Eine Infiltrationsmethode zur Messung der hydraulischen Leitfähigkeit im Felde

An infiltration method for measuring the saturated hydraulic conductivity under field conditions A new field method to measure the hydraulic conductivity under field conditions, developed by Reynolds and Elrick (1985), is presented and compared with a laboratory method using 100 cm³ cylinder cores.     

Atmosphärische Deposition von Bioelementen in Agrarökosysteme 1. Mitteilung: Deposition von Bioelementen mit dem Niederschlag

Atmospheric deposition of bioelements in agrar-ecosystems 1. Report: Deposition of bioelements by precipitation The bioelement deposition by precipitation was measured in 1977–1981 in Göttingen (Niedersachsen). The bioelement concentrations and the deposited quantities are in good agreement with the results of other authors. The mean pH-values of the collected precipitation water in 1980 and '81 in Göttingen was 4,60. The difference to the pH-values measured by Ulrich et al. (1979) in the Solling is explained by the different geographical locations of the ecosystems in connection with the transport of dust and variations in the composition of the soils of the areas. From the view of plant nutrition and soil acidification the contribution of the deposition by precipitation is insignificant for agriculture. Only about 6% of the typical annual Ca-leaching from loamy soils are caused by the H⁺ input by precipitation. The rest is caused by other influences, especially the soil respiration.     

The effect of ignoring individual heterogeneity in Weibull log-normal sire frailty models

The objective of this study was, by means of simulation, to quantify the effect of ignoring individual heterogeneity in Weibull sire frailty models on parameter estimates and to address the consequences for genetic inferences. Three simulation studies were evaluated, which included 3 levels of individual heterogeneity combined with 4 levels of censoring (0, 25, 50, or 75%). Data were simulated according to balanced half-sib designs using Weibull log-normal animal frailty models with a normally distributed residual effect on the log-frailty scale. The 12 data sets were analyzed with 2 models: the sire model, equivalent to the animal model used to generate the data (complete sire model), and a corresponding model in which individual heterogeneity in log-frailty was neglected (incomplete sire model). Parameter estimates were obtained from a Bayesian analysis using Gibbs sampling, and also from the software Survival Kit for the incomplete sire model. For the incomplete sire model, the Monte Carlo and Survival Kit parameter estimates were similar. This study established that when unobserved individual heterogeneity was ignored, the parameter estimates that included sire effects were biased toward zero by an amount that depended in magnitude on the level of censoring and the size of the ignored individual heterogeneity. Despite the biased parameter estimates, the ranking of sires, measured by the rank correlations between true and estimated sire effects, was unaffected. In comparison, parameter estimates obtained using complete sire models were consistent with the true values used to simulate the data. Thus, in this study, several issues of concern were demonstrated for the incomplete sire model.     

Effects of Carbohydrate-free Diets on the Performance of Lactating Mink (Mustela vison) and the Growth Performance of Suckling Kits

The effects of carbohydrate-free diets on body weight changes, feed consumption, and plasma concentrations of nutrients, metabolites, and hormones in lactating mink and on growth performance in kits were investigated in a total of 108 litters during the lactation period of seven weeks. The litters were distributed in three experimental groups fed different ratios of metabolisable energy (ME) derived from protein and fat (61:38; 47:52; 33:66). The females and kits were weighed at parturition and 2, 3, 4, and 7 weeks after parturition. Blood samples were collected from females in the second, fourth, and sixth week of the lactation period. Carbohydrate-free diets fed to lactating mink can in principle support normal performance, health of the females, and growth performance of the kits. However, mink need a sufficient supply of available gluconeogenic precursors in the form of amino acids. In the present experiment, the diet with 33% of ME from protein contained insufficient amounts of gluconeogenic precursors for lactating mink, and three weeks post partum this group was excluded from the experiment. The differences in dietary protein level (61% and 47% of ME) and fat level (38% and 52% of ME) influenced the plasma concentrations of free fatty acids (FFA) and urea, but had minimal influence on plasma concentrations of other nutrients, metabolites, and hormones.     

Detection of transgenic and endogenous plant DNA in digesta and tissues of sheep and pigs fed Roundup Ready canola meal

The persistence of plant-derived recombinant DNA in sheep and pigs fed genetically modified (Roundup Ready) canola was assessed by PCR and Southern hybridization analysis of DNA extracted from digesta, gastrointestinal (GI) tract tissues, and visceral organs. Sheep (n = 11) and pigs (n = 36) were fed to slaughter on diets containing 6.5 or 15% Roundup Ready canola. Native plant DNA (high- and low-copy-number gene fragments) and the cp4 epsps transgene that encodes 5-enolpyruvyl shikimate-3-phosphate synthase were tracked in ruminal, abomasal, and large intestinal digesta and in tissue from the esophagus, rumen, abomasum, small and large intestine, liver, and kidney of sheep and in cecal content and tissue from the duodenum, cecum, liver, spleen, and kidney of pigs. High-copy chloroplast-specific DNA (a 520-bp fragment) was detected in all digesta samples, the majority (89-100%) of intestinal tissues, and at least one of each visceral organ sample (frequencies of 3-27%) from sheep and swine. Low-copy rubisco fragments (186- and 540-bp sequences from the small subunit) were present at slightly lower, variable frequencies in digesta (18-82%) and intestinal tissues (9-27% of ovine and 17-25% of porcine samples) and infrequently in visceral organs (1 of 88 ovine samples; 3 of 216 porcine samples). Each of the five cp4 epsps transgene fragments (179-527 bp) surveyed was present in at least 27% of ovine large intestinal content samples (maximum = 64%) and at least 33% of porcine cecal content samples (maximum = 75%). In sheep, transgene fragments were more common in intestinal digesta than in ruminal or abomasal content. Transgene fragments were detected in 0 (esophagus) to 3 (large intestine) GI tract tissues from the 11 sheep and in 0-10 of the duodenal and cecal tissues collected from 36 pigs. The feed-ingested recombinant DNA was not detected in visceral tissues (liver, kidney) of lambs or in the spleen from pigs. Of note, however, one liver and one kidney sample from the pigs (different animals) were positive for a 278-bp fragment of the transgenic cp4 epsps (denoted F3). Examination of genomic libraries from these tissues yielded no conclusive information regarding integration of the fragment into porcine DNA. This study confirms that feed-ingested DNA fragments (endogenous and transgenic) do survive to the terminal GI tract and that uptake into gut epithelial tissues does occur. A very low frequency of transmittance to visceral tissue was confirmed in pigs, but not in sheep. It is recognized that the low copy number of transgenes in GM feeds is a challenge to their detection in tissues, but there was no evidence to suggest that recombinant DNA would be processed in the gut in any manner different from endogenous feed-ingested genetic material.     

Biodegradation measurements confirm the predictive value of the O:C‐ratio for biochar recalcitrance

Suitable predictors of degradability are sought to support the identification of biochars with large potential to increase C sequestration in soils. We determined the biodegradation of 9 chars from hydrothermal carbonization and pyrolysis in two agricultural soils. The 200‐ and 115‐day degradation correlated strongly with the O:C‐ and slightly with the H:C‐atomic ratio of 9 and 14 biochars, respectively. Highest temperature treatment and ash content did not show similar correlations.     

Relationship Between Atmospheric Ammonia Concentration and Nitrogen Content in Terricolous Lichen (Cladonia portentosa)

Water, Air, &; Soil Pollution - To biocontrol algal bloom, a novel algicidal bacterium, Enterobacter sp. NP23, was isolated. This strain has an effective algicidal activity against Chlorella...     

Aggressive behaviour of sows at mixing and maternal behaviour are heritable and genetically correlated traits

This study was designed to estimate genetic variation in aggressive behaviour of sows at mixing, and in maternal ability for the same sows. The study included 835 sows observed for number of mild or severe aggressions performed (F_A1, F_A2), or received (F_R1, F_R2) during 30 min after grouping. Maternal ability was recorded as sows' response to vocalisation from their piglets when these were handled. Maternal behaviour was studied in 1076 sows as a body reaction (MBR) to their piglets being handled after farrowing. Genetic covariances were estimated using a multi-trait animal model, assuming traits to be normally distributed. The heritabilities of performed aggression traits were intermediate (h² F_A1=0.17, h² F_A2=0.24), but lower for received aggression (h² F_R1=0.06, h² F_R2=0.04), and heritability of maternal behaviour was also low (h²=0.08). Although estimates of genetic correlations had large standard errors, they indicate that less aggressive sows were stronger responding mothers (r_g=−0.3). We conclude that performed aggression in sows is a heritable trait, and selection against aggression is possible without offsetting maternal behaviour.     

Using the modified agricultural non-point source pollution model in German watersheds

The modified agricultural non-point source pollution model (AGNPSm) was used in this study to predict runoff volume, peak flow rate, and sediment yield in three different watersheds in Germany. It is a distributed parameter soil erosion model which uses simple approaches to hydrological and sediment calculations. Simulations were carried out in the Glonn G1 (1.2 km²), and Glonn G2 (1.6 km²), and the Salzboede (81.7 km²) watersheds in Germany. Runoff volume was predicted reliably in all three watersheds. Sediment yield predictions were excellent in the Glonn G1 and acceptable in the Glonn G2 watersheds. There were some uncertainties in the sediment yield calculations for the Salzboede watershed. This study shows that a less complex soil erosion model such as AGNPSm is able to produce reliable assessments of non-point source pollution for planning purposes.