Volume 8, Issue 4 (2006)                   JAST 2006, 8(4): 281-291 | Back to browse issues page

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Majnoun Hosseini N. Effects of Plant Density and Nitrogen Rates on the Competitive Ability of Canola (Brassica napus L.) against Weeds. JAST 2006; 8 (4) :281-291
URL: http://jast.modares.ac.ir/article-23-156-en.html
Department of Agronomy, College of Agriculture, Tehran University, Karaj, Islamic Republic of Iran.
Abstract:   (8968 Views)
To study the effects of plant density and nitrogen rates on the ability of canola (Regent  Cobra; an inbred variety) to compete with weeds, an experiment was conducted as a factorial complete block design with four replications. The treatments included four levels of plant density at 150, 190, 230, and 270 plants m-2, and four levels of nitrogen (N) fertil-izer at 0, 46, 92, and 138 kg ha–1. Results indicated that different levels of plant density and N fertilizer had significant effects on the canola’s leaf area index (LAI) and dry mat-ter accumulation, as well as on the weed’s dry matter at three stages of plant growth (ro-sette, stem elongation, and 50% flowering). The addition of N fertilizer resulted in in-creasing plant LAI and decreasing weed dry matter. Densities of 150 and 270 plants m-2, along with 138 kg ha–1 nitrogen showed the highest LAI at the rosette and stem elongation stages. The LAI at different plant growth stages was an important factor in enhancing ca-nola’s competitiveness with weeds. There were significant differences between different plant density and N fertilizer levels for traits such as plant height, pod bearing stem length, biomass and seed yield. An increase in plant density significantly decreased the pod bearing stem length and total pod numbers per plant (i.e. pod numbers in main branches and sub-branches), but increased plant height. The highest seed yield was ob-tained with 190 plants m-2 along with 138 kg N ha–1. This study revealed that optimum plant density as well as N fertilizer may increase the competitive ability of canola against weeds.
Full-Text [PDF 207 kb]   (10438 Downloads)    
Subject: Agronomy
Received: 2010/01/30 | Accepted: 2010/01/30 | Published: 2010/01/30

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