Use of Municipal Compost in Reclamation of Phosphate-Mining Sand Tailings
1972
Hortenstine, C. C. | Rothwell, D. F.
Phosphate mining produces sand tailings that are nearly sterile and almost void of plant nutrients (except for relatively insoluble P). Tailings are pumped onto sections of land to a depth of 5 to 7 m after the phosphate has been removed in the flotation process. The reclamation of sand tailings presents a unique challenge in that there is no organic matter present and fertility approaches zero. An investigation was initiated in May 1968 to study the effects of compost and fertilizer on sand tailings. Composted municipal refuse (compost) was incorporated into the top 15 cm of tailings at rates of 35 and 70 metric tons/ha with and without N-P-K fertilizer. Compost and fertilizer were reapplied in 1969. Sorghum (Sorghum bicolor L. Moench.) and oats (Avena sativa L.) were planted in May and October of each year. Cation-exchange capacity, water-holding capacity, electrical conductivity, organic matter, and K-Ca-Mg contents of the sand tailings were increased by compost applications. Plant growth was relatively poor and yields were minimal; however, forage yields were increased greatly where compost and fertilizer were applied together as compared to where fertilizer was applied alone. Both sorghum and oat yields from compost without fertilizer were a fraction of yields where mineral fertilizer was applied.
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