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Mineralization of Soil‐Incorporated Tomato Solid Waste
Author(s) -
Timm H.,
Flocker W. J.,
Akesson N. B.,
O'Brien M.
Publication year - 1980
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1980.00472425000900020009x
Subject(s) - loam , chemistry , nitrogen , mineralization (soil science) , biodegradable waste , agronomy , environmental chemistry , soil water , environmental science , waste management , soil science , organic chemistry , biology , engineering
Solid waste from the processing of tomatoes ( Lycopersicum esculentum Mill.) consisting primarily of fruit peels and seeds was incorporated into Yolo sandy loam soil, wetted, and incubated at 10, 20, or 30°C for 32 weeks. At 2‐week intervals the soil was analyzed for NO 3 ‐N, PO 4 ‐P, SO 4 ‐S, Cl, total N, organic C, and exchangeable Ca, Mg, K, and Na. Soil pH and electrical conductivity were measured at the beginning of the study and after 32 weeks. With each increment of dried tomato waste applied at rates of 2.5, 5.0, and 10.0% of air‐dry soil, the total organic C and N content of the soil increased. The amount of NO 3 ‐N released from 2.5% rate of waste at 20°C soil temperature was similar to that released from 60 ppm N applied as (NH 4 ) 2 SO 4 . Nitrogen released from waste applied at rates of 5.0 and 10.0% air‐dry soil exceeded the level of N usually applied for crop production at about 76 kg N/ha. Significant interactions occurred on NO 3 ‐N release among waste application rates, soil temperatures, and times. At 10°C, there was an increase in NO 3 ‐N released with each increase in waste application. At 20°C, a NO 3 ‐N increase occurred at 2.5 and 5.0% waste application rates, but the increase was less at 10.0 than at 5.0%. At 30°C, a marked reduction of NO 3 ‐N release occurred between 16 and 32 weeks of incubation at all rates of waste application, but was more acute at 10.0% than at lower rates. A similar response, but of lesser magnitude, occurred with release of PO 4 ‐P. Variability in release of NO 3 ‐N and PO 4 ‐P was attributable to the composition of tomato waste and to microbiological activity. Release of SO 4 ‐S was a function of waste loading rate and time. Essentially, all Cl was released within the first week of incubation. An appreciable increase of K, slight increase of Ca, minimal increase of Na, and no change of Mg was found in the soil after 32 weeks of incubation. Although tomato waste is acidic, soil pH decreased only at the highest loading rate after 32 weeks of incubation.