Dairy cattle manure effects on soil quality: porosity, earthworms, aggregates and soil organic carbon fractions

Abstract

In the European Union, the maintenance of soil quality is a key point in agricultural policy. The effect of additions of dairy cattle (Bos taurus) manure (DCM) during a period of 11 years were evaluated in a soil under irrigated maize (Zea mays L.) monoculture. DCM was applied at sowing, at wet-weight rates of 30 or 60 Mg ha−1yr−1 (30DCM or 60DCM). These were compared with a mineral-N treatment (300 kg N ha−1, MNF), applied at 6–8 emerged leaves and with a control (no N, no manure). Treatments were distributed in a randomized block design. Factors analysed were stability against wetting stress disaggregation, porosity, soil organic carbon (SOC) fractions and earthworm abundance, studied eight months after the last manure application. The application rate of 30DCM increased aggregate stability and the light SOC fraction, but not the pore volume, nor the earthworm abundance, compared with MNF. The DCM rates did not result in unbalanced agronomic advantages versus MNF, as high yields (17–18 Mg ha−1 yr−1) were obtained. In Mediterranean environments, the use of DCM should be encouraged mainly because of its contribution to the light SOC fraction which protects dry macro-aggregates from implosion (slaking) during the wetting process. Thus, in intensive agricultural systems, it protects soil from physical degradation. ; The authors thank Elena González, Irma Geli and Albert Roselló for field assistance and Montse Antúnez and Nouha Gobber for laboratory assistance. This study was supported by the National Institute for Agricultural and Food Scientific Research and Technology of Spain-INIA (project RTA2013-057-C05-05) funds. The initial field maintenance was done through different Spanish projects from the National Institute for Agricultural and Food Scientific Research and Technology (INIA) and from the Interministerial Science and Technology Research commission (CICYT): AGL2001-2214-C06; RTA2003-066-C4, AGL2005-08020-C05-03.The subsequent field maintenance by IRTA-Mas Badia and the Department of Agriculture, Livestock, Fisheries, Food and Natural Environment from Generalitat de Catalunya, is fully acknowledged. This research article received a grant for linguistic revision from the Language Institute of the University of Lleida (2015 call).