Study On Introduction Of Double-low Oilseed Rape Varieties And Cultivation Technique Systems In The Area Of Baiyin

Oilseed rape is adapted to the natural conditions of Baiyin city.Its' planted area and total yield have been declining in recent years due to variety degradation,irrational fertility management,poor cultivation practice,etc.The double-low rapeseeds are sources of healthy cooking oil and high-quality protein supplements for livestock.It is importance to develop double-low oilseed rape with top quality and high-yielding in order to increase farmers' incomes,agricultural profits and sustainable development of rural economy.The experiments on cultivation observation,variety comparison and integration of comprehensive cultivation technique systems of eight introduced double-low rape varieties were conducted from 2002 to 2005 at Wuchuan township,Baiyin distirct, Baiyin city.The achievements of the experiments were demonstrated and extended not only in the irrigated areas but also in the arid areas of Baiyin city.The following conclusions were drawn in terms of four years' researches and extension to improve production of double-low rapeseed in Baiyin city:1.New double-low oilseed rape varieties,such as Huaxie1,Zayou59,Qingyou331 and Qingza3,suitable for extension in Baiyin city,were selected,based on the evaluations of their growth periods,plant characters,economic characters and yields.These varieties with low erucic acid and low glucosinolate were of high yield, high oil content and better commercial traits,which belonged to high-yielding and high quality rape varieties and showed bright extension prospect.2.The soil temperature was increased by 2.83～4.16℃through covering rape field with plastic mulch,which facilitated rape emergence,prolonged the flowering period and increased rape yield and profit by 40.76%and 35.47,respectively.The cultivation approach could be extended in larger area.3.The optimal combination of double-low oilseed rape's plant density and planting date was with 270,000 seedlings per acre planted on April 5^th.The better combinations were with 330,000 seedlings per acre sown on April 5^th and with 270,000 seedlings per acre on April 12^th.4.The yield of the rape was affected by the concentration of boron fertilizer solution and its application time.The best yield could be achieved by spraying the rape plants with 3 percent of boron solution during the period of flowering or bolting.5.The following cultivation technique criterion of high-yielding and high quality double-low oilseed rape with plastic mulch covering in Baiyin city are put forward, based on field experiments and summarizing farmers' production experience;the key points are as follows:(1) careful field preparation and application of adequate base fertilizers.In fall when the field ploughed,fully discomposed manure of 60,000～75,000kg/hm²,borax of 7.5～15 kg/hm² and calcium superphosphate (CSP)of 500～600kg/hm² are applied into deep soil layer.In spring CSP of 250～ 300kg/hm²,urea of 150～225 kg/hm² and potassium dihydrogen phosphate(PDP) of 30～60 kg/hm² are added into the shallow layer of the field.(2) selecting suitable oilseed rape varieties,such as Huaxie1,Zhayiu59,etc.(3) planting timely with rational larger plant rate.Planting period:April 5^th-12^th;seedling number: 270,000～330,000 seedlings/hm²(4) strengthening crop management,scientific irrigation and fertilizing and timely pest control.At the stage of 2-3 true leaves,urea of 75～120 kg/hm²,ammonium dihydrogen phosphate(ADP) of 35～75kg/hm² should be applied just prior to irrigation.During the period of budding and bolting, urea of 75～120 kg/hm² and ADP of 35～75kg/hm² should be added just prior to irrigation.At early flowering stage of the rape,the mixture of three types of fertilizers and two types of pesticide and fungicide is suggested to be sprayed on the rape crops;boron fertilizer,PDP and urea are applied at 1.5,1.5 and 1.5kg/hm², simultaneously omethoate and dimethachlon / carbendazim applied at 0.3 and 0.3 / 0.375 kg active ingredient per acre,respectively.(5) timely harvesting prior to full ripening.6.To make the commercial rape seed and meal reach the double-low standard,the following main measures were extended:regionalized planting with standard regulations;refining rape varieties and supplying seed through the common resource;avoiding seed mixture between varieties;strengthening seed test and implementing seed-purchasing check.7.Demonstration and extension of new rape varieties.During the period of four years from 2002 to 2005 the accumulative demonstration area of double-low oilseed rape was up to 233.3 hm² in Baiyin city,which average yield reached 3147.6 kg/ hm²,10.2 percent higher than that of check varieties,namely,74.9 tones of double-low rapeseed was increased.The total extension area of the rape varieties reached 1841.4 hm².