3 MATERIAL AND METHODS
3.2 Description of the experimental locations
3.2.1 Experimental station Giessen
The experimental station Giessen (50°°35°N,8°°40°E) is located in the valley of the Lahn river. With about 1° 12’ northward displacement, the experimental station Giessen is relatively cooler compared with Gross-Gerau. This delays sowing and consequently harvest time by at most a week in Giessen relative to Gross-Gerau.
Topographically the station is generally even with homogenous soils rich in clay.
These mainly fluvogenic (river side ) soils are best described as having a Silty clay consistency. Despite high levels of clay, the soils are characterised by lower available field capacity with high dead water contents (around 202mm / 100cm).
Table 3.5: General characteristics of the experimental station Giessen
Factor Value
Soil specie Silty clay
Clay content 28-33%
Available field capacity (100cm) 123mm
Height above NN 158m
Long term average Air temperature 9,0°C Long term average precipitation 650mm/year
NN= Normal null (the German standard for measuring height above sea level).
The experimental field used in 2004 was previously sown with winter Vetch
(Vicia villosa) and that used in 2005 and 2006 were previously sown with winter wheat (Triticum aestivum).
Soil conditions and fertilization
Prior to each experiment a soil analysis was carried out to help in planning fertilizer applications. Soil nutrient contents were evaluated from top soil to 90 cm deep. The results are presented in table 3.6 and 3.7 below.
Table 3.6: Results of soil analysis Giessen 2005
Nutrient Results(mg/100g soil)
P2O5 21
K2O 17
MgO 18,6
Soil reactions were slightly acidic (pH 6,1)
Table 3.7: Results of mineralised Nitrogen at different soil depths
Soil depth analyse Nmin (mgNO3)/100g soil
0 – 30 cm 12,65
30 – 60 cm 13,5
60 – 90 cm 15
Total 41,15
Based on this soil analysis results, fertilizer applications were executed at the seed bed preparation stage of each experiment: The application dosages can be inferred in table 3.8 below.
Table 3.8: Fertilizer applied at the seed bed preparation stage in Giessen in 2004, 2005 and 2006
Fertilizer type Nutrients % Nutrients content Applications (kg/ha) Nitrophoska
N 16 110
P2O5 16 110
K2O 16 110
At the fourth leaf stage a second N – fertilization of 60 kgN/ha was applied using potassium ammonium sulphate fertilizer containing 27% nitrogen.
Weather and climate conditions in 2004
In order to access the effects of weather on the performances of the maize cultivars used, meteorological results of each experimental year were compared with the known long term averages for Giessen. The results are illustrated in figures 3.2, 3.3, 3.4, 3.5, 3.6 and 3.7 below.
Results of precipitation in 2004 shown in fig 3.2 below shows May to have been the wettest month as indicated by its very high rainfall compared with long term average.
In June precipitation was below long term average.
0 20 40 60 80 100 120
January February
March Aprile
May
June July August
September October
November December months
precipitation units mm
Precipitation Long term average Precipitation 2004 (mm)
Fig. 3.2: Developments in precipitation over Giessen in 2004 compared with respec-tive long term averages (ppt = precipitation; lta = long term average)
This was the period of stem elongation for the maize cultivars. Apart from these two abnormalities the growing season (April to October) was generally favourable in Giessen.
Fig. 3.3 shows results of temperature regime over Giessen in 2004. According to this illustration Giessen was normally warm as temperatures were very close to long term averages at all months especially during the growing season.
0 5 10 15 20 25
1 2 3 4 5 6 7 8 9 10 11 12
m onths
temperature units °C
Tem perature Long term average°(C) Tem perature 2004 (°C)
Fig. 3.3: Developments in atmospheric temperature over Giessen in 2004 compared with respective long term averages ;( temp=temperature; lta = long term average)
Temperatures in mid April were above 10°C suggesting good potentials for germi-nation. A higher than long term value in August also suggests good dry down poten-tials for maize especially the early maturing cultivars.
Weather and climate conditions in 2005
Results of precipitations as shown in figure 3.4 indicate a wetter growing season (April to October) compared with the long term averages as well as with 2004.
0 20 40 60 80 100 120
January February
March Aprile
May
June July August
September October
Novem ber
Decem ber
months
precipitation units mm
Precipitation long term average(mm) precipitation 2005 (mm)
Fig. 3.4: Developments in precipitation over Giessen in 2005 compared with res-pective long term averages (Ppt = precipitation; lta = long term average) Like in 2004 may was the wettest month and June the driest. However unlike in 2004, the drier June was equivalent to observations made from long term averages. The growing season was also normal even though wetter than 2004.
Results of average temperatures over Giessen in 2005 are compared with long term averages in figure 3.5. It can be observed that temperatures were above long term averages for all the months within the growing season except in August where temperatures were same as the long term average.
-5 0 5 10 15 20 25
January February
March Aprile
May
June July August
September October
November December months
temperature units °C
Temperature Long term average °C Temperature 2005 °C
Fig. 3.5: Developments in atmospheric temperature over Giessen in 2005 compared with respective long term averages (temp=temperature; lta = long term average)
The temperature above 10°C observed in mid April was a favourable sign for good germination potentials as is known for maize.
Weather and climate conditions in 2006
Figure 3.6 shows 2006 to be a very problematic year as compared with 2004 and 2005. March and mid August were the wettest months and April was even drier than long term average.
0 10 20 30 40 50 60 70 80 90 100
January February
March Aprile
May
June July August
September October
November December MONTHS
PRECIPITATION UNITS MM
Precipitation Long term average Precipitation 2006 (mm)
Fig. 3.6: Developments in precipitation over Giessen in 2006 compared with re-spective long term averages (Ppt = precipitation; lta = long term average
The growing season (April to October) can be seen to be drier than 2004 and 2005.
July was the hottest month and corresponded with the period of Anthesis in the middle late and late maize cultivars as well as grain filling stages for the early and middle early cultivars. This Couple with the cooler April and may explain the reason why 2006 is described as problematic.
Figure 3.7 shows the temperature distribution over Giessen in 2006 and compares it with long term averages of each month. The growing season (April to October) can be seen to be drier than 2004 and 2005. July was the hottest month and corresponded with the period of Anthesis in the middle late and late maize cultivars as well as grain filling stages for the early and middle early cultivars. This Couple with the cooler April and may explain the reason why 2006 is described as problematic.
-5 0 5 10 15 20 25
January February
March Aprile
May
June July August
September October
November December month
temperature units°C
Temperature Long term average°(C) Temperature 2006(°C)
Fig. 3.7: Developments in atmospheric temperature over Giessen in 2006 compared with respective long term averages (temp=temperature; lta = long term average)