Filter-Press Cake as a Fertilizer

Abstract

This study on the use of filter-press cake as a fertilizer material may be summarized as follows: 1. It is a byproduct of the sugarcane mills consisting principally of a mixture of cane fibers, sucrose, coagulated colloids including cane wax, albumoids, and phosphates of lime, plus sand and son. 2. It is a soft, spongy, lightweight, amorphous dark-brown to black material. When fresh from the filter-presses it contains about 60 percent of moisture, and about 15 percent when air-dry. 3. Its chemical composition averages 2.19 percent of N, 2.77 percent of P₂O₅, 0.44 percent of K₂O, and 3.05 percent of CaO, plus considerable quantities of the minor elements. 4. It did not produce appreciable yield increases when used on sugarcane in combination with commercial mixed inorganic fertilizer. 5. It was beneficial to tomatoes growing on a Coto clay when used at a rate of 10 tons per acre, but yields were higher when commercial fertilizer was used. 6. Ten tons per acre significantly increased yields of peppers on a Juncos clay. 7. Pigeon peas and corn responded to neither filter-press cake nor regular fertilizers. 8. Tobacco yielded more when filter-press cake was used as a nitrogen source, but ammonium sulfate produced higher yields still when used to supply equivalent amounts of N. 9. Yams did not respond to the use of filter-press cake. 10. Filter-press cake alone did not produce as good results on sweetpotatoes as commercial fertilizer. 11. Filter-press cake increased the yield of yautías. 12. Plantains did not respond to filter-press cake when grown on a Lares clay. 13. Pineapples gave a mixed response to applications of filter-press cake. When damage caused by biological-parasitic factors was properly controlled, the filter-press cake applications did not increase yields. 14. The composition of filter-press cake, as compared with that of other organic fertilizers showed it to be about equal (except for low K₂O) to animal manures but not to animal tankage or seed meals. 15. If applied about 6 weeks prior to planting, the decomposition of fresh filter-press cake will not produce "burning" on vegetable crops.