细化搜索
结果 1-10 的 95
Productivity benchmarks for community-based genetic improvement of Abergelle, Central Highland and Woyto-Guji indigenous goat breeds in Ethiopia
2019
Jembere, Temergen | Haile, Aynalem | Dessie, Tadelle | Kebede, Kefelegn | Okeyo Mwai, Ally | Rischkowsky, Barbara A.
Productivity benchmarks for community-based genetic improvement of Abergelle, Central Highland and Woyto-Guji indigenous goat breeds in Ethiopia
2019
Jembere, Temesgen | Haile, Aynalem | Dessie, Tadelle | Kebede, Kefelegn | Mwai, Ally Okeyo | Rischkowsky, Barbara
Assessments of production parameters and flock productivity were made in three indigenous goat breeds of Ethiopia. The goat breeds included Abergelle (AB), Central Highland (CH) and Woyto-Guji (WG). Objectives of this work were to estimate production parameters including three month weight (3mw), kidding intervals (KI) and litter size (LSB) at birth for the breeds and to assess their productivity at flock level that could be used as benchmark for evaluation of genetic progress to be realized. As AB is used for milk production, adjustment was made to their 3mw. The overall mean of 3mw (kg) were 7.44, 10.96 and 9.38 for AB, CH and WG goat breeds, respectively. Generally, wet season, male sex and single birth resulted in higher 3mw for three breeds. The overall means of KI were 362, 268 and 309 days for the breeds in respective order. The overall means of the LSB for the goat breeds, in respective order, were 1.03, 1.40 and 1.09 per doe per parturition. The flock productivity ranged from 0.27 to 0.53. Higher LSB, survival to three months (S3M), 3mw and number of parturition per year (N) resulted in higher flock productivity. CH goat breed had the highest flock productivity. The parameters estimated in this paper could be used as benchmarks for the designed CBBP of goats in the studied localities.
显示更多 [+] 显示较少 [-]Reproduction and survival analysis of Boer and their crosses with Central Highland goats in Ethiopia
2019
Mustefa, A. | Banerjee, S. | Gizaw, Solomon | Taye, M. | Getachew, T. | Areaya, A. | Abebe, A. | Besufekad, S.
Growth performance of Boer goats and their F1 and F2 crosses and backcrosses with Central Highland goats in Ethiopia
2019
Mustefa, A. | Gizaw, Solomon | Banerjee, S. | Abebe, A. | Taye, M. | Areaya, A. | Besufekad, S.
This study aims to investigate genetic and non-genetic factors affecting growth performance of Boer goats and their crosses with Central Highland goats (CHG) reared on-station at Ataye site of Debre-Birhan Agricultural Research Center in Ethiopia. A total of 512 kids of Boer (B), F1 (B X CHG) and F2(a) (F1 X F1) crossbreds and backcrosses F2(b) (B X F1) born from 381 kiddings recorded between 2012 and 2017 were used for the analysis of body weight at birth, at weaning, at six-month, at yearling and body weight gain to weaning, weaning to six-month and six-month to yearling. The overall least-squares means across genotypes for birth weight (BW), weaning weight (WW), six-month weight (6MW), yearling weight (YW) were 3.05±0.06 kg, 10.9±0.36 kg, 12.5±0.51 kg and 18.3±0.88 kg, respectively for Boer and 2.62±0.04 kg, 8.80±0.22 kg, 11.2±0.31 kg and 16.7±0.48 kg, respectively for F1. Similarly, the BW and WW of the F2(a) and F2(b) were (2.50±0.13 kg and 8.37±0.74 kg) and (2.94±0.15 kg and 9.80±0.75 kg) respectively. The overall least-squares means across breed groups for daily weight gain to weaning, weaning to six-month and six-month to yearling were 83.9±3.76 g, 25.6±3.29 g and 27.6±2.69 g, respectively for Boer, and 67.0±2.26 g, 31.5±2.00 g and 28.4±1.46 g, respectively for F1. Similarly, daily weight gains to weaning was 67.7±7.66 g and 78.7±7.74 g for the F2(a) and F2(b) respectively. Sex, type of birth, year of birth and season of birth affected the studied traits, while, doe parity has no significant effect except at the later age weight gain. In conclusion, the overall growth performances of all the studied genotypes were below expectations which indicates their sub-optimal adaptability to the study area. In addition to the genotype, the non-genetic factors affect the growth performance, so improvement in growth performances is possible by minimizing environmental effects.
显示更多 [+] 显示较少 [-]Reproductive performance indicators of dairy cattle in selected small-scale dairy farms in semi-arid Eastern Kenya
2019
Mungube, E.O. | Njarui, D.M.G. | Maichomo, M.W. | Olum, M.O. | Ndirangu, P.N. | Kabirizi, J. | Ndikumana, J. | Mwangi, G.
Use of the LiDAR combined forest inventory in the estimation of sample trees height
2019
Seleznovs, A., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Smits, I., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Dubrovskis, D., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia)
Latvia University of Life Sciences and Technologies, Latvia Precision of the forest inventory planning is still one of the most important problems in the forestry nowadays. The aim of this research was to estimate the sample tree height results of the combined forest inventory (LiDAR CFI) and LiDAR (Light Identification Detection and Ranging) height data by calculating an average value from sample tree neighbouring pixel values in the ripening Scotch pine forest stands, comparing the results with the measurements of the height in the area. For the update of LiDAR calculated data and LiDAR CFI height results, the increment algorithms of the Latvian State Forest Research Institute ‘Silava’ were used, comparing the results with the sample plot measurements. Both results showed a close correlation – in the case of LiDAR CFI with R2 =0.82, LiDAR data with R2 =0.93, demonstrating a standard deviation: 2.40 and 2.75, accordingly and standard error: 0.11 and 0.13, accordingly. The results indicate that both technologies can be used in the forest management, offering reliable information about the forest inventory. Positive values were reached by minimizing the human error factor, which is problematic for the field inventory.
显示更多 [+] 显示较少 [-]Development of young stands after different intensity regeneration fellings
2019
Klavins, I., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Kalvite, Z., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Libiete, Z., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
The share of the renewable resources used continues to grow due to environmental, economic and political reasons. Consequently, intensification of forest management is on-going and expected to continue in the future. Logging residues, such as treetops, branches and stumps, are a significant renewable energy source. Since the logging residues are noticeably richer in nutrients than conventionally harvested stems, there is a concern related to the negative impact of intensified harvesting on the ecosystems, productivity of the sites and sustainability of forestry in general. To evaluate the impact, this study has compared different intensity harvesting effect on the next rotation young stand productivity in eight sites in Latvia. In a nutrient-rich site, the productivity of Norway spruce was higher in the whole-tree harvest (WTH) subplot comparing to stem-only harvesting (SOH) subplot three years after the planting. Productivity of Scots pine in oligotrophic conditions was observed to be higher in SOH subplot comparing to WTH subplot two and three years after planting. Furthermore, in a site on a mineral soil relatively richer in nutrients no significant differences were observed. Comparing WTH to whole tree harvest + stump biomass (SB) extraction subplots, the productivity of Norway spruce was higher in WTH four to five years after the planting; in a mixed stand of Norway spruce and black alder no productivity differences of spruce were detected, but productivity of black alder was higher in WTH+SB subplot five years after the planting; in black alder stands a significantly higher productivity was observed in WTH subplot four and five years after the planting.
显示更多 [+] 显示较少 [-]Medium-term impact of stump harvesting on general soil parameters in Hylocomiosa site type
2019
Libiete, Z., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Bardule, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Klavins, I., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Kalvite, Z., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lazdins, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
Conifer tree stumps are a prospective source of bioenergy, but there are considerable uncertainties and risks associated with this forestry practice, and environmental consequences of stump harvesting are little studied in the Baltic countries. One of the major concerns is related to the risk of nutrient leaching that may cause pollution of watercourses and decline of tree growth in the next forest generation. The main aim of the present study was to estimate the effect of stump harvesting on general soil and soil solution parameters in three clear-cut areas located in Hylocomiosa site type (dominant tree species prior to clearfelling – Picea abies L. (Karst.)) over a period of 6 years after the stump removal. Two types of treatments were compared: whole-tree harvesting with only above-ground biomass removed (WTH) and whole-tree harvesting combined with the stump removal (WTH+SB). We found no acidification effect of soil and soil solution. Soil C and N stocks six years after harvesting were similar in the plots with and without stump removal, and demonstrated similar pattern of change in both studied treatments (WTH and WTH+SB). Nutrient content and patterns of change varied with the site and year, suggesting that the effects are rather site- than treatment-specific.
显示更多 [+] 显示较少 [-]Analysis of landscape paintings to highlight the importance of forest ecosystem services in Latvia
2019
Paulina, I., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Libiete, Z., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
Forests and woodlands provide a wide variety of ecosystem services that are usually classified within three categories: provisioning services, regulating (supporting) services and cultural services. While provisioning and regulating services are widely analysed, there is a lack of information about the cultural ecosystem services, particularly some sub-categories of these. In this study, we have focused on inspiration for creativity as a sub-category of cultural ecosystem services provided by forests and analysed the depiction of forest ecosystems in landscape paintings of Latvian artists. It may be concluded that forest ecosystems serve as an important source of inspiration for creativity and art, as may be seen in the landscape paintings of Latvian artists of the 20th century. Characteristic landscape features of birth and living places of the artists are reflected in their works. The performed analysis is the first of its kind in Latvia, and it may be further expanded, either by incorporating other aspects of creativity or adding economic dimension, for example, by surveying the art market.
显示更多 [+] 显示较少 [-]Dynamics of meteorological and hydrological droughts in the agricultural catchments
2019
Kubiak-Wojcicka, K., Nicolaus Copernicus Univ., Torun (Poland)
The aim of the paper is to determine the relationship between meteorological drought and hydrological drought in the agricultural basin of the River Osa (northern Poland) in the years 1966-2015. Meteorological droughts appear as a result of insufficient amount or lack of atmospheric precipitation. As a consequence of meteorological droughts occurrences, there appear hydrological droughts which are characterized by low discharges of a river. Standardized Precipitation Index (SPI) and Standardized Runoff Index (SRI) indicators were used for the identification of droughts at various accumulation periods, i.e. 1, 3, 6, 9 and 12 months. In the years 1966-2015, there were identified from 63 (SPI-1) up to 10 meteorological droughts (SPI-12), while hydrological droughts – from 22 (SPI-1) to 8 (SPI-6, 9 and 12). The strongest relationship between the two kinds of droughts occurred in the periods of accumulation from 9 to 12 months. The values of the correlation coefficient between the meteorological and hydrological droughts were above 0.5 in those cases. Those indicators can be used for a system of early drought warning, which is of particular importance for crop production in agricultural areas. Long-lasting meteorological droughts contribute to increase of water intake for irrigation purposes, thus deepening the hydrological drought. As a consequence of the prolonged and intense hydrological drought, further irrigation may be impossible due to too low river discharges.
显示更多 [+] 显示较少 [-]