here”?
This spring (2017) SDSU Extension’s Anthony Bly and farmer, or shall we say “citizen scientist,” Al Miron got together to look at the influence of tillage, cover crops and manure on infiltration in a number of fields in Minnehaha County, SD. They compared soils in two long term (9 year) no-till fields, two conventionally tilled fields that had not been tilled for a year and one field that was deep tilled in the fall and then again tilled with a field cultivator in the spring. Al and Anthony did 4 repetitions at each site and came up with some interesting results as concerns the effect of cover crops and tillage. The “aha” moment experienced by the grower who loaned the team some tilled land to do the study on is important as his paradigm was “more tillage = less infiltration”. As this farmer saw the results, especially of the 5th (double-tilled) field, he was sold on the idea pretty quickly!
Dr. Tom Schumacher, SDSU, (Retired) walks us through the experimental setup he used with large rainfall simulators, the type developed for the Universal Soil Loss Equation (USLE), on three different tillage systems. The data Dr. Tom discusses is based on experimental runs conducted four years after this land was taken out of CRP and then continuously treated under three different farming systems: moldboard plow, a chisel plow and no-till. With the use of TDR probes that sense moisture at 10 cm (4inches) and 40 cm (16 inches). In this video, Dr. Tom discusses how much quicker water infiltrates into the no-till system and explains why that is. The chisel plw treatment discussed at the end is somewhat in between the no-till and moldboard plow treatments – notice the chisel plow surface still gets saturated and water has a tough time getting into the soil profile at 16” showing a 50-minute delay.