- Rapeseed should preferably be grown on one and the same field at time intervals of at least three years.
- The field to be cultivated with rapeseed should be cleared by the end of July.
- Good precursor crops are peas, beans, wheat and barley (early varieties). Rapeseed is an excellent precursor crop thanks to its capacity to release a large amount of nutrients into a rich vegetable mass that decomposes easily in the arable soil layer.
RISKS TO AVOID:
- Due to the fact that pulses and sunflower get easily infected with Sclerotinia sclerotiorum, their use for crop rotation purposes should be avoided.
- Be aware that rapeseed is sensitive to the remnant effect of certain herbicides, and in particular to the effect of the herbicides belonging to the sulphonylureas class.
Rapeseed should be grown in:
- Clayey soils;
- Heavy soils and sandy soils, rich in humus and nutrients, and sufficient rainfalls (all of which are conducive to high productions and big profits)
Avoid growing rapeseed in:
- Very clayey soils which are likely to keep the soil moist. In addition to the problems that are usually associated with the structure of this type of soils and with the planting preparation works, rapeseed survival over winter may also be a risk worth considering.
- Extremely light soils and flat lands. Insufficient rainfalls may jeopardize rapeseed crops.
- Soils exposed to late frost risk. The danger of stem bursting and flower dying due to frost need to be carefully considered.
|FERTILIZATION IS ONE OF THE TECHNOLOGICAL ELEMENTS WITH THE HIGHEST IMPACT ON CROP YIELD|
Rapeseed is a crop with high demands on phosphorus. In most cases, it is advisable to fertilize the soil with phosphorus before sowing. On soils that are poor in phosphorus, specialists would even recommend applying fertilizer to the plowed ground, so that, after the preparation of the germinal bed, the rape seedlings may find phosphorus very quickly in the shallow soil layers. Non-fertilization with phosphorus (especially in soils with a low phosphorous content) would badly affect the rapeseed production. In rapeseed cultivation, phosphorus deficiencies may occur during the first stages of vegetation, i.e. even in the second week after plant emergence, because phosphorus from the seed reserves is depleted within the first seven days. Poor phosphorus uptake is most often manifested in young plants, after long periods of cold weather.
This fertilization is highly important for plant resistance to diseases, drought and frost.
This is the macroelement that is the most needed by the plants.
At end of winter, the above the ground part of a promising rapeseed crop should have a biomass of at least 500-600 g /sqm (fresh substance). To achieve this biomass rate, rapeseed plants would absorb between 35-45 kg N / ha. When seeded optimally and on a reasonably fertilized soil, rapeseed can use most of this quantity of nitrogen from what the soil alone supplies. If the rapeseed crop is grown after a high-yield grain crop whose straws were chaffed and incorporated into the soil, the occurrence of the so called “nitrogen starvation” phenomenon should be avoided (by applying 7-10 kg of nitrogen per ton of mulch incorporated). A high level of biomass accumulating into the soil before winter will lead to high losses of nitrogen, which will be only partially recovered by the crop, in addition to a higher risk of plants getting dried over winter.
Sulfur comes third in the order of importance after nitrogen and phosphorus. However, the best way to cater for the sulfur needs of the crop is to apply complex granular fertilizers. This type of fertilizers are rich in sulfur, are easier to apply and are good for both basic and acid soils. Rapeseed is the plant that best responds to sulfur-based fertilization. In many cases, sulfur deficiency is detected early on in the case of rapeseed and only after a few years in the case of cereals. Basically, in oil plants, the yield increases directly in proportion to the dose of 60 kg S / ha. Specialists believe that, in case of sulfur deficiency, the losses can reach to as high as 1,000-2,000 kg / ha.
Boron does not migrate heavily into the plant, which means that it should be supplied whenever the need arises (mainly in autumn and in spring). Soils that are predisposed to boron depletion include sandy soils, soils with a pH of more than 7, soils with low or very high content of organic matter, compacted and / or dry soils; amended soils.
- B-based fertilization in autumn: In autumn, Boron plays an important role in root growths, nutrient conveyance and accumulation of reserve substances. In autumn it is recommended that Boron be applied to the soil in a dose of 200-300 g / ha.
- B-based fertilization in spring: In spring, Boron is mainly responsible for the growth of the pollen tube and for the uniformity of the plant flowering. In spring, Boron may also be applied on the foliage, in a dose of 300-500 g / ha.
- Weeds – Weed control in rapeseed crops shows several particularities, which are mainly related to the sowing period, the distance between rows etc. and which make rapeseed more resistant to weeds compared to most other crop plants. However, high rapeseed yields can be only be obtained if we take a few basic weed control measures. Weed control uses exclusively anti-grass herbicides (wild cruciferous plants should be killed through tilling, crop rotations etc.), coupled, where necessary, with weed-harrowing in spring).
- Pests – Rapeseed is targeted by many pests (Meligethes aeneus, Psylliodes chrysocephala, Brevicoryne brassicae, Entomiscelis adonidis) against which 2-3 treatments must be applied at appropriate intervals and using adequate products.
Rapeseed crop is harvested 7-9 days after its treatment with desiccants directly in the field by means of a harvester adapted for rapeseed culture.
- If no desiccants are used (which is otherwise uneconomical in the case of small surfaces), harvesting the rape would pose difficulties, even in hybrids that are highly resistant to shaking. It is therefore recommended to use autumn rapeseed hybrids, which have indehiscent fruits that are resistant to falling down (vigorous stems, capable to withstand a harvest of over 2,500-3,000 kilograms per hectare) and allow the rapeseed to be harvested without application of desiccants.
- Application of all the technological measures that are designed to ensure uniformly ripened crops (land leveling, perfect sowing and fertilization, weed control) are paramount in this case.
- After harvest, the rapeseeds are kept spread in 5-10 cm thick layers and are shoveled daily until they reach a moisture content of 9%. However, artificial drying is more advantageous method.
- KEEP THE DEVELOPMENT OF BIOMASS AT A MINIMUM (except for late sowing), to prevent an early elongation of the stalk and the excessive consumption of the reserve sugars stored in the root for foliage growth purposes.
- INCREASE PHOSPHORUS SUPPLY AND ENSURE A GOOD GERMINAL BED STRUCTURE to facilitate root system development.
- AVOID THE DEVELOPMENT OF A LARGE AMOUNT OF ORGANIC MATTER ON THE SURFACE, which may delay seed germination. Preserve the moisture in the germinal bed ø. Although an important factor to consider during autumn, DENISTY is not the main goal to pursue. Rapeseed has a very good branching capacity, in general.
- DENSITY in the spring depends on the resistance of the plate over the winter, so the accumulation of dry mass is important.
- WHEN WINTER COMES, rapeseed should ideally have an eight millimeter collet (the portion between the stem and the root), an eight millimeter root and a total of eight leaves.
KEY POINTS TO CONSIDER IN DIFFERENT PHENOPHASES:
High efficiency after the first nitrogen application in spring
- Long-lasting effects after the last application, owing to that further applications are no longer possible due to crop height and flowering.
- Ensure sufficient supply of potassium to cater for the crop’s high demand for potassium and to eliminate the water stress risk.
- Ensure sufficient accumulation of dry mass before flowering, given that there is a strong competition in acquiring assimilates and nutrients among the different overlapping processes (vegetative growth, flowering, pod formation and seed filling).
Flower induction, flowering and pod (hull/husk) formation
- Ensure nitrogen availability and the capacity of the plant to absorb nitrogen as long as possible. After the flowering stage, rape will go through a critical nitrogen absorption phase.
- Ensure enough amount of sugars before the flowering stage (a rich content of sugars facilitates nitrogen transformation) Ø Ensure sugar synthesis and accumulation up until the end of the flowering stage (provide for sufficient light intensity, water and potassium supply).
- Keep the sap flowing through the plant as much as possible, to facilitate transfer of sugars to the seed (accumulation of lipids)
- Make sure the plant develops a strong root system, the photosynthesis at shell (pod) level is as intense as possible and the nitrogen is available in sufficient quantity and for as long as possible.
- Keep in mind that only the first flowers will grow into pods (hulls/shells); therefore, the flowering should be grouped and homogeneous, so as to increase fecundation rate and obtain uniform pod formation (less crop losses)
Maintain an intense photosynthesis process for as long as possible, as a way to achieve and maintain a good synthesis of sugars, which are the main energy source and the carbon skeleton for the production of fatty acids.
CICh’s position with regard to rapeseed growing – IN AUTUMN
- CEREALFOS or NP 8.30 0 NGOOO+AMESAL + ME– high phosphorous deficiency, ~ 180 – 200 KG/HA
- NP 5.24.0 NGOOO + AMESAL + ME– low to medium phosphorous deficiency, ~ 200 -250 KG/HA
- NPK: 4.20.10. + NGOOO+ AMESAL + ME– apply potassium in the sowing stage, ~ 200 – 250 KG/HA
KEY ISSUES TO CONSIDER!
- ALL SOLID FERTILIZERS CONTAIN NGOOO IN NITROGEN, WHICH MAKES THEM CAPABLE TO PROVIDE A GRADUAL AND CONTROLLED RELEASE OF NITROGEN THROUGH THE NITRIFICATION INHIBITOR
- THE PRESENCE OF 200 N AMESAL IN ALL THE COMPLEX FERTILIZERS ELIMINATES THE CONCERNS AS TO WHETHER THE SOIL PH IS ACIDIC OR BASIC, BECAUSE FERTILIZERS OF THIS TYPE FACILITATE THE RELEASE OF AL AND FE IONS IN ACID SOILAND OF CA AND MG IONS IN ALKALINE SOILS, RESPECTIVELY.