REVIEW OF THE MAIN CROPS AND THEIR VARIETIES
The vegetation period of oil seed rape is about 120 days. The length of vegetation of oil seed rape depends on weather conditions, and the variety. There is spring and winter oil seed rape grown in Latvia . The spring oil seed rape has better growing stability than winter varieties, but the yields of spring rape are not so high. The winter oil seed rape often is hardly damaged by the winter conditions. Reason of it sometimes is also the late sowing. The winter oil seed rape should be sown in the end of July or beginning of August, nevertheless, this rule not always is observed.
Factories for cooking oil production use most of Latvian produced rapeseeds. Latvia also provides export to other countries. Rapeseeds are used also for bio fuel production.
The oil seed rape in Latvia recently has gained popularity since it is good for sale. There are many small oil workshops and one big factory in Latvia .
The widely growing winter varieties are 'Express', 'Karola', 'Kasimir', 'Lirajet', 'Valesca' (originator Germany), 'Amber'(originator Sweden).
The widely spring growing varieties are 'Amica', 'Iris', 'Liaison', 'Licosmos', 'Olga', 'Ouantum', 'Ural', 'Lara', 'Heros' (originator Germany), 'Bingo', 'Star' (originator Denmark), 'Sponsor', 'Mascot', 'Senator' (originator Sweden). CROP PHYSIOLOGY
Winter rape should be sown in the end of July, or the beginning of August, 1-2 cm deep. Spring oil seed rape should be sown as early as possible. If the soil temperature is > 15°C and soil moisture is sufficient, seed germinate in 3-4 days. The point of growing is sensitive to unfavorable weather conditions (frost, hail), pests and others that may damage shoots. For wintering winter rape must have 8-10 leaves, the diameter of root neck must be >8 mm. The wintering is natural and does not influence seed yield if the point of growing is live. he yield depends on the leaf area in the phase of flowering. The amount of potential pods and number of seeds in pod is developed from every stress (diseases, pests, meteorological conditions). The seeds are brown to black, pods are yellow, and breakable.
SOIL
Oil seed rape is a soil selective crop. Loose soils with high fertility and deep plough layer are optimal for oil seed rape growth. More suitable are sandy loam- loamy soils. Oil seed rape grows also in light soils in case of rich content of humus and calcium and if there is enough humidity. Negative impact on the growth has low water content, and excessive rainfalls. More suitable are soddy- podzolic and soddy- carbonat soils. The optimal pH is 6,2-7,5.
CLIMATE
The oil seed rape is modest as to the requirements of temperature. It starts germination at +2 ° C. The optimal temperature for germination is +15 ° C. The rain is more required at emergence and flowering of oil seed rape. Sowing of oil seed rape in the second half of May can cause uneven maturity and high losses in yield. The vegetation period of spring oil seed rape is 100 - 130 days. The growth of winter oil seed rape in Latvia is complicated. Very often during wintering the sowings of oil seed rape may be destroyed by frost. Winter oil seed rape better uses the moisture in spring and therefore has higher yields. Winter oil seed rape is a better competitor to weeds while in sowings of spring oil seed rape the weeds problem is very topical.
RADIATION
Oil seed rape is the long day plant. Therefore conditions of Latvia - in spring and in summer - the periodicity of long day illumination stimulate its development. Winter wheat better stands frost in winter when in autumn there is sunny weather while accumulating more carbohydrates in wintering plant parts. The optimal plant density is 80- 120 plants per m2 .
|
