Allelopathic Effects of Various Plan Extracts and Mulch Materials on Weed Suppression and Productivity in Wheat-Maize Cropping System under Rainfed Conditions.

Abstract

Four sets of experiments were conducted in the pots as well as under field conditions during 2013 and 2014. Two experiments under pot condition for maize and wheat were conducted at Government Fruit Nursery Farm, Agriculture Extension Department District Haripur. Two experiments at field condition for maize and wheat crop were conducted at farmer field village Mang, Tehsil and District Haripur, Khyber Pakhtunkhwa, Pakistan. The objectives of the study were to investigate different weed control techniques and select appropriate methods for weed control in wheat and maize cropping system. To determine various combination of allelopathic plants extract for weed management in wheat and maize cropping systems. To determine the allelopathic effects of various mulch materials for weed management in wheat and maize cropping systems under field conditions. To explore the role of phenolic compounds present in test species for weed management in wheat and maize crops and to recommend the feasible and efficient weed control method in wheat and maize crop under rainfed conditions. The first sets of experiments was conducted in clay pots on maize in the presence of weeds in completely randomized design with eight treatments comprising untreated control, Moringa oleifera leaves extract spray (MLE), Parthenium hystorophorus leaves extract (PLE) spray, Cannabis sativa leaves extract (CLE) spray, M. oleifera + P. hystorophorus leaves extract (MLE + PLE) spray, M. oleifera + C. sativa leaves extract (MLE + CLE) spray, P. hystorophorus + C. sativa leaves extract (PLE + CLE) spray and M. oleifera + P. hystorophorus + C. sativa leaves extract (MLE + PLE + CLE) spray. The analysis of data revealed reduction in number of leaves of weeds, leaf and shoot length of various weeds of maize where moringa + parthenium + cannabis leaves extract was sprayed as compared to untreated control and other treatments. It was also noted that combined application of extracts was much effective in controlling weeds as compared to sole application. The data showed maximum improvement in number of leaves, leaf and shoot length of maize was recorded when mixture of moringa + parthenium + cannabis leaves v extract was applied as compared to alone moringa, parthenium and cannabis leaves extract. The 2nd pot experiment was conducted on wheat in the presence of weeds The analysis of data revealed inhibitory effects on number of weed leaves, leaves and shoot length of various weeds of wheat crop where mixture of moringa + parthenium + cannabis leaves extract was sprayed as compared to sole spray of moringa, moringa + parthenium, moringa + cannabis and parthenium + cannabis leaves extract. While wheat improved its number of leaves, leaf and shoot length where mixture of moringa + parthenium + cannabis leaves extract was applied as compared to sole application of moringa, parthenium and cannabis leaves extract. Various phenolic compounds were detected in moringa, parthenium and cannabis leaves. Maximum phenolic compounds were present in parthenium followed by cannabis and moringa. The 3rd experiment conducted under field conditions on maize comprised eight treatments: untreated control, wheat straw mulching, dry leaves of eucalyptus mulching, rice straw mulching, grass clipping mulching, living mulch intercropping of (soybean), black plastic mulching and herbicide (Primixtra) spray @ 400 ml acre-1 to evaluate their effect on weed density, relative weed density, fresh and dry biomass of different weed species of maize at 25, 50 and 75 DAS (days after sowing). The analysis of data revealed that weed density increased where no mulch was used followed by soybean and dry leaves of eucalyptus while primixtra herbicide @ 400 ml acre-1 and black plastic significantly reduced weed density followed by rice and wheat straw mulch. Similarly, more reduction in weed density, relative weed density, fresh and dry biomass in all weed species was recorded for primixtra @ 400 ml acre-1 and black plastic, rice straw and wheat straw mulch. Maximum weed density, relative weed density, fresh and dry biomass of all the weed species was found where soybean was intercropped with maize and grass clippings were used. Plant height, number of leaves, leaf area, cobs length, weight, number of grains per cob, 1000-grains weight, grain yield and root shoot of maize progressively improved where primixtra herbicide @ 400 ml acre-1, black plastic mulch, rice, wheat straw, eucalyptus leaves were used. However, more economic benefits were obtained from dry leaves of eucalyptus followed by rice straw mulch. The 4th field experiment conducted at field conditions with wheat comprised eight treatments: control, maize stalk mulching, dry leaves of mulberry mulching, sugarcane bagasse mulching, grass clipping mulch, living mulch intercropping of lentil crop with vi wheat, black plastic mulch and herbicides topik @ 120 g & buctrilsuper @ 300 ml acre-1 to evaluate their effect on weed density, relative weed density, fresh and dry biomass of different weed species of wheat under rainfed conditions at 25, 50 and 75 DAS. The analysis of data revealed highest reduction in weed density, relative weed density, fresh and dry biomass in all the weed species where herbicides topik @ 120 g & buctrilsuper @ 300 ml acre-1 and black plastic mulch were applied followed by sugarcane bagasse as compared to control and living mulch. There was maximum weed density, relative weed density, fresh and dry biomass of all weed species where lentil was intercropped with wheat and dry leaves of mulberry were used. There was significant effect of various mulch materials on seed germination percentage, wheat growth and agronomic traits. More improvements in wheat plant height, number of leaves, leaf area, number of tillers, number of spike, spike length, number of grains and 1000-grains weight were observed where topik @ 120 g & buctrilsuper @ 300 ml acre-1, black plastic mulch and sugarcane bagasse and living mulch was used as compared to control. More economic benefits were obtained from sugarcane bagasse and grass clippings were used. In Conclusion moringa, parthenium and cannabis have allelopathic potential to suppress various weeds of maize and wheat. In case of foliar spray of various plants leaves extracts, moringa + parthenium + cannabis were found more effective than any other combinations to manage weeds. Hence in maize, rice and wheat straw and dry leaves of eucalyptus have more allelopathic potential and suppressive effects on maize weeds under rain-fed condition. In case of wheat, sugarcane bagasse has suppressive effect.