Effects of different weed management methods on spatial and temporal dynamic of weed populations and saffron above ground biomass

In order to describe the spatial and temporal distribution of saffron weed seedling populations, geostatistical techniques were used under different management conditions and theirs effect on saffron above ground biomass production over the two growing seasons at three saffron fields each with an areaof 2000 m2, located in Southern Khorasan, Iran. The dominant weed population and saffron leaf dry weight were recorded at 144 points of each saffron field based on a 4×4 m grid at the end of plant growing season. Saffron leaf dry weight was determined at the same place of weed seedling in two years. Weed spatial autocorrelation was indicated by semivariogram analysis and weed density and saffron above ground biomass relationship were determined by cross semivariogram analysis and Spearman’s correlation coefficient at the end of two growing seasons. The density and spatial distribution of weed seedling varied under different weed management practices at both years. Semivariograms analysis showed moderate to strong spatial dependence (50.1-89.6%) for total weed distribution patterns based on fields and years. Saffron above ground biomass dry weight showed moderate to strong spatial patterns (51.1-92.5%) on the three fields. Cross-semivariograms analysis and Spearman’s correlation coefficient showed considerable spatial continuity between saffron above ground biomass and weed density patterns on the different fields. Baesd on our results, in spite of different weed control methods, patchy distribution of weeds can cause spatial heterogeneity in above ground saffron biomass on the fields.