Allelopathic potential of weed species invading Kallar grass (Leptochloa fusca (L.) Kunth) in saline agricultural land

Cynodon dactylon (L.) Pers., Desmostachya bipinnata (L.) Stapf, Kochia indi ca Wight, Polypogon nonspeliensis (L.) Desf., Sporobolus arabicus Boiss., a nd Suaeda fruticosa (L.) Forssk. established in well-defined patches in sal ine fields planted with Kallar grass (Leptochloa fusca (L.) Kunth). Water e xtracts, shoot material of different species decomposing in soil and leacha tes from soils amended with shoot materials inhibited seed germination and/ or growth of Kallar grass to varying degrees. Each species showed allelopat hic potential against Kallar grass in one or more tests. Six allelochemical s viz., benzoic, ferulic, caffeic, p-OH-benzoic, vanillic and syringic acid s were identified in water and/or hydrolysis extracts of different species. Four of these compounds (present in all species) inhibited seed germinatio n and seedling growth of Kallar grass. Allelopathic influence of invading s pecies and autotoxicity are important factors causing elimination of Kallar grass from weed patches and its decreased productivity in older stands.