Effect of different agronomical measures on yield

The objective of this paper was to obtain information about the effect of interactions and different agronomical measures on autumn saved herbage of different sites in Central Europe (Czech Republic, Germany, Hungary, Poland). Within the different sites, the effect of the factors pre-utilisation (accumulation since June, July or August) and winter harvest date (November, December or January) on dry matter (DM) yield and digestibility of organic matter (DOM) was investigated over three consecutive years. All results were examined by analysis of variance and least-significance differences (LSD) were calculated (with P < 0.05). For all years, date of winter harvest was the most important source of variance. The highest yields were attained in November (varied from 2.3 to 0.8 t/ha), the lowest in January (from 1.5 to < 0.2 t/ha). The highest DOM concentration (from 70.4 to 52.4% of dry matter) was reached in November, and it decreased until January (from 59.6 to 35.2% of dry matter). Predominantly caused by the prevailing climatic conditions, the DM yields of the sites varied considerably during winter, showing a significance for the interaction winter harvest date × site as well as for the factor site. The utilisation of autumn saved herbage, pre-utilised in July, might be the best opportunity providing an adequate quantity and DOM for suckler cows until the end of the year, but the prevailing climatic conditions at different sites in Central Europe finally decide on the practicability of winter grazing.

Competitive grassland systems, such as yearround outdoor stock keeping of suckler cows or beef cattle herds, became more important during the last years particularly for peripheral sites in Central Europe (Langholz,  1992; Opitz von Boberfeld, 1997; Möller et al., 2002). Thereby, the extension of the grazing period into late autumn and winter by using autumn saved herbage reduces the supply of cost intensive preserved forage such as silage or hay (Hughes, 1954; Boeker, 1957; Corbett, 1957; Deblitz et al., 1993; Freeze, 1999). Regarding

the animal welfare during winter grazing, autumn saved herbage as the main pasture source has to provide the grazing livestock with an adequate supply of herbage mass and forage quality (Opitz von Boberfeld, 1997). Available knowledge about DM yield and DOM, as an important feature determining forage quality, is limited to findings from the USA (Taylor and Templeton, 1976; Balasko, 1977; Matches, 1979; Bartholomew et al., 1997), but due to the increasing importance of winter grazing systems, recent results from investigations in Central Germany were released by Opitz von Boberfeld and Wöhler (2002), Opitz von Boberfeld and Wolf (2002), Wolf (2002) and Wöhler (2003). DM yield and DOM of autumn saved herbage strongly depend on the length of the growing period before winter and the date of utilisation in winter (Gardner and Hunt, 1955;  errish et al., 1994), whereas the special climatic conditions during winter additionally influence the development of DM yield and DOM decisively (Baker at al., 1965; Balasko, 1977). A shorter growing period before winter utilisation improved DOM, but it led to lower DM yields at the same time (Opitz von Boberfeld and Wolf,  2002; Wolf and Opitz von Boberfeld, 2003). Wolf (2002) demonstrated a superior role of the winter-green

species Festuca arundinacea for winter grazing in Central Germany. Furthermore, Wöhler (2003) demonstrated that autumn saved herbage based on the existing plant communities Lolio- or Festuco-

Cynosuretum in peripheral sites of Central Germany produced sufficient DM yield and DOM for suckler

cows or beef cattle until the end of the year. In the context of these results winter grazing could also

be interesting for farmers in Poland, Hungary and in the Czech Republic (Golinski et al., 2003; Tasi

et al., 2003; Skladanka, 2004), but knowledge about the effects of different agronomical measures under

these climatic conditions is hardly available. Besides, some investigations revealed that under low-input conditions different sites conformed to similar DM productivity and forage quality during the growing season (Opitz von Boberfeld and Sterzenbach, 1999; Buchgraber and Pötsch, 2000) and in winter (Wöhler, 2003; Banzhaf, 2004). In this context an international project was established investigating the influence of pre-utilisation and date of winter harvest on DM yield and forage quality of autumn saved herbage at sites in the Czech Republic, Hungary and Poland compared to data from Central Germany. This paper presents the

results concerning DM yield and DOM, the 2nd  communication (Opitz von Boberfeld et al., 2006, in press) examines the results concerning crude protein, energy and ergosterol concentration.

 

MATERIAL AND METHODS

The trials were established in low-input pasture  systems as randomised block designs with three replications at five different sites in Central Europe. Data describing site specific conditions and the dominating species are given in Table 1. The swards in Elkenroth I (Germany) and Brody (Poland) were classified as Lolio-Cynosuretum, Elkenroth II (Germany) as Festuco-Cynosuretum community. Vatin (Czech Republic) was Festuco- Cynosuretum as well, but had a higher proportion of different species of other plant communities.

In Gödöllö (Hungary) the trial was established on a permanent Festuca arundinacea sward. In general, all examined swards were dominated by grass species at a proportion >80%. Simulating the deposition of excreta by grazing ruminants, each year all plots were fertilised with 50 kg N/ha in August. Table 2 shows weather conditions during the winter grazing period with regard to days with snow cover. As the snow cover never occurred in October, only the period from November to January of each year is presented. All trials were

observed over three consecutive years. Besides the influence of the factor site, the other factors were: pre-utilisation (accumulation before utilisation in winter since the beginning of June, July or August) and date of winter harvest (beginning of November, mid-December or end of January). To determine DM yield, the plots were harvested at a standardised stubble height of 5 cm. The snow cover lasting during January of the year of observations one and three and December of year two in Gödöllö as well as during January of year one and

two in Vatin made it impossible to do the harvest on schedule. Consequently, cuts on these variants were postponed to February and March, respectively. For analyses, samples from each plot were dried at 60°C and ground to pass a 1mm screen. DOM was estimated using the in vitro fermentation technique of the Hohenheim Gas Test (Anonymus, 1997) applying formula 41f (Menke and Steingass, 1987) including the variables rumen liquid and crude protein. All results including DM yield refer to 103°C and were examined by analysis of variance with P < 0.05 as the level of significance. At first, the sites were analysed separately, but as the residual errors of several sites did not differ significantly, the analysis of variance was done considering all sites by involving the factor site (Heyland and Kochs, 1978; Weber, 1986). Furthermore, least-significance

differences (LSDsite/pre-utilisation/winter harvest date) at P < 0.05 were calculated. Generally, the years were observed separately to avoid interactions of higher order which would be difficult to interpret.

 

Table 1. Site specific data

 

Site

Elkenroth I,

Germany

Elkenroth II,

Germany

Brody,

Poland

Gödöllö,

Hungary

 

Vatin,

Czech Republic

Region

 

Lahn-Dill

region

 

Lahn-Dill

region

 

Wielkopolska

region

 

Central

Danubia

 

Bohemian-Moravian

uplands

 

Altitude

(m above sea level)

 

420

 

460

 

92

 

230

 

553

 

Mean annual

temperature (°C)

 

6.7

 

6.7

 

8.0

 

11.5

 

6.1

 

Soil type

 

Cambisol

 

Stagnic Luvisol

 

Poorly mineralised

Histosol

 

Dystric

Cambisol

 

Stagnic Luvisol

 

pH

(in 0.01 MCaCl2)

 

5.3

 

4.5

 

6.5

 

3.9

 

5.6

 

P (mg/kg soil)*

 

27.9

 

14.8

 

240.0

 

62.5

 

7.8

 

K (mg/kg soil)*

 

50.6

 

66.4

 

116.2

 

239.0

 

102.9

 

Dominating

species