Sites

The graduate research group focuses on seven sites in two different climate regions (temperate and subtropic). Selection criteria were - except for the climatic conditions - the dominant soil texture and fertilization or tillage, respectively. Three of the sites are located in Germany and four in the Oman. In Germany, the experiments are carried out on two sites near Göttingen (Garte-Süd, Hohes Feld) and on the long-term fertilization trial Darmstadt. A coastal oasis near Sohar and three oases in the Al Jabal al Akhdar mountain range were chosen as experimental sites in the Oman (see below).

Location:

The long-term fertilization trial of the Institute for Biodynamic Research is located near Darmstadt (latitude 49° N, longitude 8° E).

Site conditions and experimental design: 

The mean annual air temperature at the Darmstadt site which is 100 m above sea is 9.5°C level, the mean annual precipitation 590 mm. The predominant soil type is sandy Orthic Luvisol (87% sand, 8% silt and 5% clay in the topsoil).

The fertilization trial which comprises farmyard manure treatments with and without application of biodynamic preparations and inorganic fertilization started in 1980. A split-block design with nine treatments (three types of fertilizers at three levels) with four replicates (Tab. 2 and 3, Fig. 3 and 4) was chosen to investigate yield development, product quality and resource allocation in the first experimental phase, key soil processes and functions in the second and yields and long-term effects on soil organic matter contents in the third phase.

Treatments (since 1980):

Design: 9 treatments (3 types of fertilizer at 3 levels) with 4 replicates; split block design

*From 1980 to 1984 and in 1988 and 1989 supplemented in single cases by liquid manure, castor or horn meal; since 1990 in each year liquid manure was used as second N portion to cereals.

Site conditions:

Latitude 49° N, longitude 8° E; 100 m above sea level, annual averages 9.5°C air temperature and 590 mm precipitation; sandy orthic luvisol with 87% sand, 8% silt and 5% clay in the topsoil.

Legend:

• types of fertilization: CM, CMBD, MIN
• fertilization levels: 1, 2, 3
• replicates: a, b, c, d

More information is available on the website of the Institute for Biodynamic Research

Location:

Garte-Süd is located at the experimental station of the University of Göttingen Reinshof, Hohes Feld at the experimental station Marienstein in Angerstein.

Site conditions and experimental design:

Garte-Süd is characterized by a mean annual temperature of 8.7 °C and a mean annual precipitation of 645 mm (elevation: 165 m above sea-level). The climatic conditions at Hohes Feld are comparable to those at Garte-Süd. Both sites are characterized by loamy soils which developed from loess (predominant soil type: Haplic Luvisol). Important soil properties of the experimental field Reinshof are shown in Table 1.

On both sites, long-term tillage trials have been carried out for more than 30 years. At “Hohes Feld”, the experiments started in 1965, at “Garte-Süd” five years later. The two different tillage systems which are investigated on both sites are

• conventional tillage(CT) with a mouldboard plough to a maximum depth of 25 cm, followed by one pass with a rotary harrow and
• minimum tillage (MT) with a rotary harrow to a maximum depth of 8 cm.

Each of the two tillage treatments is replicated eight fold at Garte-Süd and three fold at Hohes Feld (Fig. 1 and 2).

¹⁾ according to the German soil classification

• Site Website

Location:

The experimental sites - one coastal oasis and three mountain oases - are located in the northern part of the country. Their exact location can be depicted from Fig. 5.

Site conditions:

The coastal oasis near Sohar is located 50 m above sea level. The mean annual temperature is 30 °C. The mean annual precipitation is below 100 mm, but air humidity is high throughout the whole year. The predominant soil type is Irragric Cambisol with sand as dominant soil texture. All experiments on this site will be carried out at an experimental station.

The site conditions of the oases in the Al Jabal al Akhdar mountain range (elevation 995 m above sea level) differ markedly from those of  the coastal oasis especially with respect to the mean annual temperature, which is distinctly lower (19 °C) and the dominant soil texture which is silt. The predominant soil type is Irragric Anthrosol. The mean annual precipitation of 100 mm is slightly higher than near Sohar. Alfalfa, wheat, sorghum and other crops are grown in complex summer-winter crop rotations on terraced fileds. Soil moisture is regulated in both regions by irrigation.

Location:

The study area is located in the Emilia-Romagna region, the core area of Italian cattle and pig farming. The area is located on the outskirts of the town of Gazzata, between Reggio Emilia and Modena, on the southern edge of the Pianura Padana (Po Valley). The study plot was established in April 2010 for the experimental period of one year.

Location:

Mean annual average temperature is 13.8 degreesC and annual precipitation is 843 mm. Typical of the alluvial soils of the Pianura Padana, the soil of the study area in the plow horizon (0-30 cm) has a clay content of 46 % (43 % silt, 13 % sand), the soil type is silty clay. The pH (_H2O) in the soil is 8.1.

Experimental approach:

Plot experiment with application of different manures and digestate (from biogas plants in the region), partially mechanically separated. Application dates: May and September 2010, followed by tillage by power harrow (May) and plow (September). _NH3 emissions were recorded directly after application and _N2Oemissions and _Nmin at weekly intervals.

Location:

Sites are located in eastern and southern Germany, Lüttewitz (51degrees7', 13degrees13') and Zschortau (51degrees27', 12degrees21') in Saxony, Friemar (50degrees57', 10degrees46') in Thuringia, and Grombach (49degrees14', 09degrees01') in Baden-Württemberg.

Location:

The 4 experimental sites are located between 110 and 310 m above sea level, mean annual temperatures between 8.0 degreesC and 9.3 degreesC and mean annual precipitation between, 512 mm and 776 mm. Friemar, Grombach and Lüttewitz have similar textures (2-5 % sand, 65-80 % silt, 18-30 % clay). Zschortau has a much higher sand content (27 % sand, 58 % silt, 15 % clay). Soil types are brown-black earth (Friemar, Ut4), parabrown earth (Grombach, Lüttewitz, both Ut3) and parabrown earth-pseudogley (Zschortau, Slu).

Experimental approach:

Between 1990 and 1997, the Institute for Sugar Beet Research (IfZ, Göttingen) set up a long-term experiment at various Südzucker AG sites to investigate the influence of tillage systems on physical and chemical soil properties. For each site, an experimental field (2.5 to 8 ha) was divided into strips, on each of which a tillage system is applied. The sites serve as replicates. We are investigating the following tillage systems:

• Plow (conventional tillage, CT): the basic soil tillage is done with a Scharpflug with a plowing depth of 25-30 cm.
• Mulch (conservation tillage, minimum tillage, MT): tillage is done with a disc harrow or cultivator to a depth of 10-15 cm.
• No-till (no-tillage, NT): No tillage is done except shallow seedbed preparation (3-5 cm) with a cultivator or disc harrow before sowing sugarbeet.

Different C and P pools, aggregate size distribution, aggregate recharge rates, net N mineralization, and_CO2 and _N2Ooutputs are investigated.

Location:

The Lindhof experimental farm of Kiel University is located about 20 km north of Kiel on the Eckernförde Bay (54degrees north latitude, 9degrees east longitude).

Site conditions:

The climate is mild temperate and oceanic, with an average annual temperature of 8.0 degreesC and an average annual precipitation of 926 mm. The soil is relatively heterogeneous, the soil types are brown earths, parabrown earths, pseudogleye and colluvisols. The predominant soil type is a sandy loam or loamy sand.

Experimental approach:

A field experiment with several factors was set up at the Lindhof of Kiel University. Listed here are only the variants and experimental approaches we sampled.

A) Short and long term effects of a tillage treatment and different fertilizer application

On the grassland established in 1994, a field trial was started from the year 2005 with the following factors:

1. renewal procedure
a. Control permanent grassland (grassland established since 1994)
b. Grassland plowing followed by grassland reseeding
c. Grassland plowing in the fall with winter wheat as an intermediate field use and subsequent grassland reseeding.

2. manure fertilization
a. 0 kg N/ha
b. 240 kg N/ha in the form of cattle manure

3. Year of renewal measure
a. 2005
c. 2008

B) Effects of previously differently treated soils on the establishment of a grassland.

This field experiment was started in 2010 and includes the treatments

a. Control permanent grassland (existing grassland stand since 1994)
b. Grassland conversion followed by grassland reseeding
c. Arable land with grassland seeding.

All treatments were laid out in triplicate in a randomized block design.

Soil, gas and liquid samples are being analyzed on the trial plots in Trenthorst and Kleve, which should provide information on changes in the carbon and nitrogen balance and the processes set in motion by grassland conversion.

Trenthorst:

The experimental plots are located on the premises of the Institute of Organic Agriculture, Johann Heinrich von Thünen Institute, Federal Research Institute for Rural Areas, Forests and Fisheries in Trenthorst, near Lübeck (53degrees N; 10degrees E). Trenthorst is 14 m above NN and has an average annual temperature of 8.1 degreesC with a mean annual precipitation of 687 mm. The area is located in the ground moraine landscape in the southern Schleswig-Holstein hill country with typical heavy soil classified as pseudogley.

Kleve:

The experimental plot is located on the grounds of the Haus Riswick experimental estate, North Rhine-Westphalia Chamber of Agriculture in Kleve (51degrees N; 6degrees E) on the Lower Rhine.Kleve is 12 m above NN and has an average annual temperature of 9.8 degreesC with an average annual precipitation of 760 mm. The heavy soil typical of this Altauen region has been classified as autochthonous Vega.

• Ehlers, W., Werner, D. & Mähner, T. (2000): Wirkung mechanischer Belastung auf Gefüge und Ertragsleistung einer Loess-Parabraunerde mit zwei Bearbeitungssystemen. Journal of Plant Nutrition and Soil Science 163, 321-333.
• Raupp, J. (2001): Manure fertilization for soil organic matter maintenance and its effects upon crops and the environment, evaluated in a long-term trial. Rees, R.M., Ball, B.C., Campbell, C.D. & Watson, C.A. (eds.): Sustainable Management of Soil Organic Matter. CAB International, p. 301-308.