Short-term intensive management of Lespedeza cuneata in old-fields and prairies: Sustainable management through organic fertilization (and a bit of herbicide)

Background/Question/Methods

Management of old-fields and prairies often enhances their envasability. For example, the growth and establishment of Lespedeza cuneata in old-fields and prairies in the Midwest is often enhanced by typical management and restoration strategies. In addition, strategies utilized to control low densities of L. cuneata are not effective for fields with high densities. We tested an intensive management strategy suitable for public lands to reduce L. cuneata to densities that promote establishment of native grasses and forbs.  In a degraded prairie at Wilson Creek National Battlefield in Missouri we examined the effects of herbicide (PastureGard), organic fertilizer (4-1-4; Bradford Organics) and mowing on L. cuneata density and cover, and overall species richness and cover. A fully factorial randomized block design was used (six blocks, eight treatments, six plots per treatment, 48 5 m² plots).

Results/Conclusions

Initial L. cuneata density was 98 stems per m². Herbicide completely killed L. cuneata during the two years of study. However the herbicide also had a negative effect on some desirable species. Fertilization reduced cover of L. cuneata by over 50%. Mowing alone, as expected, increased L. cuneata density and cover; however, mowing and fertilization together reduced L. cuneata density and cover. Fertilization promoted desirable species. Results suggest that while herbicide is probably needed initially to reduce L. cuneata density and cover, a low concentration slow release organic fertilizer can be applied to promote competition; and most importantly, be used in the sustainable management of old-fields and prairies.