Abstract
Mineralization studies are the first step in determining the usefulness of an amendment such as fertilizer, and are essential to creating guidelines for dairy waste management to help producers make informed decisions. Our goal was to assess the effects of dairy raw, composted, and digested manure amendments on C, N, and P mineralization to evaluate the feasibility of their in-farm production and use as organic fertilizers. The liquid and solid fractions of dairy effluent (LDE, SDE), dairy effluent digestate (DED), onion–cattle manure digestate and compost (OCMD, OCMC) were characterized by chemical and spectroscopic methods. Soil microcosms with LDE, SDE, DED, OCMD and OCMC and the C, N and P mineralization were determined periodically. Elemental and structural differences among amendments led to contrasting profiles of C, N, and P mineralization, and thus to differences in nutrient availability, immobilization, and CO2 emission. All processed materials were more stable than untreated waste, reducing C emissions. Digestates showed net C immobilization, and supplied the highest levels of available N, creating a relative P deficit. Instead, the compost supplied N and P via mineralization, producing a relative P excess. Future studies should aim at evaluating fertilization strategies that combine both kinds of amendments, to exploit their complimentary agronomic characteristics.
Highlights
The management of waste in dairy farming is associated with inefficiencies in the cycling of nutrients, leading to the environmental pollution of watercourses
Forosmt admaye2n1dtomdeanyt7s0a(1n0dwteheeksc),oSnDtEroslhsowed peaked at seven days,ththe ehigChOes2t CreOl2eraesleeadsefdrcoommptahredOtoCaMll tChedoethcerreaamsenddamtetnhtsa, tyestadmurpinligntghet9im1-dea,y (13 reaching its minimumwveeaklsu) esaamtp2li1ngdtaimyse, (t3hewemeeisksiso)n.sAoft tthheiSsDeEatrrleyatsmaemntpwlienregntoitmstea,tisLtiDcaEllyhdaidfferent the highest CO2 similar levels of emissfiroonmftohleloemwiessdiobnys oSfDsoEilsawndiththLDe EdaigndesOtaCtMesDD
The dairy effluent digestate (DED) showed a decrease in the C content and increases in total nitrogen (TN) and No fractions, which reduced both C/N and C/No ratios compared to liquid fraction of the dairy effluent (LDE), reflecting the recalcitrant nature of the remaining No In the anaerobic digestion process, labile organic matter is transformed to CH4 and CO2, while recalcitrant compounds accumulate [37,38], and the inorganic elements (N, P, K) are preserved in the digestate [39]
Summary
The management of waste in dairy farming is associated with inefficiencies in the cycling of nutrients, leading to the environmental pollution of watercourses. The situation is pressing in developing countries such as Argentina, where the lack of legislation and guidelines, along with the low adoption rates of waste management technologies, accompany the accelerated consolidation of dairy farms triggered by slim margins of production and 40% annual inflation rates [1,2]. These are critical issues the Instituto Nacional de Tecnología Agropecuaria (INTA), the governmental agency responsible for agro-technology transfer, is addressing with dairy farmers throughout the country. Effluents from milking and cleaning are sent to nearby ponds; stored effluents are used for agronomic purposes in 60% of the farms without any further processing [1,4]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
