The Method Of Dressing Nitrogen Only Once In The Whole Growing Stage On The Base Of Basic Fertilizer In Rice

The two-year trail was run from 2000 to 2001 at the field experimental farm of the Institute for Yangzhou University to evaluate the conventional variety 941 with 18 leaves at 7.5Kg/666.67m2 N application rate which was addressed only once in the whole life on the base of basic fertilizer. The different N addressed time was chosen in the 6 periods of leaf age: 13 14 15 16, 17, 18 leaf, respectively(The code was N13, N14, N15, N16, N17 N18, respectivily). The contrasted treatments were CK1 without N application and CK2 with N application only as basic fertilizer. The soil was loamy sand with organic matter 1.2% .Total N 0.12% , 88.7 mg/kg assimilable K2O 36.3 mg/kg P2O5 .Three replicates were conducted. The main results were as follows:(l)The sequence of grain yield was N15>N16>N14>N17>N13>N18, and the former three results were recorded higher than 650 Kg/666.67m2 due to the correspondence between the number of ear per 666.67m2 and the number of gram per spike.(2) With the increase of leafage when N was addressed, head milled rice amylose content and gel consistency respectively were regularly decreased in a slight degree, while the percentage of chalkiness protein content were linearly increased . As a whole, a correspondence could be formed between the high grain yield and those parameter of quality of rice in some degree.(3)Data on the construction of mass biosome and the type of plant indicated that N15 N16. N14, the three treatment of all that was applied to, contained the appropriate dynamics of leafage, more excellent plant type, good relationship between source and sink with larger number. The higher increasing rate of dry matter and its transport rate at the middle and later growing stage were also given. All these founded the important biological base for the correspondence between high yield and good quality.(4)The sequence of N utilization efficiency was N15>N16>N14>N17>N13>N18,and N15 N16 N14 were over 40%, higher 10% than mat of adopting conditional N addressed method. N addressed productivity of the three treatment was also higher than the others. All these indicated that the appropriate period of N addressed should chose Nl 5, N16 N14.Wholly, these results showed that the period of N addressed chosen in N14, N15 and N16 was the cause of higher yield good quality and higher N utilization efficiency, by which a new approach of addressing N only once in the whole life on the basement of basic fertilization in conventional rice in the lower reaches of Yangtze Rive was constructed.