Improved efficiency of grazing dairies using complementary pasture species and irrigation scheduling

Improved efficiency of grazing dairies using complementary pasture species and irrigation scheduling

Summary

Forage species were established on dairy farms to determine growth rates and biomass production under grazing management. Warm season species were established, but yield data will not be taken until summer 2008. Growth rates and mass of cool season species were determined while being subjected to a flexible grazing system common to grazing dairies. Available water content of major soil types on two farms were determined and soil moisture meters placed into soils from which irrigation can be scheduled. Cup lysimeters have been placed into the soils to gather nitrate leaching information to generate a nitrogen budget for the farms.

Objectives/Performance Targets

1. Screen warm and cool-season annual and perennial pasture species for seasonal forage productivity under grazing conditions.

2. Determine moisture release curves for the major soil types found on cooperating grazing dairies and monitor soil moisture content from irrigation practices during periods of negative water balance.

3. Create a nitrogen budget to determine when, and by how much, the dairies are deficient in nitrogen supply from pasture legumes

4. Develop educational and outreach information for training producers and related industries as to the merits and needs of grazing dairies

Accomplishments/Milestones

Our time-line for the first year was to establish cool and warm-season perennial forages and to gather growth rate and distribution information from annual cool-season forages. Our research findings thus far are that cereal rye and annual ryegrass provide excellent grazing tolerance and growth rates and distribution complement one another. Both were selectively grazed by dairy cattle in replicated plots. Triticale and wheat lack one or more of the following: rapid growth rates, grazing tolerance, or distribution of growth over time. One cool season perennial grass, festulolium, was harvested on the same schedule as the annual forages as it rivaled the annual ryegrasses by yielding more, providing earlier grazing in late winter/spring. The major soil types on each farm were sampled and moisture release curves determined. Soil moisture sensors and telemetry equipment were placed under two center pivot irrigation systems at each of two farms. Soil water will be monitored under each pivot. Sensors will be used to determine timing and amount of irrigation water under one pivot, while producers will manage the second pivot on each farm based upon previous methodology. Cup lysimeters have been placed in each soil type on the farms to monitor subsurface water conditions and determine nitrate leaching. Nitrate leaching information will be used to help calculate an on-farm nitrogen budget. Nitrogen inputs from fertilizer, feed, and legumes will be determined on a monthly basis, and outputs from milk, nitrate leaching, and urea volatilization used to determine periods of the year when nitrogen supply is in surplus or deficit. This information will be used to prescribe when mineral nitrogen applications might be most effective or unnecessary.

Impacts and Contributions/Outcomes

One of the direct impacts of the research effort is that both of our cooperating dairies see the benefit of having soil moisture sensors on their farms. Last year Grassy Flats (Al and Desiree Wehner, owners) spent nearly $45,000 on energy for their farm. They understand the concepts of the soil moisture sensors and are committing to place soil moisture sensors on other farms, as are the owners of Grassy Flats. Our cooperators spend time with us and observe the research plots whenever we travel to the farms for observations or harvesting. They see the differences in forage growth first-hand and are already modifying allocation of their fields for planting next fall. This provides us confidence that our data is relevant and that upcoming field days and farmer training sessions will be meaningful. We had one county agent training day on March 27, 2008 and students from the Forage Management Class (taught by Dr. Hill) visited the Greenstone Grazing farm on March 29. Data from plot work was presented, a plot visit and a pasture walk was conducted, and the grazing dairy philosophy presented by the Greenstone owners. Students and county agents alike are keen on the system.

Currently there is tremendous interest in grazing dairies located in Georgia. Since inception of our research efforts, 11 new properties have been purchased for, or have been developed into grazing dairies. Much of this interest has been generated by our farm cooperators, the Greenstone Grazing Group and Grassy Flats. However, visitors to their farms have seen the type of research being conducted and understand the commitment from the University of Georgia to provide quality practical information for productivity and efficiency. We have also networked with the Georgia Department of Agriculture and are working closely with Deputy Commissioner Terry Coleman to a) devise reasonable designs for nutrient management facilities for grazing dairies (current recommendations are based upon confinement facilities and are excessive for grazing dairies) and b) recruit environmentally-conscious dairy operations into the state. For example, the state hosted 40 individuals from outside of Georgia on Friday April 11 to explain the virtues of grazing dairies in Georgia. Our extension specialist (Dennis Hancock) was present to provide information from the SARE grant to the producers and assist with technical questions concerning Georgia dairying. We have also partnered with New Zealand Grazing Systems, Inc. to send 10 students to work on grazing dairies in New Zealand, with the objective of providing a more qualified pool of farm managers to operate the grazing dairies. Furthermore, our farm cooperators are committed to providing avenues for farm managers to acquire ownership of farms.

Collaborators: