Role of Inorganic and Organic Fractions in Animal Manure Compost in Lead Immobilization and Microbial Activity in Soil

Abstract

This study aimed to identify how the ratio of inorganic-to-organic components in animal manure compost (AMC) affected both lead immobilization and microbial activity in lead-contaminated soil. When AMC containing 50% or more inorganic fraction with high phosphorous content was applied to contaminated soil, the amounts of water-soluble lead in it were suppressed by over 88% from the values in the soil without compost. The residual fraction under sequential extraction increased with the inorganic fraction in the AMC; however, in those AMCs, the levels of microbial enzyme activity were the same or less than those in the control soil. The application of AMC containing 25% inorganic fraction could alter the lead phases to be more insoluble while improving microbial enzyme activities; however, no suppression of the level of water-soluble lead existed during the first 30 days. These results indicate that compost containing an inorganic component of 50% or more with high phosphorus content is suitable for immobilizing lead; however, in the case where low precipitation is expected for a month, AMC containing 25% inorganic component could be used to both immobilize lead and restore microbial activity.

Potential for Lead Release from Lead-Immobilized Animal Manure Compost in Rhizosphere Soil of Shooting Range

“…The lead-sorbed inorganic and organic fractions were mixed at a ratio of 1 : 3, and the mixed sample was used as the lead-sorbed compost. The mixing ratio of the inorganic and organic fractions was a suitable ratio for lead immobilization [16] and was within the average values for Japanese AMC [25].…”

“…The ratio of each fraction in the nonplanted soil containing the lead-sorbed compost was 8% for the exchangeable fraction, 28% for the carbonate fraction, 28% for the Fe/Mn oxide fraction, 13% for the organic fraction, and 23% for the residual fraction, demonstrating that 36% of lead in the soil (exchangeable and carbonate fractions) was present in relatively soluble states. According to other studies [15,16], wherein the lead distribution by sequential extraction was investigated using the lead-contaminated soil amended with the AMC, the residual and exchangeable fractions ranged from 17% to 49% and from 0% to 1%, respectively. The residual and exchangeable lead fractions in this study were compatible with those previously reported, although the leadimmobilized compost was applied to the noncontaminated soil in this study.…”

“…Although these advantages may encourage the application of AMC onto contaminated soils, less is known about the mechanisms of immobilization by AMC [12,13] compared with other inorganic and organic waste materials [14], particularly the applicability of AMC to the shooting range soil and the remobilization of lead that was once immobilized by AMC. Katoh et al [13,15,16] conducted several studies to elucidate the mechanisms of lead immobilization by AMC using the inorganic and organic components of specifically fractionated AMC to understand the suitable chemical properties of AMC to immobilize lead present in the shooting range soil. The studies revealed that the inorganic components in AMC can immobilize lead more effectively than the organic components [13].…”

“…On the basis of these results, Katoh et al [13,15] suggested that compost that contains an inorganic content with a high phosphorus level, such as swine manure compost, and an organic component that has undergone maturation, such as cattle manure compost, was the most suitable to immobilize lead in soils. In addition, they pointed out that inorganic/organic components ratio of 25 : 75 was suitable to both immobilize lead and restore microbial activity in the shooting range soil [16]. Furthermore, it was demonstrated that such AMC can reduce lead bioavailability in the soil, resulting in a reduction in lead uptake by plants [15].…”

Performance test of organic planting bags for woody plant seedlings

“…Djoyowasito et al [14] develop organic planting ribbon (OPR) describing a kind of organic component significantly affecting organic plating bag performance [14][15][16] . As the research of Wataru et al [17] , these observations would be explained by the higher level of water-soluble organic matter and its sorption and decomposition in the soil thereby increasing the incubation time. Finding out that coconut fiber can improve the strength of organic planting bags.…”