Long‐term effects of mulching,traditional cutting and no management on plant species composition of improved upland grassland in the Czech Republic

A shortage of available livestock for utilizing grassland biomass in Central Europe is challenging for the management of both semi‐natural grasslands and previously intensified (limed, fertilized and reseeded) upland grasslands. An alternative method of grassland management is mulching, in which aboveground biomass is cut, crushed and subsequently spread on the surface. This paper reports on an experiment to compare three different mulching frequencies (one, two and three times per year) with an unmanaged treatment and traditional management of two cuts per year (control) on a previously improved upland meadow. Plant species composition was monitored over 13 years. Traditional management of two cuts with biomass removal was the most suitable method for maintaining plant species richness and diversity, and both were reduced significantly in the once‐mulched and especially in the unmanaged treatment. Tall dicotyledonous weeds such as Urtica dioica, Cirsium arvense and Aegopodium podagraria were promoted by the unmanaged treatment and by mulching once a year. Higher frequency of defoliation had positive effects on the spread of short forbs such as Taraxacum spp., Plantago lanceolata and Trifolium repens. After eight years, there were changes in sward structure in the unmanaged and mulched‐once‐a‐year treatments, with increase in the tall/short species ratio. In conclusion, repeated mulching cannot substitute fully for traditional two‐cut management in improved upland meadows without decreasing plant species richness and diversity, and changing the sward structure. Although mulching once a year may prevent invasion by shrubs and trees, it also supports the spread of weedy species similar to no management.     

Identification of cassava (Manihot esculenta Crantz) genotypes with early storage root bulking

Early bulking (EB) cassava varieties shorten the growth period from planting to harvesting. Cassava is preferred by farmers to many other crops because of its high-yielding potential and ability to survive a 4- to 6-month dry season. However, the crop in some cases is only able to remain alive during the dry season without further starch accumulation. This and some other factors, such as pest destruction during dry season and inability to use the same land for cultivation of other crops such as vegetables, therefore necessitate the development of EB cassava genotypes. The objective of this study was therefore to identify EB cassava genotypes using the difference in fresh storage root yield (FSRY) at different plant ages. Thirty-four cassava genotypes were evaluated at Umudike and Otobi in Nigeria in two seasons at two plant ages of 7 and 12 months after planting (MAP) for FSRY. The data generated were used to classify the cassava genotypes as EB or late bulking (LB). Cassava genotypes with less than 100% increase in FSRY at 12 MAP over the yield at 7 MAP were regarded as EB, whereas those with more than 100% increase were regarded as LB genotypes. This basis was used considering the fact that root thickening in cassava commences at about 2 MAP; hence, the root yield at 7 and 12 MAP represents accumulation of assimilates for 5 and 10 months, respectively. About 65%, 62%, and 79% of the genotypes were classified as EB genotypes at Otobi, Umudike, and across the two locations, respectively.     

Seasonal variations in the morphology of the seminal vesicles of the African straw-coloured fruit bat (Eidolon helvum)

The study investigated seasonal changes in the morphology of the seminal vesicles of Eidolon helvum in a typical African tropical environment. Seminal vesicles of forty-eight bats were examined during the early rainy, late rainy and peak dry seasons, using gross anatomical, histological and ultrastructural techniques. The interlobular connective tissue septa from the external capsule demarcated the glandular parenchyma into numerous lobules of tubulo-alveolar glands. A simple cuboidal epithelium of mono- or bi-nucleated cuboidal cells lined the glandular mucosa during the rainy season. This was replaced by a bistratified cuboidal epithelium, whose upper layer of cells showed evidence of degeneration, during the dry season. The PAS-positive secretory products appeared to be numerous during the rainy season, but few and clumped together during the dry season. The mean gross weight, interlobular septal thickness, acini diameter and epithelial height of the glands varied significantly with season. Ultrastructural features of the secretory cells during the rainy season showed well-developed cytoplasmic organelles, numerous electron lucid secretory vesicles and electron-dense granules. Secretory epithelial cells of the seminal vesicles are very active during the rainy season, while regeneration of degenerated epithelium in preparation for the next reproductive cycle occurs during the dry season.     

Responses of soil and plants to spatio-temporal changes in landscape under different land use in Imo watershed,southern Nigeria

Soil and plant compositions have been affected by human activities in Imo watershed, southern Nigeria. The study examined the responses of soil and plants to changes in landscape under different land use. It was hypothesized that though forest had higher soil organic carbon (OC) and organic matter (OM), it was the most altered land use with substantial loss of biodiversity. Data were collected covering soil properties and plant compositions. Arable land (AL), forestland (FL), grassland (GL), shrubland hills (SL), urban built-up green (UL), Freshwater swamp-mangrove wetland (WL) and water bodies (WB) were classified as the main land use by using ArcGIS 10.1 and Food and Agricultural Organization (FAO) land-use classification system. One-way analysis of variance followed by post-hoc test was used to determine the mean differences in years and land use for various soil properties and plant parameters. Results revealed that soil nutrient concentrations decreased by at least 50% across land use. Leucaena leucocephala, Vernonia amygdalina, Panicum maximum, Lablab purpreus, Vernonia nigritiana and Elaeis guineensis were dominant with high cover. Species diversity showed significantly negative correlations with species evenness and R-factor (p < 0.05), but positive correlations with total nitrogen and OM and OC (p < 0.001). To restore and increase soil and plant biodiversity, human activities need to be regulated by introducing sustainable agriculture and logging.     

Studies on the development of omasum in west african dwarf goats (<Emphasis Type="Italic">Capra hircus</Emphasis>)

This work studied the sequential morphological changes of omasum in foetuses, neonates and adult West African Dwarf (WAD) goats by gross and light microscopic methods. The mean omasal volume was 1.37 ± 0.36, 4.2 ± 0.4, 8.7 ± 6.9 and 60.1 ± 8.6 ml for gestation day 87 and 146 foetuses, neonates and adults respectively. Grossly the mucosa exhibited longitudinally oriented primary, secondary, tertiary and quartnery laminae with smooth surface in foetuses and numerous papillae in the adults. Microscopically it was lined by stratified squamous epithelium which was divided into larger lighter luminal and smaller darker basal zones in gestation day 60 foetuses. The core of the laminae contained extension of the inner muscular tunic. The basal zone developed lateral evaginations (corial papillae) into the lighter zone of the laminae in gestation day 106 foetuses. By term these corial papillae approached the luminal surface. The papillae emerged above the luminal surface in 4 week old neonates. The papillae were fully developed in adult goats. The mean papillary height and width were -205.1 ± 34.0, 67.0 ± 9.6; 235.0 ± 86.5, 185.0 ± 42.3 and 570.3 ± 60.0, 290.1 ± 66.3 μm for foetuses, neonates and adult goats. The inner circular layer was thicker than the outer longitudinal layer of the muscular tunic. The central muscular layer of the laminae originated from the inner circular layer with attachment to the outer muscular layer in adults. This attachment could be adaptation for better anchorage and muscular contraction of the laminae in WAD goats.     

Dynamics of soil-derived greenhouse gas emissions from shelterbelts under elevated soil moisture conditions in a semi-arid prairie environment

Soil moisture is known to be a major control of greenhouse gas (GHG) emissions from agricultural soils. However, there is little data regarding GHG exchange from the organic matter-rich soils characteristic of shelterbelts—especially under elevated soil moisture conditions. In the present study, we quantified CO₂, CH₄ and N₂O fluxes from shelterbelts under elevated soil moisture (irrigated) and semi-arid (rainfed) conditions. Studies were carried out at the Canada-Saskatchewan Irrigation Diversification Centre (CSIDC) near Outlook, Saskatchewan. Non-steady state vented chambers were used to monitor soil GHG fluxes from three shelterbelts in 2013 and 2014. The shelterbelts consisted of a single row of caragana with a north–south orientation and a single row of Scots pine with either a north–south or east–west orientation. Each shelterbelt was divided into two areas based on whether or not it received irrigation. During the 2-year study period, N₂O emissions from the irrigated shelterbelts (IR-SB) (0.93 kg N₂O-N ha^?1) were significantly greater than those from the rainfed shelterbelts (RF-SB) (0.49 kg N₂O-N ha^?1). Soil CH₄ oxidation was significantly lower in the IR-SB compared to the RF-SB (?0.85 and ?1.20 kg CH₄-C ha^?1, respectively). Irrigation activities stimulated CO₂ production/emission in 2014, but had no effect on CO₂ emissions during the much drier 2013 season. Correlation analyses indicate a strong dependence of CO₂ and CH₄ fluxes on soil moisture in both IR-SB and RF-SB sites. There was a significant relationship between N₂O emissions and soil moisture for the IR-SB sites in 2013; however, no such relationship was observed in either the IR-SB or RF-SB sites in 2014. Our study suggests that changes in precipitation patterns and soil moisture regime due to climate change could affect soil-atmosphere exchange of GHGs in shelterbelts; however, elevated soil moisture effect on GHG emissions will depend on the availability of N and C in the shelterbelts.