Nowadays, the issue of saving the harvest or at least reducing the losses due to climate conditions, morphological and biochemical factors are becoming increasingly important. Rape is one of the most attractive and sensitive cultures of farmer solutions.
Over 60 million tons of rapeseed is grown worldwide, and in EU countries - 19 mln. tons. Historically, over 250 000 hectares of rape are growing in Lithuania, however, due to the new regulation of pesticide use, rape areas are declining. Variety selection, crop rotation, cultivation technology - everything has a significant impact on rape harvest, but perhaps the most important step is harvesting. Early harvesting, when harvesting moisture higher than 20%, can result in huge losses in cleaning and drying while delaying increases the loss caused by spillage and mechanical impact. If extended collector for the rape can be used to reduce mechanical impact, other measures are needed to control bio-opening, especially in the case of high temperatures such as this year.
One of the main reasons for the loss of rapeseed harvest is the self-extinction of legumes before harvesting. As the plant matures, the natural opening of the pods is determined by the methylene and auxin produced by the biochemical processes, which determine the activity of the enzymes. The opening of leggings is a natural process, which makes plants sow their seeds to survive and grow wild. Although this mechanism has advantages in nature, scientist Hossain and others have found that the natural opening of rape legumes in agriculture leads to high yield losses. From 10 to 15 percent (about 90,000 tons of harvest in Lithuania) of the harvest is lost due to the self-extinguishing of rapeseed legumes before harvesting. Researchers led by Prof. L.Spoke found that prolonging the harvest increases the loss to 20%. Most of the seeds from the pods come out of the rape when the maturity is full.
The second reason for the opening of legumes is associated with the frequent change of meteorological conditions just before harvesting. Humidity and temperature changes make the pins open early.
The third reason is rapeseed maturation. Also, when harvesting rape, the pods are hacked, dropped too low and the crop rotators or passive separators on the side of the cutter are turned too high. Two-stage active separators reduce the losses of rapeseed several times (Domeika et al., 2008).
University of California scientists in a new study introduced the influence of high temperatures and "heat waves" on early self-opening of pods. When investigating plant vegetation at different temperatures, it was observed that at higher temperatures, the plant gene promoting faster maturation and opening of the legumes (known as the IND genus) is significantly stronger. This study has drawn guidelines for breeders who will have to reduce the effect of this gene at high temperatures, but at present, even the most advanced smaller self-opening pods are not ready for the temperature and humidity or drought shock caused by warming.
Due to unusually high temperatures and low humidity this year, Lithuanian farmers are hoping for much smaller than normal harvests, as well as earlier harvesting than usual. Late this year is particularly risky, especially if rainy weather, or worse - storms will reach Lithuania just before harvest. This happened in Canada in 2012, with heavy rain escorted by heavy heat, so some farmers lost up to 70% of the harvest. Historically, about 65% of the fields in Lithuania are harvested late, not at the optimum time, which increases harvest losses. Rapeseed sprouted in the field germinates and becomes weeds that require additional time and financial costs to combat.
Lithuanian scientists have been intensively researching the loss of rape harvest over the last ten years, both due to the opening of the biological pods and the mechanical impact, as well as the various additives - sealers for use before harvest and reducing possible losses. A major international recognition study led by prof. D. Steponavičius stated that the preparations of the rapeseed leg have a significant effect on the preservation of the harvest. Harvesting in time can save up to 100 kg per hectare, while harvesting delays of at least 7 days, the most efficient product (marketed as Smart Contact) helped save up to 350 kg/ha. This product, based on a mixture of silicones and acrylic, compared to other products (pinholes or latex polymer products), has functioned 2-3 times more efficiently depending on different conditions.
• Selection of varieties with low self-opening of pods.
• Harvest without delay, do not wait for maximum moisture loss.
• Reduce the speed of the combine and, if possible, choose a suitably extended collector.
• Two weeks before harvesting, use the "Smart Contact" rapeseed sealing product.
New biologically activated ammonium nitrate fertilizer was introduced in the Lithuanian market and successfully tested by the farmers.