On-farm evaluation of ridging and residue management options in a Sahelian millet-cowpea intercrop. 1. Soil quality changes     

C.L. Bielders  K. Michels  A. Bationo 《Soil Use and Management》2002,18(3):216-222

Abstract. In the Sahel, promising technologies for agricultural intensification include millet stover mulching and ridging. A four year on-farm experiment was set-up in order to assess the effect of various combinations of these two technologies on soil chemical and physical quality in a millet ( Pennisetum glaucum (L.) R. Br.) –- cowpea ( Vigna unguiculata (L.) Walp.) relay intercropping system. Treatments included bare surface, ridging, a surface applied banded millet stover mulch (2 t ha^–1) and a banded millet stover mulch (2 t ha^–1) buried in ridges. The latter three treatments were implemented exclusively in the cowpea rows, with an annual rotation between the millet and cowpea rows. Both the bare and ridge plots experienced a rapid loss of organic carbon, acidification and the development of extensive surface crusts but no increase in bulk density or penetration resistance. In the year of application, mulching improved soil quality in the cowpea row with respect to pH, organic carbon and exchangeable K⁺ and Mg⁺⁺ content, penetration resistance and bulk density, and it reduced the decline in exchangeable Ca⁺⁺ and total N content. In the year following mulch application, a general decline in soil chemical quality was observed in the millet row, except for organic carbon content, and a positive residual effect was observed on penetration resistance and bulk density. As a rule, the effects of mulching in the year of application tended to be stronger in the ridged treatment with buried residue than in the banded surface mulch. In the year following application, this tendency was reversed. For the purpose of reducing soil degradation by nutrient mining and wind erosion, a banded surface mulch therefore appeared more effective than buried mulch.  相似文献   

Application of a Full-scale Constructed Wetland for Tertiary Treatment of Piggery Manure: Monitoring Results   总被引：1，自引：0，他引：1  

E. Meers  F. M. G. Tack  I. Tolpe  E. Michels 《Water, air, and soil pollution》2008,193(1-4):15-24

Many industrialized regions in the world are faced with local overproductions of animal manure requiring processing in an economic sound manner. Intensive animal production in Flanders and the Netherlands has resulted in a considerable overproduction of animal manure. Spreading the excess manure over arable land has resulted in contamination and eutrophication of groundwater and surface waters. Over the last 4 years, research was conducted towards the potential of more economic constructed wetlands for the final treatment step. Although, initial results with laboratory flow field experiments were insufficient to reach stringent discharge criteria (Meers et al., Water Air Soil Pollut 160:15–26, 2005a), progressive optimisation of the tertiary treatment as well as of the preceding conditioning has resulted in a consistently performing pilot scale system (1,000 m³ year^?1 capacity) with effluent concentrations below the discharge criteria of 15 mg l^?1 N, 2 mg l^?1 P and 125 mg l^?1 COD (chemical oxygen demand), at a cumulated cost (operational plus investment) of 3–4 € m^?3 of pre-treated pig manure. Construction of full-scale installations with annual capacity of 10,000–25,000 m³ based on this pilot model are scheduled, with the first installation currently under way. The concept has the potential to provide a low cost, in situ treatment system allowing animal farmers to process excess animal manure themselves without the requirement of expensive ex situ treatment based on industrial scale membrane technology facilities. This paper presents the research findings of the first year of the pilot scale installation.  相似文献   

Biological Control of Leaf-Cutting Ants Using Forage Grasses: Nest Characteristics and Fungus Growth     

K. Michels  N. Cromme  A. Glatzle  & R. Schultze-Kraft 《Journal of Agronomy and Crop Science》2001,187(4):259-267

One of the major pasture pests in the neotropics is the leaf-cutting ant Acromyrmex landolti , which cuts monocots to nourish a symbiotic fungus as a food source. The objective of the present study was to characterize ant nests and to test the effect of six forage grasses on grass consumption and fungus properties of A. landolti nests. Grasses tested in a 7-week field experiment during March and April 1997 in the Paraguayan Chaco were Cynodon nlemfuensis , Panicum maximum , Cenchrus ciliaris , Brachiaria brizantha , Digitaria milanjiana and Urochloa mosambicensis . In a bioassay, grass species were evaluated with regard to fungus growth in the laboratory. Results showed that ant nests at that time of year were deeper and had more chambers than often reported in the literature. The two least and most preferred grasses were B. brizantha and C. ciliaris , and C. nlemfuensis and D. milanjiana , respectively. Consumption of the first two grasses was strongly reduced during the second half of the experiment, approaching zero in the last week. The highest fungus weights were found in nests fed with C. nlemfuensis and D. milanjiana . Fungus colony weight and colour proved to be adequate parameters with which to rate the vigour of the fungus; weight was lowest in nests fed with B. brizantha and C. ciliaris . In the bioassays, B. brizantha and D. milanjiana plant saps reduced the fungal growth most and least, respectively. In conclusion, D. milanjiana and C. nlemfuensis can be regarded as highly susceptible to A. landolti , and B. brizantha as resistant; the other grasses cannot be assigned to either group. The bioassay proved to be a quick way of testing the ability of a grass species to inhibit fungal growth.  相似文献   

Distribution and metabolism of D/L-, L- and D-glufosinate in transgenic, glufosinate-tolerant crops of maize (Zea mays L ssp mays) and oilseed rape (Brassica napus L var napus)   总被引：1，自引：0，他引：1  

Ruhland M  Engelhardt G  Pawlizki K 《Pest management science》2004,60(7):691-696

The aim of the present study was to determine whether post-emergence application of glufosinate to transgenic crops could lead to an increase in residues or to the formation of new, hitherto unknown metabolites. Transgenic oilseed rape and maize plants were treated separately with L-glufosinate, D-glufosinate or the racemic mixture. Whereas about 90% of the applied D-glufosinate was washed off by rain and only 5-6% was metabolised, 13-35% of the applied L-glufosinate remained in the form of metabolites and unchanged herbicide in both transgenic maize and oilseed rape. The main metabolite was N-acetyl-L-glufosinate with total residues of 91% in oilseed rape and 67% in maize, together with small amounts, of 5% in oilseed rape and 28% in maize, of different methylphosphinyl fatty acids. These metabolites were probably formed from L-glufosinate by deamination and subsequent decarboxylation. The residues were distributed in all fractions of the plants, with the highest contents in treated leaves and the lowest in the grains (0.07-0.3% in maize and 0.4-0.6% in oilseed rape). There was no indication of an accumulation of total residues or of residue levels above the official tolerances for glufosinate.  相似文献   

Fate of Macronutrients in Water Treatment of Digestate Using Vibrating Reversed Osmosis     

C. Vaneeckhaute  E. Meers  E. Michels  P. Christiaens  F. M. G. Tack 《Water, air, and soil pollution》2012,223(4):1593-1603

In the transition from a fossil to a bio-based economy, it has become an important challenge to maximally recuperate and recycle valuable nutrients coming from manure and digestate processing. Membrane filtration is a suitable technology to separate valuable nutrients in easily transportable concentrates which could potentially be re-used as green fertilizers, in the meantime producing high quality water. However, traditional membrane filtration systems often suffer technical problems in waste stream treatment. The aim of this study was to evaluate the performance of vibratory shear enhanced processing (VSEP) in the removal of macronutrients (N, P, K, Na, Ca, Mg) from the liquid fraction of digestates, reducing their concentrations down to dischargeable/re-usable water. In addition, the re-use potential of VSEP-concentrates as sustainable substitutes for fossil-based mineral fertilizers was evaluated. Removal efficiencies for N and P by two VSEP filtration steps were high, though not sufficient to continuously reach the Flemish legislation criteria for discharge into surface waters (15 mg N l⁻¹ and 2 mg P l⁻¹). Additional purification can occur in a subsequent lagoon, yet further optimization of the VSEP filtration system is advised. Furthermore, concentrates produced by one membrane filtration step showed potential as N–K fertilizer with an economic value of €6.3 ± 1.1 t⁻¹ fresh weight (FW). Further research is, however, required to evaluate the impact on crop production and soil quality by application of these new potential green fertilizers.  相似文献   

The German Environmental Specimen Bank     

Tobias Schulze  Mathias Ricking  Christa Schröter-Kermani  Andrea Körner  Hans-Dietrich Denner  Karlheinz Weinfurtner  Andreas Winkler  Asaf Pekdeger 《Journal of Soils and Sediments》2007,7(6):361-367

Goal, Scope and Background  

The European Water Framework Directive implies a risk based sediment management. In this approach, sediments are recognised as secondary sources of contaminants, and suspended particulate matter (SPM) as the carrier. For that reason, the concept of the German Environmental Specimen Bank (ESB) includes the establishment of these specimens. The ESB is characterised by a high quality assurance system of standard operation procedures (SOP) to preserve the integrity of the specimens under cryogenic conditions for transportation, storage and handling. The aim of this study was (1) the development and validation of SOPs for the collection of sediment and SPM, and (2) the adaptation and standardisation of sampling techniques for the ESB. This paper provides information about sediment and SPM as new specimens in the ESB.  相似文献   

Observations of a comet on collision course with the sun     

Michels DJ  Sheeley NR  Howard RA  Koomen MJ 《Science (New York, N.Y.)》1982,215(4536):1097-1102

A brilliant new comet (1979 XI: Howard-Koomen-Michels) was discovered in data from the Naval Research Laboratory's orbiting SOLWIND coronagraph. An extensive sequence of pictures, telemetered from the P78-1 satellite, shows the coma, accompanied by a bright and well-developed tail, passing through the coronagraph's field of view at afew million kilometers from the sun. Preliminary orbital calculations based on the observed motion of the comet's head and morphology of the tail indicate that this previously unreported object is a sungrazing comet and may be one of the group of Kreutz sungrazers. It appears from the data that the perihelion distance was less than 1 solar radius, so that the cometary nucleus encountered dense regions of the sun's atmosphere, was completely vaporized, and did not reappear after the time of closest approach to the sun. After this time, however, cometary debris, scattered into the ambient solar wind, caused a brightening of the corona over one solar hemisphere and to heliocentric distances of 5 to 10 solar radii.  相似文献   

SUMO modification of Huntingtin and Huntington's disease pathology     

Steffan JS  Agrawal N  Pallos J  Rockabrand E  Trotman LC  Slepko N  Illes K  Lukacsovich T  Zhu YZ  Cattaneo E  Pandolfi PP  Thompson LM  Marsh JL 《Science (New York, N.Y.)》2004,304(5667):100-104

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Nitrogen release and mineralization potential of derivatives from nutrient recovery processes as substitutes for fossil fuel‐based nitrogen fertilizers          下载免费PDF全文

I. Sigurnjak  J. De Waele  E. Michels  F. M. G. Tack  E. Meers  S. De Neve 《Soil Use and Management》2017,33(3):437-446

The need to meet rapidly increasing demands for synthetic nitrogen (N) while reducing dependence on fossil fuels has been driving widespread attention to the recuperation and reuse of nutrients present in digestate and animal manure. The N release and mineralization potential of animal manure (AM), digestate (DIG), liquid fraction of digestate (LFDIG) and mineral concentrate (MC) were assessed in comparison with N availability from calcium ammonium nitrate (CAN) as a reference. The release was highly dependent on the product ‐N/N_total ratio, while mineralization occurred only for products containing more than 5% of organic N. The magnitude of the released N, on average after 120 days of an incubation experiment, was in the order: CAN > MC > LFDIG > DIG ≥ AM. These results indicate that only the N release from MC exhibited patterns similar to CAN, suggesting that this product will provide plant available N in a similar fashion as synthetic fertilizers. The N release from LFDIG was higher than AM, but did not closely follow the pattern of CAN. The N availability in LFDIG may be increased using substrates richer in N, such as animal manure or waste food and not only plant residues.  相似文献   

Growth of the femur in the rabbit     

O Khermosh  A Tadmor  S L Weissman  C H Michels  R Chen 《American journal of veterinary research》1972,33(5):1079-1082

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