Hand-held Flame Cultivation: Developing a sustainable weed control method in cranberry production

Hand-held Flame Cultivation: Developing a sustainable weed control method in cranberry production

Summary

Dewberry (Rubus sp.) is a serious weed in commercial cranberry production. It spreads quickly, reduces yield, crowds out cranberry vines, and is very difficult to control with current methods. Flame cultivation (FC) may offer a non-herbicide option for management of this weed. Our preliminary work with hand-held FC has shown that relatively short exposures (6-9 sec) with an open flame FC can decrease dewberry biomass; other work showed that cranberry recovers well from exposure to FC. The goal of the proposed research is to identify the best timing and application recommendations for the practical use of FC for dewberry control in cranberry cultivation. To study the link between burning, effective weed control, and carbohydrate depletion, the field work will be combined with laboratory work that will provide information on the seasonal carbohydrate reserves in the dewberry plant. These data will be used to develop recommendations for the best time of year to use FC for dewberry control. The outcome of this study has the potential to reduce environmental and health risks by reducing chemical inputs, and to increase crop productivity by providing weed control. Information generated by this study will be disseminated to the cranberry growers via bogside workshops, newsletters, Extension meetings, web media, fact sheets or other appropriate forums.

Objectives/Performance Targets

1. Objective: Conduct a 2-year replicated on-farm study in the summer of 2011 utilizing hand-held FC for control of dewberry to investigate the effects of frequency and seasonal timing of FC applications. Qualitative measurements of stem number and length will be taken periodically, and aboveground biomass samples will be collected at the conclusion of the study to evaluate treatment effects.

Completed: The experiment was established on a cranberry farm in East Wareham, Massachusetts in June of 2011. Plots 0.25 m x 0.25 m were established on bog edges were dewberry plants were growing. Qualitative measurements of dewberry stem number and lengths of stems were made for each plot on June 23, 2011. Plots were randomized within each replicate, received one of seven different treatments with an open flame handheld cultivator (no treatment, a single treatment in June, July or August, or two treatments June/July, June/August, or July/August). All treatments were replicated 5 times. End-of-season measurements of dewberry stem number and lengths of stems were made September 26, 2011 and September 28, 2011. Plots were marked, and plants within each plot will be re-measured in June 2012. All aboveground biomass and approximately 10cm of roots will be collected from each plot in 2012.

2. Objective: Analyze carbohydrates in root samples from dewberry plants treated with FC in a 2010 experiment (root samples to be collected in 2011) and in the proposed 2011 experiment (Objective 1, root samples to be collected in 2012) to gather quantitative data on how FC treatments affects the amount of dewberry reserve carbohydrates.

Completed: Roots from plants treated in 2010 were collected on June 27, 2011. Approximately 6-cm sections of roots 1 cm in diameter or larger were dried and ground according to the proposed protocol. They will be analyzed with HPLC this winter.

3. Objective: Conduct a replicated study of two untreated dewberry populations to determine seasonal variations of stored carbohydrates in dewberry. Due to the destructive nature of root sampling, areas need to be identified were dewberry are growing without cranberries present, but in conditions similar to those found on a commercial farm. One site will be an area adjacent to a commercial cranberry farm, and the other at area at the UMass Cranberry Station. This information will be used to refine FC timing, so that treatments are administered at the time when seasonal reserves are known to be the lowest.

Completed: Root samples were taken at both study sites at five collection dates based on dewberry phenological stage: bud break, full leaf expansion, flowering, fruit ripe, and onset of dormancy. Four entire plants were excised from site at each sampling time. Approximately 6-cm sections of roots 1 cm in diameter or larger were dried and ground according to the proposed protocol. They will be analyzed with HPLC this winter.

Accomplishments/Milestones

Although the grant period of performance began August 1, 2011 activities related to this project began earlier, as stated in the grant proposal. In order to study the seasonal fluctuations of carbohydrate reserves in the dewberry plants, two populations of dewberry plants were identified in April 2011. Dewberry roots were sampled from these populations when dewberry plants were at bud break (April 20, 2011), full leaf expansion (May 24, 2011), and flowering (June 13, 2011). These root samples were dried and ground in preparation for HPLC analysis.
Also in June of 2011, the 2-year replicated on-farm study was initiated to study the effects or varying the timing and number of flame cultivator treatments on dewberry plants. A farm was identified as the study site, and 0.25 m x 0.25 m plots were established on bog edges were dewberry plants were growing. These plots were marked to allow them to be followed into the following year. Qualitative measurements of dewberry stem number and lengths of stems were made for each plot on June 23, 2011. Flame treatments were made to plots that were designated to receive a June treatment after measurements were taken.
In 2010 an experiment was initiated that was identical to the experiment initiated in June 2011. This previous 2010 study was completed in June 2011. On June 27, 2011 root samples were collected from dewberry plants treated in the 2010 experiment. These root samples were dried and ground in preparation for HPLC analysis.
On July 21, 2011 flame treatments were made to plots that were designated to receive a July treatment. On July 28, 2011 root samples were taken from the two populations being studies for the seasonal carbohydrate fluctuation study when dewberry plants had ripe fruit. These root samples were dried and ground in preparation for HPLC analysis.
August flame treatments were made to designated plots on August 23, 2011. An end-of-season evaluation was made of all experimental plots where qualitative measurements of dewberry stem number and lengths of stems were made for each plot on September 26 and 28, 2011 prior to the cranberry bog being harvested for fruit.
A final set of root samples were taken from the two populations being studied for the seasonal carbohydrate fluctuation study when dewberry plants had become dormant. This stage was determined to be when all leaves were either absent or entirely red. These root samples were dried and ground in preparation for HPLC analysis.
This study is progressing according to schedule. The weather patterns for this fall have been unusually warm, and it is possible that the dewberry plants will be affected by these mild temperatures (i.e., delayed dormancy). It would be ideal to repeat the study on seasonal fluctuations of carbohydrate reserves for additional years and compare the results across years and incorporate weather into the analysis. This is something to consider for future projects.
This winter, HPLC analysis will be done for roots collected from the previous 2010 experiment, as well as all of the roots collected in 2011 for the seasonal fluctuations of carbohydrate reserves study (2011?), and preliminary data analysis will begin.
In the spring of 2012, approximately 1 year after the initiation of the flame cultivator study, the plots will be evaluated for dewberry stem number and stem length. All of the aboveground dewberry plant material will be collected, dried, and weighted to evaluate biomass. A 10 cm root sample will be taken from each plot, dried and ground in preparation for HPLC analysis.
After all the data are collected, and HPLC analysis has been completed, the data will be statistically analyzed. Results, conclusions, and potential management recommendations made from information generated by this study will be disseminated to the cranberry growers via bogside workshops, newsletters, Extension meetings, web media, fact sheets or other appropriate forums. Results will also be submitted for publications in refereed scientific journals, and presented at professional and extension meetings.

Impacts and Contributions/Outcomes

Less than 5 months have elapsed since the SARE Student Grant period of performance began. Due to the short length of time represented by this annual grant report, this project has not had any impact on agricultural sustainability as of yet. However, in the near future I anticipate presenting some of the results of this work at the UMass Cranberry Station Annual Research and Update Meeting in January 2012, which is attended by over 250 growers. The presentation will also be made available online through UMass Amherst ScholarWorks website.
In the near future, this work will help to support agricultural sustainability by demonstrating that chemical alternatives for weed management can successfully be employed on cranberry bogs to control dewberry. This has the potential to reduce environmental and health risks by reducing chemical inputs, and to increase crop productivity by providing weed control.

Collaborators: