| 【Objective】The objective of the study was to explore the best topdressing period of main rapeseed
varieties that suitable for Yellow River Irrigation District of Ningxia. 【Method】The randomized block experiment was
designed to study the change of growth of the variety“Huayouza 62” and the effects of nitrogen, phosphorus and potassium
contents in different parts of the plant on the yield of rapeseed. 【Result】 The highest yield of rapeseed was obtained
when applying 60% of basal nitrogen fertilizer and 40% of topdressing nitrogen fertilizer in the seedling stage, with the yield
reaching 4 889.1 kg per 667 m2. The plant height of rapeseed increased in a curve during the whole growth period. The
chlorophyll content increased rapidly in the early growth stage and the chlorophyll content reached the highest at 60 days.
With the advancement of the fertility process, the N content gradually decreased, the roots decreased in the early stage, and
decreased slowly in the late stage; the leaves decreased slowly in the early stage and increased gradually in the late stage;
the stems decreased slowly in the early stage and rapidly in the late stage. The change of P content of the roots has been
decreasing slowly; the growth of stems showed a relatively great upward trend, and it increased slowly after 45 days; the leaves decreased slowly in the early stage, and showed little increase during the whole growth period. The K content decreased
first and then increased slowly, but decreased in late harvest stage, with slight decrease. The total nitrogen(TN) content of
rapeseed increased first and then decreased. The TN content varied from 4.10% to 5.46% and the highest nitrogen accumulation
amount in treatment 2 was 0.78 g/plant. The total phosphorus(TP) content increased first and then decreased. Then the TP
content increased and decreased again. The total potassium(TK) content increased first and then decreased, and the highest
TK contents of the three treatments were obtained at about 40 days, with the highest contents of 4.02%, 4.22% and 4.39%,
respectively. 【Conclusion】 The variety“Huayouza 62”of Yellow River Irrigation District of Ningxia should be selected for
topdressing at seedling stage, and the effect was best when applying 60% of basal nitrogen fertilizer and 40% of topdressing
nitrogen fertilizer in the seedling stage . |
