Kurt Schlösser,Studium der Naturwissenschaften. 163 Seiten,UTB 809, 1979     

J. Richter 《植物养料与土壤学杂志》1980,143(2):254-254

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Ion transport through unsaturated soils: field experiments and regional simulations     

T. Kumke  T. Streck  & J. Richter 《European Journal of Soil Science》2002,53(1):57-70

This paper describes the movement of anions and cations through soils at the regional scale using block‐scale and regional simulations of one‐dimensional ion transport through cultivated soils. The simulations were based on field experiments in a region of about 10 km² in Lower Saxony, Germany. Transport was modelled with the convection–dispersion equation, and the cation exchange was described using the Gapon equation. We evaluated the spatial variation of cation exchange parameters, obtained estimates valid at the block scale, and simulated the one‐dimensional transport of anions and cations. The movement of anions and cations was simulated over blocks using effective transport parameters calculated from local transport parameters. The approach led to a good agreement between measured and predicted concentrations of Br^–, Na⁺, K⁺, Ca²⁺ and Mg²⁺ on four different 1 ha blocks. However, the mean concentrations of K⁺ in the soil solution in the uppermost horizons could not be described satisfactorily by the model. For the regional simulations, transport and exchange parameters were estimated by block kriging. All variograms of the exchange parameters were spatially structured with correlation lengths varying from 100 m to 300 m. Results of the regional simulations imply that Cl^– and K⁺ were transported substantially deeper in the southern part than in the northern part of the area. The transport depth of the ions strongly depended on the pore water velocities. The simulation of solute transport to the water table showed the influence of the depth of water table on the estimated travel times, superimposing the influence of the transport parameters in the region. The results of the regional simulations also emphasize the importance of careful fertilization, especially in regions with shallow water tables such as in the north of the area.  相似文献   

Die Verlagerung physikalisch wechselwirkender Ionen in Böden - Modellentwicklung und -kalibrierung -     

Jens Utermann  Jrg Richter 《植物养料与土壤学杂志》1988,151(3):165-170

Leaching of physically interactive ions in soils - Model development and calibration - A deterministic approach is presented in order to describe vertical leaching of physically interactive cations (K⁺, Na⁺, Ca²⁺, Mg²⁺). Model calibration with undisturbed and disturbed Eutric Gleysol columns under quasi-stationary conditions shows good agreement between measured and simulated concentration profiles. Interaction with the soil matrix is measured on the base of exchange isotherms (Beckett, 1964). Gapon coefficients are derived directly from the slope of the Q/I relationships. In the case of non-linearity of the exchange isotherms it is necessary to use Gapon coefficients, variable in time and space. KCl application induces K⁺ fixation in every case, which can be described by a simple diffusion approach. Leaching phenomena in one of the undisturbed columns can only be explained on the base of a dual pore system.  相似文献   

Die Rolle der mikrobiellen Biomasse und des mineralisch fixierten Ammoniums bei den Stickstoff-Transformationen in niedersächsischen Löß-Ackerböden unter Winter-Weizen. I. Poolgrößenveränderungen     

Rolf Nieder  Elisabeth Neugebauer  Astrid Willenbockel  Jrg Richter 《植物养料与土壤学杂志》1995,158(5):469-475

Significance of microbial biomass and non-exchangeable ammonium with respect to the nitrogen transformations in loess soils of Niedersachsen during the growing season of winter wheat. I. Change of pool sizes Nitrogen transformations in loess soils have been examined by laboratory and field experiments. After straw application (· 8 t · ha^?1), N in microbial biomass (N_mic) increased by about 20 mg · kg^?1 soil (· 90 kg N · ha^?1 · 30 cm^?1) after 9 days of incubation (20 °C). Another laboratory experiment yielded an increase of about 400 mg of NH₄+-N · kg^?1 fixed by minerals within 1 h after addition of 1 M NH₄+-acetate. Defixation of the recently fixed NH₄+ after addition of 1 M KCl amounted to only 60 mg · kg^?1 within 50 days. In a field experiment with winter wheat 1991, an increase in N_mic of about 80 kg N · ha^?1 · 30 cm^?1 was observed from March to June. After July, growth of the microbes was limited by decreased soluble carbon concentrations in the rhizosphere. Different levels of mineral N-fertilizer (0, 177 and 213 kg N · ha^?1) did not affect significantly the microbial biomass. The same field experiment yielded a decrease of non-exchangeable ammonium on the “zero”-fertilized plot in spring by 200 kg N · ha^?1 · 30 cm^?1. The pool of fixed ammonium increased significantly after harvest. After conventional mineral N-fertilizer application (213 kg N · ha^?1). NH₄+-defixation was only about 120 kg N · ha^?1 · 30 cm^?1 until July.  相似文献   

Modelling the variability of UK sugar beet yields under climate change and husbandry adaptations     

G. M. Richter    A. Qi    M. A. Semenov  & K. W. Jaggard 《Soil Use and Management》2006,22(1):39-47

In the future, UK summers are likely to be warmer and drier. Modelling differential water redistribution and uptake, we assessed the impact of future drier climates on sugar beet yields. Weather was generated for 1961–1990 (BASE) and predictions based on low‐ and high‐emission scenarios (LO, HI) described in the most recent global climate simulations by the Hadley Centre, UK. Distributions and variability of relative soil moisture deficit (rSMD) and yield gap (drought‐related yield loss, YG_dr = 1?actual yield/potential yield), and sugar yield were calculated for different time‐lines using regional weather, soil texture and management inputs. The rSMD is estimated to exceed the senescence threshold with a probability of 75% (2050sLO) to 95% (2080sHI) compared with 65% (BASE). The potential yield loss, YG_dr, is likely to increase from 17% (BASE) to 22% (2050sLO) to 35% (2080sHI). However, increasing potential growth rates (CO₂ × temperature) cause average sugar yields to rise by between 1.4 and 2 t ha^?1 (2050sLO and 2050sHI respectively). Yield variation (CV%) may increase from 15–18% (BASE) to 18–23% (2050s) and 19–25% (2080s). Differences are small between regions but large within regions because of soil variability. In future, sugar yields on sands (8 t ha^?1) are likely to increase by little (0.5–1.5 t ha^?1), but on loams yields are likely to increase from 11 to 13 t ha^?1 (2050sHI) and 15 t ha^?1 (2080sHI). Earlier sowing and later harvest are potential tools to compensate for drought‐related losses on sandy soils.  相似文献   

The effect of salinomycin on apparent digestibility, indices of rumen fermentation and fattening and slaughter yields of cattle     

G H Richter  G Flachowsky 《Archives of Animal Nutrition》1991,41(1):85-96

The influence of salinomycin (0, 15, 30 and 60 mg per animal and day) on apparent digestibility of artificially dried grass was investigated in four experiments with five wether each. Three long term individual feeding experiments (210 to 252 days) with 72 growing bulls were carried out. The influence of various salinomycin levels (100 to 300 mg per animal and day) were investigated on parameters of rumen fermentation as well as fattening and slaughtering results. Salinomycin decreased insignificantly (P greater than 0.05) the apparent digestibility of organic matter (71.0; 70.1; 68.7 and 68.4%) and crude carbohydrates (71.8; 70.3; 69.2 and 68.5% resp.). The digestibility of other nutrients was not influenced. Supplementation of salinomycin reduced molar concentration of acetate (49 to 115) and butyrate (22 to 82) and increased propionate (110 to 199 mmoles per mol) in rumen liquid. Dry matter intake of bulls declined (0.8%, 13.5 and 24.6; 4.7% of experiments 1 to 3) when salinomycin was added. Daily weight gain (6.5 and 1.0%) and feed efficiency (6.8 and 6.3%) of bulls supplemented with salinomycin were improved in experiments 1 and 3. Significant decrease of feed intake of bulls of experiment 2 affected decline of weight gain probably as consequence of high salinomycin levels. Slaughtering results (except experiment 2) and body composition of bulls were not significantly influenced by salinomycin. Under consideration of own results and some references 10 to 20 mg per kg dry matter or 50 to 150 mg salinomycin per fattening bull and day are recommended as optimal level.  相似文献   

Learning capability as a testing method for brain damage caused by O2 deficiency     

P Arnold  E G?pfert  S Richter 《Archiv fuer experimentelle veterinaermedizin》1984,38(6):793-799

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Laparoskopische Untersuchungen zum Tertiärfollikelwachstum im Brunstzyklus beim Merinofleischschaf     

Karl-Heinz Kaulfuß  reas Richter  Joachim Schulz 《Reproduction in domestic animals》1994,29(1):22-37

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Pseudomonas aeruginosa infection in squirrel monkeys     

N C Lausen  A G Richter  A L Lage 《Journal of the American Veterinary Medical Association》1986,189(9):1216-1218

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Leptospirosis and coccidial infection in a guanaco     

C Hodgin  T W Schillhorn van Veen  R Fayer  N Richter 《Journal of the American Veterinary Medical Association》1984,185(11):1442-1444

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