Investigating forage radish and compost as a means of alleviating soil compaction in established bramble and blueberry fields

View the project final report

• 2013 annual report
• 2014 annual report
• 2015 annual report

Commodities

• Fruits: berries (blueberries), berries (brambles)

Practices

• Education and Training: on-farm/ranch research
• Production Systems: organic agriculture
• Soil Management: soil analysis, soil chemistry, organic matter, soil quality/health

Brambles are grown on over two thousand eight hundred acres in New England, of which five hundred eighty acres are in Connecticut. As part of an on-going berry project with Cornell looking at soil health, soil compaction measurements were recorded using a penetrometer in established berry blocks on five Connecticut farms in 2012. Four of the five blocks have compacted soils, as well as poor production and poor plant growth as determined by the growers. Research supports the use of cover crops and incorporating compost into soils to alleviate soil compaction in annual cropping systems and as a pre-plant management tool in perennial crops. This project will investigate using these tools on three cooperator farms within the plant row, in established blueberry and bramble fields. There will be three treatments, replicated three times for statistical analysis: (1) An untreated check; (2) Seeding forage radish within the plant row, a brassica known for penetrating compact soils, for being a tender plant that will winter kill in our climate and that decomposes in a relatively short time in the spring to avoid competition with the berry plants; and (3) A surface application of compost within the plant row. Measurements of plant growth and crop yield, as well as penetrometer readings will be recorded to determine if the treatments had an impact. Results will be disseminated at a field day at a cooperator farm, through factsheets, poster, presentations at grower meetings including the New England Vegetable and Fruit Conference.

This project will address the issue of soil compaction in an established perennial berry crop in the plant row and methods of alleviating the problem. The PI and cooperating growers will measure the change in soil compaction by comparing three treatments: 1. the use of a forage radish cover crop within the berry plant row; 2. top dressing compost within the berry plant row; and 3. An untreated check. Soil compaction will be measured taking psi readings with a penetrometer at the 0 inch to 6 inch depth, and the 6 inch to 18 inch depth in the soil. With soil compaction reduced, an increase in berry plant growth and an increase in yield is expected.

The forage radish is a tender plant that quickly germinates when seeded in early fall, is killed with low winter temperatures and decomposes in a relatively short time in the spring. The large taproot, often growing to one to two feet, penetrates compacted soils, increases large pore spaces and decomposes quickly, increasing water and air filtration and opening soils for greater root penetration. Expected timeline for reducing soil compaction and increasing soil pore space is within the first year with the forage radish. Other deep rooted cover crops, such as rye and oats, are not winter killed and will require herbicides or hand weeding in the spring to eliminate competition with the berry plants for water and nutrients, and therefore not under consideration.
Compost is well known for its ability to improve soil organic matter, water holding capacity, suppress weeds, reduce soil compaction and increase pore space through the activity of earthworms and soil microbes. As a pre-plant soil management tool for berry crops, compost is incorporated into the soil.

Unincorporated compost, expected to provide the same benefits, although not as quickly as incorporated compost, should begin to reduce soil compaction and increase the soil pore space during the first year after application as the soil microbes decompose the compost, with greater impact in years two and three. The compost will be tested for nutrient content at the University of Connecticut’s soil analytical lab prior to its application. This will allow the grower cooperators to adjust additional nutrient applications s/he would make to the planting based on the soil test results that were obtained as part of the Cornell Berry Crop Soil Management project.

Base-line measurements of soil compaction (penetrometer readings), plant growth and yield will be recorded in the spring and summer of 2013 in the three treatment areas: untreated check, compost, forage radish. Each treatment will be replicated three times for statistical analysis. Plant growth measurements will be recorded just prior to treatment applications to provide a baseline measurement for growth during the 2013 season.

The treatments will be applied in September of 2013.

Berry yield, in pounds, will be recorded during the summer of 2014. Plant growth measurements will be recorded in September 2014 and will include the number of new canes and the length of the new growth per bush for blueberries and per square foot for brambles. Soil penetrometer readings will be recorded in September 2014 and compared to readings taken prior to the treatment applications. Data will be statistically analyzed during the fall of 2014.

The outreach component will focus on increasing awareness of the negative impact of soil compaction on berry plant growth and yield, methods to alleviate the problem in a post-plant situation, and the impacts of the treatments on berry yield and plant growth. Disseminating the results of this project will include producing educational print materials – factsheets and a poster. The factsheets will be written by the PI with input from the cooperating growers, and disseminated via the University of Connecticut’s IPM website, the University of Connecticut’s fruit email listserve, in newsletters and at grower meetings. The PI and cooperating growers will hold a field day at a cooperator grower farm during the late summer 2014 for fruit growers, extension and research personnel and interested non-growers. Cooperating growers and the PI will explain the project and the results. PI will advertise the field day via the University of Connecticut’s fruit email listserve, press release, on the University of Connecticut’s IPM website and the Crop Talk newsletter. Cooperator growers will be active in speaking at the field day and at fruit grower winter meetings. The results will also be shared at the New England Vegetable and Fruit Conference in Manchester NH.