Raw waste milk as a pasture amendment

Raw waste milk as a pasture amendment

Summary

Spaying dilute raw milk onto pastures is a novel, untested practice that has recently gained widespread prominence as a potential means of increasing forage production and quality. This partnership project investigated if foliar applications of dilute raw milk on pasture would improve the productivity, palatability and quality of pasture using an on-farm testing method on two organic dairy farms.

In 2012, two Vermont organic dairy farms, Choiniere Family Farm and Applecheck Family Farm, partnered with University of Vermont researchers to examine the impact of raw milk on pasture yield, forage quality and soil fertility. Each of the farms followed a similar research protocol. Dilute raw milk (2X) applied at a rate of 20 gallons active ingredient per acre was compared to a non-treated control, replicated in six paddocks on each farm. The raw milk treatment was sprayed in June immediately after a grazing when the grasses were about three to four inches in height.

Just before the next grazing period, pasture samples were collected for yield, quality, Brix measurements, botanical composition and percent dead matter. Measurements were collected again two grazing periods later in August and also include soil samples to determine any affect on soil fertility. Preliminary results indicate that there is no significant difference in forage quality, soil quality, and forage production between areas sprayed with milk and non-treated control areas. This may have been influenced by the extremely droughty conditions this year.

The detailed analysis of the results of a similar concurrent greenhouse study will provide more results. The final data is now being analyzed. Preliminary results were presented at a University Vermont Seminar and in a Vermont Grass Farmer’s Association Newsletter and final results will be presented at the Vermont Grazing and Livestock Conference in January and at the Northeast Pasture Consortium meeting in February.

Objectives/Performance Targets

Assess changes in pasture soil health, and forage production, quality, and palatability that occur as a result of a dilute foliar application of waste (or raw) milk.

The impact of raw milk on soil health was examined though a large field study and two controlled greenhouse studies. Milk was applied at the rate of 20 gallons/acre to pastures on two Vermont farms using a paired design. The soil electrical conductivity, moisture, organic matter, and nutrient content were measured in each of the 24 experimental units. Results were expanded upon using control greenhouse studies examining soil respiration rates and nitrogen mineralization rate in microcosms with and without milk.

The impact of raw milk on forage production and quality was examined through a large field study and two controlled greenhouse studies. In the field, forage from experimental units with and without milk was collected and carefully analyzed. Researchers measured forage pre-grazing mass, forage consumption, forage botanical composition, forage quality, and forage sugar content. Through additional greenhouse experiments, researched measured the same parameters in a more controlled setting and under a different temperature conditions.

Provide graziers with a prototype On-Farm Testing (OFT) methodology that can be replicated on other farms in order to test other products and practices.

We are currently researching and discussing the material. The manual will be developed during the spring of 2013.

Accomplishments/Milestones

Farmers select paddocks for experiment (Farmer): Accomplished
Farmers at Choiniere Family Farm and Applecheck Family Farm both selected six paddocks for the study. The size of the study area was 1.56 and 0.88 hectares, respectively. Graduate researcher (Jamison) thoroughly pre-sampled each field to determine the initial variation is pasture mass, forage BRIX content, and dominate forage species. The results were used to estimate number of samples necessary to achieve significant results.

Plots within paddocks delineated with small permanent flags: Accomplished
Paddocks were carefully divided in half and delineated with small flags. The location of each flag and the perimeter of field were also recorded using a GPS. Using this information, we were able to determine the exact size of each paddock and the exact amount of milk necessary.

Milk or Water was applied in appropriate locations: Accomplished
Milk was sprayed by the farmers on appropriated pastures on June 7th and July 10th at Applecheek and Choiniere Farm, respectively. We decided not to spray the water on the control plots; the extremely low dose (1 drop per square foot), was not expected to make any different. We were not able to measure milk quality parameters due to the difficulty of shipping small quantities of milk across country in a timely, yet cost-effective fashion.

Applecheeck farm was sampled every day from June 26th through June 30th. Choininere Family Farm was sampled from July 13 through July 19th. In addition to the work outlined in the grant, researchers also conducted two greenhouse experiments examining the impact of milk on forage. One experiment examined the impact of a foliar milk application on forage grown in a sterile medium under hot and cool conditions; the aim was to (1) determine if the mechanism of action was related to soil microbes and (2) determine if temperature stress influenced the results. The second experiment examined the impact of milk on forage root growth rate and density and forage growth rate and tillering rate. Finally, in conjunction with the field research, researchers developed a simple method using digital image analysis to measure the amount of dead material in a forage sample.

Pasture sampled to determine pre-grazing mass, botanical composition, brix, and forage quality in each replicate: Accomplished
A more accurate measure of pasture pre-grazing mass was obtained using quadrate cutting rather the rising plate (as outlined in the grant). From each experimental unit 30 forage samples were cut, dried and weighed. This process is the industry standard for determine pasture mass however, it is appreciably more time consuming than estimating the pasture mass using a rising plate. Consequently, we did not have time to estimate cow forage preferences (via observation) as previously indicated in the grant.

Botanical composition and forage quality were measured on aggregate of 30 samples obtained from each experimental unit. Forage quality parameters were measured on each sample by Dairy One. The proportion of dead material in each sample was measured using a newly developed using digital image analysis technique. Brix values were determined in 20 randomly chosen areas using a single grass species within each experimental unit on each farm.

In addition to the objectives outlined in the grant, we measured the soil electrical conductivity and moisture using a probe in 30 locations within each experimental unit. We also collected 30 soil samples from each experimental unit at each farm. Soil samples from each experimental unit were aggregated, sieved, ground, and sent to University of Vermont Agricultural and Environmental Testing Laboratory for detailed soil quality analysis. At Choiniere Family farm we also used a digital imaging to estimate the incidence and severity of fungal diseases within 20 white clover patches in each experimental unit.

Pasture grazed by cows and grazing patterns of cows recorded (Farmer): Not Accomplished
Farmers did successfully graze their cattle in each experimental paddock within 4 days of applying the milk. However, researchers were not able to record the grazing patterns of the cows. Because the process of collecting forage pre-grazing mass samples was extremely time consuming, we did not have enough time to systematically monitor cow grazing habits. There were no obvious preferences from one treatment to the other when turned out on a paddock. Furthermore, we opted to preserve the forage quality samples as soon as possible in a refrigerator rather than wait at the farm observing cattle; in doing so, we obtained a more accurate measure of forage quality.

Pasture sampled to determine post-grazing mass: Accomplished
Pasture post-grazing mass was sampled using a calibrated rising plate in each experimental unit within three days follow cattle grazing.

Choiniere Family Farm fields were resampled on August 12 through August 17. Applecheck Farm field were resampled on August 22 through August 27.

Pasture sampled to determine pre-grazing mass, botanical composition, brix, and forage quality in each replicate: Accomplished
During the second sampling event at each farm, we chose to use the rising plate to estimate pasture mass. Preliminary analysis of the data from the first sampling event showed no significant difference in the forage mass of the experimental units with and without milk treatment. As a result, we decided that the rising plate would provide an adequate measure of pasture mass during the second grazing event.
Botanical composition and forage quality were measured on aggregate of 30 samples obtained from each experimental unit. Forage quality parameters were measured on each sample by Dairy One. The proportion of dead material in each sample was measured using a newly developed using digital image analysis technique. Due to the extreme dryness of the grass, we were not able to obtain accurate brix measurements.
In addition to the objectives outlined in the grant, we measured the soil electrical conductivity and moisture using a probe in 30 locations within each experimental unit. We also collected 30 soil samples from each experimental unit at each farm. Soil samples from each experimental unit were aggregated, sieved, ground, and sent to University of Vermont Agricultural and Environmental Testing Laboratory for detailed soil quality analysis.

Pasture grazed by cows and grazing patterns of cows recorded (Farmer): Not Accomplished
Farmers did successfully graze their cattle in each experimental paddock within 4 days of applying the milk. However, researchers were not able to systematically record the grazing patterns of the cows due to the time constraints of pasture sampling. There were no obvious preferences from one treatment to the other when turned out on a paddock.

Pasture sampled to determine post-grazing mass: Accomplished
Pasture post-grazing mass was sampled using a calibrated rising plate in each experimental unit within three days follow cattle grazing.

Soil samples collected and analyzed: Accomplished Earlier

After reviewing the literature, we felt that we were more likely to observe a difference in soil quality within 60 days after the milk was applied. Therefore, we chose to sample the soils twice during the season, during each large forage sampling event. In addition, we also used a soil probe to determine the soil moisture and electrical conductivity during each sampling event.

From October through December 2012, graduate student researcher conducted two additional greenhouse based experiments examining the impact of milk on forages. One experiment used gas chromatography to examine the impact of milk on soil respiration rates. The other experiment tested the impact of milk of litter decomposition and nitrogen mineralization rate. As a result, researchers had less time to devote to data analysis and creating fact-sheets.

Analysis of data (Graduate Student): Some completed, Rescheduled for winter of 2013
Although much of the data analysis was completed, some complicated analyses still remain. These will be completed during the winter and early spring of 2013.

Organization of data into factsheets, handouts, posters, etc: Rescheduled for January of 2013
Once most the data analysis is complete, graduate student researcher will develop factsheets and a poster outlining the results. These will be presented at upcoming conferences.

Host on-farm field day highlight experimental results and techniques to conduct on farm research: Rescheduled for the Spring of 2013
The field day has been rescheduled for some-time in late spring / early summer, although an exact data has not yet been chosen.

The results are scheduled to be presented at the upcoming Vermont Grazing and Livestock conference in January.

The results will be presented during a poster session at the NE Pasture Consortium meeting in Febuary by Bosworth. The title of the poster is, “Raw Waste Milk as a Pasture Amendment”

As a result of this research, researchers will submit two papers for publication. One will be a methods paper entitled, “Simple, low cost method of separating living and dead pasture plant tissue using image spectroscopy”. It describes a new method of determining the amount of dead forage in a sample using digital image analysis. The method was developed in conjunction with the field research. A draft of the paper is attached.

The second paper describes the effects of milk on pasture using both the field and greenhouse studies. It is currently in the works and will be completed by the summer of 2013.

Impacts and Contributions/Outcomes

Preliminary results indicate that there is no significant difference in forage quality, soil quality, and forage production between pastures sprayed with milk and non-treated control pastures. This may have been influenced by the extremely droughty conditions this year. The detailed analysis of the results of a similar concurrent greenhouse study will provide more results.

Initial results were presented at a University of Vermont Plant and Soil Science Seminar (approximately 20 attendees). A brief article outlining the study was also submitted to The Solar Dollar, the Vermont Grass Farmer’s Association Newsletter.

Collaborators: