不同土壤培肥措施对华北高产农田原生动物丰度的影响

Impact of soil fertility maintaining practices on protozoa abundance in high production agro-ecosystem in northern China

为了解华北高产农田生态系统中秸秆还田、有机肥和化肥投入水平等土壤培肥措施对原生动物群落丰度的影响,1999年10月～2000年9月在山东桓台冬小麦套种夏玉米的田间试验中进行了取样分析.田间处理1～处理9,依序为:全还,麦还,全还+化肥1,麦还+化肥1,全还+化肥2,麦还+化肥2,全还+化肥3,麦还+化肥3和全还+化肥1+有机肥处理.应用3级10倍环式稀释培养法对土壤中鞭毛虫、纤毛虫、肉足虫3类群原生动物的丰度进行了测定.结果显示:该研究地块肥力状况良好;土壤鞭毛虫和肉足虫占有绝大比例,分别为总丰度的39.47%和59.22%,纤毛虫仅占1.31%;土壤原生动物丰度在不同培肥处理中表现出相似的季节性动态变化特征;比较不同土壤培肥措施条件下的原生动物丰度水平为:全还＞麦还,全还+化肥1+有机肥＞麦还+化肥1,麦还+化肥2,麦还+化肥3＞全还+化肥1,全还+化肥2,全还+化肥3;化肥对原生动物丰度表现出明显的抑制作用,而有机肥对原生动力丰度表现出明显的促进作用.化肥的施用量水平对土壤原生动物丰度的影响无显著性差异,作物秸秆采取何种还田方式对土壤原生动物丰度的影响也是不显著的,如麦还+化肥培肥地块的原生动物丰度仅略高于全还+化肥.

The experiment was carried out on cultivation patterns Shandong Province, China from October 1999 to September 2000. fertility maintaining practices, such as chemical fertilizer application straw to the field affected the dynamics of the protozoa community in treatments of fertility maintaining practices in the field were chosen of winter wheat and summer corn in Huantai County, The purpose of the study was to understand how soil level, the use of organic manure, and the return of crop a high production agro-ecosystem in northern China. Nine （where the symbol “＋” means combination application, “chemical fertilizer1” means used 600kg/（hm^2· a）, “chemical fertilizer2” means 20% less than “fertilizer1” for the application 480 kg/（hm^2· a）, “chemical fertilizer3” means 20% more than “fertilizer1” for the application 720 kg/（hmhm^2· a））： ① wheat straw ＋ corn straw, ② wheat straw, ③ wheat straw ＋ corn straw ＋ fertilizer1, ④ wheat straw ＋ fertilizer1, ⑤ wheat straw ＋ corn straw ＋ fertilizer2, ⑥ wheat straw ＋ fertilizer2, ⑦ wheat straw ＋ corn straw ＋ fertilizer3, ⑧ wheat straw ＋ fertilizer3, and ⑨ wheat straw ＋ corn straw ＋ fertilizer1 ＋ organic manure randomly designed and applied in the experimental plots. The abundances of protozoa flagellate, ciliate, and amoeba in the soil sampled by stages were measured in the laboratory using the MPN method of thee level ten-fold dilution and cultivation. The results showed that： ① the fertility level of the soil in the study was higher; ② the proportion of flagellate and amoeba in the protozoa community were both higher than that of ciliate, which were 39. 47%, 59. 22%, and 1. 31% respectively; ③ similar seasonal dynamics characteristics of soil protozoa total abundance in different treatments of fertility maintaining practices were found suggesting that protozoa abundance reached a peak value in March, September and November, while falling to lowest levels from May to June and in October. ④ the comparison of average protozoa abundance in different treatments appeared in sequence from wheat straw ＋ corn straw 〉 wheat straw, wheat straw ＋ corn straw ＋ fertilizer1 ＋ organic manure 〉 wheat straw ＋ fertilizer1, wheat straw ＋ fertilizer2, wheat straw ＋ fertilizer3 〉 wheat straw ＋ corn straw ＋ fertilizer1, wheat straw ＋ corn straw ＋ fertilizer2, wheat straw ＋ corn straw ＋ fertilizer3. ⑤ there was higher protozoa abundance in the plots applied organic manure than in no organic manure application plots, suggesting that organic manure promoted the increase of soil protozoa abundance; and ⑥, equal protozoa abundance was found in the plots with different fertilizer levels combined with crop straw, however their protozoa abundances were a little lower than in the plots where only straw was applied （such as wheat straw ＋ corn straw ＋ fertilizer 〈 wheat straw ＋ corn straw, while wheat straw ＋ fertilizer 〈 wheat straw）, indicating that the chemical fertilizer restrained the increase in protozoa abundance in the single straw application plots. This suggests that the return way of straw application to the field had little affect （p〉0.05） on the abundance of protozoa community and that it may not be an important factor in protozoa abundance. This was particularly so in plots where the return of straw was combined with chemical fertilizer.