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Untersuchungen zum Einfluß von Konkurrenz auf die Bestandesentwicklung von Sommerraps bei unterschiedlicher Gunst der Umweltbedingungen
Author(s) -
Geisler G.,
Shrief S. A.,
Ibrahim A. F.,
Shabana R.
Publication year - 1992
Publication title -
journal of agronomy and crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.095
H-Index - 74
eISSN - 1439-037X
pISSN - 0931-2250
DOI - 10.1111/j.1439-037x.1992.tb01026.x
Subject(s) - kurtosis , competition (biology) , agronomy , skewness , plant density , biology , mathematics , horticulture , sowing , statistics , ecology
Investigations on the effect of competition with regard to the stand development of spring oilseed rape as dependent on environmental conditions Field experiments were conducted to investigate the frequency distribution in spring oilseed rape as dependent on environmental growing conditions and plant density. As measures for frequency distribution skewness and kurtosis were estimated. The plant character determined was single plant dry matter. To understand the changes in the stand structure, samples were taken at the following developmental stages: rosette, begin of flowering, end of flowering and ripeness (harvest). Plant densities ranged from 60 plants/m 2 , 90 plants/m 2 till 120 plants/m 2 The results show that under unfavourable growing conditions, generally speaking, the values of (positive) skewness and kurtosis increase with the development of the plants; under favourable growing conditions, however, the values of skewness and kurtosis decrease from rosette till harvest. Under unfavourable growing conditions as well as favourable ones, the values of skewness and kurtosis increase with strengthening of plant competition as consequence of increasing plant density. However, the trend during development and the height of the values as well as the quantitative relationships are strongly controlled by the general growing conditions. Frequency distribution, therefore, is not only a result of plant competition but also of differences in resources due to the general conditions of the location.