Suchergebnisse

9 Pag., 6 Tabl., 1 Fig. ; Greater demand for corn (Zea mays L.) stover for bioenergy use may lead to increased corn production acreage with minimal surface residue cover, resulting in greater risk for soil erosion and phosphorus (P) losses in runoff. A rainfall simulation study was conducted to determine the effects of spring-applied dairy cow (Bos taurus) manure (none, in-barn composted, and exterior walled-enclosure pit) with >200 g kg−1 organic solids content following fall corn biomass removal with and without incorporation (chisel plow [CP] and no-till [NT]) on sediment and P in runoff. Runoff was collected from a 0.83-m2 area for 60 min following the onset of rainfall simulation (76 mm h−1), once in spring and once in fall. Runoff dissolved reactive P (DRP) and dissolved organic P (DOP) concentrations were positively correlated with manure P rate and were higher in NT compared with CP. Conversely, sediment and particulate P (PP) concentrations in runoff were inversely correlated with manure P rate (and manure solids) and were higher in CP compared with NT. Runoff volume where no manure was applied was higher in NT than in CP in spring but similar in fall. The addition of manure reduced runoff volumes by an average of 82% in NT and 42% in CP over spring and fall. Results from this study indicate that surface application of dairy manure with relatively high solids content may reduce sediment and PP losses in runoff without increasing the risk of increased DRP and DOP losses in the year of application where corn biomass is harvested. ; This research was supported by the Univ. of Wisconsin-Madison Graduate School and Nonpoint program. M.R. Yagüe would like to acknowledge the Aragon Government for its financial support of the postdoctoral stage in Soil Science Depart. at the Univ. of Wisconsin-Madison. ; Peer reviewed

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.