The environmental impact of maize cultivation in the European Union: Practical options for the improvment of the environmental impact. - Case study Germany -

&KULVWRSK)LQNH.DUVWHQ0|OOHU6XVDQQH6FKOLQN%lUEHO*HURZLWW-RKDQQHV,VVHOVWHLQ

Research Centre for Agriculture and Environment in cooperation with the Department of Forage and Grass Research of the Institute for Agronomy and Plant Breeding, Georg-August-University of Göttingen

Göttingen, in november 1999 Environmental impact of maize cultivation: case study Germany 1

&RQWHQWV

&8/7,9$7,21$1'87,/,=$7,212)0$,=(,1*(50$1<

87,/,=$7,21 BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB  '(9(/230(172)7+(0$,=($&5($*( BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB  )$&7256)520$123(5$7,21$/9,(:BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB  $*52120<%$6(62)7+(0$,=(&8/7,9$7,21BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB  )(57,/,=$7,21$1'3/$173527(&7,21,10$,=(&8/7,9$7,21 BBBBBBBBBBBBBBBBBBBBB 

&$6(678',(62)&8/7,9$7,212)0$,=(,1:(6(5(06

'(6&5,37,212):(6(5(06 BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB  /$1'86(')257+(&8/7,9$7,212)0$,=(,1:(6(5(06 BBBBBBBBBBBBBBBBBBBBBBBB  <,(/'2)0$,=( BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB  /,9(672&.352'8&7,21$1'&255(6321',1*0$185(48$17,7,(6,17+(585$/ ',675,&76 BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB  ())(&76217+((19,5210(17$1'$92,'$1&(675$7(*,(6BBBBBBBBBBBBBBBBBBBBBBB 

(19,5210(17$//<&203$7,%/(&8/7,9$7,212)0$,=(

0($685(6)25$1(19,5210(17$//<&203$7,%/(&8/7,9$7,212)0$,=(BBBBBBBBBB  ())(&7,9(1(66:,7+&216,'(5$7,212)(19,5210(17$/*2$/6 BBBBBBBBBBBBBBBBBB  23(5$7,21$/$1'6758&785$/5(48(676 BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB  (;$03/(62)35$&7,&$/,03/(0(17$7,21 BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB  )8785('(9(/230(176 BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB 

6800$5<

/,7(5$785( Environmental impact of maize cultivation: case study Germany 2

 &XOWLYDWLRQDQGXWLOL]DWLRQRIPDL]HLQ*HUPDQ\

1.1 Utilization

The cultivation of Maize (]HDPD\V L.) in Germany is undertaken primarily to produce feed for cows, pigs and poultry (maize for silage including green-maize, grain maize, corn cob mix, maize coarse meal with husks). As well as being used for producing sugar, grain is also used by the food industry to produce maize-meal-products, snacks, cornflakes etc., and in pharmaceutical processes. As a renewable raw material, maize starch is used in the manufacture of paper and cardboard (it is an important additive in wastepaper processing). New packing and impact protection materials are produced in new extraction moulding procedures from maize-semolina. Sugar-maize, normally marketed directly as whole ear maize, is finding wider markets (GERMAN MAIZE-COMMITTEE E.V. 1999, FEDERAL MINISTRY OF AGRICULTURE 1995, CHAMBER OF AGRICULTURE HANNOVER 1995). How the maize will be used determines the procedure of the maize cultivation. In Germany, maize is grown as grain maize, ear maize or maize for silage. Grain maize: The ripe grains are harvested and used as feed or industrially processed. Ear maize becomes corn-cob-mix (CCM) or coarse maize meal with husks (used exclusively for forage) and is normally not as ripe because harvesting begins earlier. Parts of the maize ear as well as the husks surrounding the maize ear are harvested. They are crushed and preserved in a humid environment and used as a high energy forage. Silage maize is harvested as a whole plant, chopped into small pieces and preserved as basic forage even if the maize grains are not yet quite ripe. In Germany the area cultivated with maize amounted to 1.58 million ha in 1998 (GERMAN MAIZE-COMMITTEE E.V. 1999). The largest maize-cultivating federal states of Germany are Bavaria with approximately 400,000 ha and Lower Saxony with almost 300,000 ha, followed by North Rhine-Westphalia, Baden-Württemberg and Brandenburg (Figure 1). In Germany, 78% of the maize-cultivated acreage is maize for silage, 16% is grain maize and 6% is corn cob mix (Figure 2). The acreage of maize for silage includes the relatively small arable lands used for maize coarse meal with husks and green-maize which is used only as fresh feed. It can be seen that there is a strong concentration of silage maize cultivation in the northwest and southern parts of Germany because many intensive fattening bull farms, partially interconnected with dairy farming, are located in these regions (North- West-Germany and South-East-Bavaria). This leads to a high amount of semi-liquid manure. The semi-liquid manure can easily be spread on land with maize-cultivation because the maize tolerates an excess fertilization with nitrogen without yield loss. Environmental impact of maize cultivation: case study Germany 3

6FKOHVZLJ +ROVWHLQ 75.834 ha 0HFNOHQEXUJ :HVWHUQÃ3RPHUDQLD 13% 86.089 ha 8%

/RZHUÃ6D[RQ\ 293.848 ha Berlin 16% %UDQGHQEXUJ 6D[RQ\ $QKDOW 116.750 ha 1RUWKÃ5KLQH:HVWIDOLD 77.317 ha 11% 216.894 ha 8% 20% 6D[RQ\ 7KXULQJLD 74.530 ha +HVVH 52.681 ha 8% 33.385 ha 8% 5KLQHODQG 3DODWLQDWH 7% 20.348 ha 5% 6DDUODQG

3.182 ha %DYDULD 8% %DGHQ 392.583 ha :UWWHPEHUJ 18% 131.998 ha 15%

maize-cultivated area (total): 1.576.159 ha = 13% of the arable land )LJXUH$UDEOHODQGLQWKHIHGHUDOVWDWHVRI*HUPDQ\DQGWKHSHUFHQWDJHXVHGIRU PDL]HSURGXFWLRQLQ(source: GERMAN MAIZE-COMMITTEE E.V. 1999)

Grain maize has the highest demand for warmth of all maize. This is why there is a concentration of maize in Southern Germany, i.e. in the Rhine-valley (Baden-Württemberg) and in the main and lower Rott valley (Bavaria) as well as near Passau (Bavaria), primarily in market-fruit-farms. Early and middle-early varieties of maize grow also in climatically more unfavourable border-situations of the low mountain regions and in the lowlands of North-West-Germany. Here, the dominant areas of cultivation are on the intensive livestock farms of Lower Saxony (Südoldenburg) and North Rhine-Westphalia (Westphalia-Lippe) – mainly on farms with livestock which have a supply of manure. Environmental impact of maize cultivation: case study Germany 4

Bavaria 304845

Lower-Saxony 224832

North Rhine-Westphalia 136625

Baden-Württemberg 73659

Brandenburg 107085 Corn-Cob-Mix

Mecklenburg-West. Pom. 84145 Grain Maize Saxony-Anhalt 67214 Schleswig-Holstein 75604 Maize for Silage (in numbers) Saxony 66907

Thuringia 48140 Germany total* = 1.576.159 ha therefrom Maize for Silage = 1.235.130 ha Hesse 26599 Grain Maize = 251.106 ha Corn-Cob-Mix = 89.923 ha Rhineland-Palatinate 15735

Saarland 3102 * incl. Berlin, Bremen, Hamburg

0 50000 100000 150000 200000 250000 300000 350000 400000 450000 DFUHDJHÃ LQÃKD Ã )LJXUH0DL]HFXOWLYDWLRQLQWKHIHGHUDOVWDWHVRI*HUPDQ\VXEGLYLGHGLQWRWKH XWLOL]DWLRQIRUPV VLODJH PDL]H JUDLQ PDL]H DQG FRUQ FRE PL[ (source: GERMAN MAIZE-COMMITTEE E.V. 1999).

1.2 Development of the maize acreage

Since the mid-1960’s, the cultivation of maize had increased substantially in both parts of Germany (Figure 3). Across the whole of Germany maize is now grown on 13% of the arable land. The main factor which has enabled this increase is the development of new strains of maize which will grow in cooler areas. The development of Triazin, e.g. Atrazin, for weed control, improvements in harvesting and preservation technologies and in seeding techniques (e.g. single grain seeds), have all supported this increase. In terms of acerage, the expansion of maize for silage acreage has already reached its peak in the former FRG in 1986. Previously grown labour-intensive forage crops (fodder-beets, grass and clover-grass, lucerne) were substituted with maize for silage. In 1992, 73% of the acreage of forage crops in Germany were sown with maize for silage. This share has remained constant since then. Environmental impact of maize cultivation: case study Germany 5

)5* H[FHSWWKHQHZIHGHUDOVWDWHV

1000000 931 557 893 767

900000 879 499 Maize for Silage 861 640 800000 Grain Maize/CCM

700000 694 599

600000

500000 430 300 400000 DFUHDJH LQKD 307 115 300000 289 346 227 452 190 575 200000 181 001 118 819 100 143 96 061

100000 99 497 49 886 47216 46898 26 821 6787 6798 0 6 249 1950 1955 1960 1965 1970 1975 1980 1985 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 1999 preliminary )LJXUH  'HYHORSPHQW RIPDL]HLQWHUPV RI DUHD RI ODQG FXOWLYDWHG KD LQ WKH )5* H[FHSWWKHQHZIHGHUDOVWDWHV IURPIRUVLODJHPDL]HDQGJUDLQPDL]HLQFOXGLQJ FRUQFREPL[(source: STATISTICAL FEDERAL-OFFICE 1999)

*'5QHZIHGHUDOVWDWHV

1000000

900000 Maize for Silage 800000 Grain Maize/CCM 700000

600000

500000 471 654 438730 373 490 400000 372 289 364 613 360 484 336 855 DFUHDJH LQKD 300000 258470

200000

100000 35 718 33 914 10089 2 868 600 5 253 1975 994 930 1678 4594 0 2620 1950 1955 1960 1965 1970 1980 1985 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 1999 preliminary )LJXUH'HYHORSPHQWRIPDL]HLQWHUPVRIDUHD RI ODQG FXOWLYDWHG KD LQWKH*'5 DQGWKHQHZIHGHUDOVWDWHVIURPIRUVLODJHPDL]HDQGJUDLQPDL]HLQFOXGLQJFRUQ FREPL[(source: STATISTICAL FEDERAL-OFFICE 1999) Environmental impact of maize cultivation: case study Germany 6

Because of the more favourable weather conditions in the south, Southern Germany expanded its maize cultivation before the northern areas. In the former GDR, as early as the 1970s, more than 300.000 ha maize was grown for forage-production (Figure 4). Today the new federal states produce 30% of the total silage maize and 10% of the grain maize in Germany. With the change in production-systems of the former GDR and the reduction of livestock husbandry, the land area used for silage maize has fluctuated over the last few years. Since 1996, the acreage used for maize for silage has decreased in both the new and old federal states. The reduced demand for beef (BSE-crisis) has had an effect on livestock production and consequently on forage production.

1.3 Factors from an operational view

Grain maize is an important cash crop for farms without livestock - above all in Bavaria and Baden-Württemberg. In the typical cultivation areas of Mid and Southern Bavaria (the rural districts of Erding, Rottal-Inn, Landshut) and the area enclosed in the Rhine valley up to 60% of arable land is cultivated with maize (ZSCHEISCHLER 1990). In the North-West-regions of Germany with high levels of livestock, maize for silage and CCM are essential components of the feed-rations for cows and pigs. Grain maize is used for poultry forage. In the district of Weser-Ems more than 30% of the arable land is cultivated with maize (CHAMBER OF AGRICULTURE WESER-EMS 1998a). In intensive livestock farms, ear maize is grown as an alternative to grain maize, relieving the farmers of the high costs of drying. This particular harvest and preservation technique also makes the production of profitable forage with maize possible in the cooler regions of Germany. The cultivation of maize for silage plays a large role in forage-growing farms. Maize for silage is a valuable, high energy, basic forage and cattle seem to enjoy it so that forage intake is high. Protein rich basic forage rations (with grass silage) in grassland-farms can be complemented with maize-silage. The maize-silage increases the calorific value of the forage and ruminants then use the proteins more effectively. Also the quality of the basic forage itself increases and a better basic forage leads to higher livestock productivity and the purchase of forage concentrates can be reduced. These benefits are additional to those of higher productivity per acre and the improved nutrient acquisition (particularly for farmyard manure). The operational nitrogen balance of a farm can be improved by cultivating maize. In organic agriculture, maize for silage-cultivation still plays a minor role although the productivity and the energy-content of the forage plant are topics of interest (GERMEIER 1997). Since 1990, the arable land growing organic maize for silage amounts to less than 2% of all the land used for organic agriculture. Over the same time period, conventional farms grew maize for silage on 13% of their fields (FEDERAL GOVERNMENT 1990-1998). • data for the maize-cultivation In order to give an overview of the status of maize production in agriculture the standard marginal contributions are presented in Table 1. It should be remembered that a subsidy of 443 to 797 DM/ha (1999) is paid for maize, depending on the federal state and region.

7DEOH$YHUDJHJURVVPDUJLQDOFRQWULEXWLRQIRUWKHPDLQPDL]HFXOWLYDWLRQ SURFHGXUHVLQ*HUPDQ\LQ(in DM/ha without consideration of the subsidy) Environmental impact of maize cultivation: case study Germany 7

XWLOL]DWLRQIRUP FURSÃ\LHOG JURVVÃ\LHOG YDULDEOHÃFRVWV part - tonnes/ha without subsidy total seedes fertilizer weed control machines other AGMC JUDLQÃPDL]HÃ 6RXWKÃ)5* 9 2160 1730 274 272 270 515 399  PDL]HÃIRUÃVLODJHÃ 1RUWKÃ)5* 45 2250* 1716 281 421 269 615 130  FRUQÃFREÃPL[Ã 1RUWKÃ)5* 12,5 2000** 1636 269 280 250 767 70  for comparison ZLQWHUÃZKHDWÃ 6RXWKÃ)5* 7,5 1800 1148 130 260 271 427 60  WULWLFDOHÃ 1RUWKÃ)5* 6,5 1495 997 125 239 163 420 50  assumtion: * value of maize silage = 50 DM/t x 45 = 2250 DM AGMC = average gross marginal contribution ** value of corn cob mix = 160 DM/t x 12,5 = 2000 DM sources: Chamber of Agriculture Hannover 1999, KTBL average gross marginal contribution 1997/98

1.4 Agronomy bases of the maize-cultivation

Maize is very self-sufficient and therefore it can be grown as a monoculture. Its demand for warmth during germination and early development (frost-sensitivity) leads to a late sowing from the end of April until mid-May, depending on the region. The 311 maize varieties which are officially recognised in Germany (1999) are adapted to local climatic conditions.

7DEOH  &ODVVLILFDWLRQ RI 0DL]H YDULHWLHV LQ 0DWXULW\ (source: GERMAN MAIZE- COMMITTEE E.V. 1999)

0DWXULW\JURXS 5LSHQHVVQXPEHU DYHUDJHGDLO\WHPSHUDWXUH 0D\6HSWHPEHU early until 220 14,0-15,0 °C middle-early 230-250 15,0-15,5 °C middle-late 260-290 15,6-16,4 °C late 300-350 16,5-17,4 °C

* Ripeness-number approximately corresponds to the FAO-number

The maize hybrids are divided into maturity-groups, for both silage and grain use (Table 2). The ripeness number for silage is based on the ripening behaviour of the entire plant and the ripeness number for grain only takes into account the maize ear. Maize grows, like potatoes and sugar beets, as a row-culture. Depending on the harvesting technology and its use, the distance between the rows is normally 75 cm and the population density 9-13 plants/m2. If no mechanical weed control takes place, the distance between the rows can be reduced to 30 cm. This increases the ability of the plants to exploit nutrients (CHAMBER OF AGRICULTURE WESER-EMS 1999), although appropriate sowing- techniques and a row-independent harvesting technology must be used. Harvesting is normally contacted out. The cultivation of maize causes soil erosion in some regions of Germany. This occurs mainly on hillside land with easily eroded soil material. The risk of soil erosion is greater in spring because maize is grown in rows and covers the ground late (LÜTKE ENTRUP & ZERHUSEN 1992). To protect the soil and to redevelop old neglected deposits of toxic waste the Federal Soil Protection Law of 1998 (SOIL PROTECTION LAW 1998) should reduce erosion where it is avoidable with the help of suitable measures (FEDERAL MINISTRY OF AGRICULTURE 1999). Despite the relatively high water use efficiency (3,3 g Dry Matter/ 1 kg water), the water demand of maize is considerably on the basis of the high output. In order to avoid yield losses, the water-demand should be especially catered for during June and July. In the classic dry areas of East and Central Germany as well as at Upper Rhine valley and in the water Environmental impact of maize cultivation: case study Germany 8 catchment area of the Eifel, considerable shortfalls can occur in the water supply of the plants. In order to supply the high water need some farmers irrigate their maize. Maize is harvested in the autumn and late-autumn (September-December). Large, heavy harvesters to harvest and chop the maize for silage are used. Fair-weather is required for harvesting which is different than, for example, sugar beet. Over the last few years "stay green" varieties of maize for silage have been used which extend the time for an optimal harvest and a high silage quality is possible and soil compaction can be avoided. Primarily farmers grow winter wheat which is adopted to late sowing as the following crop in a rotation, if maize is not grown again (LÜTKE ENTRUP & ZERHUSEN 1992).

1.5 Fertilization and plant-protection in maize cultivation

• IHUWLOL]DWLRQ The European limit for nitrate in drinking water (EC-nitrate-guideline of 1991) was put into practice in Germany in 1996. The German government implemented an ordinance for the principles of good technical practice for fertilization in agriculture (FERTILIZATION ORDINANCE 1996). This fertilization ordinance regulates the application of fertilizers, restricts times for the use of semi-liquid manure, compares nutrients and establishes a duty to record fertilization for the first time on a national basis. It also lays down a maximum amount of manure which can be spread (maximum average content of 170 kg N/ha for each agricultural enterprise). Concrete limits for mineral fertilizers, however, are not given in the ordinance, nor are maximum levels of fertilization per acre for certain cultures (OSWALD 1998). This ordinance is interpreted further by the individual governments of each federal state. In contrast to other grain-types, maize has a period of especially intensive growth after a slow initial development. For this reason, plant-available nutrients (mainly phosphate) are placed near the seedling during planting (underground fertilization). Maize is very effective at using mineralized nitrogen from manure because of its long vegetation time, which lasts until autumn (AUFHAMMER 1988). The following statements are based on official guidelines with respect to fertilization: 1LWURJHQ: For an exact calculation of the N-fertilizer requirement, the mineral-nitrogen- content of the soil between the 6 and 8 leaf stage of the maize is measured. Only when the maize-plants are so far developed they can incorporate nutrients in considerable quantities. The difference between the measured nitrogen level and what is appropriate should be made up with mineral and/or manure fertilizer. The appropriate level of nitrogen is determined on a regional basis (180-200 kg N/ha) and depends on the expected profits. 3KRVSKRUXV: It promotes the initial development, bloom and fruit-formation as well as starch-storage. Dependent on the variety of maize grown, 40 – 50 kg/ha of phosphorus per crop is removed and should be replaced by fertilization. 3RWDVVLXP: Beside the positive influence on the water supply, potassium promotes the development of mass in the shooting phase and increases the steadiness of the maize. Also the resistance of the plant against illnesses and pests increases. Maize has a high potassium requirement. The removal of potassium from the soil depends on the use of the maize and varies from 140 to 250 kg K/ha. 0DJQHVLXP: The demand of maize for magnesium is comparatively low and is met by normal fertilization with manure in livestock farms (grain maize removes 20 kg Mg/ha and silage maize 40 kg Mg/ha). These figures do not necessarily reflect what happens in practice. It can be assumed that manure is used at high levels as well as other fertilizers. Maize tolerates a high level of Environmental impact of maize cultivation: case study Germany 9 fertilizer and in intensive livestock farms large quantities of semi-liquid manure need to be disposed of.

• SODQWSURWHFWLRQ The use of pesticides is regulated by the nationally applicable 'law to protect crops', short: plant protection law (PLANT PROTECTION LAW 1998) which came into effect on 14. May 1998. In water protection areas some pesticides are forbidden (PLANT- PROTECTION-APPLICATION-ORDINANCE 1997). Pesticides which are allowed today for the cultivation of maize are not yet included in the list of forbidden pesticides.

Direct plant protection precautions for maize are, essentially, aimed at weed control. In the Southern, and therefore warmer regions of Germany, the fight against the European corn borer (Ostrina nubilalis) is important. As a preventative measure, the harvest residuals are crushed and deeply ploughed in. Two biological measures are available to combat the corn borer. The use of slip-wasps (Trichogramma) and the spraying of a bacillus thuringiensis preparation are practicable. Insecticides are less important. Fungicides are not applied during the cultivation of maize. Coating the seed to prevent the development of the fruit fly larvae (Oscinella frit) is standard practice. Maize does not compete well with weeds in its early development stage and this has meant that there is an economic necessity to deal with them. &KHPLFDOZHHGFRQWURO: After the discontinuation of Atrazin (application was prohibited in Germany from 1991) new herbicides and mixtures were developed. They are used before sowing, before or after plant shooting. In some regions of Germany, herbicide-resistances have appeared with intensive maize cultivation. Some weeds are very difficult to eliminate. In the North of Germany: cock’s-foot grass ((FKLQRFKORDFUXVJDOOL), hairy crabgrass ('LJLWDULDVDQJXLQDOLV), and in South Germany: millets (6HWDULDJODXFD YLULGLV), fat hen (&KHQRSRGLXPDOEXP) and black nightshade (6RODQXPQLJUXP) are serious weeds. 0HFKDQLFDOZHHGFRQWURO: farmers can work between the rows with various types of mechanical hoes. Up until harvesting the use of the blind-currycomb is also possible. In Germany, mechanical weed control is used only to a minor extent because agrochemicals are cheaper. A combination of chemical and mechanical weed control can be implemented by band spraying. This helps to reduce the use of pesticides, but only a few farmers use this technique (LÜTKE ENTRUP & ZERHUSEN 1992). Environmental impact of maize cultivation: case study Germany 10

 &DVHVWXGLHVRIFXOWLYDWLRQRIPDL]HLQ:HVHU(PV

In the state of Lower Saxony, the cultivation of maize has become very important over the last few decades, particularly for forage-production. The land area used for silage maize increased up until the middle of the 1980s to 200,000 ha (figure 5). The breeding of early maize varieties and developments in harvesting technology have led to an increase in the land given over to maize since the beginning of the 1980s. The acreage of grassland, which is very significant for the natural environment, water protection and for producing forage on the farms, has continuously decreased over the last 30 years. Today maize is often cultivated on former grassland. If wet periods frequently occur over the winter, maize can be sown late in comparison to other crops.

/RZHU6D[RQ\ 1 400 000

1 200 000

1 000 000

800 000 Grain maize(CCM) Maize for Silage 600 000

DFUHDJH LQKD Permanent Grassland 400 000

200 000

0 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 (1999 preliminary) )LJXUH 'HYHORSPHQWRIWKHFXOWLYDWLRQRIPDL]HDQGWKHDFUHDJHRIJUDVVODQGLQ /RZHU6D[RQ\(source: STATISTICAL FEDERAL-OFFICE 1998)

In 1998, 60% of the total area used for the cultivation of maize in Lower Saxony was in Weser-Ems region, although it is only 31% of the farmland of Lower Saxony. This highlights the strong concentration of the maize in this region.

2.1 Description of Weser-Ems

The Weser-Ems district is in the west of Lower Saxony and borders the Netherlands (figure 6). It possesses an agricultural chamber of its own, based in Oldenburg. Weser-Ems includes the towns of Delmenhorst, Emden, Oldenburg, Osnabruck and Wilhelmshaven and 12 other rural districts (table 3 ). Environmental impact of maize cultivation: case study Germany 11

)LJXUH/RFDWLRQRI:HVHU(PVLQ*HUPDQ\DQGLW VUXUDOGLVWULFWV

• climate - and soil circumstances A moderate maritime climate prevails in Weser-Ems. The average precipitation is 810 mm per year. Inland, it rains between 650 and 700 mm per year. The average temperature is to 8.5°C. From May until September, which is vital for the growing of maize, the average temperature is approximately 15°C. Conditions for the silage maize cultivation and CCM are good. The production of grain maize is only possible with early maturing varieties. An energy-intensive drying of the maize-grains is normally necessary because the maize has a water content of 30-35%. Some farmers use propion-acid for a conservation. One finds the following soil circumstances in the Weser-Ems (figure 7): Marsh grounds of different types have been formed in the coastal-area from young sea sediments. Further inside of Weser-Ems on the post ice-age grounds, soil has been formed over pleistocene sands and old moraines. There are extensive moor areas nearby which transforms to meadow around the wider river valleys. The grounds in the most southern part of the area have developed from loess-sediments, although in Weser-Ems this area is small. Podzols, podzol- brown-earths, Podzol-Para-brown-earth and moors are among the frequent inland soil-types. Environmental impact of maize cultivation: case study Germany 12

Soil-types are silt, clay and humus sands. The sandy soils have a relatively low mechanical filtering ability and middle to high water permeability. There is a relatively high potential for fertilizers and pesticides to be carried into the groundwater by rain.

red: Coastal-marsh

yellow: Sandy soil from the post ice-age

green: humus-moor soil

brown: brown and parabrown- earth on loess sediments

source: FEDERAL-OFFICE FOR SOIL- RESEARCH OF LOWER SAXONY

)LJXUH6RLOPDSRI:HVHU(PV

• structure of agriculture Dairy farms are mainly in the coastal rural districts of Aurich, Wittmund and Wesermarsch, where there is a high proportion of grassland. In these forage-growing farms, the little arable land is frequently used every year to produce silage maize. The share of maize is low in relation to the agricultural land (incl. grassland), but it is high in relation to the arable land (table 3). In the rural districts Vechta, Oldenburg, Cloppenburg and Emsland grassland is less important. Here, intensive livestock farms with pig and/or poultry have been established. Environmental impact of maize cultivation: case study Germany 13

7DEOH6L]HVRIILHOGDQGJUDVVODQGVDQGSURSRUWLRQRIODQGXQGHUPDL]HLQWKH UXUDOGLVWULFWVRI:HVHU(PV(source: LOWER SAXONY DEPARTMENT FOR STATISTICS 1999)

farmland therefrom therefrom maize-share rural districts in ha grassland arable land of the arable in ha in ha in % of farmland land Ammerland 44.488 31.923 15.041 32% 51% Aurich 85.367 54.672 31.100 36% 14% Cloppenburg 97.778 21.655 76.519 78% 37% Emsland 168.767 25.792 143.206 32% 85% Friesland 43.576 32.940 10.774 25% 26% Graf. 60.906 18.644 42.369 69% 42% Bentheim Leer 71.334 59.742 11.715 16% 42% Oldenburg 67.145 21.899 45.496 68% 27% Osnabrück 124.023 29.517 95.195 76% 27% Vechta 66.458 10.639 56.124 84% 33% Wesermarsch 61.362 59.009 2.412 4% 57% Wittmund 47.246 33.744 13.581 29% 24% total 943.708 400.176 543.532 32% 58%

The size of farms in the Weser-Ems region is lower then the average for Lower Saxony. Most farms have a size of 30-50 ha agricultural land (table 4). There is a below average number of farms with more than 50 ha of land in the Weser-Ems region. This is reflected by the importance of livestock production which is less dependent on the size of the farms. 7DEOH  $JULFXOWXUDO EXVLQHVVHV JURXSHG E\ TXDQWLW\ RI WKH DJULFXOWXUDO XVHG ODQG (source: STATISTICAL FEDERAL-DEPARTMENT) :HVHU(PV /RZHU6D[RQ\ size farms farms from... to under.... ha number share number share in % in % 1 - 2 3.836 11,0 8.887 11,2 2 - 5 4.559 13,1 10.468 13,2 5 - 10 3.977 11,4 8.506 10,7 Environmental impact of maize cultivation: case study Germany 14

10 - 15 2.586 7,4 5.504 6,9 15 - 20 2.207 6,3 4.710 5,9 20 - 30 4.419 12,7 8.304 10,4 30 - 50 7.215 20,7 13.797 17,4 50 - 100 5.372 15,4 14.927 18,8 100 and more 710 2,0 4.369 5,5 total 34.881 100 79.472 100

2.2 Land used for the cultivation of maize in Weser-Ems

Weser-Ems 23,9% 5,3% 2,7%

Rural Districts: Corn Cob Mix Gr.Bentheim 33,5% 5,3% 2,9% (% arable land)

Emsland 22,7% 4,5% 5,0% Grain Maize (% arable land) Osnabrück 18,5% 5,5% 3,4%

Vechta 17,8% 12,9% 2,5% Maize for Silage (% arable land) Cloppenburg 27,6% 8,3% 1,3% Oldenburg 22,9% 2,8% 1,6% 0,4% Ammerland 50,3% 0,4% Wesermarsch 56,9% 0,1% Friesland 26,0% 0,1% Wittmund 23,6%

Leer 41,6% 0,1% Aurich 13,6% 0,1% 0% 10% 20% 30% 40% 50% 60% )LJXUH$UDEOH/DQGXVHGIRUWKHFXOWLYDWLRQRIPDL]HLQWKH:HVHU(PVLQ VXEGLYLGHGE\XWLOL]DWLRQIRUP(Source: LOWER SAXONY DEPARTMENT FOR STATISTICS 1999) Figure 8 shows that the predominant regions for maize as grain maize and CCM are Vechta, Cloppenburg, Emsland, Osnabruck and Bentheim where these crops are grown to a considerable extent. These rural districts show with 70-85% the highest proportion of agricultural land which is arable (compare table 3). In the grassland-regions (rural coastal districts), silage maize is grown almost exclusively as a high energy basic forage which is important for cattle. The high quality of silage maize leads to its extended use. On heavy marshes, timely sowing is not always possible and the harvest is difficult. Higher precipitations (up to 900 mm) and lower summer-temperatures in the coastal-situations retard the ripening of the maize.

2.3 Yield of maize

• data from survey of the Lower Saxony department for statistics Environmental impact of maize cultivation: case study Germany 15

Figure 9 shows the average yields achieved with silage and grain maize for 1994-98 in the rural districts of Weser-Ems.

Grain maize Maize for Silage t/ha dry material (14% water) Grain Maize incl. CCM 1994-98 t/ha green material 8 Maize for Silage 1994-98 45

7 40

6 35

5 30

4 25 Leer Aurich Vechta Emsland Friesland Wittmund Oldenburg Osnabrück Ammerland Weser-Ems Gr.Bentheim Cloppenburg Wesermarsch Lower Saxony )LJXUH$YHUDJH\LHOGVRIJUDLQPDL]HDQGVLODJHPDL]HLQWKHUXUDOGLVWULFWV:HVHU (PV(source: LOWER SAXONY DEPARTMENT FOR STATISTICS 1995-99)

The average yield-level in Weser-Ems corresponds closely to the Lower Saxony state average. Between the individual rural districts, however clear differences in yield exist with both maize types. These differences amount to about 10 dt/ha grain with the grain maize and about 58 dt/ha green-mass-yield with the silage maize. In the coastal-regions, the harvests of grain maize tend to be lower than in the inland (compare the left half of figure 4, the rural districts from Aurich to Wesermarsch). The yields of silage maize show no region-specific variation.

• Yield data of the Weser-Ems agricultural chamber A more elaborate illustration of the yield, and quality parameters of silage, and grain maize in the Weser-Ems from 1996 to 98 is shown in table 5. The data were collected in the framework of trials of different varieties by the Weser-Ems agricultural chamber. It should be noted that the results were achieved under optimum production and technical conditions. The results of yield and quality correspond to the upper level of results from real farms. Due to climatic conditions only early and middle early varieties were used. Average results for 1996-98, show that the early silage maize varieties exhibited approximately 10% better dry matter ripening behaviour, and approximately 10% higher starch content, than the middle-early kinds. However small yield reductions in terms of dry- mass were noticeable for the early varieties compared to the middle-early varieties. Although the differences in yield for grain maize between the early and middle-early varieties for grain maize were very small, the early varieties had a higher dry matter content and so are preferred on farms.

7DEOH$YHUDJH\LHOGVIRUVLODJHDQGJUDLQPDL]HLQ:HVHU(PVUHVXOWVRIWKH YDULHWDOWULDORIWKHIHGHUDOVWDWHYDOXHVFRUUHVSRQGWRWKHDYHUDJHRIEORFNV Environmental impact of maize cultivation: case study Germany 16

(Source: AGRICULTURE-CHAMBER WESER-EMS 1999)

Maturity-group early Maturity-group middle-early (old FAO-number until 220) (old FAO-number 230-250) 0DL]HIRU6LODJH 1996 1997 1998 96-98 1996 1997 1998 96-98 dry matter t/ha 15,8 20,2 17,6 17,9 15,6 21,3 18,3 18,4 dry matter content % 32,0 37,7 34,3 34,3 28,4 35,5 31,1 31,7 energy-yield MJNEL/ha 96394 129195 112811 112800 96349 135444 115978 115146 net energy content MJ NEL/ kg dm 6,16,46,46,36,06,46,36,2 starch yield t/ha 4,39 6,69 5,91 5,66 3,82 6,76 5,60 5,39 starch content % in dm 27,9 33,2 33,8 31,6 24,4 31,8 30,7 29,0

*UDLQPDL]H grain yield t/ha 8,44 10,8 10,33 9,86 8,76 11,19 10,34 10,1 dry matter content of grain** % 61,7 69,2 64,1 65 59,8 67,5 60,6 62,6 dm = dry matter * grain yield at 86% dry matter in t/ha ** at the time of harvest

2.4 Livestock production and corresponding manure quantities in the rural districts In some rural districts of Weser-Ems a strong concentration of the livestock population can be seen (SCHÜRMANN 1998). The highest livestock densities occur in the districts of Vechta and Cloppenburg. Cows, pigs and poultry are kept here in high densities, see table 6. In Germany, cattle need to be housed from the end of November until the middle of April in stables because of the climatic conditions. Often cows are housed the whole year. This implicate high amounts of manure, which have to be stored and later spread out on the land. A very high density of maize-cultivation takes place in these areas. In some forage-growing farms of the rural coastal districts very intensive maize-cultivation occurs. In these areas the limited arable land is used almost exclusively to cultivate maize for silage, i.e. maize is grown as monoculture. Fertilization of maize is mainly achieved with semi-liquid manure from cattle (quantities of 40-50 m³/ha).

7DEOH'HQVLW\RIOLYHVWRFNLQPDQXUHXQLWV  '( SHUKDLQWKHUXUDOGLVWULFWVRI :HVHU(PV(Source: LOWER SAXONY DEPARTMENT FOR STATISTICS 1996)

Rural district Livestock-density manure- cattle pigs poultry total ** fertilizer DE/ha LF DE/ha LF DE/ha LF DE/ ha LF kg N/ha Ammerland 0,91 0,13 0,03 1,11 89 Aurich 0,68 0,07 0,01 0,79 64 Cloppenburg 0,80 0,78 0,42 2,02 162 Emsland 0,58 0,53 0,17 1,30 104 Friesland 0,86 0,05 0,01 0,96 77 Graf. Bentheim 0,83 0,50 0,23 1,59 127 Leer 0,88 0,03 0 0,94 75 Oldenburg 0,63 0,40 0,25 1,32 105 Osnabrück 0,54 0,54 0,29 1,41 113 Environmental impact of maize cultivation: case study Germany 17

Vechta 0,74 1,04 1,4 3,21 257 Wesermarsch 1,00 0,01 0 1,07 86 Wittmund 0,84 0,06 0 0,93 74

Weser-Ems total 0,73 0,40 0,24 1,41 113 Lower Saxony 0,49 0,23 0,11 0,86 69

* 1 manure unit (DE) corresponds to farmyard manure of 80 kg N from animal production ** incl. horses and sheep LF = farmland

In the rural district Vechta, the produced manure can not properly be utilized on the existing agricultural land. The maximum allowable quantity stipulated for spreading within an agricultural enterprise is 170 kg N/ha. Therefore excess must be exported into the neighbouring districts, partly with a “semi-liquid manure stock exchange”. This entails additional costs for transportation and spreading-expenses for the livestock farmers.

2.5 Effects on the environment and avoidance-strategies

In some regions of Weser-Ems, the nitrate-values measured in the groundwater are sometimes considerably higher than the EC-drinking water-limit of 50 mg nitrate per litre. The rural districts involved are Oldenburg, Cloppenburg, Vechta and Bentheim in which approximately one third of the wells in the network of controlled water supplies show nitrate-values of 50-100 mg Nitrate/l and above (FEDERAL OFFICE FOR ECOLOGY OF LOWER SAXONY 1997). Exactly how the cultivation of maize causes this is not precisely calculable. This is mainly because the number of samples which have been taken over several years is small. Most field attempts restrict themselves to calculating leaching of nitrate by using nutrient-balances or soil-examinations. The calculation of simple nitrogen balances per farm or better per field is easy done and helps to detect an incorrect fertilization (GÄTH 1997) The samples taken by LORENZ (1997, 1992) in Weser-Ems show that the scale of the nitrogen leaching cannot be derived from simple nitrogen balances, although measurements of soil nitrate do allow for an indication of the potential of leaching of nitrate. The areas concerned, Oldenburg, Cloppenburg, Vechta and Bentheim, produce only slightly higher values of maize than the average for the Weser-Ems, although they do have a higher agricultural acreage and a clearly higher farmyard manure-amount per ha, see table 6. The cultivation of maize need not lead to elevated nitrate-displacements in principle. More important is the question of optimal fertilization. The cause of the groundwater problems in the four livestock intensive rural districts is therefore seen predominantly in areas with a high level of manure spreading takes place. Maize, which tolerates an over supply of semi- liquid manure without suffering damage, primarily functions as a "waste disposal-plant " for surplus farmyard manure. In practice, 40-50 m³ per hectare of semi-liquid manure from cows or pigs is spread on maize fields. Additional underground fertilization with a mixture of diammoniumphosphate and calcium ammonium nitrate at 1:1 (approximately 1.5 dt/ha) is a standard measure. The result is fertilization of maize at 180 - 220 kg N/ha with semi-liquid cattle manure and from 204-276 kg N/ha with semi-liquid pig manure. In practice, the nitrogen extraction of maize for the average-yield in the Weser-Ems is approximately 150- 200 kg N/ha. This highlights the difference between the applied nitrogen and what is used by the crop (GÄTH 1997). Manuring with semi-liquid pig manure, especially, leads to surplus nitrogen. Environmental impact of maize cultivation: case study Germany 18

Another problem is the enrichment of the soil with phosphate. According to the statistics from soil examinations by the Agricultural Lab Oldenburg, in 1981 only 11% of soils in the Weser-Ems showed a very high phosphate content (>30 mg P2O5/100g soil). By 1994 this had risen to 45%. Over fertilisation with manure is the cause of this development (before all semi-liquid manure is applied). The farmers prefer the fertilization of maize with manure. Additionally, underground fertilization with phosphate-containing fertilizers is applied to maize (CHAMBER OF AGRICULTURE WESER-EMS WESER-EMS 1998b) The development and the implementation of environmentally compatible production strategies for maize cultivation in the Weser-Ems happens on several levels: · realization of cultivation tests especially in water-protection and water-priority-areas · cultivation consultation especially in water-protection and water-priority-areas · voluntary cultivation-agreements in water-protection and water-priority-areas

&XOWLYDWLRQWHVWV In the Weser-Ems studies are currently being undertaken relating to the cultivation of maize. The main themes of these studies are questions about the effects of different variations of organic and mineral nitrogen fertilization, underground fertilization, under seeding, previous crops and row distances in view of soil-nitrate development, nitrate-leaching, yield and quality of the harvest crops. Consequently, the following tendencies have been noticed on the basis of the short running time of the trials (at most 4 years): • There is a close connection between the level of the nitrogen fertilization for maize and the residual soil-nitrate values remaining in the soil after the harvest. Nitrogen fertilisation above the optimal nitrogen supply, especially, leads to a clear increase in the risk of nitrogen being leached from the soil. This risk is less if the land is used as a frequently cut meadow or culivated with winter-rye or winter-barley. (BENKE ET AL. 1999) • Between September and December the soil nitrate content after the cultivation of maize is clearly higher than that after winter-grain (CHAMBER OF AGRICULTURE WESER- EMS 1998 b) • Sowing grasses into established maize stands (maize plants 20 cm high) can reduce the amount of residual nitrate in the soil at the end of the vegetation period. Undersown maize does not necessarily reduce maize yield as long as the seeding of the grass is not done to early. The early sowing of Italian ryegrass, especially, can clearly reduce the residual soil nitrate level. (CHAMBER OF AGRICULTURE WESER-EMS 1998 b) • Managing the soil with a plough leads to a higher soil nitrate level than with a cultivator. (CHAMBER OF AGRICULTURE WESER-EMS 1998 b). • The scale of nitrate leaching depends, very much, on the annual weather, and, particularly, the weather circumstances in the winter (BENKE ET AL. 1999).

&RQVXOWDWLRQ Current information about the cultivation of maize is available to the farmers through professional journals, regional weekly papers and reports/minutes of the agriculture-chamber Weser-Ems. Farmers, who work in water protection- and water priority areas (approximately 3700 farmers), receive a specific advisory services (in addition to the regular service), that takes place by order of the water company. In the district Weser-Ems 19 water consultants are responsible for 66 water-protection and water-priority areas. These areas have an acreage of 120.000 ha; approximately 70.000 ha of them are used for agriculture. Besides the group- consultation (inspections, viewing demonstration fields, general information events) and the information from briefs and newsletters, the individual farm should be adviced.

9ROXQWDU\DJUHHPHQWV Environmental impact of maize cultivation: case study Germany 19

7DEOH6HOHFWLRQRIYROXQWDU\DJUHHPHQWVIRUWKHFXOWLYDWLRQRIPDL]HFXOWLYDWLRQLQ ZDWHUSURWHFWLRQDUHDVLQWKHGLVWULFW:HVHU(PV(Source: DISTRICT-GOVERNMENT WESER-EMS 1999)

PHDVXUHV LPSRVWV SD\PHQW planning of fertilization with implementation of the measures 25 DM/ha assessment of farmyard manure spreading of semi-liquid manure with spreading in the sprouting plant cover, 2 DM/m³ for max. special technology working in of the semi-liquid manure 30 m³/ha underseeding sowing with driller until maize is 50 cm 200 DM/ha combination heel/ band spraying Weed control in maize field with heel in 80 DM/ha combination with a band spraying catch crop cultivation before maize no legumes, ploughing up earliest 4 weeks before 100 - 150 DM/ha seeding; when rape was the previous crop, no fertilization installation of demonstrations-trials 300 DM + x building of storage for semi-liquid at least 6 months storage 80 DM/m³ manure Environmental impact of maize cultivation: case study Germany 20

In water-protection and water-priority-areas farmers can commit themselves within the scope of voluntary agreements to undertake certain styles of management or cultivation-measures, which serve to protect the water. They receive financial support for this (table 7). Also, agreements can be adjusted to a farm’s specific situation in cooperation with the water consultant. The voluntary agreements allow farmers some advantage for implementation water sparing measures which would entail economic disadvantages if there were no financial rewards. In 1998, 3.300 voluntary agreements were completed in the Weser-Ems (CHAMBER OF AGRICULTURE WESER-EMS 1999).

6XFFHVVDQGEHQHILW Reducing the leaching of nitrates is a long-term task. In water protection areas a more appropriate treatment of the environment can be made practice. The primary motivating force for improved practices are the financial incentives, included in the voluntary agreements. However, is not clear if these agreements are enough to maintain or improve the water quality in the long term. In certain areas (above all those with permeable sandy soils), drastic measures are certainly needed in order to protect the groundwater on a long-term basis. Improved fertilization techniques could contribute to reducing leaching so that plants absorb a higher proportion of the plant available nutrients, including nitrates. Furthermore it should be remembered that the voluntary agreements are only effective in water protection areas which are set up on a regional basis. In other regions, where no protection has been established, improper plant production (primarily inappropriate fertilization management) negatively effects the groundwater. Maize tolerates very high quantities of manure. For this reason the fertilizer-quantity spread on maize fields either should be regulated or the cultivation of maize itself has to be made unattractive by political measures, like for example by reducing profits or subsidies. Environmental impact of maize cultivation: case study Germany 21

 (QYLURQPHQWDOO\FRPSDWLEOHFXOWLYDWLRQRIPDL]H

Since the beginning of the eighties, measures for the environmentally compatible cultivation of maize have been tested and specifically developed from the points of view of the soil and protecting the water. Their effectiveness with respect to environmental goals is different and depends on the location. Individual measures or complex cultivation strategies intervenes in different ways and to differing degrees in operational and agrarian structural contexts. And finally depends on the willingness of the farmers to put environmentally compatible maize- cultivation-systems into the practice.

 0HDVXUHVIRUDQHQYLURQPHQWDOO\FRPSDWLEOHFXOWLYDWLRQRIPDL]H

The procedures of an environmentally compatible cultivation of maize discussed in the following text can be applied generally or targeted to individual situations. They also can be combined and integrated into environmentally compatible production systems. Some procedures may be impractical in some locations. For example, the mechanical weed control can be difficult on humid locations; in dry-areas, the natural water-balance restricts the use of underseeding and catch crops.

• ZHHGFRQWURO Today, a new generation of herbicides which are less dangerous to eluvium endangered are available for the cultivation of maize. The use of herbicides can be restricted by the use of time limits (permitted periods of time for its application). Young maize-plants are especially sensitive to competition between the 4 and 6-leaf-stage. Before and after this time, weeds can be tolerated to a greater degree. Later the maize-plants shade the ground so intensively that the growth of weeds is hindered. (AMMON & IRLA 1996) Row culture offers the possibility of mechanical weed control. A combination of chemical control in the row (band spraying) and mechanical control between the rows increases the success of weed control.

• IHUWLOL]DWLRQ The prerequisite for appropriate fertilization of maize is an assessment of the nutrient content in the farm manure. On top of the corresponding requirement fertilizer quantity, the time of spreading also plays an important role for a proper plant nutrition. Above all, farm manure should be applied so that the offered nitrogen can be absorbed by the plants and does not lead to a burden on the environment. With the help of a special technique (band spreading), it is possible to apply the semi-liquid manure near the surface by the growing maize. For the precise recording of quantitative fertilizer requirements of the maize, several parameters should be considered (LÜTKE 1996, LAURENZ 1996): - the nitrogen requirement of the maize according to yield expectation, in line with controlled trials in the region (estimate) - the nitrogen supply of the soil at the beginning of the main growth period of maize (late Nmin-Method) (measurement) - the long-term nitrogen delivery from the soil according to ground type = estimation - the nitrogen delivery from harvest remains, catch crops and nitrogen fertilization from the previous crop (estimation). If a higher quantity of semi-liquid manure accumulates on a livestock farm than can be used on land given to maize (so that the fertilization of nitrogen is not higher than nitrogen extraction), then the manure should be distributed more evenly over the entire farm area. Environmental impact of maize cultivation: case study Germany 22

This means, preferably, all crops should be fertilized with semi-liquid manure (ZERHUSEN- BLECHER & LÜTKE ENTRUP 1997). With a very high livestock density the semi-liquid manure may need to be exported, the livestock numbers reduced or the area of the farm increased.

• FURSURWDWLRQFXOWLYDWLRQ The cultivation of catch crops, before maize is planted, primarily serves to cover the ground through the winter. Depending on the previous crop, the number of any hibernating catch crops can be considerable. With conservation tillage it is often useful to kill the catch crops and weeds with a non selective herbicide directly before the sowing of the maize. Catch crops planted after maize should guarantee the reception of remaining nutrients. Because of the relatively late harvest of maize in most of the cultivation-areas in Germany, the selection of maize varieties is restricted to a few types which require late seeding dates. The need of catch crops during their development can be catered for by sowing them as an underseed in maize. Thereby a higher catch crop mass can still be achieved in comparison to stubble seed in the autumn. Under seeds can also consist of grasses and of legumes. The procedure "maize-meadow" was specifically developed in Switzerland for regions where many roughages are used and precipitation is sufficient (AMMON & GARIBAY 1995). The maize is sown into an existing turf with the technique of rotary sowing. The grass cover between the rows is usually kept short with mechanical methods. In addition, the reduction of the maize share in a crop rotation should be regarded as an important aspect with diverse environmentally relevant effects, above all if it is interconnected with the introduction of other plant cultures.

• VRLOPDQDJHPHQW With conservation tillage , the seed is brought into a catch crop cover that has experienced frost over winter or was destroyed with a total herbicide. The minimum level of plant activity in a soil can be destroyed by long term fundamental soil management (plough); therefore different soil management systems as well as special- machines have been developed.

 (IIHFWLYHQHVVZLWKFRQVLGHUDWLRQRIHQYLURQPHQWDOJRDOV

An environmentally compatible cultivation of maize should have the goal of reducing nitrate leaching and erosion of the soil, to prevent herbicide contamination of the groundwater and to increase the biodiversity. The measures of integrated weed control, management of fertilization, crop rotation-formation and soil management clearly differ in their effectiveness for the different environmental goals (table 8).

- decrease soil erosion To maintain the soil and to conserve its fertility, the procedures of a reduced soil management system (conservation tillage, minimum cultivation), under-seeding and inter- cropping make a necessary contribution. In addition, they can decrease the unfavourable effects of a close maize rotation. According to the seeding time and growth-conditions, under-seeding can serve different functions. Early under-seeds can fix a nitrogen surplus, which can appear during the summer. While they achieve a certain erosion-protection in a short time, they mainly promote the acceptability of the ground in the autumn. Late under-seeding can hold nutrients in the system over the winter and maintain a ground-cover. Through the application of conservation tillage procedures and non-turning soil management, up to 70% ground cover Environmental impact of maize cultivation: case study Germany 23 can be reached. As little as 30-50% ground cover can considerably decrease drainage from the surface and the soil loss. (SOMMER & BRUNOTTE 1997)

- decrease nitrate leaching The entry of nitrates into the groundwater can clearly be restricted by orienting the nitrogen fertilization towards the demand of the plant, the total soil nitrogen content and the actual delivery of nitrogen. Classification numbers about the nitrogen extraction ascertained by the harvested material, soil-nitrate assessments and the inclusion of weather dates can be used - also like in the grain-cultivation - for a targeted, location-adapted fertilization of maize. Above all, the loss of surplus nitrogen in the autumn can be prevented by underseeding, which grow after the maize harvest as catch crops. In livestock farms, a considerable part of the accruing semi-liquid manure quantities are applied to maize. Procedural solutions allow its use, in line with requirements, which decreases the level of nitrogen compounds and smells being released into the atmosphere. After spreading, up to 65% of the ammonium-nitrogen can be lost through gaseous release. Therefore, the semi-liquid manure should be incorporated into the soil immediately after spreading or, in the case of manuring, a standing plant cover has to be spread close to the surface with the help of a special technique (band spreading).

- prevent herbicide leaching The measure to reduce the danger of herbicide leaching has been partially carried out through public regulations (prohibition of atrazin!). Consistent compliance with these regulations and further regulations very directly effect the harmful potential of leaching herbicides (GUTSCHE 1997). The use of machine heels and time restrictions lead to a reduction in the use of herbicides. Although this allows, at least temporarily, a higher level of weed infestation it can lead to an increase in the biodiversity. Use of mechanical weed- control through hoeing is not possible in silt-rich, hilly terrain because of the high risk of soil erosion. Instead, chemical procedures can be applied in connection with reduced soil management procedures.

- increase biodiversity Increasing the rotation of the crops by reducing the proportion of maize, cultivation of catch crops in narrow, close maize rotations, planting maize cover or tolerating weeds covering the spaces between the rows or at certain times (see above) increases the biodiversity in the maize fields and in the landscape. Reduced soil management techniques for the cultivation of maize have positive effects on the activity of the soil flora and fauna (soil organisms) (JÄGGLI ET AL. 1995). Environmental impact of maize cultivation: case study Germany 24

7DEOH  (IIHFWLYHQHVV RI GLIIHUHQW PHDVXUHV RI WKH HQYLURQPHQWDOO\ FRPSDWLEOH FXOWLYDWLRQ RI PDL]H ZLWK UHVSHFW WR FHUWDLQ HQYLURQPHQWDOJRDOV

Environmental goal Measure decrease soil decrease nitrogen decrease herbicide increase erosion leaching contamination biodiversity Weed control • substitute herbicides which may leach o o ++ o • economic thresholds (time-limits) + o + o until + • combination band spraying, mechanical control –o +++ • mechanical control – o +++ ++ Fertilization • investigation of the nitrogen content of the manure o + o o • well timed organic and mineral fertilization o++oo (based on the use of fertiliser by the plant cover) • late nitrate examination of the soil o ++ o o • distribution of organic manure (farm or farmland), o + until +++ o o Crop rotation / cultivation • catch crop cultivation before maize ++ o o + • catch crop cultivation after maize o ++ o + • under-seeding + ++ until +++ + ++ • maize-meadow +++ +++ ++ ++ • reduction in proportion of maize in the crop rotation ++ + until +++ – until + + Soil management • conservation tillage ++ o o until – o • minimal tillage +++ o – o

Effectiveness with respect to the environmental goal: + low ++ middle +++ high –negative o no effect Environmental impact of maize cultivation: case study Germany 25

 2SHUDWLRQDODQGVWUXFWXUDOUHTXHVWV

In sections 3.1 and 3.2 the measures discussed for the decrease of the environmental burden by the cultivation of maize make different demands of production techniques as well as the operational assumptions. If these demands are not met, the measures cannot be realized. The respective demands of the measures, their costs and effects on profit determine their acceptance in agricultural practice. Generally it can be said that the less a measure costs and the less negative influence the measure has on profit, the sooner it is accepted in the practice. In table 9 environment protecting cultivation measures are estimated with respect to their technical production and yield effects and their acceptability by farmers and are shown schematically. These evaluations represent no solid, invariable measurements and, in individual cases, cannot apply independently from local and operational realities. Altogether there are measures which can be put into practice easily without greater consequences for maize production and measures which do not cause a considerable change in practices of the farms. The effects of the measures on the structure of costs and profits can be very different. Changes in herbicide application, on the whole, lead to higher costs, while machine costs and working times are reduced with soil management procedures. Mineral fertilizer can be saved by a more economic use of organic manure. Decisions need to be made whether new special machines are purchased, or whether it is more favourable to have the work done by a private contractor. Farmers frequently do not have their own appliances for machine-hoeing, so, currently, they are still dependent on employing private contractors where postponements in time can occur. If the optimal time for hoe treatment is missed, reductions in yield are the consequence. This situation does not contribute to an increasing acceptance of mechanical weed control measures. Weed-hoe machines can be used well on dry locations. On rather humid grounds, the restriction in time of the optimal treatment-conditions leads to strong doubts. Moreover optimal weather and ground-structure and the absence of problematic weeds are prerequisite for successful mechanical weed control. Used by itself mechanical weed control necessitates the timely use of special-machines, and can spill weeds between the maize plants. If mechanical weed control is combined with under-seeding, then the under-seedlings can be planted relatively late into the maize cover, which had previously been hoed.

In border locations of the maize cultivated areas, conservation or minimum tillage can have a disadvantageous effect because of lower soil-temperatures. When methods to turn the soil are abandoned completely, root-spreading weeds need to be considered whose control normally necessitates the use of a total herbicide. In order to prevent a one-sided development of problematic weeds by practising the method of minimum cultivation, crop changes should be increased as a preventive measure (more diverse crop rotations, changes of summer and winter crops). The introduction of catch crop cultivation before or after maize needs no special change in the production technology of the maize and puts no further demands on the farm. Favourable effects of catch crop cultivation on soil qualities or the health of following crops has been roughly estimated in a favourable light. At locations with a tendency of an early summer dryness, the need for water of the maize can be reduced by planting winter catch crops prior to the maize. Underseeding has two contrary risks; on the one hand the under seed can fail with unfavourable conditions for emergence (dryness), on the other hand, a well established and luxuriant development of the underseed can introduce yield influencing competition for the maize. The cultivation of underseeds requires experience and skills in plant cultivation from the farmer (choice of plant species, date and method of seeding). The expansion of the crop rotation and the reduction of the maize-share can have considerable consequences for the farm, from the management of forage to livestock husbandry. Environmental impact of maize cultivation: case study Germany 26

An improvement in the environmental compatibility of agricultural production procedures must not be inevitably interconnected with an escalation of expenses. For example, the method of minimal soil cultivation implies a reduced intensity of cultivation. Since farmers, in line with the fertilizing regulations, have had to record dates of use of manure and bought-in fertilizers, willingness has climbed to use the nutrient of the manure more economically on their farm. The saving of mineral fertilizers obviously has an effect on a farm’s results.

With the realization of an environmentally compatible and profit oriented cultivation of maize, conflicts between goals of environmental protection and economy in the cultivation of maize have to be managed in the context of each individual farm. The behaviour of farm managers is decided by legal, agrarian-political and location-specific basic conditions, personal attitudes, the level of training and information, the operational facts and, not ultimately, by economic considerations. Environmental impact of maize cultivation: case study Germany 27

7DEOH'HPDQGVRIWKHPHDVXUHVIRUDQHQYLURQPHQWDOO\FRPSDWLEOHFXOWLYDWLRQRIPDL]HWKHLUHIIHFWVDQGDFFHSWDQFH

Measure Demands of the measure Effect on *) Acceptance #) of the measure yield risk expenses to farmers Weed control • substitute herbicides which may leach information οο ↑ 1 • economic thresholds (time-limits) weed exaltation, information ο↑ ο 2 • combination band spraying - mechanical control Special machines οο ↑ 2 • mechanical control Special machines ↓↑ ↑ 3 Fertilization • investigation of the nitrogen content of the manure sampling and analysis οο ↑ 2 • well timed organic and mineral fertilization (based on improved techniques for manure spreading ο↑ ↑ 2 the use of fertiliser by the plant cover) • Late nitrate examination of the soil sampling and analysis οο ↑ 2 • distribution of organic manure (farm or farmland), band spreading technology for semi-liquid manure in οο↓ - ↑ 1 growing plants and distribution on the farmland • reducing of organic fertilization export of manure, expansion of the agricultural land, oo ↑ 3 reduction in the livestock numbers Crop rotation / cultivation • catch crop cultivation before maize expenditure for cultivation, increasing water demand, ο↑ ↑ 1-2 seed time for maize perhaps belated • catch crop cultivation after maize expenditure for cultivation, soil management / total οο ↑ 1-2 herbicide • under-seeding expenditure for cultivation ο↑ ↑ 3 • maize-meadow Changed cultivation technology, high water demand ↓↑ ↑ 3 • reduction in proportion of maize in the crop rotation procurement of forage οο ↑ 3 Soil management • conservation tillage special sowing technology, catch crop cultivation οο ↑ 2 • minimal tillage special technology for soil treatment and seed ο - ↓↑ ↑ 3 *) ο no one #) 1) high, measure can be introduced easily into practice ↑ increase 2) middle, introduction necessitates additional advice ↓ decrease 3) low, introduction necessitates financial incentive Environmental impact of maize cultivation: case study Germany 28

 ([DPSOHVRISUDFWLFDOLPSOHPHQWDWLRQ

A first crucial step for the implementation of environmentally compatible maize-cultivation techniques into agricultural practice is the consistent application of legal restrictions and the principles of proper agriculture (CHAMBER OF AGRICULTURE HANNOVER & WESER-EMS 1991). Despite diverse consultation and enlightenment activities in the scientific community, the agrarian administration and water management, many farmers retain their conventional production procedures, so a demand for action still exists. The soil protection law and the fertilizing regulations prescribe soil preservation treatment procedures and an environmentally compatible management of fertilization. Golden rules for the successful maize cultivation like plow furrowing, high amounts of semi-liquid manure and the use of Atrazin are no longer valid. The change in the basic legal conditions has led to an uncertainty of production in the farmers. In the following, a few individual examples from practical experiences are briefly discussed. The different procedures of an environmentally compatible cultivation of maize have become accepted very differently in practice. On the one hand, this is related to the complexity of the location realities and the demands of the respective measure. On the other hand, state-specific agrarian political basic conditions must be taken into account. While in the erosion endangered maize cultivating areas of Baden-Württemberg the conservation tillage of maize in catch crop cover which has suffered frost has already become standard (HUGGER 1997), farmers in Lower Saxony still clearly underestimate the danger of erosion from the cultivation of maize in the lowlands and show little readiness to implement improved cultivation methods for maize (LÜTKE ENTRUP et al.1995). The acceptance of mechanical weed control measures in the cultivation maize is still low. The procedures have been developed and tested, but the technology is expensive and the application of herbicides appears even more certain. The nationwide prohibition of applying Atrazin in 1991 has already reduced the effects on ground and surface water from this herbicide. Since then, numerous maize herbicides are available in diverse combinations which allow for a targeted use against individual weeds. The considerable rise in demand for consultation offers a chance to test and to put into practice other weed regulation procedures. In almost all states, extensive production procedures in agriculture are promoted according to the ordinance (EEC) No. 2078/92. Overall it is about so-called relinquishment measures (fertilization, plant-protection) which are mainly employed by farms working with low intensities in less productive locations (OSTERBURG ET AL. 1997). Measures like herbicide relinquishment have not yet been able to establish themselves in the cultivation of maize, therefore only 2% of maize areas in Baden-Württemberg have seen these measures promoted (HUGGER 1997). The large maize producing states, Baden-Württemberg, Bavaria, Brandenburg and Saxony, already promote targeted soil preservation measures like land planting, the conservation tillage and under seeding. These are measures that can, on the basis of land used, be integrated into an environmentally compatible maize production system. (PLANKL 1996; OSTERBURG ET AL. 1997) With particular promotion programs and the creation of network projects in regional show farms North Rhine-Westphalia has attempted to put scientific viewpoints of integrated agri- culture into the practice and to introduce them as examples (LÜTKE ENTRUP et al. 1992). In Lower Saxony, demonstrations have proved to be very effective by which measures of environmentally friendly cultivation have been exhibited as examples on agricultural farms, so that the results can be seen as positive examples for a whole cultivation region. If these pilot projects are combined with investment aids into new technology, well trained and interested farmers change over time to environmental compatible production techniques. On basis of the laws controlling waterways, financial compensation for farmers and a special consultation service, the protection of water can be implemented and financed. From 1994 to Environmental impact of maize cultivation: case study Germany 29

1996 in Lower Saxony over 13 million DM were spent on additional consultation in water- protection and water catchment areas (FEDERAL OFFICE FOR ECOLOGY OF LOWER SAXONY 1998). Catch crop cultivation and the use of special machines for the surface application (band spreading) of semi liquid manure, which are also applicable in the cultivation of maize, have been adopted on a wide basis. Underseeding or even changes in crop rotation are done only from a few farmers. (FEDERAL OFFICE FOR ECOLOGY OF LOWER SAXONY 1997)

In the Weser-Ems region the cultivation of maize is usually forbidden in water protected areas nearby the fountain (BEVERBORG 1996). But more recent experience shows that the cultivation of maize can be integrated well into a water dependency program (FREDE & DABBERT 1998). For quite a time, the support of environmentally compatible maize- cultivation techniques has taken place through voluntary cooperation between water management and agriculture which are oriented towards environmental indicators. Such packages of measures that are developed as common actions of all involved social and interest groups can clearly be the most successful. Criteria for this are the multidisciplinary cooperation of the administration (water management, land use system, agriculture, landscape management) and the intensive consultation and dialogue with the farmers.

 )XWXUHGHYHORSPHQWV

In sections 3.1 to 3.4 measures were introduced and appraised for an environment saving cultivation of maize which has been examined and tested scientifically, and their application have been established in practice. In agrarian research, one looks for further possibilities of more efficient and environmentally compatible cultivation. The following is an outline of which technical improvements in production could attain importance in the medium term in the practice of the cultivation of maize, as well as which innovations appear desirable. Newer implements for mechanical weed control try, with the help of atmospheric pressure controlled from the ground, to antagonize weeds between the rows. The procedure is not yet fully established, and suffers from restrictions in the ground condition and weather, like the other mechanical technologies currently available. The success of weed control between rows could, however, be clearly improved and this method could replace the band spraying of herbicides. Although there is considerable scientific and practical experience of thermal procedures of weed control, the high expense of the method raises questions of profitability especially for fodder plant. This means that further developments of this technology need to address the cost factor. In recent years a dynamic development in the area of breeding herbicide resistant maize varieties with the help of genetic engineering methods has taken place. Environmental benefits and environmental risks that could result from the introduction of herbicide resistant maize are controversially discussed. Another point of criticism is the even stronger market power of the agricultural industry, if seed and herbicide are sold by the same company. Normally, a resistance against non-selective herbicides used in chemical weed control and a transition to herbicides which have less risk of endangering the eluvium would be made. Later weed control would be possible, however, with narrow limits because competition losses appear and the spreading technology is at its limits. It is still to be established in what way reduced soil management procedures, in combination with the cultivation of herbicide resistant varieties, can be realized more certainly and without yield losses. Bt-Maize ensures an effective protection against the European corn borer which is the most significant maize pest in some regions of Germany. By means of genetic engineering procedures a gene from the bacterium Bacillus thuringiensis (Bt) has been incorporated into this maize. So the maize plant is able to produce a toxin which damages the European corn Environmental impact of maize cultivation: case study Germany 30 borer. The questions of its selective effectiveness and the ability of the corn borer to become resistant have not been completely clarified (ENVIRONMENT-FEDERAL-OFFICE 1998). To guarantee fertilization in line with plant requirements would mean a great step forward. This entails that the assessment of nutrient concentrations as well as available nutrient levels in the farm manure (semi-liquid manure) as well as in the soil could take place more quickly and more advantageously than happens with the conventional measurement techniques. Above all, methods such that farmers themselves could apply would be advantageous. Recently considerable technical progress has been made in navigating with the help of GPS (globally positioning system) which also has an effect on agriculture. Surfaces and machines moving on it can be located. Broadly, a great potential to avoid environmental burdens is envisaged through specific and exact treatment, fertilization and maintenance of land. With GPS items can be placed with a precision of a few meters. New possibilities arise with this technical development, especially for proper nutrient management and chemical weed control. In the cultivation of maize this technical advance could be used with positive effects for the environment, by distributing nutrients and herbicides on land accurately, economically, and efficiently. Environmental impact of maize cultivation: case study Germany 31

 6XPPDU\

Maize is an important crop in German arable farming, with variations between regions. It plays a dominant role in forage production. The development of the area under maize reached a maximum in the early eighties and has remained almost constant since. Maize is mainly used for silage, although the acreage of grain maize has increased over the last few years, with considerable variation between years due to annual weather conditions. Agriculture always has environmental effects. Adverse effects are in part a result of inherent characteristics of cropping but they are strongly effected by the location of the farm (i.e. climate and soil) as well as farm structure and farm management. The inherent effects of maize are similar to those of other row crops, e.g. sugar beets and potatoes. Intensive maize growing is closely related to intensive animal husbandry as maize is a highly valuable forage. For historical reasons, intensive livestock production developed mainly in regions which are less favourable for arable farming. This has further aggravated the environmental problem of maize production. Various measures to reduce the environmental impact of maize have been developed since the eighties. New legislation came into force laying down environmental standards for agricultural production. Additionally, agricultural research and advisory services increasingly focus on the development of farming systems which are more friendly to the enviroment. Several management options for an environmentally sound maize production have already been proved in practice: Conservation tillage systems, integrated weed management (hoeing, band spraying, time limits), biological pest control and fertilization (mineral fertilizers, organic manures) which take into account the nutrient demand of the crop and the supply of the soil. However, each management strategy has to be adapted to site and farm specific conditions. In regions with a high density of livestock, for example in the Weser-Ems, it is important that farmyard manure is meaningfully utilised in large quantities. Since agricultural land is, however, normally restricted optimal fertilization management is often required. Here, maize plays a crucial role because it does not react negatively to an excess phytilicetion like, for example, cereals does. The export of farmyard manure into livestock-poor regions is expensive and only practical where lawful limits (FERTILIZATION ORDINANCE) force this. It can be shown that in general it is possible to grow maize with less adverse environmental effects. However, such systems are often more expensive and, hence, have not become standard in practical farming. An improved advisory service, practical demonstration of the possibilities and financial support have already increased the acceptance of an environmentally sound crop management of maize. Measures to reduce adverse environmental effects of maize in practical farming also depend on the nutrient management Environmental impact of maize cultivation: case study Germany 32 of intensive livestock production systems and on the readiness of farmers to share special technical equipment with other farmers. Environmental impact of maize cultivation: case study Germany 33

 /LWHUDWXUH

AMMON, H.-U. UND GARIBAY, S. (1995): Die Maiswiese - ein neues Anbauverfahren. Mais 23 (2), 68-71.

AMMON, U. U. E. IRLA (1996): Unkrautbekämpfung im Acker- und Futterbau. Landwirtschaftliche Lehrmittelzentrale, CH-3052 Zollikofen, S. 30-36

AUFHAMMER, WALTER (1998): Getreide- und andere Körnerfruchtarten: Bedeutung, Nutzung und Anbau. Stuttgart: Ulmer

BENKE, M., M. KAYSER, B. THOMANN UND A. KAYSER (1999): Begleitende Untersuchungen des oberflächnenahen Sickerwassers mittels der Saugkerzen- Methode zur kontinuierlichen Erfassung der Verlagerung und Auswaschung von Nitrat-Stickstoff, Phosphat und Kalium aus landwirtschaftlich genutzten Flächen. Forschungsbericht des Forschungs- und Studienzentrum für Veredlungswirtschaft Weser-Ems in Vechta. BEVERBORG, R. (1996): Maisanbauverbot in Wasserschutzgebieten. Landwirtschaftsblatt Weser-Ems (12), 26-30. DISTRICT-GOVERNMENT WESER-EMS (1999): Freiwillige Vereinbarungen nach § 47 h NWG (Niedersächsisches Wasserhaushaltsgesetz) im Regierungsbezirk Weser-Ems 1999. Oldenburg. FEDERAL MINISTRY OF AGRICULTURE (1995): Bericht des Bundes und der Länder über Nachwachsende Rohstoffe 1995. Schriftenreihe des Bundesministeriums für Ernährung, Landwirtschaft und Forsten, Reihe A: Angewandte Wissenschaft, Sonderheft. FEDERAL MINISTRY OF AGRICULTURE (Hrsg.) (1997): Die europäische Agrarreform - Pflanzlicher Bereich. Broschüre für das Erntejahr 1998, Bonn im November 1997. FEDERAL MINISTRY OF AGRICULTURE (1999): Broschüre über eine gute fachliche Praxis der landwirtschaftlichen Bodennutzung; Bonn. GERMAN MAIZE-COMMITTEE E.V. (Hrsg.) (1999) : Sortenspiegel mit allen Landessortenversuchen Mais; außerdem: Internetseiten unter www.maiskomittee.de. FREDE, H.-G. UND DABBERT, S. (Hrsg.) (1998): Handbuch zum Gewässerschutz in der Landwirtschaft. Ecomed, Landsberg. GÄTH, S. (1997): Methoden der Nährstoffbilanzierung und ihre Anwendung als Agrar- Umweltindikator. In: Deutsche Bundesstiftung Umwelt (Hrsg.): Umweltverträgliche Pflanzenproduktion - Indikatoren, Bilanzierungsansätze und ihre Einbindung in Ökobilanzen. Zeller Verlag, Osnabrück, Initiativen zum Umweltschutz 5, 115-126. Environmental impact of maize cultivation: case study Germany 34

GERMEIER, C.U. (1997): Möglichkeiten und Grenzen des Anbaus von Winterzwischenfrüchten und der Anwendung von Verfahren reduzierter Bodenbearbeitung im ökologischen Maisanbau. Beitr. 4. Wiss.-Tagung Ökol. Landbau, Bonn: 403-409 GUTSCHE, V, (1997): Pflanzenschutzbezogene Indikatoren einer nachhaltigen Landwirtschaft - Problem und Lösungsansätze. In: Deutsche Bundesstiftung Umwelt (Hrsg.): Umweltverträgliche Pflanzenproduktion - Indikatoren, Bilanzierungsansätze und ihre Einbindung in Ökobilanzen. Zeller Verlag, Osnabrück, Initiativen zum Umweltschutz 5, 101-113. HUGGER, H. (1997): Umweltorientierter Maisanbau in Baden-Württemberg. Fachtagung: Umweltgerechter und ertragsorientierter Maisanbau, Soest, 8.-9.7.1997, 192-199. JÄGGLI, W., OBERHOLZER, H.-R. UND WALDBURGER, M. (1995): Vier Maisanbauverfahren 1990-1993. Auswirkungen auf das Bodenleben. AgrarForschung 2 (9), 361-364.

LAURENZ, L. (1996): Mais: Späte Nmin-Probe senkt die Düngekosten! In: top agrar, 4, S. 54-56

LORENZ, F. & G. STEFFENS (1997): Stickstoffaustrag und Stickstoffbilanz nach Gülledüngung im Lysimeterversuch. VDLUFA-Schriftenreihe 46, 595-598. LORENZ, FRANK (1992):Gülledüngung mit ergänzenden Mineral-N-Gaben zur Erzielung optimaler Erträge bei niedrigem Nitrataustrag. Göttinger Bodenkundliche Berichte, 99. LÜTKE ENTRUP, N. UND ZERHUSEN, P.(1992): Mais und Umwelt. Schriftenreihe Studien zur Agrarökologie, Band 4, Verlag Dr. Kovac, Hamburg LÜTKE ENTRUP, N., GRÖBLINGHOFF, F.-F. UND ZERHUSEN, P. (1992): Verfahren und erste Ergebnisse zum Wissenstransfer integrierter Pflanzenbauverfahren in die Praxis. Mitt. Ges. Pflanzenbauwiss. 5, 63-66 LÜTKE ENTRUP, N., HENSCHE, H.-U., BRODOWSKI, N. UND KERSTIN, D. (1995): Umweltrelevante Verhaltensmuster der Landwirte - Umsetzungsstrategien und Transferdefizite für den integrierten Pflanzenbau in Nordrhein-Westfalen. Forschungsberichte des Fachbereichs Landbau Soest Nr. 1, Universität- Gesamthochschule Paderborn

LÜTKE ENTRUP, N. (1996): Mais: Nmin-Probe Mitte Mai ziehen. In: Deutsche Landwirtschaftliche Zeitung (dlz), 4, S. 42-44. CHAMBER OF AGRICULTURE HANNOVER (Hrsg.) (1995): Nachwachsende Rohstoffe - Möglichkeiten und Chancen für den Industrie- und Energiepflanzenanbau. 2. Aufl. CHAMBER OF AGRICULTURE HANNOVER & WESER-EMS (Hrsg.) (1991): Leitlinien - Ordnungsgemäße Landbewirtschaftung. Hannover Environmental impact of maize cultivation: case study Germany 35

CHAMBER OF AGRICULTURE WESER-EMS (1999): Ergebnisse von Prüfungen und Feldversuchen mit Mais Erntejahr 1998. Oldenburg

CHAMBER OF AGRICULTURE WESER-EMS (1998a): Ergebnisse von Prüfungen und Feldversuchen mit Mais Erntejahr 1997. Oldenburg

CHAMBER OF AGRICULTURE WESER-EMS (1998b):Projekt Anlage, Betreuung und Auswertung von Versuchsflächen in Wasserschutzgebieten. Abschlußbericht 1995- 97. FEDERAL OFFICE FOR ECOLOGY OF LOWER SAXONY (Hrsg.) (1997): Auswertung der Ergebnisse ausgewählter Modellgebiete als Grundlage für Empfehlungen zur Durchführung der landwirtschaftlichen Zusatzberatung - Abschlußbericht, 2.Aufl., Hildesheim FEDERAL OFFICE FOR ECOLOGY OF LOWER SAXONY (Hrsg.) (1998): Grundwasserworkshop des Niedersächsischen Landesamtes für Ökologie, 29. Oktober 1997 in Hildesheim OSTERBURG, B., WILHELM, J. UND NIEBERG, H. (1997): Darstellung der regionalen Inanspruchnahme von Agrarumweltmaßnahmen gemäß Verordnung (EWG) 2078/92 in Deutschland. Institut für Betriebswirtschaft der FAL Arbeitsbericht 8/97, Braunschweig-Völkerode OSWALD, PETER (1998): Zur Entstehung der Düngeverordnung. DLG Arbeitsunterlagen: Die Düngeverordnung auf dem Prüfstand. 60-67, Frankfurt: DLG. PLANKL, R. (1996): Synopse zu den Agrarumweltprogrammen der Länder in der Bundesrepublik Deutschland - Maßnahmen zur Förderung umweltgerechter und den natürlichen Lebensraum schützender landwirtschaftlicher Produktionsverfahren gemäß VO (EWG) 2078/92. Institut für Strukturforschung der FAL, Arbeitsbericht 12/9196, Braunschweig-Völkerode SCHÜRMANN, CHRISTIAN (1998): Entwicklungsprobleme in den intensiven Veredlungregionen Niedersachsens unter besonderer Berücksichtigung der Düngeverordnung. Diplomarbeit, Universität Göttingen SOMMER, C U. J. BRUNOTTE (1997): Bodenbearbeitung und Bodenfunktionen im Konzept des umweltverträglichen Maisanbaus. Fachtagung "Umweltgerechter und ertragsgerechter Maisanbau", Universität-Gesamthochschule Paderborn, S. 149. ENVIRONMENT-FEDERAL-OFFICE (1998): Monitoring von Umweltwirkungen gentechnisch veränderter Pflanzen (GVP). Fachgespräch vom 4.-5. Juni 1998, Texte 77/98, Berlin. ZERHUSEN-BLECHER, P. UND LÜTKE-ENTRUP, N. (1997): Nährstoffbilanzen im Maisanbau - eine Analyse aus praktischen Betrieben. Fachtagung: Umweltgerechter und ertragsorientierter Maisanbau, Soest, 8.-9.7.1997, 122-133. ZSCHEISCHLER, J. (1990): Handbuch Mais: umweltgerechter Anbau; wirtschaftliche Verwertung. DLG-Verlag, Frankfurt (Main), 4. Aufl. Environmental impact of maize cultivation: case study Germany 36

/DZVDQGRUGLQDQFHV

SOIL PROTECTION LAW (Bundes-Bodenschutzgesetz): Gesetz zum Schutz vor schädlichen Bodenveränderungen und zur Sanierung von Altlasten vom 17. März 1998. BGBL I S. 502. FERTILIZATION ORDINANCE: Verordnung über die Grundsätze der guten fachlichen Praxis beim Düngen vom 26. Januar 1996. BGBL I S. 118, geändert durch VO v. 16.7.1997, BGBL I S. 1835. PLANT PROTECTION LAW: Gesetz zum Schutz der Kulturpflanzen in der Fassung der Bekanntmachung vom 14. Mai 1998. BGBL I S. 971., ber. S. 1527. WATER SUPPLY LAW: Gesetz zur Ordnung des Wasserhaushalts in der Fassung der Bekanntmachung vom 12. November 1996. BGBL I S. 1695, geändert durch G v. 30.4.1998, BGBL I S. 823.

6WDWLVWLFDOGDWD

FEDERAL MINISTRY OF AGRICULTURE: Statistisches Jahrbuch über Ernährung, Landwirtschaft und Forsten der Bundesrepublik Deutschland. Landwirtschaftsverlag GmbH, Münster-Hiltrup, 1993, 1996, 1997.

FEDERAL GOVERNMENT: AGRARBERICHT - Agrar- und ernährungspolitische Berichte der Bundesregierung. Bonn 1990-1998. LOWER SAXONY DEPARTMENT FOR STATISTICS (1994-1999):Statistische Berichte Niedersachsen, Bodennutzung und Ernte. Hannover. STATISTICAL FEDERAL-DEPARTMENT: Fachserie 3 - Reihe 3 - Landwirtschaftliche Bodennutzung und pflanzliche Erzeugung. 1990-1997.