| In recent years, the dilemma of China’s rapeseed production are as follows:First, the current rapeseed production in China is still manual work-based, labor large amount of high labor intensity, low labor productivity, leading to high production costs, relatively poor efficiency. It is estimated that in rape production costs, labor costs accounted for60to70percent of an acre of land consuming work about12to15, labor costs240-300RMB. According to the tests showed that in China uses the rape direct seeding cultivation pattern in our country, compared to the tradition transplants the cultivation pattern reduction to employ labor2-3for seedling transplanting in per acre. Second, different former crop harvest time resulting in the next crop planting season a corresponding change, current rape sowing time of the different fields in the Yangtze River basin from late September start, lasted until the end of October, up to30days before and after above. Third, farmers still follow conventional transplanting cultivation model of nitrogen fertilizer in field management, has not been commensurate with the sowing of direct seeding oilseed rape nitrogen application patterns, leading to high nitrogen, benefits decline, pollution risks increase. In response to these problems, Huashuang No.5is used for testing materials in this article, through field trials to study on different sowing date, different levels of nitrogen and nitrogen dressing ratios on growth of rape, process of dry matter accumulation, yield, quality and economic characters of rapeseed, pursuing to the change rule and forms mechanism of rapeseed for better cultivation performance. Research results show that:1. Different sowing date and different ratios of base and topdressing of nitrogen levels effects on growth and development of the rape:Firstly, Sowing date, nitrogen rate and its ratio of base and topdressing are all have an impact on the whole growth stages. Among them, sowing date has the greatest impact of all, as we put off the sowing date, the Seedling emergence stage delayed, the index of rapeseed such as the plants height, the maximum of leaf length and width, green leaves number, total leaf number, leaf area index, the root neck width, the ground and underground dry weight are all decreased over through wintering stage, concrete manifestation as follows:Compared with the sowing day of Sept.15, Oct.25sowing rape index declined significantly in four growth stages, the plants reduced51.2%-80.22%high, the green leaf number reduced2-8piece, the total number of leaves reduced2.17-5.09piece, leaf area index fell23%-57.2%,root neck crude fell18.9%-45.32%,dry matter weight reduced4%-16.48%,the beginning flower to the mature period shorted, For broadcast on15Sept.5, Oct.5, Oct.25, from sowing seeds to the emerging,time respectively needs5,8,12d,and flowering to maturity time costs72,69.3,64.3d.The nitrogenous fertilizer is remarkable to the rape growth period, but the biggest impact for t under the conditions set nitrogen fertilizer application rates in3level (12kg/667m2,18kg/667m2,24kg/667m2) of12kg/667m2nitrogen deficiencies (for nitrogen insufficient) the height of plants, green leaves number, total leaf number, leaf area index, above and below ground dry weight detection value lower than18kg/667m2and24kg/667m2nitrogenous supplement,18kg/667m2nitrogenous supplement followed by.Different ratio of base and topdressing of nitrogen takes significant impact on the growth of rapeseed. In the stages of development generally showing that:the earlier the sowing date, and the bigger ratio of base and topdressing of nitrogen supplement the better processes are under growing, otherwise bad. Late sowing time and ratio of base and topdressing small,because lack of basic fertilizer supply will resulting in poor seedling growing, Conversely the big ratio of nitrogen, because of large nitrogen supplement will growing more quickly to promoting the growth of rapeseed than other late sowing plants.2. Different sowing date and different ratios of base and topdressing of nitrogen levels effects on yield of rapeseed:Sowing date on yield of rapeseed is the most significant, showing a growth yield of rapeseed in advance with the sowing date, on sowing date of September15will get the highest yield, up to507.20g/667m2, and compared to the latest broadcast of Oct.25the gap up to212.09g/667m2, more double of the yield. With the sowing date postponed, the rapeseed plant height, coarse roots, dry weight per plant, effective pod number, number per pod,1000-grain weight had a significant reduction. The experimental data were as follows:compared with the rapeseed sowed on Sept.15, rape sowed on October25plants height reduced by8.79%-26.36%,11.32%-35.97%reduction of the main inflorescence length, once branches had a decrease of13.3%-21.57%, the effective number of pods decreased by23.34%-46.63%,24.67%-69.62%reduction of yield per plant, grain weight decreased by13.89%-38.53%. After increase nitrogen offered levels, the yield come to increase and will get the highest yield when Nitrogen reach to18kg/667m2. too much or too little of nitrogen are all makes rape failure, in this test, compared to the others, the nitrogen fertilizer application rates of12kg/667m2will get the lowest output of yield, with the increase of nitrogen provided primary branches, secondary branches, pods per plant, yield per plant, grain weight was significantly increased, but when the fertilizer had amounted to24kg/667m2except the grain weight other indicators are all decreased.In this study, ratios of base and topdressing of nitrogen levels catch up with production relations are as follows:time early, small dressing ratios, harvest yields higher; delayed sowing, large dressing ratios, harvest yields higher; normal planting period and dressing ratios, harvest yields higher. Due to broadcast period ahead of, seedlings in winter period will lack of nitrogen and effect of rapeseed growth and yield formation in the next years.3. Different sowing dates effect on the quality of rape:Components under different sowing rapeseed larger differences. Defer sowing rapeseed protein content increased oil content tends to decrease, compare to the sowing date, Sept.15seed content of1.2%-19.83%protein higher than Oct.25and its oil content lower10.45%-31.93%than Oct.25. Content of erucic acid and linolenic acid content are reduced as sowing date postponed. linoleic acid content was significantly higher with the sowing date postponed, glucosinolate composition of rapeseed in high levels on late sowing date, oil acid content of rapeseed on early or late sowing dates than are much higher normal sowing. Under the conditions of the same sowing date, grain protein content increase with nitrogen increased the oil content decreases. |
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