- 學位論文
玉米-水稻輪作系統下施肥管理對根圈土壤酵素活性及細菌族群結構之影響
Effects of Fertilization Management on Rhizosphere Soil Enzyme Activities and Bacterial Community Structure under a Maize-Rice Crop Rotation System
摘要
本研究選擇台灣農業試驗所之試驗田，探討於玉米-水稻輪作系統下七種不同施肥管理對作物根圈土壤中與C、N、P、S元素循環及微生物活性有關之七種酵素（β-配醣酶、β-胺基葡萄糖苷酶、芳香基醯胺酶、尿素酶、酸性磷酸酯酶、芳香基硫酸酯酶及去氫酶）活性以及細菌族群結構之影響。試驗田之玉米-水稻輪作始自1995年8月，其試驗設計採逢機完全區集（RCBD）設計，而七種施肥管理如下：對照組、化肥-N、堆肥、堆肥+1/3N、堆肥+2/3N、綠肥+1/3N、泥炭+1/3N，各處理四重覆。 研究結果顯示：玉米水稻輪作系統下，施用「堆肥」、「堆肥+1/3N」或「堆肥+2/3N」之施肥管理於玉米及水稻生長期間均顯著促進本研究之七種根圈土壤酵素活性（P＜0.05），前述玉米及水稻堆肥用量分別為5.17及4.43 t ha-1，化肥N用量分別為140及120 kg ha-1。在玉米生長期中，根圈土壤尿素酶、酸性磷酸酯酶及去氫酶之活性於膝高期較高，根圈土壤芳香基硫酸酯酶之活性於雄穗抽出期較高，而根圈土壤β-配醣酶、芳香基醯胺酶及β-胺基葡萄糖苷酶之活性於收穫期較高；在水稻生長期中，根圈土壤尿素酶、芳香基醯胺酶及β-胺基葡萄糖苷酶之活性於抽穗期較高，根圈土壤β-配醣酶於最大分蘗盛期有顯著較高之活性，根圈土壤芳香基硫酸酯酶及去氫酶之活性於收穫期較高，而根圈土壤酸性磷酸酯酶之活性則無一定之趨勢。相關分析結果顯示：七種根圈土壤酵素活性與玉米田土壤之有機質、銨態氮、硝酸態氮、無機態碳、有效性磷、水溶性磷以及微生物生質碳含量呈顯著相關（P＜0.05），而與水稻田土壤之有機質、銨態氮、硝酸態氮、無機態碳、有效性磷、水溶性磷、硫酸鹽、微生物生質碳及氮含量呈顯著相關（P＜0.05）。以逢機擴增多型性DNA（Random amplified polymorphic DNA，RAPD）測定細菌族群結構所得到之結果顯示：施用「堆肥+2/3N」施肥管理之細菌族群結構和其他六種施肥管理之細菌族群結構有顯著差異（相似度為0﹪），而其他六種施肥管理間之細菌族群結構則無顯著差異（相似度為67-100﹪），亦即施用「堆肥+2/3N」施肥管理顯著影響根圈土壤之細菌族群結構。
並列摘要
The objectives of this study were to examine the effects of fertilization management on the rhizosphere soil enzyme activities（b-glucosidase, b-glucosaminidase, arylamidase, urease, acid phosphatase, arylsulfatase and dehydrogenase related to C, N, P, and S cycles）and bacterial community structure under a maize-rice crop rotation system in an experimental field in Taiwan Agricultural Research Institute. The maize-rice rotational cropping system was initiated in the experimental field since August 1995. The experimental design was a randomized complete block design with four replications and seven fertilization managements, including：Check, Chemical N, Hog manure compost, Compost + Chemical 1/3N, Compost + Chemical 2/3N, Green manure + Chemical 1/3N, and Peat + Chemical 1/3N. The results showed that Hog manure compost, Compost + Chemical 1/3N, and Compost + Chemical 2/3N managements significantly increased the activities of rhizosphere soil enzymes in this study（P＜0.05）. Among the maize crop growing stages, the activities of urease, acid phosphatase, and dehydrogenase in rhizosphere soils were highest in the knee-high stage, that of arylsulfatase was highest in the tasseling stage, and those of b-glucosidase, b-glucosaminidase, and arylamidase in were highest in the harvesting stage; among the rice crop growing stages, the activities of urease, b-glucosaminidase, and arylamidase in rhizosphere soils were highest in the active tasseling stage, that of b-glucosidase was highest in the heading stage, and those of arylsulfatase and dehydrogenase in rhizosphere soils were highest in the harvesting stage. In general, those seven rhizosphere soil enzyme activities significantly correlated with organic matter, ammonium-nitrogen, nitrate-nitrogen, inorganic nitrogen, available phosphate, water soluble- phosphate, and microbial biomass carbon content in maize field（P＜0.05）, and significantly correlated with organic matter, ammonium nitrogen, nitrate nitrogen, inorganic nitrogen, available phosphate, water soluble phosphate, sulfate and microbial biomass carbon and nitrogen content in rice field（P＜0.05）. The results of random amplified polymorphic DNA（RAPD）analysis showed that the structure of rhizosphere soil bacterial community on Compost + Chemical 2/3N management was significantly different from the other six managements（0 ﹪similarity）, and there was no significant difference among those of six managements（67-100 ﹪similarity）.