These are the following pictures from October 2013 of demonstration cover crop plots:
Forage Radish:
Rye:
Vetch:
Mix: (the forage radish dominates)
Lupin:
Fallow:
And this is what the same demonstrations looked like in May, 2014:
The entire field:
Forage Radish: (notice the residue cover and large holes)
Vetch:
Mix:
Lupin:
This weekend, a total of 4 hours was spent measuring the height of the corn in all 24 plots and another 6 hours harvesting, shucking, weighing and measuring the sugar content of 7 of the plots.
Corn from One Plot.
Variety in Corn Size and Quality.
Brix Measurement.
The Brix is an optical tool used to measure the percentage of sugar in a liquid. Hence, squeezing the juice out onto the cover.
The field season is wrapping up. This week soil samples and penetrometer readings were taken at Adam’s Berry Farm. A penetrometer measures resistance as it is pushed down. It is used to indicate levels of compaction in the soil. Without doing a statistical analysis, at first glance the numbers trend towards higher levels of compaction in areas with forage radish. Take my query with a grain of salt, perhaps the penetrometer is reading increased compaction in the forage radish plots because the large diameter of the root is pushing soil horizontally and thus causing compaction. A plethora of research has shown that forage radish can increase infiltration after decomposition. However, in the interim it may cause a loss of micro and macro pores in the soil and increase compaction.
Penetrometer.
Seven weeks after planting, this is what Adam’s Berry Farm looks like:
There are six plots. The farthest three are difficult to see in this picture. The bright green on the right is forage radish, the middle darker green is winter rye, and the bright green is a mix of rye, vetch, forage radish, and lupine.
Adam’s Berry Farm, October 3, 2013.
The lupine is farming a low-lying canopy.
Lupine.
The stand if vetch is filling in slowly. At about 2.5 inches, the vetch is nearly as high as the lupine.
The rye comes in second to forage radish for tallest of the six plots.
Rye.
One lone lupine is visible and slight numbers of vetch and rye are present. The mixed plot is dominated by forage radish. I am curious to see if the vetch and rye accelerate their growth as frost damage reduces the biomass of the forage radish.
Mix
A few forage radishes on the edge of the forage radish and mix plots were quite large.
Large Forage Radish Up Close.
The forage radish in the middle of the plot was quite small due to competition for resources.
Small Forage Radish Up Close.
The fallow plot is overtaken with chickweed.
Fallow.
Some preliminary results show correlations with iron, manganese, and sulfur, but not phosphorus of four sampling dates at The Intervale Community Farm.
Click image to enlarge.
Each X axis label corresponds to a date:
1=May 3, 2012: after snow melt
2=Oct 18, 2012: before Saturation
3=April 5, 2013: before saturation
4=July 4, 2013: after saturation
The Y axis is the p-value. There is better statistical significance the closer the point is to zero. For example, sulfur shows a higher correlation with length of water saturation/elevation and less correlation in-between dates of high saturation. Iron is an even more extreme example of this. There is almost no iron/elevation relationship during sampling dates that are not after saturation. This may be due to field management practices like discing that redistribute nutrients evenly. On the other hand, manganese is the most muted form of this trend.
Phosphorus tells a surprising story. Considering the relationship between phosphorus and iron, I would expect phosphorus to follow a similar trend to the other nutrients included on the graph. One possible reason may be that vegetation is larger at higher elevations given more favorable growing circumstances (less saturation=more aeration=less environmental stress) and since the crops are larger up-slope, they seek out and acquire more phosphorus, encouraging a relationship between elevation unrelated to length of saturation and phosphorus in soil.
On August 27th, the last round of samples was collected from ICF. A 2X2 soil core was taken at 31 locations. Of the 31 samples taken, 26 showed signs of orange pigment concentrations, otherwise known as iron accumulation. Many samples looked like this:
Picture of soil sample taken after drying in the oven at 70°C overnight. Orange pigment also visible in the field.
Insoluble ferric oxide can be reduced to soluble ferrous oxide by microorganisms when soils are water-logged and micro-organisms are looking for a source of oxygen.
That equation looks like this:
*Note that Fe2O3 is Iron(III) oxide or Fe(III). The “(III)” is indicative of the number of oxygen molecules. Likewise the “(II)” in Iron(II) hydroxide relates to the number of oxygen molecules.
This process happens in a larger context. Soil micro-organisms have a preferred order of oxygen source. This is the order from highest to lowest preference: Oxygen->Nitrogen->Manganese->Iron->Sulfur->Carbon. I can remember this order of preference with the mnemonic device: Only Nadia MaNages FEral Squirrels Casually.
At any rate, iron concentrations can be indicative of redoximorphic features, which are evidence of either poorly drained soils or frequently water logged soils.
So, after the water recedes (or dries), and oxygen is introduced back into the soil, the soluble iron can return to iron oxide.
As the reverse of the above equation shows:
You can find more information about iron in the ecosystem at large here: Earth’s Ferrous Wheel.
This is a great visual representation of the iron cycle. Please note that the following picture includes uptake of heavy metals not addressed in the blog post.
In hopes of bringing a better field day and collecting more data on how cover crops effect soils, Adam’s Berry Farm was seeded 12 days ago with Winter Rye, Hairy Vetch, Forage Radish, Perennial Lupine, and a mix of all four. Here is what they looked like as of yesterday, August 27th. Compare the forage radish and hairy vetch plots. They both have the same seeding rate at 10lb/acre, but have very different coverage so far.
To find out more about the field day, visit: http://nofavt.org/events/cover-crops-cope-effects-flooding-soil-fertility
The winter rye is nearly 3 inches tall.
So far there has been poor emergence of hairy vetch.
The forage radish has the most impressive stand yet.
Slowly, but surely this perennial lupine will grow to have good coverage.
This plot of rye, vetch, radish, and lupine will show how a cover crop cocktail can affect soil fertility. We will also be able to see how the different cover crops compete. Will rye dominate? Does lupine stand a chance?
The following three images show what the plots look like next to each other. A buffer is on either side of the plots.
Radish close, Vetch in the back
Rye up front, Lupine in the back.
Here you see the sparsely germinating mix, followed by the fallow plot in the back.
There will be a field day to show test plots and reveal preliminary results. It will be on Tuesday, September 17, 2013 from 4:00- 7:00 p.m. at Adam’s Berry Farm and Arethusa Farm, followed by lite refreshments at the Intervale Center. More information to come.
Arethusa Corn Plot before hoeing. No disease noted so far.
Jeff Philly of Arethusa Farm planting the second round of cover crops on August 16th.
Adam’s Berry Farm research site planted with forage radish, perennial lupine, winter rye, hairy vetch, a mix of all four, and a fallow plot.
The College of Agriculture and Life Sciences Department at Cornell University have created a internet tool to more successfully assess necessary rates of nitrogen application throughout the season. A decent amount of land use history is necessary, such as soil type, prior crop, and date of nutrient applications. However, mid-season soil sampling is not necessary. One of the great advantages of Cornell’s Adapt-N management, is that it takes into account weather variations that affect nitrogen mineralization specific to farm location. You can find out more here and sign up to use this management system.
The following images are from the Adapt-N webpage’s “About” tab.
Figure 1. The influence of early season weather on optimal N rates.
Figure 2. Risking greater losses with pre-plant application.
Figure 3. Risking greater losses with pre-plant application.
It’s now in the height of agricultural season here at the Intervale in Burlington, Vermont. Corn makes for a good indicator crop because it is sensitive to nitrogen deficiencies in the soil.
Corn at Arethusa.
On Friday, July 26th, the research site at Adam’s Berry Farm was disced. It has yet to be put under a basket weeder before the corn can be planted. The re-growth post discing has delayed indicator crop plant date, which is already very late due to all the rain saturating the soil for weeks on end.
Nearly ready beds at Adam’s Berry Farm.
The research sponsored by a SARE Partnership Grant examines a small depression in a currently cultivated field that is prone to flooding for soil fertility changes that correlate with elevation. In a way, the data found can also be used to extrapolate how soil fertility changes with duration of water saturation. The site we are studying is located on the Intervale Community Farm in Burlington, Vermont
Intervale Community Farm. The small field depression is located under the brown stalks to the right of the tire tracks.
On the way back from the Intervale Community Farm, I noticed the waterline on the trees from the flooding that occurred from the downpours we had earlier in the summer.
Flood waterline on trees.
The research sponsored by a SARE Graduate Grant examines how cover crops can ameliorate soil damage associated with flooding on three flood-prone sites: Intervale Center land, Adam’s Berry Farm, and Arethusa Farm. At each site, four replicates of cover crops are randomly ordered. The effects on soil health of lupine, winter rye, hairy vetch, forage radish, and a blend of all four of these will be compared each other and fallow plots.
My path to see the research site remaining in cover crop (due to prolong saturation) on Intervale Center land was blocked by a fallen tree.
Fallen tree blocks path to Intervale Center site.
The research site on Adam’s Berry Farm needs some more cultivation before corn can be planted. Rain is in the forecast and may delay field preparations.
The corn at Arethusa Farm has come up. Unfortunately, the disuniformity of the soil caused an irregular seeding rate.
Upcoming plans for the research sites include one last round of soil samples, planting corn by hand at Adam’s Berry Farm (this will guarantee that germination rate can be accounted f0r), and tissue analysis of the corn crop.
floodedsoils 