Recipient Organization
CORNELL UNIVERSITY
(N/A)
ITHACA,NY 14853
Performing Department
Horticulture
Non Technical Summary
Strawberry growers in New York, the 8th largest strawberry producer in the country, face many difficulties in maintaining healthy strawberry fields. In addition to stress from cold and damp weather, soils often contain low levels of pathogens that can affect roots under suboptimal conditions. High organic matter content is thought to sustain biological soil health in the face of these conditions. An earlier survey of strawberry farms in NYS indicated that almost all have low levels of biological soil health which may reflect low levels of beneficial microorganisms and less competition for disease organisms. This may partially explain the long term decrease in yield per acre in NYS reported by the National Agricultural Statistics Service and the increasing incidence of black root rot that growers report. One difference between berry fields with low biological soil health and adjacent fields of vegetables with higher values is that strawberry growers use a large amount of straw for winter protection each year. One might expect that large additions of organic matter would enhance soil health, but it is possible that this large annual influx of straw might actually reduce microbiological activity, increase soil moisture in already wet soils, and make plants more vulnerable to disease. The goal of this project is to learn if various soil amendments/mulches and depth of tillage affects biological soil health, and if so, what is the nature of those amendments that deplete, rather than enhance, soil health. The second phase is to implement practices on the farm that data suggest will maintain higher levels of soil health, while still providing for winter protection. Growers would then have to use fewer pesticides to manage disease and will subsequently have higher yields and healthier soils.
Animal Health Component
90%
Research Effort Categories
Basic
10%
Applied
90%
Developmental
(N/A)
Goals / Objectives
To understand how various mulches/soil amendments and depth of cultivation affect biological soil health and strawberry performance over multiple years in a perennial strawberry production system. Specific questions to address are:Do different soil amendments vary in their ability to affect levels of organic matter, total carbon, soil respiration, and potentially mineralizable nitrogen indicating biological soil health in perennial strawberries?How do these variables and the composition of organic matter change over time?Does straw incorporation have specific negative impacts on strawberry root health?Are various amendments associated with yield in strawberries?Does cultivation depth impact organic matter, total carbon, soil respiration and potentially mineralizable nitrogen?Can practices be implemented to improve biological soil health in fields where indicators are low?Outreach:To promote ways to improve soil health by working directly with strawberry growers, and developing resources for use by growers.
Project Methods
Our research proposal consists of three components. First, soil amendments consisting of different C:N ratios (grass clippings, straw, sawdust) will be incorporated into a field prior to planting strawberries. The amount of dry biomass will be the same for each treatment, and will be equivalent to the typical amount used for winter mulching with wheat straw. Two different types of tillage/cultivation (deep or shallow) will be used to manage weeds and vegetative growth throughout the life of the planting. Strawberry plants will be monitored for growth, productivity and root health, while the soil will be monitored for measures of soil health, microbial respiration, PMN and total C (see below). Second, depending on the results of the first two years of our study, we will attempt to increase active carbon and biological soil health at three strawberry farms and determine the impact on strawberry root health. Third, we will communicate our results to growers, along with new management recommendations, through field days, workshops, and on farm demonstrations. A very active website (fruit.cornell.edu) will be updated to include results from our study. We will hold a field day at one of the grower farms where soil health management will be discussed.A completely randomized plot design with 8 treatments will be laid out at Cornell's research farm in Ithaca, NY. Each plot will be 12x15 feet with 4 rows of strawberries in each plot, 4 feet apart, 15 feet long. The two edge rows as well as a 4-foot buffer on the long edge will serve as a buffer. Grass, straw, and sawdust will be used as amendments (G, S, D). Thirty-two pounds (14.6 kg) dry weight of each will be spread uniformly in each plot (same rate as a standard winter straw mulch application of 4 tons per acre). Control plots will not be amended. Grass, straw, sawdust, and the control treatments will either be shallow tilled or deep tilled throughout the life of the planting when weed control is necessary. Each of these 8 treatment combinations will be replicated 4 times. Soil amendments will again be added at the same rate in fall 2014. The field will be protected with two layers of row cover during the winter to prevent frost damage.Soil samples from each block will be taken prior to tilling, and then two months later, and again in September. Soil will be sampled three times each growing season. Four representative in-row soil cores and inter-row soil cores from the top 15 cm of each block will be collected and mixed together. Any debris or mulch on top of the soil will be brushed away before a core is collected. All soil samples will be collected on the same day. Samples will be stored in a cooler packed with ice until transported back to the lab where they will be stored at 38°F until tested.PMN will be measured within a week of sampling. PMN will be measured using the method described in the CSHT manual (Gugino et al. 2009). Briefly, two 8 g samples of field moist soil sieved to 2 mm will be put into two 50 mL centrifuge tubes. To one tube 40 mL of 2.0 M potassium chloride will be added and shaken for one hour. The solution will be filtered and 20 mL will be collected and analyzed for ammonium using the colorimetric method (Gugino et al. 2009). To the second sample 10 mL of deionized water will be added and then hand shaken. It will be incubated for 7 days at 86°F before 3 mL of 2.67 M KCl is added to the tube. That tube will then be shaken for an hour and filtered. Again 20 mL will be collected and analyzed for ammonium. The difference between these two concentrations is the nitrogen mineralization rate (Gugino et al. 2009).Soil respiration will be measured using a potassium hydroxide trap for CO2. Field moist soil will be sieved through a 4 mm sieve and stored at 38°F for two weeks to reduce the effect of sample mixing on microbial respiration (Heart et al. 1994). Then, 20 g will be put into a Mason incubation jar with KOH in a separate beaker inside the jar and 30 mL of distilled CO2-free water in the bottom to keep the soil moisture high. The Mason jar will then be incubated at 30°C for a little over 3 weeks, testing the KOH conductivity every few days at first and later every week. The KOH will have a known base conductivity. As the CO2 from the soil microbial respiration reacts with the K in the KOH solution, the conductivity will decline and the rate of decline can be used to calculate the respiration rate. Each time respiration is measured the KOH trap will be replaced and more water will be added if necessary to keep soil moisture levels constant. Soil moisture will also be sampled every sample date as it is a key predictor for many soil biological processes.The Dumas combustion method as described by Grewal et al. will be used to measure total organic C (1991). Soil will be air-dried and passed through a 2 mm sieve, then ground and passed through a 150μl sieve. The soil will be put in a tin capsule and then flash combusted. C will be measured in the form of CO2 using a thermal conductivity detector and will be reported on an oven-dry basis (Grewal et al. 1991).Throughout the season disease pressure will be monitored, especially black root rot, and yield data will be collected at harvest. At the final sampling date, soil will be submitted to the CSHT lab to evaluate their biological indicators and these will be compared to our indicators of soil health.Depending on results, three growers will be identified and practices that improve soil health will be implemented on farm. Outreach activities will be designed based on the findings. The timing of on-farm meetings will depend on the practices to be implemented.