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Copyright of Southwest China Journal of Agricultural Sciences is the property of Editorial Department of Southwest China Journal of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Southwest China Journal of Agricultural Sciences is the property of Editorial Department of Southwest China Journal of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Southwest China Journal of Agricultural Sciences is the property of Editorial Department of Southwest China Journal of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on the soil nutrient data in 2009 and 2013，the research on spatial-temporal variability of organic material，total nitrogen， available P and available K was conducted in the surface soil ( 0-20 cm) of rubber plantation of Jiangcheng Rubber Company with the method of geostatistics and GIS technology. The result indicated that the spatial distribution of total nitrogen was mainly affected by structural factors，while the distribution of available P was highly influenced by random factors，and the effect of random factors gradually decreased on the distribution of organic material while increased on the distribution of available k. The spatial distributions of organic material and total nitrogen were extremely similar. From 2009 to 2013，the fastest decrease appeared in the northwest and the north，while the fastest increase appeared in the southwest，with a general trend of decrease in all parts. The area portion at the level of organic material lack increased from 19. 7 % to 36. 1 %. All parts showed a normal even above normal level in total nitrogen content，however，the area portion at the level of abundance decreased from 77. 8 % to 59. 6 %. From 2009 to 2013，available P showed the fastest decrease in the south and the north and a slight increase in some parts in the northwest and the east，with a general trend of decrease in all parts and the content remained under normal level. From 2009 to 2013，available K showed the most significant decrease in the northeast and the south and a significant increase in the southwest， with a general trend of increase in all parts and the content remained at or even above normal level，the variation of which appeared as varying from normal to abundant level，the area portion at abundant level increased from 69. 9 % to 71. 9 % ， while the area portion at normal level decreased from 29. 8 % to 28. 1 %. The soil nutrient of rubber plantation of Jiangcheng Rubber Company varied significantly，which showed significant decline in the content of available P，organic material and total nitrogen and slight increase in available K. These variations were caused by the change of fertilization structure and sharp increase of rubber latex yield [ABSTRACT FROM AUTHOR]

The result of variation analysis of 81 introduced flax germplasm resources of main agronomic characters showed that there was sig­nificant genetic diversity. Through the factor analysis, we classified three factors, yield factor, seeds per capsule factor and plant shape fac­tor,which could representthe 7characters.The correlation analysis determined the relationship among the characters. By clusteranalysis, the 81 materials could be classified into 3 groups, which provided the basis for the different breeding objectives. [ABSTRACT FROM AUTHOR]

Аccording to total P absorption per plant，grain weight and relative value of root volume in low P stress，the rice germplasm could be divided into 5 genotypes： I root extend adaption，II low concentration adaption，III waste， IV high P utilization efficiency，V passiveness adaption. VI high P utilization efficiency should be chosen when screening tolerant genotypes in low phosphorus because it could pro duce more biomass per unit P. 7 varieties with high P utilization efficiency were achieved，which were Niandali，Shuangchengnuo，Youmangxiaohongbandao，Maguzi，Laoyehuzi，Chengdejinzu，Nuozi. [ABSTRACT FROM AUTHOR]