Development and implementation of soil conservation

K. AUERSWALD A. EICHER

J.

FILSER

A. KAEMMERER M. KAINZ R. RACKWITZ J. SCHULEIN

H.

SOMMER

S. WEIGAND

K. WEINFURTNER

Development and implementation of soil conservation strategies for sustainable land use - the Scheyern project of the FAM

In: H. STANJEK (ed.):

European Society for Soil Conservation - Second International Congress Tour Guide. Techn. Univ. Mtinchen, Freising-Weihenstephan,

1996

Field Trip 2 Development and implementation of soil conservation strategies for sustainable land use - the Scheyern prqject of the FAM

The mid-congress tour leads to the Scheyern Experimental Farm of the Munich Research Association for Agricultural Ecosystems (= FAM) where a long term monitoring for maner, energy and information fluxes in two different management systems is on the way. A survey of the FAM is given by the brochure •• Ecosystem Research in the Agricultural Landscape« in your congress documents. The former landscape was characterized by intensive farming on fields up to 25 ha in size and steep slopes (up to 30 %), and by an insufficient number of structural elements, such as hedges, lynchets or buffer strips. As a result, typical problems observed were compaction, erosion, and overfertilization, of soil with subsequent pollution of surface and ground water, as well as impoverishment of flora and fauna. Redesigning the landscape and implementation of new cultivation systems - integrated and organic farming - aimed toward minimizing these ecological hazards (for a description of the measures see the FAM-brochure: "Ecosystem research in the agricultural landscape" , p. 10-14, in your congress documents). Scheyern is located 40 km north of Munich in the Upper Bavarian Tertiarhiigelland (Tertiary Upland

Esse September 1996

Geographical survey 25

Geology and Geomorphology 26

hills) . The Tertiiirhiigelland extends from the Munich gravel plain and the old moraines (Riss-time) in the south to the Danube Valley in the north. This hilly landscape slopes from the southwest (approximately 560 m above sea level) to the northeast to the Danube (360 m a.s.!.) and east to the Isar (410 m a.s.! .). The largely amochthonuous stream systems of the Paar and the 11m drain to the Danube, those of the Glonn and the Amper to the Isar. The Paar and the Amper themselves originate in the moraine region of the alpine foothills. The Tertiiirhugelland is divided by a closely-meshed and finely-ramified valley network into numerous hills and crests, which rise either gently or sometimes steeply 3060 m from the borroms of the valleys (Hofmann, 1986). Scheyern is located at the boundary between the loessloam-clay-ridge and the loess-loam-sand-ridge parts of the Tertiiirhiigelland. The Kiostergut Scheyern experimental station covers approximately 150 ha of arable land and pasture at an airitud(: of 445 to 498 m above sea level. Adjacent to the experimental station in the somh is a spruce-dominated forest. Two streams, one . coming from that forest in an easterly direction through the arable land and one coming through a meadow valley from the somh, drain into l:he monitored Teufilsweiher (devil's pond). The Teufilsweiheris the first pond in a chain aligned somh-north. These former fish ponds belong to the Benedictine monks. The second dominant somh-north directed valley in the research area does not have a surface drainage nowadays. Another chain of ponds, stretching west-east, is still used for fishery. The Upper Bavarian Tertiirhugellandlies in the area of the Somhern German Molasse Basin, a sedimentary trough, which as a foredeep accumulated the debris of the rising peripheral areas in the Tertiary age (starting 65

Field Trip 2

million years ago), in particular of rhe emerging alpine chains. The land surface is builr by deposirs of rhe Upper Freshwater Molasse, which comprises coarse and fine sediments of rhe foreland. These sediments were formed under terrestrial condirions afrer rhe sea had retreared. The fluviaric and limnic sedimentarion of rhe Upper Freshwarer Molasse occurred during rhe Upper Miocene, about 15 to 10 million years ago, and reaches thicknesses of 150 to 250 m (Hofmann, 1986). The deposirs of rhe Upper Freshwarer Molasse form an alrernaring sequence of gravelly sands, sands, silrs, marls and clays. These sediments were filled into rhe molasse basin from rhe easrern Kalka/pen (calcareous Alps) and central Alps by a far-reaching river sysrem sloping from the easr (around Landshur) [0 the wesr (around Augsburg) . With increasing disrance from th,~ source area, increasingly fine-grained sediments were deposited. Grain size distributions comprise mainly sandy gravel with a maximum in the fine gravel and medium sand fraction. Sands with a maximum in the me·dium and fine sand fraction and clays wirh clay comems rarely exceed 500 g kg- I (Hofmann, 1986). In the re·search area gravel size diversity reaches a maximum with an average of 110 g kg- I gravel. Maximum values fOIl" stone contents were 900 g kg-I. In rhe fine earth fraction «2 mm) maximum contents of sand lie above 900 g kg-I, of silt ar 810 g kg- I and of clay ar 600 g kg- I (Si·· nowski, 1995). Ar the end of rhe Upper Miocene the Tertiiirhugelland area was tectonically uplifred. Ar thar rime ir changed from being a sedimentation area [0 an erosion area. Nowadays it is drained to rhe easr by rhe Danube sys·· tern. Valleys developed especially in sandy and silty rna·· terials less resisrant [0 weathering.

ESse September 1996

27

The area was finally formed dluring the Pleistocene by solifluction, loess deposition and subsequent erosion in the periglacial zone. Under permafrost conditions the soil surface thawed in the warmer summer months and sled downhill on a film of perged water at the frost boundary. This process is more pronounced on hills exposed to the sun. Thus, south- and west-exposed slopes became steeper. The prevailing westerly winds led to a preferred loess and loess loam deposition on eastern and northeastern slopes (lee side). The valley asymmetry, which is typical for the area, evolved from both processes. Gravels of tertiary substrates consist mainly of quartz (90 %) with some admixtures of crystalline and sedimentary rocks (Hofmann, 1986). Clay mineralogy in Scheyern shows little variation: Most samples were dominated by smectites (64-84 %) with minor contributions of illite (10-29 %) and kaolinite (4-13 %) . Only valley sediments had lower amounts of smectites «50 %) and higher amounts of illites and kaolinites (Scheinost, 1995). Clay mineralogy of Tertiary and Quarternary substrates is very similar, indicating that the loess was transported over short distances from the gravel plains of the Danube, Lech, Amper and Isar and from within the Tertiiirhiigefland. In Scheyern sandy-gravely substrates and some clayey still-water sills of the tertiary build the hilltops and eroded westerly-exposed slopes, whereas most of the area (85 %) is covered by a thin film (less than 2 m) of loess loam or loess (Sinowski, 1995). The hilly relief has a relief energy of 32 m km- 1 (Auerswald & Kainz, 1990). The flat east and northeast exposed slopes incline 50 to 90 m km -I, the steeper south, west, and northwest, exposed slopes have a gradient of up to 390 m km- I (Sinowski, 1995).

28

Field Trip 2

The climare of rhe Upper Bavarian Tertiiirhugelland is characrerized by an annual average precipiration from 700 ro 850 mm. The average annual remperature is 78 dc. The higher lying regions have markedly higher precipiration amounts than rhe lower lying ones. The large amount of precipiration in summer is norable wirh almost rhree rimes rhe precipitiarion in July as in March. The Tertiary Upland Hills are a rain barrier and both summer rhundersrorms and hail are not infrequent. The broad valleys of rhe rivers and ro some extent rhe asymmerrical valleys roo are endangered by lare and early frosrs (Hofmann, 1990). In the Scheyern area average precipiration amounts ro 825 mm, 528 mm of which fall in rhe summer months (May ro Ocrober, Auerswald & Kainz, 1990). A mean rain erosiviry of 69.6 N h- i was calculared, wirh maximum values in June, July, and August (66 % of rhe roral erosivity in this period) . The Tertiiirhiigelland is an old farming country. Archaeological excavarions indicate agricultural activities in the area since the Younger Srone Age. In 1119 A.D., rhe Scheyern Benedictine Abbey, ro whom mosr of the research area belongs, has been mentioned for rhe firsr rime in rhe lirerature. Due ro rhis long-term cultivarion, the mosr important geomorphologic process in rhis present landscape is warer erosion. This is resrified by very rhick kolluvial soils in dry valleys. Along rhe surface drainage streams alluvial marerial covers the fen soils, which developed, before agricultural usage ser off erosIOn. Scheyern lies at the western end of the Hallertau, rhe world's largesr hop growing area, thar srrerches between Munich and Ingolsradr around rhe rowns of Pfaffenhofen, Wolnzach and Mainburg. The Hallertau encom-

ESse September 1996

Climate

Cultivation

29

Soils

30

passes the central territory of rich loess loams with the sandy Tertiiirhugelland adjoining to the north. On the experimental station hop was grown on three fields in the last twenty years preceeding the research project. In 1985 the Hallertau had a hop cuirivating area of 167 km 2 . The average area per farm devoted to growing hop was 4.41 ha. The purity decree of 1516 (brewing only with hop, mair and water) and the hop origin act of 1919 established the world-wide fame of Hallertau hop. 60 % of the hop harvest 005561 tons was exported to over a hundred countries in 1984. Hop requires a great deal of sunshine for a good aroma and sufficient rainfall particularly in June, July and August for a high yield and high content ofbirrer substances. Such conditions prevail in the Hallertau, both on the loamy and on sandy soils (with the appropriate fertilization). Hop is a deep rooted plant with root depths down to 4 m and more. Irs root system reacts sensitively to soil compaction. It needs deep and readily roorable soils. Within a short time it forms large plant masses. The hop requires tall poles and wires to entwine itself on and large amounts of fertilizer and pesticides. In the soil inventory of the experimental station the former hop fields were found to have a much higher level of extractable nutrients and harmful chemicals such as copper. Further informations about hop see "Underseeds in Hop" on page 4. The formation, distribution and association of soils in the Upper Bavarian Tertiiirhugelland are closely related to the parent material (coarse- and fine-grained deposits of the molasse on the one hand. and loess and loess loam as wind-formed covering sheets on the other), the (moderately moist) climate, the hilly undulating relief characterized by valley asymmetry and the water relationships determined particularly by the horizontal and

Field Trip 2

vertical changes between water-permeable and water-retaining deposits. Under those soil forming factors more or less waterlogged brown earths (Eutrochrepts) and Pseudogleys (Epiaquepts) formed In large areas (seeTable 5). horizon

depth

clay

/ em

Cl. ...

"no

silt

sand

pH

Corg

/ g kg' ·

Fed

Fea/Fed

/ g kg' ·

Ap

0·26

25

38

37

6.5

1.5

8.8

0.50

PSwI

26·36

48

33

19

4.9

0 .3

15.0

0.20

PSw2

36·60

49

33

18

4.3

0.3

13.2

0.24

PSd

60·90

43

37

20

4.3

0.2

18.5

0. 17

IISdl

90-118

32

37

41

4.2

0.1

8.6

0. 15

II Sd2

118+

20

13

67

4.3

0. 1

6.0

0.34

Ap

0·28

II

22

67

5.8

2.0

11.2

0.20

Byl

28·40

9

22

68

6.3

0.7

8.5

0.25

By2

40·67

9

17

74

6.4

0.3

13.5

0.07

(Sw)Byl

67·92

14

12

74

6.4

0.2

13.5

0.09

IICy

92+

10

11

79

6.5

0. 1

25.8

0.09

0-

.

'E..

UJ

C ...

-5

::;

""t:l

::J u

~

:0-

Table 5: &cursion soil profiles: a) fine montmorillonitic mesic Aerie Epiaquept (Pelosol-Pseudogley aus Tertiiirton) b) Loamy mixed mesic 1Jpic Udorthent (Braunerde aus kiesigem Tertiiirsand)

A description of all sample profiles is given in Table 6 on page 32.

ESse September 1996

31

w

German Bodenform -(Wiltmann & Hofmann. 1981)

tv

:n (1)

0:: >-3

::l.

AIea I %

12

Braunerde aIlS lehmigem. fein- und mittclsandigem Molassematerial. verbreitet mit schwachen Kies- und UiBlehmbeimengungen

fine-loamy Dystric Eurrochrepr

22.0

3

Braunerde aus LoBlehm mir Beimengungen von sandigen bis sandig-lehmigem Molassemarerial

coarse-silry Oysrric Eurrochrept

18.8

2b

Braunerde aIlS LoBlehm

fine-silry Oystric Eutrochrept

17.8

17b

Braunerde aus lehmiger Oeckschichr (3-6 dm) tiber ronigem Molassematerial

fine-silry over fine Oysrric Eurrochrepr

6.4

6a

Kolluviurn aIlS lehmigen Abschwemmassen

fine-loamy Typic UdiRuvenr

5.4

4

Braunerde aus Lofllehmdeckschichr (3-5 dm) tiber LofllehmRidlerde

fine-loamy Oysrric Eurrochrepr

5.1

14

Kolluviurn aIlS sandigen Abschwemmassen

coarse-loamy Typic Udifluvenr

4.1

31b

Gley. srellenweisc riefhumos. aus lehmigen Talsedimenten

fine-loamy Mollie Endoaquepr

4.1

13

Braunerrle aIlS lehmiger Occkscbichr (3-G dm) tiber ± lehmigem. fein- und mirrcJsandigem MoJassemarerial

fine-loamy oVer sandy D-y'Suic Eutrochrept

3.5

"0

tv

Soil Taxonomy (Scheinost. 1994)

Table 6: Area coverage ofsoil types on the experimental station Klostergut Scheyern according to the classification of the "Standortkundlichen Bodenkarte" (soil map) ofBavaria (Sinowski, 1995)

German Bodenform (Wiuma-nn & Rofmann . 1981)

Soil Taxonomy (Scheinosr. 1994)

Area I %

18a

Peiosol-Braunerde aus lehmig-sandiger Deckschicht 0.5-3 dm) libcr tonigcm Molassematerial

fine Vertic Eutrochrept

3.2

32b

Anmoor-Glcy. stdlcnwcise humusreicher Glcy aus lehmigen Talsedimemen

fine-loamy Mollie Endoaquept

3.1

30b

Braunerde-Gley aus lehmigen Talsedimemen

fine-silty Aerie Fluvaquem

2.3

11

Braunerde aus schwach lehmigem. fein- und mittelsandigem Molassemarerial

coarse-loamy Dystric Eurrochrept

1.3

17a

Braunerde aus sandiger Deckschichr (3-6 dm) liber tonigem Molassematerial

coarse-loamy over fine Dystric Eurrochrept

1.3

16

Braunerde aus glimmerreichem. schluflig-Iehmigem Molassematerial

coarse-loamy Dysrric Euuochrept

0.9

21b

Quellen-Gley aus sandigen bis lehmigen Deckschich ten liber tonig-Ichmigem bis lehmig-tonigem Molassematerial

t'