Long-term response of undersory vegetation on a highly erosive Louisiana soil to fertilization

Abstract

Responses of vegetation on highly eroded Kisatchie soils to a broadcast application of 600 lb/acre of 16-30-l 3 granular fertilizer were monitored for 12 years. Understory woody and herbaceous vegetation responded to fertilization immediately, and thus the soil surface was protected from erosion sooner in the fertilized area than in the two unfertilized areas. After 1 year, herbage on the fertilized area increased to 4,712 lb/acre, and woody plants shaded about 13 percent of the soil surface. Herbage and shade cover increased more slowly on the two unfertilized areas. After 12 years, herbaceous plant yield was 964 lb/acre in the fertilized area and averaged 614 lb/acre in the unfertilized areas, and understory woody plants shaded 19 percent of the soil surface in the fertilized area and an average of 27 percent of the soil surface in the unfertilized areas. The frequencies of occurrence of many plant species increased or remained almost constant, but low panicums, Dicanthelium spp., disappeared from all areas over the 12-year period.