Effects Of Varieties And Nitrogen Management On Nitrogen Accumulation And Parameters Of Precise Ferizilizaion In Rapeseed (Brassica Napus L.)

The present paper were to study the effects of rapeseed varieties and nitrogen management on plant nitrogen uptake and parameters of precise fertilizaion. To study the difference of nigrogen accumulation and parameters of precise fertilization in different seed yield types of conventional rapeseed varieties, 73 conventional rapeseed varieties were cultivated in 2006-2007 and 98 conventional rapeseed varieties were cultivated in 2007-2008. The rapeseed varieties were classified into 5 seed yiled types (A, B, C, D and E) based on their seed yield by the MinSSw method. Nitrogen accumulation and parameters of precise ferzilization of different seed yield types were studied. To study the differences of nitrogen uptake and parameters of precise fertilizaion between rapeseed hybirds and theirs parents, six parents(conventional rapeseed) and their F1 combinations from 6×6 complete double allele crosses were cultivated. To study the effects of nitrogen management on nitrogen uptake and parameters of precise fertilizaion. Suyou-211 were cultivated in 2005-2006 and 2007-2008. The purpose of these experiments was to clarify the effects of rapeseed varieties and nitrogen management on parameters of precise fertilizaton, and to provide fundamental information for precise fertilization. The main results were as follows:1.The amount of nitrogen accumulation had a close relationship with varieties and nitrogen management in rapeseed. There was no significant difference of nitrogen accumulation of whole plant and different organs of various seed yield types before flowering. After flowering the amount of nitrogen accumulation increased as seed yield increasing between various seed yield types. At mature stage, the amount of nitrogen accumulation of whole plant and different organs of various seed yield types increased as seed yield increasing between various seed yield types and the difference of them between various seed yield types was significant. The amount of nitrogen accumulation of whole plant and seeds of hybrids was more than that of parents regardless of nitrogen conditions. The amount of nitrogen accumulation of stem and pod shell of hybrids was significantly more than parents in low nitrogen conditions, and it was reverse in high nitrogen. The amount of nitrogen accumulation of whole plant and different organs increased in seeding nitrogen application, bolting nitrogen application and normal nitrogen application. And there was a tendency that it increased as increasing nitrogen application.2.Differences of the amount of nitrogen required by 100 kg seed of various seed yield types were significant, and the amount of nitrogen required by 100 kg seed of high seed yield type was less than that of low seed yield type. There was significantly linear negative correlation between the amount of nitrogen required by 100 kg seed and seed yield. But the amount of nitrogen required by 100 kg seed as diminished as seed yield increasing of various seed yield types. Under 2007 condition, the amount of nitrogen required by 100 kg seed of middle high seed yield type and high seed yield type was 5.1kg and 5.35kg respectively; under 2008N0 condition was 5.63 kg and 5.64 kg respectively, under 2008N1 condition was 6.61kg and 6.78 kg, the difference of it was less than 5%. The amount of nitrogen required by 100kg seed of hybirds was 5.07 kg and 6.56 kg respectively under N0 and N1 conditions, and it of parents was 5.57kg and 7.54 kg respectively. Hybirds was about 9%~13% lower than parents. There was significantly linear positive correlation between the amount of nitrogen required by 100 kg seed and nitrogen application. When 100 kg nitrogen fertilizer was applied as niromal nitrogen application, the amount of nitrogen required by 100kg seed increased by 0.93 kg.3. There were significant differences of the amount of nitrogen supplied by soil to various seed yield types. Soil supplied more nitrogen to high seed yield type than to low seed yield type. It was significant linear postive correlation between the amount of nitrogen supplied by soil and seed yield. When seed yield increased 100 kg/hm2 under 2007 and 2008N0 condition, the amount of nitrogen supplied by soil increased by 3.71 kg/hm2 and 2.40 kg/hm2 respectively. Under 2007 and 2008N0 condition, the amount of nitrogen supplied by soil to middle high seed yield type and high seed yield type increased by 4.0 kg/hm2 and 12.2 kg/hm2 respectively, the increasement was 2.6% and 6.6%, mean value was 5%. The amount of nitrogen supplied by soil to hybirds was 160.06 kg/hm2, and to parents was 140.65 kg/hm2. It to hybrids was 16.98% higher than parents, and the difference between hybirds and parents was significant.4. There were no significant differences of fertilizer-N recovery efficiency of various seed yield types of conventional rapeseed. Fertilizer-N recovery efficiecy of middle high seed yield type and high seed yield type was 39.84% and 41.15% respectively and mean value was 40.5%. Fertilizer-N recovery efficiency of hybirds was 35.88%, and of parents was 42.23%. It of hybirds was 6.35 percents lower than that of parents. There was significant secondary correlation between fertilizer-N recovery efficiency and the amount of nitrogen application as basal and seeding nitrogen application or bolting nitrogen application. Fertilizer-N recovery efficiency decreased when increasing the amount of nitrogen applied as normal fertilization,but the decrease was small. Nitrogen application increased from 150 kg/hm2 to 300 kg/hm2, the range of fertilizer-N recovery efficiency was 48.95%~50.42%, mean value was 49.69%. Therefore, the fertilizer- recovery efficiency of a certain rapeseed variety was stabile under the similar condition and with the same cultivated management.