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EFFECT OF WILD OATS (AVENA FATUA L.) DENSITY ON WHEAT YIELD AND ITS COMPONENTS UNDER VARYING NITROGEN REGIMES

GUL HASSAN^* AND HAROON KHAN

Abstract: A field study was conducted at Malakandher Research Farm, NWFP Agricultural University, Peshawar during Rabi 2003-4 to quantify the competition between wheat and wild oats. The experiment was laid out in randomized complete block design with four replications under a split-plot arrangement. The experiment comprised of 3-nitrogen levels (75, 100 and 125 kg ha^-1), kept in main plots, while six wild oats densities (0, 10, 20, 30, 40 and 50 plants m^-2) assigned to sub-plots. Ghaznavi-98 variety of wheat with a sub-plot size of 5x 1 m² was seeded in the 3rd week of November 2003. The data were recorded on density of wheat (m^-2), density of wild oats (m^-2), wheat and wild oats leaf area plant^-1 (cm²), wheat and wild oats plant height at maturity (cm), wheat spike length (cm), number of grains spike^‑1, grain weight spike^‑1 (g), 1000 grains weight (g), biological yield (t ha^-1) and grain yield (t ha^–1). Moreover, grain and straw were also analyzed to estimate the uptake of nitrogen, phosphorus and potash by the test species. All the data except the chemical analyses were subjected to ANOVA technique using MSTATC Computer software. The data revealed significant differences for the wild oats densities for most of the traits studied, the differences for nitrogen levels and interaction were significant only in grain yield and spike length, respectively. The comparison of means revealed that density of wheat decreased with an increase in wild oats density. Only 150 plants m^-2 was recorded under 50 wild oats seeded m^-2 as compared to 262 plants m^-2 in the monoculture of wheat. Plant height of wheat was also influenced by the oats density. At 50 wild oats, the wheat height was 83.333 cm as compared to 90.125 cm in the monoculture wheat. Similarly, the grain size was also affected by the presence of wild oats. As low as 12% lower sized grains were recorded under 50 oats plants m^-2 as compared to monoculture of wheat. The adverse effect of oats on yield components reflected on the grain yield. More than 50% reduction in yield was noticed at the highest density of wild oats as compared to monoculture of wheat.

Department of Weed Science, NWFP Agricultural University Peshawar-25130, Pakistan