Mitigating fertility effects of flooding with variable rate amendment
Researchers from the University of Vermont and farmers from the Intervale farming community will investigate how small farmers can use the concept of variable rate amendments to mitigate flood related patterns of soil fertility deficiencies. In early spring 2012, Gorres and Ruhl met with participant farmers Thomas Case of Arethusa Farm (Site 2) and Becky Maden of Intervale Community Farm (Site 1) to identify currently cultivated, flood-prone land that is also suitable as a research site. We planned three sampling dates for soil samples and electrical conductivity readings. The first two data sets have been collected. Spatial information for the the first data set has been analyzed using semivariogram analysis and kriging showing correlation between elevation and some nutrients. A WordPress blog, FloodedSoils, shares information about soil degradation caused by flooding and information about my NESARE funded experimental field sites.
Goal 1: Correlate spatially referenced soil fertility tests (soil tests) with
a. electrical conductivity measurements as a potential, more affordable fertility assessment
Accomplished: In progress. EC readings were taken in May 2012 at both sites. EC readings were not taken in September 2012 due to equipment malfunction. Further EC readings are scheduled for April 2013.
b. elevation and seasonal high water table as a proxy for flooding likelihood.
Accomplished: In progress. Elevation for each sample location (60 per site) was measured using a construction level on both sites in May 2012. In September 2012 elevation was measured on Site 1 for 30 sample locations. Elevation at Site 2 was not measured in September 2012 because the field failed to meet the standards (ie it was not cultivated). Further elevation readings will be taken on Site 1 in April 2013.
c. nutrient deficiency symptoms as a biological indicator of fertility needs.
Accomplished: In Progress. Soil samples for each sample location (60 per site) were taken using a standard 2” soil core were taken on Site 1 and Site 2 in May 2012. In September 2012 soil cores were taken on Site 1 for 30 sample locations. All samples were anlayzed for bulk density and fertility analysis. Samples from Site 1, September 2012 were measured for organic matter by LOI and mineral nitrogen content calorimetrically after KCl extraction. The field at site 2 was not cultivated and thus we did not collect data in September 2012. However, we will work with the farmer to get more pre and post flood information for that field.
Goal 2: Explore spatially referenced fertility data by combining the data to give averages for
a. an entire depression
b. elevation referenced zones, such as bottom, mid-slope and top of depression
c. by contour intervals
Accomplished: In progress. Maps of bulk density, organic matter and soil nutrient concentrations were rendered with GS+ geopspatial software for data taken in May and September 2012. Further analysis on elevation and spatially referenced data is in progress.
Goal 3: Identify spatial patterns of nutrient needs. Specifically, we will address the question whether proxies for soil tests (Goal 1) can guide fertility recommendations.
Accomplished: This will be accomplished in the spring of 2013 after all data has been collected and analyzed.
Goal 4: Prescribe and apply amendments in accordance with the spatially distributed nutrientneeds.
Accomplished: In progress. This will be done in spring of 2013 after data has been collected and analyzed.
Goal 5: Outreach
a) Factsheet: “Farmer’s Guide to Fertility Patterns in Flood Prone Fields”. In progress. This will be completed in the spring of 2013 after spring analyses are available.
b) Conduct a field day at one of the participating farms. Accomplished: No. This will be held in the spring of 2013. Lindsey Ruhl began a blog in the spring of 2012 with weekly posts from September-November. Ruhl’s blog, FloodedSoils, is hosted by WordPress and has focused on how climate change effects precipitation rates, certain soil fertility processes, soil damage associated with flooded, certain cover crops, and my experimental design. To date, the blog has had over 250 hits. In addition, Ruhl was a speaker at UVM’s Department of Plant and Soil Science seminar series and presented on issues of and cover crop remediations for flood damaged soils. The information will be presented at the NOFA Winter Conference.
1) Case and Maden advise on suitable research areas.
2) Soil sampling for fertility will be conducted early in May by Gorres and Ruhl. An aliquot of each sample will be sent for soil testing, the remainder of the soil will be analyzed in the lab for organic matter, and active carbon (Ruhl). After these tasks are done, the fields will be surveyed and additional field tests such as electrical conductivity and moisture will be carried out by Gorres and Ruhl.
3) Farmers will receive fertility recommendations (from graduate student and PI) and plan their planting and fertilizer schedules accordingly. Farmers will apply nutrients.
1) Ruhl and Gorres met with Maden to survey and agree upon a site. Ruhl met with Case to survey and agree upon a site.
2) 60 soil samples were collected using a 2” soil core and 120 electrical conductivity readings were taken on May 3rd, 2012 at site 1. 61 soil samples and 122 electrical conductivity readings were taken on May 17th, 2012. 24 penetrometer measurements were taken at Site 1 on August 3rd, 2012. Each sample of soil, electrical conductivity reading, and penetrometer measurement was collected and correlated with topography using surveying equipment.
3) Farmers will receive fertility recommendations after samples from the second sampling date, October 2012, are processed by UVM’s AETL.
May 2012 – April 2013: Statistical analysis will be conducted (Ruhl, Gorres)
There are three sampling dates: summer 2012, fall 2012, and spring 2013. Samples from summer and fall 2012 have been submitted to the University of Vermont’s AETL lab. Kriging GS+ Version 9 software was used to analyze summer 2012 samples for spatial correlation. Fall 2012 samples are currently being processed by UVM’s AETL. Spring 2013 samples have not been taken.
June 2012: Farmers will plant their crops.
Squash was planted in late May 2012 in Site 1. Site 2 was not cultivated. In early spring 2012, Ruhl visited with Thomas Case at Arethusa Farm and an area for cultivation and study site was agreed on. This had been under cultivation and it was understood that the field would be managed for agricultural use. This area is highly prone to flooding and in effort to reduce profit-loss, Site 2 was not seeded. This study was not the farmer’s priority and the arrangement was forgotten. This was a deviation in what had been standard practice for Arethusa on this land. We have increased the number of sampling points at Site 1 but will work with the Arethusa to get post flood data.
June 2012 – October 2012: Case, Maden, Gorres and Ruhl will assess crop health using visual cues for nutrient deficiencies. Yield of crop in plots will be assessed.
Case did not have crops to assess at Site 2. Maden made no note of significant nutrient deficiencies on Site 1. Gorres and Ruhl took height measurements of squash and sampled leave tissue for analysis in August, 2012. We did not coordinate harvest date with yield measurements.
October 2012: Soil sampling and testing to assess residual nutrients after harvest (Gorres and Ruhl). 27 soil samples were taken at Site 1 on October 18th, 2012. Electrical conductivity readings were not taken due to malfunctioning hardware and the hardware has yet to be corrected. Organic matter for October 18th samples was measured by loss on ignition. See May 2012 for more detail. A set of Watermark Sensors was installed on Site 1 to log information about soil moisture and flooding (saturation) every two-hours at the site
October 2012 – April 2013: Gorres and Ruhl will write grants to NIFA-AFRI, CIG and SARE to continue this work.
In June 2012, a Graduate Student Grant was submitted to NESARE. Gorres and Ruhl were awarded funds for project, Mitigating and Preventing Flood-Related Soil Quality Degradation Using Cover Crop Blends. This research project studies the effects of forage radish, lupine, hairy vetch, winter rye, separately and as a blend, have on ameliorating soil issues associated with flooding like fertility, compaction, and infiltration rates. The CIG proposal, submitted in April 2012, Mitigating and Preventing Flood-Related Soil Quality Degradation Using Cover Crop Blends, was not awarded. A preproposal to AFRI, Multi-Functional Cover Crops That Mitigate Soil Structure and Fertility Issues Caused by Flooding, was submitted in December 2012. Gorres is waiting for response.
May 2012 – April 2013: Gorres and Ruhl will write “Farmer’s Guide to Fertility Patterns in Flood Prone Fields.”
This is in progress. Data is being analyzed.
Impacts and Contributions/Outcomes
Fertility data for May 2012 soil fertility data and August vegetation data has been analyzed for the factsheet “Farmer’s Guide to Fertility Patterns in Flood Prone Fields” using semivariance analysis with GS+ Version 9 software. We have been invited to present our information on flooded soils at the NOFA Winter conference.
University Of Vermont
258 Jeffords Building
Plant and Soil Science
Burlington, VT 05405