稻田土壤种子库研究进展

土壤种子库是指存在于土壤表面和土壤中全部存活种子的总和。稻田土壤种子库是地上杂草产生的根本来源。我国是一个水稻种植大国,目前关于稻田土壤种子库的研究还不够全面和深入。研究稻田土壤种子库对于防治稻田草害具有重要指导意义,同时也是种子库研究领域的一个重要补充。取样方法和取样时间是研究土壤种子库的关键所在。而萌发法是最常见的判定方法。关于稻田土壤种子库大小的结论相差很大,从103~105 m-2不等。稻田土壤种子库中的杂草主要有19科55种,一般的稻田可检出10科或20种左右。种子的垂直分布格局主要受耕作强度的影响。70%~80%甚至更多的杂草种子分布在0~10 cm。稻田土壤种子库由于萌发、捕食、衰老和种子散布等原因具有季节动态。轮作制度、耕作方式、不同施肥处理以及除草方式等对稻田土壤种子库有重要影响。连续多年的田间管理会使种子库的大小、分布和物种组成产生年际变化。目前,需要加强长期定位研究,扩大研究区域和研究内容,重点研究杂草种子的休眠萌发机制和种子命运研究,为杂草治理提供更准确的信息。

Progress in the researches of seed bank in rice paddy fields

Seed bank is defined as the summation of viable seeds existing on soil surface and in soil.Seed bank in rice paddy fields is basic source of weeds above ground.However,studies on the soil seed bank in rice paddy fields in China,which is a large country for rice cultivation,are not adequate enough and need more comprehensive and in-depth research.Soil seek bank study in rice paddy fields plays a significant role in implementing the prevention and management of the weeds and is complementary to seed bank research as well.Sampling method and sampling time are crucial in soil seed bank research.Among others,germination method is used most widely to determine the soil seek bank.The conclusions about the size of soil seed bank vary considerably,from 103 m-2 to 105 m-2.There are about 55 species of seeds belonging to 19 families in the soil seed bank.Generally,10 families or 20 species of seeds could be observed in ordinary paddy fields.The pattern of vertical distribution of seeds is mainly affected by tillage intensity.About 70%-80% and even more seeds are scattered in 0-10 cm soils.Soil seed bank exhibits seasonal dynamics due to the effects from germination,predation,aging,and seed dispersal.Rotation system,tillage approach,fertilizer application,and weed control method together have important influence on the soil seed bank of paddy soil.Continuous field management for years would lead to interannual variability in the size,distribution,and species composition of the soil seek bank.In order to provide more accurate information for weed control,we need to enhance the long-term research,expand the scope and region of research,and emphasize on mechanisms of seed dormancy and germination and seed fate.