Using No-Till to Establish Lotus in a Grass Pasture

By

Amy Peters, Livestock Agent

OSU Extension Service

                                    CCES 1013

May 1, 2006

Introduction

   No-till is the process of seeding selected species without working up entire fields through tillage.  In this project, the idea was to use a low-cost method to increase the protein content of the species present in the pasture, while simultaneously minimizing the amount of disturbance to the soil and species already present.

   The no-tillage method gives farmers in coastal regions an opportunity to increase the protein content of their pastures, thus minimizing the amount of supplementation required and maximizing the grazing potential of their existing pastures.  In this experiment, we used the no-till method to seed big trefoil (Lotus uliginosus and Lotus major L.), a legume species known to be adapted to coastal climates, into a pasture in Coos County, and then monitored its establishment for three years following project implementation.   

Methods

   Two adjacent coastal floodplain pastures were selected in the Coquille River valley.  One pasture was seeded with Lotus via the no-tillage methodology, while the other was left unseeded as a control for statistical comparison.  Two transects were constructed in each pasture (four total); each ran the length of the pasture.  Data was collected yearly by monitoring each transect using a 10cm x 10cm sampling square every 10 steps and identifying species present within the square.  The transects were walked in 2002, immediately after seeding to establish a baseline, and then in 2003, 2004, and 2005.

   Data were analyzed as binary count data (Lotus present vs. Lotus absent) in each year.  If Lotus was present, it was assigned a 1, if absent, the plot was assigned a 0.  The two transects from each pasture (treated vs. control) were pooled and analyzed for each year using Fisher’s Exact Tests, which allow for comparisons between data that is categorized as count data.

Results

   Once the 2005 data was collected, it was analyzed to determine the effectiveness of the no-till process on the establishment of Lotus in the treated pasture.  Table 1 illustrates the number of plots in the pooled transects that contained Lotus in the treated pasture when compared to the untreated pasture.

Table 1.  Transect plot results for Lotus presence and absence in the treated and control pastures in 2005.

   A Fisher’s Exact Test of this data provided convincing evidence of a difference in proportions of Lotus present between the test plot and the control plot in 2005.  Specifically, the results of the Fisher’s Exact Test indicated that the proportion of sites within the test plot transects containing Lotus after treatment was greater than could be attributed to chance (normal approximation p-value = 0.01355).

   Data from years 2003 and 2004 indicated an increasing prevalence of Lotus in the pastures with time, although its presence was not significant until 2005, where it was present in nearly 5.6% of the transect plots. 

Conclusions

   The results of this experiment indicated that the no-till method can result in successful establishment of legumes in coastal pastures.  However, the increase observed in this study may not offset the costs of seeding.  It is important to note that one of most important things to do when attempting to establish a new forage species is to reduce competition from species that are already established, especially perennials with their extensive root systems.  In this trial, the pastures were grazed and mowed in an attempt to minimize the potential for competition.  Ideally, chemical control would be used, and would provide a much higher likelihood of success, and may, in fact, increase the cost-effectiveness of no-till efforts.

References

Cuomo, G.J., D.G. Johnson, and W.A. Head, Jr.  2001.  Interseeding Kura Clover and Birdsfoot Trefoil into existing cool-season grass pastures.  Agronomy Journal, 93:458-462.

Fitzsimmons, J.P.  1993.  Pasture renovation with herbicide suppression of weeds and no-till seeding of orchardgrass.  M.S. Thesis, Oregon State University, 58pp.

Forage Information System.  2006.  Oregon State University: Comprehensive resource for forage-related topics: Big Trefoil (Lotus uliginosus, Lotus major L.).  http://forages.oregonstate.edu

Neumeister, J.H.  1994.  A comparison of vegetation suppression and sod-seeding methods using perennial ryegrass in the renovation of non-irrigated permanent pastures in western Oregon.  M.S. Thesis, Oregon State University.  70pp.