Suchergebnisse

Abstract
Intensive pig farming produces large amounts of slurry, which is applied to agricultural soils as fertilizer. A 7-year field study was performed to check the effect of pig slurry on soil properties and on the accumulation of some essential nutrients and heavy metals in a calcareous silty-loam soil (0–0.3 m) and in barley (Hordeum vulgare L.) plants in two cropping seasons with contrasting amounts of rainfall. Five fertilization treatments, control (no N applied), mineral fertilizer (90 kg N ha−1), and different N doses of pig slurry (146, 281, 534 kg N ha−1), were applied at sowing of a barley crop. Organic carbon, available P and K, and total P in soil increased with slurry dose. No differences were found in Co, Cr, Fe, Mn, Ni, and Pb soil concentrations. Slurries increased Cu, Mn, and Zn extractions and plant concentrations of P in straw and Zn in grain. However, the lowest slurry rate was able to maintain the highest grain yields while improving fertility. The results of this research study support the sustainability of pig slurry fertilization at appropriate rates in relation to soil chemical quality.

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).

Fertilization with animal residues together with no-tillage is being widely used in dryland Mediterranean agriculture. The aim of this work is to assess the potential impacts of these combined anagement practices on oribatid mite species, and to evaluate their potential use as bioindicators of soil disturbances. From an experiment established ten years ago, eight fertilization treatments (including minerals or pig slurries), all combined with minimum tillage (MT) and no-tillage (NT), were studied. Four of these combinations were sampled three times during the winter cereal cropping season. The rest, and a eighbouring oak forest, were only sampled close to the end of the season (May). In total, 34 oribatid species and 4140 individuals were recovered. Oribatid abundance responded positively (p < 0.05) to the reduction of tillage intensity (NT) and marginally (p < 0.1) to slurry fertilization at sowing (close to maximum legislation allowed rate: <210 kg N ha−1 yr−1). At this slurry rate, Shannon index of diversity varied through the season, and was higher in May in MT than in NT plots. The Berger–Parker index of abundance signals plots without slurries as the most disturbed (compared with the forest). Nitrogen slurry over-fertilization reduced abundance of Oribatula(Zygoribatula) connexa connexa , but the impact on the most relevant species depended on the tillage system: Epilohmannia cylindrica cylindrica dominated in MT plots; under NT it was balanced by Tectocepheus velatus sarekensis and Passalozetes (Passalozetes) africanus. Scutovertex sculptus is also very negatively affected by tillage.Oribatida are a good target for the biological indication of soil disturbances associated to agricultural management.