Effect of Establishment Methods and Weed Management Practices on Some Growth Attributes of Rice

Studies were carried out for two years to evaluate the effect of methods of sowing and weed control practices on the productivity of transplanted and direct wet-seeded rice in Dera Ismail Khan, NWFP, Pakistan. The experiment was laid out in a randomized complete block design with a split plot arrangement. The planting techniques viz. transplanting and direct seeding were maintained in main plots while weed control practices included the use of granular herbicide Sunstar 15WG （ethoxy sulfuron）, Machete 60EC （butachlor）, conventional hand weeding, and the weedy check （control） were assigned to the sub-plots. Data were recorded on weed parameters like weed density and dry weed biomass 60 and 90 days after sowing （DAS）; agronomic parameters including plant population, number of panicles and paddy yield and physiological parameters like leaf area index and net assimilation rate 45 and 90 DAS. The planting methods and weed management significantly influenced most of the parameters studied. The data revealed that the paddy yield and its components were significantly higher in the transplanted method than that in direct-seeded method, while the weed density and biomass were lower in the transplanted plots than the direct-seeded plots. Among weed management tools, the maximum paddy yield was obtained in hand weeding, closely followed by herbicide application Machete 60EC during both cropping seasons.

Integrated Weed Management Through Tillage and Herbicides for Wheat Production in Rice-Wheat Cropping System in Northwestern Pakistan

Conservational tillage （CT） in combination with broad spectrum herbicide may be more efficient and economical in controlling weeds, reducing cost of cultivation, and enhancing wheat yield. Field experiments were carried out to evaluate the effect of tillage and herbicides on weeds and wheat yield under rice-wheat cropping system （RWCS）. The results indicated that broad spectrum herbicides particularly, carfentrazone ethyl ester＋ isoproturon （Affinity 50 WDG） reduced weeds density by 93 and 95% compared to control and also produced the maximum grain yield （6 818 and 6 996 kg ha-l） and HI （harvest index, 44.7 and 44.6%） in 2007-2008 and 2008-2009 growing seasons, respectively. The maximum weeds infestation and the lowest yield were recorded in control. Tillage methods significantly influenced grain yield and HI, while no significant effect on all other parameters. The overall mean yield was significantly higher in zero tillage （5 575 kg ha-l） and reduced tillage （5 584 kg ha-l） compared to CT （5 479 kg ha-^-1）. Besides increasing wheat yield, Affinity 50 WDG and zero tillage are important weed management practices that can be integrated into wheat production in RWCS. However, in case of perennial weeds or insect pests＇ infestation, CT in combination with Affinity 50 WDG would be more productive than conservation tillage.

Effects of irrigation and weed-control methods on growth of weed and rice

A field experiment was conducted to study the effects of weeds control methods and an irrigation model on rice growth as well as water consumption and weed quantity in the paddy field.In conventional paddy rice production,one of the most important irrigated crops,a significant amount of irrigation water is lost due to percolation and evaporation.A new irrigation model called the Rain-Catching and Controlled Irrigation(RCCI)model has been developed as a viable water-saving technology in the production of paddy rice.In this study the performance of the RCCI model has been analyzed under mulching,hand weeding and weedy conditions in Jiangsu Province of China.The experiment was laid out in Randomized Complete Block Design(RCBD)with three replications and nine treatments.The three replicates consisted of three water management regimes:high dry high flooding(HD-HF),high dry low flooding(HD-LF),and shallow and frequent irrigation(SF)water treatment.The RCCI model was adopted in HD-HF and HD-LF while Flooding Irrigation(CFI)was adopted in SF as a control.The nine treatments were equally divided under mulching,hand weeding and weedy conditions.The lowest and maximum irrigation water delivery was 244.86 mm in mulching and 429.22 mm in hand weeding,respectively at HD-HF.And the lowest and maximum irrigation water delivery was 300.1 mm in the mulching field and 680.72 mm under hand weeding,respectively at HD-LF.The Nanjing 44 rice variety was used.It was observed that weed density and dry weight were significantly influenced by the amount of irrigation water in all the mulching,hand weeding and weedy plots.Considering yield and the number of irrigations,the RCCI model produced better results than CFI.Mulching under RCCI was an effective method to control weeds and reduce labor cost.In addition,mulching decreases the use of herbicides and the risk of pollution.On the other hand,mulching could improve yield and save water.