Use of Irrigation on Pasture-Based Dairies to Determine Forage and Irrigation Type Efficiencies

*The main objective is to provide information for producers to develop a pasture system that enhances their lifestyle while securing long-term sustainability. As one of these producers states “if we take care of the land (pasture), it will take care of the cows”. *Determine cost-effectiveness of various irrigation systems across different forage species. This should include not only costs but time commitments. Results may also indicate amount of reduced imported feedstuffs. *Determine water use efficiency between irrigation systems and forage species *Develop webpage for farmers to plug and play various scenarios to determine combinations best for their system

Relevance to Sustainability and Regional Agricultural concerns

Nearly one third of the dairy cows in Missouri are managed for pasture diets. Pasture-based dairy producers have recently begun exploring the possibility of irrigation to mitigate the issues of drought rather than the continued practice of importing purchased feeds or expansion of land base. Estimates of pasture costs in Missouri are 4 cents/pound/dry matter. Modeling suggests irrigation can increase dry matter yields 30-90% depending on water application quantities and indicates costs ranging 1.5 to 7 cents/pound/additional dry matter. Costs are related to irrigation system type and forage species response rates. The goal will be to address cost benefits of irrigation in comparison to purchase of supplemental feeds or harvested from additional land. Well managed systems can reduce soil loss as well as water/nutrient run-off by timely forage harvest and reduction of commercial fertilizers. The limiting factor for success/sustainability is rainfall/water to maintain consistent forage growth. Family-owned pasture dairies have expressed an interest in irrigation to mitigate this issue but are concerned regarding the investment required without knowing the potential benefits of cost versus return. This research will provide information for producers to make an economically viable decision and reduce their need to import feed and other nutrients.

Activities and Outreach

Year 1 and 2 April: Farm visits with participating dairies to access and evaluate farm. Assignment of pasture paddocks (irrigated and non-irrigated) will be made to determine areas to be measured for forage mass change. Every effort will be made to have replication of the forage(s) under irrigation and dry land for that specific farm. Forms will be provided for weekly non-forage data measurements. University faculty will meet with participating farms to train on use of ATV bike pasture reader. Farm staff will also be trained to upload data to the university website. Producers will develop a time-share agreement for use of the ATV/sonar reader. The sonar reader (mounted to the front frame of the ATV bike) measures forage height and density using sound waves (similar to submarine technology). Accuracy has consistently been high with an R2 greater than 0.8.

May: Data collection will begin for each farm to establish a baseline. Farm site visit to ensure farmers understand and equipment is functioning correctly. Farmers will measure each treatment paddock weekly and upload data to site. Weekly non-forage data will be submitted via email. Data to be collected by producers: 1) Weekly pasture measurements with ATV sonar reader 2) Non-forage data includes dates grazed, fertilization, stocking rate and pertinent weather data (rainfall, temperature,) 3) Estimate time spent with irrigation system weekly Measuring paddocks weekly allows us to determine the growth rate (amount of pasture grown) for that period of time. Producers use this information to determine amount of supplement fed, nitrogen application, stocking rate and surplus forage harvest dates. It essentially allows a producer to predict ahead 2-4 weeks on what their farm will look like and what it needs.

June through August: Data collection continues

September: End of data collection

The beginning and ending dates are generalities and will be based on the growing season and need for irrigation.

October onward: Data and cost analysis and development of equations of forage response to irrigation begins.

Year 2 June Discussion Group meeting on Farm 1 July Discussion Group meeting on Farm 2 August Discussion Group meeting on Farm 3 September Discussion Group meeting on Farm 4, 5, 6 Discussion group meetings typically have a focus subject for that particular farm. Discussions will focus on water usage and efficiencies between the systems and differences noted between forage species.

October onward: Final data/cost analysis, compilation and development of equations of forage response to irrigation.

Upon completion of data analysis, a guide sheet and chapter for the Missouri Dairy Grazing manual will be written which will discuss forage response rates for the various forages measured. Discussion on observations related to water usage and efficiencies between systems will be noted as well. Cost analysis of the various types of irrigation systems will be provided. Over time, beyond the scope of this two year study, an equation will be developed for producers to use to estimate the forage yield response based on their system and forage species.

Roles of Ag Professional, Farmers or Ranchers

Charles Fletcher (Edgewood Dairy) Barry County, Missouri Charles will demonstrate and measure yields on the effectiveness of Spider irrigation systems on novel tall-fescue and grazing alfalfa

Mike Meier (Meier Dairy) Barry County, Missouri Mike will demonstrate and measure yields on the effectiveness of Pod irrigation on crabgrass and possible germination of crabgrass/winter wheat

Bernie Vandalfsen (Vandalfsen Farms) Jasper County, Missouri Bernie will demonstrate a and measure yields on the effectiveness of center pivot irrigation on novel tall-fescue and perennial ryegrass

Grasslands Dairy – three farms (Mariposa Dairy-Newton County; Wilson Springs Dairy-Jasper County; Thomlison Dairy-Newton County) Missouri The three Grasslands operations will demonstrate and measure yields on the effectiveness of center pivot irrigation on perennial ryegrass and novel tall-fescue

This group of producers communicates well with another. Two years ago they began the implementation of different irrigation systems. This proposed project began with comments from this group “we know this works, but not how well. We need to figure out how much water to apply and when and what forages we should use”. All of these farms will work cooperatively with one another and measure dry matter forage mass on irrigated and non-irrigated areas using an ATV bike sonar reader. ATV and sonar reader will be provided by the University of Missouri. Data such as nitrogen applications, pertinent weather information and date grazed will be uploaded to the MU data website for analysis. Farms will additionally host a field day/discussion group discussing the irrigation system and results to date.

Previous Research

Previous SARE projects from the SE and NE U.S. have had irrigation as part of their projects. University of Wisconsin provides a guide sheet demonstrating a near doubling of forage under irrigation. This is near intuitive as we would expect forage to grow with water. However, these projects did not compare various irrigation systems or species effect. Modeling irrigation systems at the University of Missouri suggests nearly double the yield increase then suggested from the NE SARE projects. Additionally, the modeling suggests time of year (growing days) has significant impact on forage response to irrigation. Fall forage growth responses were limited regardless if soil water holding capacity was full. Data from Australia on several species certainly indicates a species effect as well as a polynomial response to irrigation across most species. Although data for row crops is readily available, information from the Midwest remains limited on forage response rate to water applied as well as irrigation system type.

Outcomes and Impact

Some of the participating farms have limited historical data on water usage. With the use of this data we hope to show 1) more efficient and timely use of water for optimum forage growth at certain times of year. Most producers have a set time and water amount they apply throughout the season. We hope the data suggests a mindset change where water application is based on soil water holding capacity, evapotranspiration and growing day heat units based on forage type.

Additionally we hope the project can identify the 2) type of irrigation system which works best from an economic and sustainable perspective. One system may have a low capital start-up but is unsustainable due to labor issues. If this hypothesis proves true, it may assist a producer in making more informed decisions on types of irrigation and forage species.

Long term objectives and outcomes will be an 3) increased awareness of the benefits and cost-effectiveness of irrigation systems. Most pasture-based producers today believe irrigation systems are cost prohibitive.

Using pre and post-trial surveys we hope to determine the knowledge base of producers and 4) predict an increase of irrigation systems in the future on pasture-based dairy operations.