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The Science Bulletin of the Faculty of Agriculture. University of the Ryukyus >
No.25 (1978/12) >

 
Title :熟畑化にともなう雑草植生の変遷に関する研究 : (1) サトウキビ畑の遷移系列調査による遷移過程の推定(農学部附属農場)
Title alternative :Studies on the shift in weed vegetation in the maturation process of fields : I. Estimation of the shift process in various stages of sugar cane fields (Agricultural Experiment Station)
Authors :石嶺, 行男
高江洲, 賢文
田盛, 正雄
Authors alternative :Ishimine, Yukio
Takaesu, Yoshifumi
Tamori, Masao
Issue Date :1-Dec-1978
Abstract :本研究は熟畑化過程の雑草植生の変遷を明らかにするため, 琉球大学農学部附属農場およびその周辺のサトウキビ単一栽培畑を経時的要因と栽培的要因を考慮して開墾畑, 新植未熟畑, 株出未熟畑, 新植熟畑, 株出熟畑, 休耕畑および原野の7つのステージに分け, その雑草群落の種組成および生活型組成を明らかにし, 熟畑化にともなう雑草植生の変遷を推定した。1.開墾畑から原野にいたるほとんどのステージに出現した上位単位の雑草群と特定のステージにのみ出現した下位単位の雑草群に分けられた。上位単位の雑草群は耕地雑草として農業上の重要性が示唆された。2.下位単位の雑草群は熟畑化とともに一年生耕地雑草から多年生耕地雑草, 非耕地雑草と変遷した。これは4組の耕地雑草群と1組の非耕地雑草群に分けられた。3.帰化植物は新植畑のオープンスペースに多く出現し, とくに中南米原産の種が最も多かった。また戦後の帰化植物はアメリカ大陸原産の種が大部分を占めていた。4.休眠型は新植畑(開墾畑, 未熟畑, 熟畑)においては一年生雑草(Th)が約50%の高い割合を占めたが, 株出畑から休耕畑さらに原野と移るにしたがって減少し, 逆に木本(M.N)は増加した。地中植物(G)はどのステージでも20%前後であった。5.あるステージと他の6つのステージ間の類似性は, 開墾畑, 株出熟畑および休耕畑が高く, 新植未熟畑と原野は低かった。6.生育型においては叢生型(t)または直立型(e)の割合が高く, つる型(&ell;)は株出畑から休耕畑, 原野としだいに増加した。根茎型は単位型(R_5), 散布型は重力散布型(D_4)の割合が高かった。7.各ステージの雑草群落の構造を生活型組成による類型構造で解析した結果, 熟畑化にともなって, Th-e・t-R_<5・3>-D_<4・1・5>からTh-e・t-R_<5・4>-D_<4・1・ 3>, さらに, Th-t・e-R_<5・3>-D_<4・1・5>, Th・N-t・e-R_<5-3>-D_<4・1・5>, N・G-e・t-R_<5・3>-D_<4・1・5>と変遷した。8.熟畑でつる性雑草およびその他の非耕地雑草が増加したことから熟畑化とともに栽培管理が悪くなっていくことが示唆された。9.任意に設定した7つのステージは種組成と生活型組成による群落構造から, 次のように遷移することが推定された。すなわち, 新植畑(開墾畑&xrarr;未熟畑&xrarr;熟畑)&xrarr;株出畑(未熟畑&xrarr;熟畑)& xrarr;休耕畑&xrarr;原野。
In the present study, the authors had investigated the fields of the University of the Ryukyus and its adjacent fields, where we used to elucidate the changes in weed vegetation in the process of maturation of the fields where sugar cane has grown by monoculture. These fields were divided into seven stages taking the time and cultivative factors into account; clearing, newly planted immature, ratooned immature, newly planted mature, ratooned mature, fallow, and uncultivated stages. Weed communities found in each stage were investigated as to their flouristic composition and life-form spectrum. 1. The species in the weed communities investigated were parted in two groups, one is epistasis which grew in most fields, the other is gypostasis which grew in certain fields. The species in epistasis were suggested importance in the sugar cane fields. 2. As maturing, the gypostasis groups have changed from annual cultivated weed to perenial cultivated weed, finally to uncultivated weed. Those groups were divided further into four subgroups of cultivated fields and one subgroup of uncultivated fields. 3. The naturalized weeds grew in open space of newly planted fields. It was showed the highest percentage that the nuturalizer had brought from Central and South America. Most of those nuturalized from the New Continent after the World War II. 4. The annual weed(Th) showed about 50% in the dormancy form of newly planted fields, but it has decreased as change from ratooned to fallow and finally to uncultivated fields, while woody plants(M, N) has increased. The geophyte(G) has accounted for about 20% in every fields. 5. The degree of similarity between one stage and other six stages was high in clearing, ratooned mature and fallow fields, but in newly planted immature and uncultivated fields were low. 6. The tussock(t) or the erect(e) was the highest percentage in every fields in the growth form. Liana form(1) has increased gradually from mature to fallow, finally to uncultivated fields. The percentage of the unit form(R_5) was high in the radicoid form, and bolochory form (D_4) was the same in the disseminule form. 7. When the authors analysed the weed communities imvestigated by a typical structure using the life-form spectrum, the structure changed from Th-e・t-R_<5.3>-D_<4.1.5> to Th-e・t-R_<5.4>-D_<4.1.3>, to Th-t・e-R_<5,3>-D_<4.1.5>, to Th・N-t・e-R_<5.3>-D_<4.1.5> and finally to N・G-e・t-R_<5.3>-D_<4.1.5> 8. In mature filds, liana and other uncultivated weeds have increased; they are suggesting higher maturation even with poorer management. 9. From the analysis of the community structure by flouristic composition and life-form spectrum, we concluded that the plagiosere can be estimated next succesion; newly planted (clearing→immature→mature)→ratooned (immature→mature)→fallow→uncultivated fields.
Type Local :紀要論文
ISSN :0370-4246
Publisher :琉球大学農学部
URI :http://hdl.handle.net/20.500.12000/4226
Citation :琉球大学農学部学術報告 = The Science Bulletin of the Faculty of Agriculture. University of the Ryukyus no.25 p.679 -694
Appears in Collections:No.25 (1978/12)

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