جستجوی مقالات مرتبط با کلیدواژه « ndf » در نشریات گروه « زراعت »

The effect of fire on vegetation of semi-arid steppe has not been studied extensively. Wildfires are rare in some steppe rangelands because of high levels of large herbivore grazing. However, grazing is sometimes restricted or excluded in areas such as national parks or the areas where afforestation projects are conducted. Therefore, sometimes, wildfires occur during the dormant season when litter (the uppermost layer of organic debris on the soil surface; essentially the freshly fallen or slightly decomposed vegetal material) mass has resulted in peak levels. Our study assessed the effects of a single fire on litter mass, forage production, and forage crude protein, Neutral Detergent Fiber (NDF), and Acid Detergent Fiber (ADF) in high altitude rangelands of Eastern Anatolia. We found significant effects of treatment (fire and no fire), years, and sampling date on all variables. Following the prescribed fire in 2011, litter mass and forage production was less in treated plots compared to untreated control plots during both years. The effect of the fire on litter and forage production was more pronounced in 2012 compared to 2013. The effects of the fire on forage quality variables were also greater in 2012 than in 2013. Forage crude protein levels were consistently higher in treated plots during all 2012 sampling periods. Similarly, NDF and ADF tended to be lower in treated plots relative to the control plots during 2012. All effects we found were more pronounced in the first growing season following the fire compared to the second growing season, suggesting a relatively transient nature of fire effects in the steppe vegetation we studied.

In the next decades, forage legumes are likely to become more important. However, predicted climate change may increase the risk of droughts and thus influence their agricultural performance. Decreases in yield due to water shortage are well documented, while influences on nutritive values are inconsistent. Therefore, we examined the effects of drought on crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF) and water-soluble carbohydrates (WSC) of six legumes, birdsfoot trefoil (Lotus corniculatus L.); marsh birdsfoot trefoil (Lotus uliginosus Schkuhr); black medic (Medicago lupulina L.); yellow alfalfa (Medicago falcata L.); sainfoin (Onobrychis viciifolia Scop.) and white clover (Trifolium repens L.) in monoculture and in mixture with perennial ryegrass (Lolium perenne L.) in a container experiment in a vegetation hall. Moderate and strong drought stress was applied during three periods in two years. Mean volumetric soil water content at the end of the moderate drought stress period was 11 vol. % and 6 vol. % under strong stress. The effect of drought on nutritive values was considerably less pronounced than on yield. While the impact of moderate stress on nutritive quality was negligible, we found decreases in CP, NDF and ADF and increases in WSC under strong stress. This may indicate that water scarcity could even increase fodder quality and digestibility. However, the choice of legume species and stand (monoculture or mixture) had stronger effects on nutritive values than drought. We conclude that the reaction of temporary drought on nutritive values seems to be less important for the selection of suitable forage legumes species than other agronomic properties under conditions of climate change.