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1.
The objective of the current study was to evaluate the effect of unrepresentative sampling of digesta particulate matter entering the omasal canal on the accuracy of fiber flow measurements. The experimental design comprised one period, one diet, and three cows as experimental units. Within each cow, the physical and chemical composition of digesta particulate matter was assessed at seven sites within the digestive tract. Three Finnish Ayshire dairy cows, equipped with ruminal and simple-T duodenal cannulas, in extended lactation were offered grass silage twice daily on an ad libitum basis. Digesta samples were collected from the rumen (dorsal and ventral sac), reticulum, omasal canal, omasum, duodenum, and rectum to determine particle size distribution in digesta, chemical composition of various particle size fractions, and distribution of two flow markers (Cr-labeled straw and indigestible NDF [INDF]) among particle size fractions. Digesta samples were wet-sieved using sieves of 2.50, 1.25, 0.630, 0.315, 0.160, and 0.080 mm. Particulate matter was analyzed for OM, NDF, and Cr concentrations, and INDF concentration was determined based on 12-d ruminal incubation. The particle size of digesta entering the omasal canal was larger compared with the omasum or the duodenum, suggesting that omasal canal samples were not representative of particle size distribution truly escaping the rumen. The concentration of potentially digestible NDF (PDNDF) decreased with decreasing particle size. The PDNDF concentration of particulate matter retained on all sieves was greatest in the rumen and gradually decreased along the digestive tract. From the reticulorumen to the omasum, the decrease was associated with decreased particle size, reflecting selective passage of particulate matter. In contrast, from the omasum to the duodenum and rectum, the PDNDF concentration decreased within each particle size fraction without effect on particle size, indicating a nonselective passage of particulate matter between these sites. Variation between particle size fractions was slightly greater for Cr concentration than for INDF concentration, indicating that unrepresentative sampling of particulate matter had a greater effect on Cr concentration compared with that of INDF. Owing to unrepresentative sampling, NDF entering the omasal canal was overestimated by 5% using INDF and underestimated by 7% using Cr as a particle phase marker. Of total NDF digestibility, proportionally 0.90, 0.07, and 0.03 occurred in the reticulorumen, omasum, and intestines, respectively. The current results indicate that, despite unrepresentative sampling of digesta particulate matter entering the omasal canal, the errors in determined NDF flow were small. The omasum may have a greater role in postruminal NDF digestion than the intestines. 相似文献
2.
Nicola M. Hall Bocary Kaya Jan Dick Ute Skiba Amadou Niang Ramadjita Tabo 《Biology and Fertility of Soils》2006,42(3):224-230
The impacts of fallow on soil fertility, crop production and climate-forcing gas emissions were determined in two contrasting
legumes, Gliricidia sepium and Acacia colei, in comparison with traditional unamended fallow and continuous cultivation systems. After 2 years, the amount of foliar
material produced did not differ between the two improved fallow species; however, grain yield was significantly elevated
by 55% in the first and second cropping season after G. sepium compared with traditional fallow. By contrast, relative to the unamended fallow, a drop in grain yield was observed in the
first cropping season after A. colei, followed by no improvement in the second. G. sepium had higher foliar N, K and Mg, while A. colei had lower foliar N but higher lignin and polyphenols. In the third year after fallow improvement, a simulated rainfall experiment
was performed on soils to compare efflux of N2O and CO2. Improved fallow effects on soil nutrient composition and microbial activity were demonstrated through elevated N2O and CO2 efflux from soils in G. sepium fallows compared with other treatments. N2O emissions were around six times higher from this nitrogen-fixing soil treatment, evolving 69.9 ngN2O–N g−1soil h−1 after a simulated rainfall event, compared with only 8.5 and 4.8 ngN2O–N g−1soil h−1 from soil under traditional fallow and continuous cultivation, respectively. The findings indicate that selection of improved
fallows for short-term fertility enhancement has implications for regional N2O emissions for dry land regions. 相似文献
3.
J. Dick B. Kaya M. Soutoura U. Skiba R. Smith A. Niang & R. Tabo 《Soil Use and Management》2008,24(3):292-301
The yield and flux of nitrous oxide (N2 O) emitted from continuous cereals (with and without urea), legumes/cereal in rotation and cereal/legume in rotation all with or without organic manure was monitored from January 2004 to February 2005. All treatments except continuous cereals had phosphate added. The cereal grown July–October in 2003 and 2004 was pearl millet ( Pennisetum glaucum) and the legume was a bean ( Phaseolus vulgaris ). The 10 m × 10 m plots were established in a semi-arid climate in Mali. The addition of organic manure and both inorganic fertilizers increased yield and N2 O emissions. Continuous cereals treated with both organic manure and urea emitted significantly less N2 O (882 g N/ha per year) than plots receiving no organic manure(1535 g N/ha per year). Growing N-fixing crops in rotation did not significantly increase N2 O emissions. This study supports the new practice of growing cereal and legumes in rotation as an environmentally sustainable system in semi-arid Mali. 相似文献
4.
Purpose
Ferrolysis is a soil-forming process, which involves destruction of clay minerals due to cyclic reduction and oxidation in acidic and periodically wet soils. The main objectives of this study were as follows: (1) to determine the influence of redox processes on clay mineral transformation in Retisols (Albeluvisols) in the Carpathian Foothills in Poland and (2) to verify the occurrence of ferrolysis in Retisols showing various degrees of bleaching.Materials and methods
Twelve representative soil profiles were selected for analysis. All were formed entirely from loess except for two profiles, in which the lowermost horizons (2C) had developed from weathered flysch rocks residuum. Soil mineral analysis was done using x-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and Mössbauer spectroscopy (MS).Results and discussion
The obtained results indicate that the qualitative and quantitative mineral compositions of the clay fraction in the E and Eg horizons obtained from Retisols in the Carpathian Foothills exhibiting marked differences in bleaching (strong, moderate, weak, and lack of bleaching) caused by periodic stagnation of water above a slowly permeable fragipan and cyclic redox processes are the same. The E and Eg horizons are characterized by the presence of 2:1 clay minerals with likely organic interlayer fillings, dioctahedral mica, kaolinite, and chlorite.Conclusions
The results indicate that (1) redox processes occurring in the soils do not affect clay mineral transformation in Retisols of the Carpathian Foothills in Poland and (2) ferrolysis is not the main soil-forming process operating in these soils. This is most likely because iron-bearing minerals are not abundant in the Retisols and/or undergo eluviation to the lower part of the soil profiles. The lower content of the clay fraction in the E and Eg horizons versus that in the lower soil horizons of the Retisols is related to clay illuviation (lessivage), and not to clay decomposition due to ferrolysis.5.
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7.
Wies&#x;aw Przybylski Danuta Jaworska Piotr Sa&#x;ek Monika Sobol Maciej Branicki Grzegorz Skiba Stanis&#x;awa Raj Urszula Jankiewicz 《Journal of animal physiology and animal nutrition》2019,103(2):593-602
The aim of the study was to evaluate the influence of inulin supply to high‐fat diet rich in saturated fatty acids (SFA) on pork quality and profile of sarcoplasmic protein in drip loss. At 50 days of age, twenty cross‐bred pigs (gilts) were randomly allotted to four groups: the control (C) group fed a standard diet, and three experimental (D1, D2 and D3) groups fed a high‐fat diet rich in SFA. Moreover, pigs from the groups D2 and D3 consumed an extra inulin supply (7% of daily feed intake) from 85 to 120 days of age (for 5 weeks) and from 50 to 120 days of age (for 10 weeks) respectively. The addition of inulin to the diet reduced meaty odour and flavour significantly, improved tenderness and overall sensory quality of pork and additionally influenced ultimate pH, L* colour parameter, lactate level and protein content in meat. The diets also affected the profile of sarcoplasmic proteins. Significant effects were observed for the following enzymes—PK/PGI (pyruvate kinase/phosphoglucose isomerase) and ALD (aldolase), which are related to the intensity of post‐mortem glycolysis. Presented data indicate that long‐term inulin supply to high‐fat diet has a positive effect on technological and sensory quality as well as protein profile of pork. 相似文献
8.
The effect of soil texture and soil drainage on emissions of nitric oxide and nitrous oxide 总被引：7，自引：0，他引：7
Abstract. Agricultural soils are important sources of the tropospheric ozone precursor NO and the greenhouse gas N2 O. Emissions are controlled primarily by parameters that vary the soil mineral N supply, temperature and soil aeration. In this field experiment, the importance of soil physical properties on emissions of NO and N2 O are identified. Fluxes were measured from 13 soils which belonged to 11 different soil series, ranging from poorly drained silty clay loams to freely drained sandy loams. All soils were under the same soil management regime and crop type (winter barley) and in the same maritime climate zone. Despite this, emissions of NO and N2 O ranged over two orders of magnitude on all three measurement occasions, in spring before and after fertilizer application, and in autumn after harvest. NO emissions ranged from 0.3 to 215 μg NO-N m–2 h–1 , with maximum emissions always from the most sandy, freely drained soil. Nitrous oxide emissions ranged from 0 to 193 μg N2 O-N m–2 h–1 . Seasonal shifts in soil aeration caused maximum N2 O emissions to switch from freely drained sandy soils in spring to imperfectly drained soils with high clay contents in autumn. Although effects of soil type on emissions were not consistent, N2 O emission was best related to a combination of bulk density and clay content and the NO/N2 O ratio decreased logarithmically with increasing water filled pore space. 相似文献
9.
S. K. Jones R. M. Rees D. Kosmas B. C. Ball & U. M. Skiba 《Soil Use and Management》2006,22(2):132-142
Soil management practices that result in increased soil carbon (C) sequestration can make a valuable contribution to reducing the increase in atmospheric CO2 concentrations. We studied the effect of poultry manure, cattle slurry, sewage sludge, NH4NO3 or urea on C cycling and sequestration in silage grass production. Soil respiration, net ecosystem exchange (NEE) and methane (CH4) fluxes were measured with chambers, and soil samples were analysed for total C and dissolved organic C (DOC). Treatments were applied over 2 years and measurements were carried out over 3 years to assess possible residual effects. Organic fertilizer applications increased CO2 loss through soil respiration but also enhanced soil C storage compared with mineral fertilizer. Cumulative soil respiration rates were highest in poultry manure treatments with 13.7 t C ha?1 in 2003, corresponding to 1.6 times the control value, but no residual effect was seen. Soil respiration showed an exponential increase with temperature, and a bimodal relationship with soil moisture. The greatest NEE was observed on urea treatments (with a CO2 uptake of ?4.4 g CO2 m?2 h?1). Total C and DOC were significantly greater in manure treatments in the soil surface (0–10 cm). Of the C added in the manures, 27% of that in the sewage pellets, 32% of that in the cattle slurry and 39% of that in the poultry manure remained in the 0–10 cm soil layer at the end of the experiment. Mineral fertilizer treatments had only small C sequestration rates, although uncertainties were high. Expressed as global warming potentials, the benefits of increased C sequestration on poultry manure and sewage pellet treatments were outweighed by the additional losses of N2O, particularly in the wet year 2002. Methane was emitted only for 2–3 days on cattle slurry treatments, but the magnitudes of fluxes were negligible compared with C losses by soil respiration. 相似文献
10.
M. C. Vaz Patto B. Skiba E. C. K. Pang S. J. Ochatt F. Lambein D. Rubiales 《Euphytica》2006,147(1-2):133-147
Summary Several Lathyrus species and in particular Lathyrus sativus (grass pea) have great agronomic potential as grain and forage legume, especially in drought conditions. Grass pea is rightly
considered as one of the most promising sources of calories and protein for the vast and expanding populations of drought-prone
and marginal areas of Asia and Africa. It is virtually the only species that can yield high protein food and feed under these
conditions. It is superior in yield, protein value, nitrogen fixation, and drought, flood and salinity tolerance than other
legume crops. Lathyrus species have a considerable potential in crop rotation, improving soil physical conditions; reducing the amount of disease
and weed populations, with the overall reduction of production costs. Grass pea was already in use in Neolithic times, and
presently is considered as a model crop for sustainable agriculture. As a result of the little breeding effort invested in
it compared to other legumes, grass pea cultivation has shown a regressive pattern in many areas in recent decades. This is
due to variable yield caused by sensitivity to diseases and stress factors and above all, to the presence of the neurotoxin
β-N-oxalyl-L-α,β-diaminopropionic acid (β-ODAP), increasing the danger of genetic erosion. However, both L. sativus and L. cicera are gaining interest as grain legume crops in Mediterranean-type environments and production is increasing in Ethiopia, China,
Australia and several European countries.
This paper reviews research work on Lathyrus breeding focusing mainly on biotic and abiotic resistance improvement, and lists current developments in biotechnologies
to identify challenges for Lathyrus improvement in the future. 相似文献