The Interspecific and Inter-parametric Differences of Forage Crops in Response to Seed Treatment with Aqueous Extracts of Animal-waste Composts

家畜排泄物コンポストの作物生育阻害効果の検定方法について検討した。7種の飼料作物(トウモロコシ、ソルガム、イタリアンライグラス、シコクビエ、アカクローバー、アルファルファ、ダイズ)とコマツナの種子発芽と初期生育に及ぼす14種の家畜排泄物コンポストの阻害効果を室内実験で比較した。阻害効果の指標として、処理後72時間の発芽率、草丈、根長、新鮮重、乾物重を測定した。コンポストの阻害効果は検定値物や指標間で異なり、単一の植物種の特定の測定指標でコンポストの阻害効果を判定することは困難であった。これらの結果は、コンポスト中の毒性成分とその作用が植物種間で異なりうることを示しており、阻害物質の同定とそれらの阻害作用機構を明らかにすることが必要である。

Experiments were conducted to find the best assay method to evaluate the inhibitory effects of animal-waste composts on crop growth. The inhibitory effects of 14 kinds of animal-waste composts on seed germination and seedling growth of 7 forage crops (corn, sorghum, Italian ryegrass, African millet, red clover, alfalfa and soybean) and Komatsuna (Brassica rapa L) were tested under laboratory conditions. The parameters measured were seed germination rate and root length, shoot length, fresh weight and dry weight of 72 h old seedlings. The inhibitory effects of animal-waste composts varied among the test plant species and parameters. It is difficult to evaluate the inhibitory effects of a given compost by using a given parameter of a single plant. These results indicate that toxic substances in composts and their activity differ among the crop plant species. The necessity to identify the causal substances and to clarify their mode of action in plant growth is also indicated.