关键词: 长期施肥, 磷素平衡, 黄绵土, 黄土高原, 有效磷, 农学阈值

Abstract: The locomotive lateralization in certain individuals among a fish population is often relative to predatory tactic and predator escape strategy. To investigate whether the locomotive lateralization exhibited in Spinibarbus sinensis (evaluated by if the individual fish run to the same direction more than 8 times out of 10 Tdetour trails), we selected 40 S. sinensis and reared individually at 20±1.0 ℃, and then we performed 10 detour trails in each individual for scoring the direction. To investigate the repeatability of locomotive lateralization, we repeated 10 detour trails by 3 more times at 3-day interval (4 series in total). Taking the 4 series as a whole, (53.4 ±3.8）% individuals exhibited lateralization with either left (19.2±1.3)% or right (34.2±4.0)% preference. Furthermore, there was no significant difference in relative lateralization index (LR) among four series. However, after marked repeating with 3 series, the proportion of individuals keeping initial direction significantly decreased from 45.0% at the first series to 21.0% (P<0.05), 16.7% and 17.1% at the second to fourth series, respectively. The proportions of individuals showing stabilized left and right lateralization were both 8.57%. It was suggested that locomotive lateralization exhibited in certain individuals of S. sinensis. However, the individuals exhibiting stabilized lateralization were much less than other fish species, suggesting that locomotive lateralization may have little contribution to the survival fitness of S. sinensis. Furthermore, the results suggested that marked repeating test was important for assessing the locomotive lateralization.

Key words: long-term fertilization, soil phosphorus surplus, loessial soil, the Loess Plateau, available phosphorus, available phosphorus agronomy threshold