effects of wheat phosphorus residuals on vetch (vicia panonioca) yields and some soil physico-chemical properties in dry land condition

this study was carried out to determine effects of phosphorus residual applied to wheat on vetch (vicia panonioca) growth, yields and some  soil  physical, chemical  properties in soil. the experiment was conducted with randomized completely block design in a field with three replications including four levels of p residual (applied for wheat p0, p15, p30, and p45 kg p2o5 in hectare) from triple super phosphate fertilizer sources. vetch seeds were planted at same place of planted wheat and applied p according to our package. after harvesting of vetch, plant samples were collected and soil samples prepared from 0-25 cm of soil depth.  results showed that phosphorus residual had significant effects on yields of seed and vetch biomass, number of cluster, root nodules, seed phosphorus concentration and uptake (p≤ 0.05),  and weight of thousand vetch seed (p≤ 0.001). phosphorus residual increased vetch growth significantly leading to increased soil organic matter, structural size and cation exchange capacity (p≤ 0.001). with increasing applied phosphorus fertilizer to wheat or soil phosphorus residual, vetch length, number of cluster, and number of effective nodules of vetch roots, also increased. greater grain and biomass yields were observed in p45 treatment. it can be concluded that phosphorus residual can effect on p uptake and vetch growth and increase p uptake. in addition soil structural stability and cation exchange capacity improved by greater vetch growth. vetch has also ability to use phosphorous residual from soil.