Muhammad Ehsan Safdar

Comparative Efficacy of Different Weed Management Strategies in Wheat

Weed management programs should focus on environmental safety along with benefits to the farmer. We evaluated the effects of various weed control methods: ?daab? practice (stale seed bed technique), manual hoeing, and the chemical method (mixture of Buctril Super 60EC [bromoxynil + MCPA] 0.45 kg ai ha-1 and Puma Super 75EW [fenoxaprop-P-ethyl] 0.75 kg ai ha-1) in combination with different planting geometries: 22.5 cm apart single row, 22.5 cm apart crisscross double row, 30 cm apart single row and broadcast sowings on weed control and grain yield of spring wheat (Triticum aestivum L.) var. Sehar 2006 at the University College of Agriculture, University of Sargodha, Pakistan, during the winters of 2009 and 2010. The chemical method, manual hoeing and ?daab? practice gave 71.44%, 30.69% and 28.60% weed controls resulting in 11.79%, 11.09% and 4.95% increases in grain yield above that of the weedy control, respectively. The 22.5 cm apart single row sowing in combination with chemical weed control proved to be the best regarding weed control (87.23%), grain yield (4073 kg ha-1) and number of fertile tillers m-2 (509.5), whereas wheat plant height (108.2 cm), number of grains spike-1 (45.90) and 1000 grain weight (45.23 g) were higher in 30 cm apart single row sowing in interaction with manual hoeing. Grain yield showed a significant negative (b = -152.8) and positive (b = 3.21) correlation with weed biomass and fertile tillers m-2, respectively. Chemical weed control, ?daab? practice and manual hoeing gave cost:benefit ratios of 2.50, 1.95 and 1.14, respectively. Although the chemical method seems the most profitable, the ?daab? practice was found to be the most advantageous if environmental concerns were taken into consideration.

Allelopathic action of parthenium and its rhizospheric soil on maize as influenced by growing conditions

A biossintese e subsequente liberacao de aleloquimicos por uma planta no ambiente e supostamente influenciada pelas condicoes de crescimento. Para aferir o efeito alelopatico de partes das plantas, bem como do solo rizosferico de losna-branca (Parthenium hysterophorus) crescendo em diferentes pontos de fazendas sob distintas condicoes na germinacao e crescimento de plântulas de milho hibrido da variedade DK 6142, um experimento foi instalado em ambiente controlado, com as sementes de milho sendo semeadas em placas de Petri sobre papel-filtro, assim como em baldes contendo substrato. Os menores valores para germinacao (30,0%), indice de germinacao (2,01), vigor de germinacao (36,3), comprimento da plântula (3,3 cm), biomassa da plântula (10 mg) e indice de vigor da plântula (99,0) de milho foram registrados sob aplicacao de extrato da folha, seguido por extrato do fruto e da planta inteira de losna-branca crescendo em Terras Altas. O solo rizosferico coletado sob plantas dessa especie crescendo proximo a canais de agua provocou maior reducao no indice de germinacao (30,8%), vigor de germinacao (40,6%), comprimento da plântula (32,6%), biomassa da plântula (35,1%) e indice de vigor da plântula (34,3%) de milho, comparado as plantas cultivadas em solo coletado em area sem vegetacao. Os efeitos fitotoxicos inibitorios tanto da losna-branca como de seu solo rizosferico foram mais pronunciados nas raizes do milho, em comparacao com a parte aerea. O maior efeito supressivo na germinacao e crescimento da plântula de milho deveu-se provavelmente a maior concentracao de fenois totais (6.678,2 e 2.549,0 mg L-1) e a presenca de compostos fenolicos, como acidos galico, cafeico, 4 hidroxy 3 methoxy benzoico, p cumarico e m cumarico, e de acido ferulico, vanilico, siringico e m cumarico no extrato aquoso das folhas de plantas coletadas em Terras Altas e de seu solo rizosferico coletado proximo a canais de agua, respectivamente.

Tree species as a potential source of bio-herbicides for controlling Parthenium hysterophorus L.

To assess the herbicidal potential of Eugenia jambolana Lam., Ricinus communis L., Ziziphus jujuba L. and Ziziphus mauritiana L. against noxious weed Parthenium hysterophorus L., germination bioassay using their 1%, 2%, 3%, 4% and 5% (w/v) and seedling growth bioassay using their 5% (w/v) (on dry weight basis) aqueous leaf extracts (ALE) were conducted. ALE of R. communis showed maximum reductions in germination percentage (79%), germination index (89%) and seedling biomass (88%) as well as maximum delays in mean germination time (211%) and time to 50% germination (265%) of parthenium whereas maximum reductions in its seedling length (47%) and seedling vigour index (97%) were shown by Z. mauritiana. Reciprocal dose–response relationship by probit regression analysis revealed that LC50 values of R. communis and Z. mauritiana are 1.04% and 1.44%, respectively. Therefore, R. communis and Z. mauritiana are potential sources of bio-herbicides against this weed.