Use of Fermentation Residue from Citric Acid Production as a Soil Amendment1
- Larry D. King2
Fermentation is used in the production of pharmaceutical chemicals, alcoholic beverages, food supplements, and organic acids. After removal of the desired product, the fermentation residue must be disposed of properly. Since these residues contain organic matter and plant nutrients, they may be useful as soil amendments.
Presscake residue from citric acid production was applied to Coastal bermudagrass (Cynodon dactylon L. Pers) which was overseeded with rye (Secale cereale L.) each fall. Presscake supplied appreciable quantities of N, P, Ca, and S. Although all plots received identical rates of supplemental inorganic P and K, single spring applications of presscake at rates up to 76 metric tons/ha (1,500 kg N/ha) were not as effective in increasing bermudagrass yields as were five periodic applications of 112 kg N/ha as NH4NO3. Higher rye yields were obtained with application of 38 metric tons/ha of presscake (375 kg N/ha) than with 180 kg/ha of inorganic N. Residual effect of presscake the year after application produced bermudagrass yields that were about 75% of first year yields.
Over a 2-year period, repeated applications of presscake supplying 224 kg N/ha per application produced identical total yields of bermudagrass and rye as did the same number of applications of 112 kg N/ha from NH4NO3. Presscake rates supplying 224 and 448 kg N/ha per application resulted in an accumulation of excess nitrate in the soil profile. Over the 3-year study period, presscake N was approximately 50% as efficient as NH4NO3 in increasing forage yields. Supplementing presscake with inorganic P did not increase forage yield.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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