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Recent results from the Cornell Organic Cropping Systems Experiment

Brian Caldwell, Matthew Ryan, and Charles Mohler
Soil and Crop Sciences Section, School of Integrative Plant Science, Cornell University

In 2015, over 1000 certified organic farms were operating in New York State (NYS Dept. of Agriculture and Markets).   Nationwide, New York ranks third in number of organic farms and organic cropland harvested (USDA 2011).  Of the approximately 5000 dairy farmers in NYS, about 430 are currently certified organic.  This number is expected to rise to 500 within two years (Fay Benson, Cornell Cooperative Extension, personal communication).  Thus 10% of NYS dairy farms will then be organic.  However, organic grain production has not kept up with demand, and well over half of feed grains sold to New York livestock farmers are from out of state (Mary-Howell Martens, Lakeview Organic Grain, personal communication). Consequently, land-grant university research is needed to support more organic feed and forage production in NYS.

The Cornell Organic Cropping Systems Grain Experiment (OCS) was initiated in 2005 at the Musgrave Research Farm in Aurora, NY. The purpose of this long-term experiment is to compare four approaches to organic production. Results from 2005-2010, including the 3-year transition period, were documented previously (Caldwell et al. 2014).  This article discusses recent findings from the experiment and its future prospects.

Experimental Design

The OCS compares organic cropping systems: high fertility (HF), low fertility (LF), enhanced weed management (EWM) and reduced tillage (RT) organic cropping systems.  We consider them systems because they are different in multiple ways.  They have evolved over time to address production challenges with help from our organic farmer advisory board.  Currently, HF employs higher nutrient additions during each rotation than the others, and uses both belly-mounted and rear-mounted cultivators.  LF receives only corn starter fertilizer once during every 3-year rotation and only rear-mounted cultivators are used.  EWM has an intermediate nutrient regimen and employs both types of cultivators, short tilled fallows, and extra cultivation to reduce weeds.  In contrast to the moldboard plow-based tillage program of the other systems, RT uses a mixture of deep zone tillage, ridge tillage, and chisel plowing depending on the crop.  It has an intermediate soil nutrient regimen.

The experiment includes four replications and two rotation entry points of each system.  Plots are 30 x 100 feet and are managed with farm scale equipment. Soils are in the Lima series, relatively flat calcareous silt loams with fair internal drainage.  All systems started with a

Caldwell - Arrow 1

 

rotation for the first six years (RT used other legumes instead of red clover in the spelt year).  A group of local organic farmers and extension educators advise on the management of this experiment.

Weed biomass in HF and RT systems was much higher than in LF and EWM by 2010 (Figure 1), and was reducing yields significantly.  It was decided by the OCS researchers based on advisory group input to change the rotation for HF and RT to address this issue.  The rotation for HF and RT was lengthened to six years:

Caldwell - Arrow 2

 

In essence, a double crop of winter barley and buckwheat was substituted instead of corn at year 4 (2013 for EP A and 2014 for EP B).  This enabled extra mid-season tillage to reduce weeds, particularly perennials.  It also meant that no red clover was grown that year.  In the other years of the rotation, crops were similar to those in LF and EWM.

Figure 1. Weed biomass in soybeans before and after 2013-2014 crop years, average of entry points.

Results 2005-2010

Results from 2005 to 2010 were reported in Caldwell et al. (2014).  Briefly, applied organic chicken manure compost increased spelt yields but not corn yields.  The LF system had the best overall financial returns.  Corn was a poor choice during the transition period to certified organic production, but soybeans performed relatively well and spelt was intermediate.  After the transition period, corn yields increased and were similar to Cayuga County averages.  Organic crops with an arbitrary 30% price premium (chosen to reflect a conservative value) were more profitable than analogous conventional crops with County average yields.  In recent years, the organic premium for corn and soybeans has often been higher than 30%.  Currently (7/8/16) it is over 100% for corn and about 50% for soybeans (USDA, Chicago Board of Trade).

Results 2011-2016

Weather extremes

The current six-year cycle, starting in 2011, will finish at the end of this season for both entry points.  HF and RT will complete one 6-year rotation and LF and EWM will complete two, 3-year rotations.  The period 2011-15 was marked with a dry July (2011) and August (2012) and two very wet Junes (2013 and 2015).  OCS stands were poor and areas of crops were severely stunted in 2013 and 2015 due to insufficient drainage, but crops tolerated the dry spells.  Figure 2 shows yields of OCS crops over the period.  Yields were normalized as a percentage of Cayuga County (if available) or NYS average yields for each year and crop, then placed in two groups based on wet or “normal” years.  Buckwheat yields were not included due to lack of State or County averages.  In 2011, 2012, and 2014, yields were close to County averages for the conventionally tilled systems, whereas in 2013 and 2015 they were quite reduced.  The RT system had about 60% of County yields in all years, regardless of June precipitation.  In the wet years, the low fertility system was affected most severely.

Figure 2. OCS yields, 2011-2015. Buckwheat not included due to lack of published County or State yields. “Normal” years were 2011, 2012, and 2014. Wet June years were 2013 and 2015.

In 2015, 8 inches of rain fell in June, whereas in 2016, the June total was only 0.74 inch, the lowest growing season monthly precipitation during this experiment.  It appears likely that such extreme weather periods will be common in the future.   Our results indicate that under organic management on this soil type, higher nutrients can ameliorate some of the negative effects of excess rainfall.  The extremely dry June of 2016 was preceded by a dry May, and drought continued into July.  Whereas the winter spelt crop looks excellent in HF, EWM, and RT as of this writing, corn growth has been slowed dramatically.  Corn harvest this fall will give us insight into whether any of these systems are better able to withstand severe dry spells.

Caldwell - Fig 3

Figure 3. Spelt prior to harvest in the High Fertility (HF) system on July 5, 2016.

New crop rotation

Weed biomass was reduced in HF and RT after the barley/buckwheat year in their expanded rotations (Figure 1).  Whether weed biomass will remain lower in these systems is not yet clear.  However, this strategy under our constraints was likely unprofitable.  The introduction of new crops such as winter barley and buckwheat into the crop mix often requires new equipment and knowledge.  Our buckwheat yields in particular were low because of equipment limitations and unfamiliarity with harvesting this crop. Local organic buckwheat farmers often use a swather and combine pickup head to harvest buckwheat.  The swather mows and gently windrows the buckwheat, allowing it to remain in the field to fully mature and dry. The windrows are then gathered into the combine using the pickup head.  Instead, we direct-harvested the crop, a method that can result in field losses (Bjorkman 2010).  Similarly, our inexperience with barley also resulted in some harvest losses.  Although we have not yet put together financial budgets for these crops, net returns for the barley and buckwheat with our yields would likely have been much lower than those from corn achieved in LF and EWM in corresponding years.  Our experiences mirrored those of many farmers when starting out with new crops.

Future plans

The OCS grain experiment begins a new phase in 2017.The first twelve years have yielded valuable insights into nutrient regimens, crop yields, and weed dynamics, but farmers are now facing additional challenges and attractive opportunities.  For example, climate change seems to make “normal” seasons rarer and rarer.  Extremes of rainfall and drought are encountered more frequently.  On the plus side, markets for organic dairy feed including balage and other forages are strengthening.  Buyers for crops such as sunflowers (Bob Gelser, personal communication) are looking for local producers.  Over the next year, we will work with our organic farmer advisory group to plan out the next 12 years of the experiment.  It will start in 2017 with a uniformity trial in which the same crop (sorghum sudangrass) will be grown over all plots.  This will allow us to assess cumulative effects on soil nutrients and weeds from 12 years of management using four different organic management systems.  In addition to updating management practices and data collection protocols, we will also work to improve the research site by installing new tile drainage in the alleyways between plots

This new phase of the Organic Cropping Systems Grain Experiment will explore scenarios and issues that we and our advisors anticipate will impact farmers in our region in coming years.

References
Bjorkman, T. 2010. Buckwheat Production: Harvesting.  Agronomy Fact Sheet 51.  Cornell Cooperative Extension.  Ithaca, NY.

Caldwell, B., C. L. Mohler, Q. M. Ketterings, and A. DiTommaso. 2014. Yields and Profitability during and after Transition in Organic Grain Cropping Systems. Agron. J. 106:871-880.

Chicago Board of Trade (accessed 7/25/16).    http://quotes.ino.com/exchanges/exchange.html?e=CBOT

NASS. USDA National Agricultural Statistics Service (accessed 7/25/16).https://quickstats.nass.usda.gov/

Schipanski, M.E. & Drinkwater, L.E. 2011. Nitrogen fixation of red clover interseeded with winter cereals across a management-induced fertility gradient.NutrCyclAgroecosyst 90: 105-119.

USDA. National Organic Grain Feedstuffs online price list(accessed 7/25/16).https://www.ams.usda.gov/mnreports/lsbnof.pdf

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