BACKGROUND Phenotypic plasticity of fitness-related traits is vital for plant species to adapt to variable environments. Chenopodium glaucum L. and Amaranthus retroflexus L. are two common weed species globally. Understanding the plasticity in life-history traits, especially in reproductive allocation, within and among these species is important for predicting their success and for managing the...

> Sowing crops following cover crops on forage may cause injuries andproductivity reduction, due reasons as allelopathy or glyphosate residues. Theobjective of this study was to evaluate the influence of differing periods betweencover crop (Urochloa ruziziensis) desiccation with glyphosate and sunflower(Aguará 4) sowing in a no-tillage system on crop development and productivity.Two assays were...

in order to determine probable effects of sowing dates on partitioning coefficient of dry matter to different organs (leaf, stem and reproductive organs) in different wheat varieties (koohdasht, zagros and tajan) an experiment with crbd design and four replications was conducted. 5 sowing dates were included (29 december, 2007, 30 january, 2 march, 27 march, 1may, 2008). in order to quantify pa...

Conventional seedbed preparation for spring sown crops in Sweden includes 3±4 harrowings followed by sowing, but there is a great interest among farmers to reduce this tillage. Since the soil is normally at ®eld capacity after winter, the conventional system implies a major risk of soil compaction and the farmer has to wait for the soil to dry before seedbed preparation can be started. A new te...

crop simulation models are increasingly used in agriculture. these models help in saving time and expenses. the objective of this study was to evaluate cropsyst model in predicting development, growth and yield of wheat cultivars from golestan province. to do this, experimental data from different experiments were gathered for kohdasht, shiroodi, tajan and zagros. model performance in simulatin...