title: Evaluation of the slurry management strategy and the integration of the composting technology in a pig farm - Agronomical and environmental implications.
abstract: The changes in livestock production systems towards intensification frequently lead to an excess of manure generation with respect to the agricultural land available for its soil application. However, treatment technologies can help in the management of manures, especially in N-surplus areas. An integrated slurry treatment system based on solid-liquid separation, aerobic treatment of the liquid and composting the solid fraction was evaluated in a pig farm (sows and piglets) in the South of Spain. Solid fraction separation using a filter band connected to a screw press had low efficiency (38%), which was greatly improved incorporating a rotatory sieve (61%). The depuration system was very efficient for the liquid, with total removal of 84% total solids, 87% volatile solids, and 98% phosphorus. Two composting systems were tested through mechanical turning of: 1- a mixture of solid fraction stored for 1 month after solid-liquid separation and cereal straw; 2- recently-separated solid fraction mixed with cotton gin waste. System 2 was recommended for the farm, as it exhibited a fast temperature rise and a long thermophilic phase to ensure compost sanitisation, and high recovery of nutrients (TN 77%, P and K > 85%) and organic matter (45%). The composts obtained were mature, stable and showed a high degree of humification of their organic matter, absence of phytotoxicity and concentrations of nutrients similar to other composts from pig manure or separated slurry solids. However, the introduction of slurry from piglets into the solid-liquid separation system should be avoided in order to reduce the content of Zn in the compost, which lowers its quality. The slurry separation followed by composting of the solid fraction using a passive windrow system, and aeration of the liquid phase, was the most recommendable procedure for the reduction of GHG emissions on the farm.
authors.affiliation: Centro de Edafología y Biología Aplicada del Segura, CSIC, PO Box 164, 30100, Murcia, Spain.
authors.forename: José A
authors.initials: JA
authors.lastname: Sáez
authors.affiliation: Centro de Edafología y Biología Aplicada del Segura, CSIC, PO Box 164, 30100, Murcia, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Clemente
authors.affiliation: Department of Agrochemistry and Environment, Miguel Hernandez University, EPS-Orihuela, Ctra Beniel Km 3.2, 03312, Orihuela, Alicante, Spain.
authors.forename: M Ángeles
authors.initials: MÁ
authors.lastname: Bustamante
authors.affiliation: Estación Experimental del Zaidín, CSIC, PO Box 419, 18080, Granada, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Yañez
authors.affiliation: Centro de Edafología y Biología Aplicada del Segura, CSIC, PO Box 164, 30100, Murcia, Spain. Electronic address: pbernal@cebas.csic.es.
authors.forename: M Pilar
authors.initials: MP
authors.lastname: Bernal
mesh_terms: D000818:Animals; D000072480:Farms; D005260:Female; D008372:Manure; D012987:Soil; D034421:Sus scrofa; D013552:Swine
chemical_list: D008372:Manure; D012987:Soil
keywords: Compost; Greenhouse gases; Management system; Pig slurry; Solid-liquid separation