Fast-growing woody plants that can be grown under short-rotation systems offer an alternative to food production on arable land, and serve as a potential source of renewable energy. In order to establish the feasibility of future large scale production under the conditions of the Czech-Moravian highland, a high density experimental field plantation including a range of available clones of Populus sp. and Salix sp. with the total area of 1.5 ha was established in early 2001 in Domanínek (Czech Republic, 49°32'N, 16°15'E and altitude 530 m). The clone experiment of Populus sp. covered 0.3 ha in the center of the plantation and included 13 clones in total, with hardwood cuttings of only 6 clones available in numbers allowing 4-replicate experiment. The plantation was established on agricultural land and the trees were planted in a double row design with a density of 10 000 trees/ha. The trial was weeded by mechanical methods, and no irrigation, fertilization, or herbicides were applied. The experiment site was harvested at the end of 2006. It was found that the biomass yields of the tested clones of Populus sp. were in the higher range of results from national and European studies in case of hybrid clones. The satisfactory survival rate in the first year, when mortality tends to be highest, was supported by relatively wet weather conditions after plantation establishment. At the end of the first rotation, the highest yields were obtained from clones J-105 and J-104 (P. nigra × P. maximowiczii) and P-494 (P. maximowiczii × P. berolinensis) with J-105 showing a mean annual increment of dry matter close to 14 t/ha. Additional experiments seem to suggest that well managed poplar plantation might produce even better values if higher survival rates can be achieved.

The aim of research was to evaluate changes of physico-chemical characteristics, somatic cell count and curd quality during lactation and their relationship in Lacaune ewes. The study was carried out on eighteen ewes of the second lactation on an organic farm in Valašská Bystřice (Czech Republic). It was found that the stage of lactation significantly affected almost all monitored traits except pH value, titratable acidity, somatic cell count and curd quality. The content of total solids, fat, total protein, casein, Ca and P was significantly increased, while daily milk yield and the content of lactose were decreasing with the advancement of lactation. The stage of lactation had a significant effect on the coagulation time that was extended with advanced lactation. Length of the coagulation time was positively correlated with contents of total protein, casein and Ca. In contrast, the curd quality was not affected by the stage of lactation and no significant correlation between the curd quality and other parameters were found, except for the coagulation time (r=0.40). It could be concluded that Lacaune ewes had a satisfactory milk yield and physico-chemical and technological characteristics of milk under relatively extensive nutrition.

FISCHER, M., TRNKA, M., KUČERA, J., FAJMAN, M., ŽALUD Z.: Biomass productivity and water use relation in short rotation poplar coppice (Populus nigra x P. maximowiczii) in the conditions of Czech MoravianHighlands. Acta univ. agric. et silvic. Mendel. Brun., 2011, LIX, No. 6, pp. 141-152 The plantations of short rotation coppice (SRC) usually based on poplar or willow species are promising source of biomass for energy use. To contribute to decision-making process where to establish the plantations we evaluated the water consumption and its relation to biomass yields of poplar hybrid clone J-105 (Populus nigra x P. maximowiczii) in representative conditions for Czech-Moravian Highlands. Water availability is usually considered as one of the main constraints of profi table SRC culture and therefore we focused on analyzing of the linkage between the aboveground biomass increments and the total stand actual evapotranspiration (ET a ) and on water use effi ciency of production (WUE P ). During the seasons 2008 and 2009 the total stand ET a measured by Bowen ratio energy balance system constructed above poplar canopy and the stem diameter increments of randomly chosen sample trees were examined. The stem diameters were subsequently converted to total aboveground biomass (AB) by allometric equation obtained by destructive analysis at the beginning of 2010. The biomass volume and its increment of particular trees were subsequently converted to the whole canopy growth and correlated with the ET a values. Our results revealed that there was a statistically signifi cant relation between water lost and biomass growth with coeffi cients of determination r 2 0.96 and 0.51 in 2008 and 2009 respectively. By using multiple linear regression analysis additionally accounting for eff ect of precipitation events and thermal time (sums of eff ective temperatures above +5 °C) the AB growth was explained from 98 and 87% in 2008 and 2009, respectively. Therefore for further analysis the multiple linear regression model was applied. The dynamic of seasonal WUE P (expressed as gram of AB dry matter per thousand grams of water) reached up to 6.2 and 6.8 g kg −1 with means 3.13 and 3.54 g kg −1 in both executed years respectively. These values are situated in higher range comparing to the other broadleaved tree species of temperate climate zone and suggest that economically profi table plantation (defi ned by yield at least in the range of 10-12 Mg ha −1 year −1 of dry matter content) will consume more than 450-500 mm per growing season and thus will demand a locality with higher and adequately temporally distributed amount of precipitation especially in rain fed areas such as the discussed Czech-Moravian Highlands.short rotation coppice, biomass increment, water consumption, water use effi ciencyThe term short rotation coppice (SRC) is generally used for any high-yielding woody species managed in a coppice system usually grown especially for energy use on arable land. Typically, these crops are harvested on a 3-7 years long ro...

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