Agricultural Land Use Index

The way land is used and managed in agriculture can have a significant impact on water quality. Some of basic land use practices used in agriculture that impact water quality include drainage, fertilization, tillage, cover crop, agroforestry, grazing, and conservation. These practices can all play roles in soil quality, nutrient cycling, run-off, erosion, and the productivity of farmland. The negative water quality impacts associated with these practices include non-point source water pollution, nutrient loading, potential increased costs associated with treating water to meet drinking and quality standards, and habitat and biodiversity reduction.

In this metric, 10 different categories of land use practices were examined and combined to create an overall score for each state. Data from the 2012 USDA Census and 2014 USDA Conservation Reserve Program were used to build the metric. For the majority of categories, percentages of total farms and acres in each state were calculated that employ each of the land use practices. Most practices were scored out of a 20 point scale while others were scored on a 10 point scale based on their limited impacts on water quality, or limited employment generally. One cater gory, Conventional Tillage, was scored in reverse for its perceived negative impact on water quality. Percentage scores were calculated out of the total 160 possible points and then a letter grade was assigned using a quintile grading scale.

Land use categories included, the number and percent of farms and land (160 total points):

1. Drained by Tile – 10 points
2. Artificially Drained by Ditches – 10 points
3. Under Conservation Easement – 20 points
4. With No Till Practices Used (Cropland) – 20 points
5. With Conservation Tillage Used (Cropland) – 20 points
6. With Conventional Tillage Used (Cropland) – 20 points, scoring reversed
7. Planted to Cover Crop (Cropland) – Excluding USDA’ CRP – 20 points
8. Rotational and Managed Intensive Grazing – 10 points
9. With Alley-Cropping and Silvapasture – 10 points
10. Enrolled in the USDA’S CRP – 20 points

Preview of Results

Overall Results for Agriculture Land Use Metric

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The overall results given as overall rank, percentage, and quintile letter grade are as follows: 1) Ohio (67%, B-) 2) Indiana (64%, B-), 3) Iowa (63%, B-), 4) Illinois (60%, B-), 5) Wisconsin (59%, C+), 6) Michigan (57%, C+), 7) Kentucky (53%, C+), 8) Minnesota (51%, C), 9) Washington (48%, C) and, 10) West Virginia (29%, D).

Data from the 2012 USDA Census and the 2014 USDA Conservation Reserve Program was used to build the index. These sources provided the number of farms or operations and the amount of acres in each state that practiced each of the 10 land use categories. From this, percentages were calculated using USDA Census data for the total farms and acreage in each state to determine the total percentage of farms and acres that utilize each of the 10 practices within each state. There was no inclusion of any metrics relating to state regulations or policies that impact agricultural land use.

A total of 10 metrics with 160 total possible points was used to create and score each state’s land use practices. The total points for each state were then divided by 160 to determine their overall percentage and letter grade score using a quintile grading scale.

Land use practices have the potential to impact water quality. However, the direct impacts on water quality can often be hard to measure, as there are predominantly indirect and secondary impacts of these land and soil management techniques. Land use practices that limit negative water quality impacts do so by improving soil quality and enhancing the natural filtration of the land.

The decreased run-off potential, erosion, and nutrient losses result in more sustainable agriculture processes when compared to conventional farming techniques. While the results within this index do not include a ranking or discussion of state regulations and policies in relation to agricultural land use, they do provide a general indicator of a state’s performance overall and within each of the individual land use metrics.

Metric Findings

• Assumptions:

  • It was assumed that all but one of the 10 land use practice categories had some water quality benefit when compared to the conventional farming alternative.
  • It was also assumed that conventional tillage had a negative impact on water quality and that the two categories relating to drainage only had incremental benefits for water quality when compared to traditional surface drainage.
  • Percentages of farms and acres utilizing each practice compared to all farms and acres in each individual state allowed for normalization of the data to compare across states.
  • Letter grades were assigned using a quintile scale.

• Findings:

  • None of the 10 index states received higher than a 67% overall score
  • The range of scores was 29%-67%
  • Indiana finished 2^nd overall with a 64% score.

• Policy Considerations:

  • This metric did not provide an overview or analysis of policy or regulations relating to agricultural land use. Further expansion of this metric could investigate adding a policy component.

For more information on State Sustainability Index’s Agricultural Land Use and Water Quality Metric, click here to find the complete SustainIN Capstone Report