Science-Based Conservation

Nan Nitro Test May 8th 2013 From 2012 – 2015, scientists will have the opportunity to test conservation practices on real farms. CCSI’s twelve Hub farmers will host a total of seventeen demonstration sites that compare their current conservation systems with programs that introduce new practices. Strip trials on each farmer’s land will quantify the impacts of cover crops, no-till/strip till, and crop rotation systems on soil chemical, physical, and biological properties and their relationships with nutrient cycling, soil water availability and crop growth. Samples include basic soil fertility, soil moisture, soil nitrate,soil temperature, cover crop biomass, and new soil health tests. Test results will be compiled and analyzed by Purdue University, a recognized leader in agriculture science.

A number of measurements will be made on all 17 sites including:

Soil Moisture May 8, 2013

  • Cover Crop Biomass – fall and spring – these samples will be dried, weighed, and sent for N analysis. Results will show productivity as well as total N uptake (plus fixation, if a legume)
  • Soil Nitrate 1) at time of fall biomass sample, 2) at time of spring sampling and termination, 3) at pre-sidedress N sampling time (PSNT). These measurements will assess the effects of cover crops on N availability at various times during the growing season.
  • Chlorophyll Meter Readings – done in the field by team members. This will help interpret the N status of the corn crop in mid-season
  • Stalk Nitrate Test – corn, black layer.  This will assess the N status of the corn crop at the end of the season
  • Standard Soil Fertility Test – These samples will reflect the overall soil nutrient status and the influence of the conservation cropping system.
  • Biological Assessments  - Soil samples will be sent to four labs for “soil health” analysis in years 1 and 3.  At least one of the labs measures soil microbial diversity and some index of soil fauna, which would give unique information about a site. These assessments will provide more experience with these newer tests and how they compare to simpler evaluations.
  • Cash Crop Yield

Soil Moisture May 8, 2013 1Additional detailed measurements will be made on a subset of fields (2 sites / hub) to quantify other aspects of soil health.

  • Soil Moisture and Temperature – monitored continuously throughout the growing season with Decagon soil moisture/temperature probes. Each system will log moisture and temperature at 2 depths and 2 positions. These measurements will directly assess the soil water availability  in the field under different conservation systems; as well as soil temperature under systems with varying levels of living or dead residues. The field measurements will be combined with measurements of soil water holding capacity performed in the lab to give a more complete picture of soil water availability and holding capacity with time under different systems.
  • Soil Penetration Resistance – measured in the spring while the soils are near field capacity (water) by a graduate student using a recording penetrometer. This measurement may reflect crop rooting ability, especially as affected by tap-rooted cover crops and functioning no-till.
  • Soil Aggregation – a measurement of soil tilth and ability to resist slaking will be sampled by the Purdue University team. As a physical property, this measurement can also indicate water availability.
  • Nitrogen Availability from Cover Crop Residue Decomposition – Small areas of both cover crop and no cover crop system will receive no N fertilizer except starter; corn yield will be estimated by hand harvest. An N Calculator from Oregon State University will be utilized to predict N release from simple data on N content of the cover crop.  The OSU tool will be evaluated for field use in the Midwest

Economic Analysis –  The Conservation Technology Information Center (CTIC) will collect input and yield information from the farmer-cooperators.  This data will be utilized to assess economic impacts of improved soil health in production agriculture.