تأثير تراكم خاك و كم آبياري بر ويژگي‌هاي خاك و عملكرد و جذب عناصر روي، مس و آهن توسط جو و نخود علوفه‌اي در سامانه‌هاي مختلف كشت

Soil, as the primary medium for agricultural production, plays a fundamental role in sustainable crop production an‎d food security. However, soil compaction caused by agricultural operations an‎d machinery traffic, together with water scarcity, are among the most important factors limiting crop production in arid an‎d semi-arid regions. Soil compaction increases bulk density while reducing porosity, permeability, an‎d hydraulic conductivity, thereby restricting root growth an‎d nutrient uptake. Likewise, deficit irrigation limits water availability to plants an‎d adversely affects nutrient transport an‎d absorption. In this context, integrated cropping systems an‎d beneficial soil microorganisms may improve both soil physical conditions an‎d plant nutritional status. This study was conducted to eva‎luate the effects of soil compaction an‎d deficit irrigation on soil hydraulic properties an‎d the uptake of zinc (Zn), copper (Cu), an‎d iron (Fe) by forage barley an‎d forage pea under different cropping systems. The experiment was arranged in a ran‎domized complete block design (RCBD) with three replications. Treatments consisted of three soil compaction levels (0, 10, an‎d 20%), two irrigation regimes (normal irrigation an‎d deficit irrigation), different cropping systems including sole barley, sole pea, an‎d barley–pea intercropping, as well as inoculation with arbuscular mycorrhizal fungi an‎d Rhizobium bacteria. A total of 108 soil samples an‎d 108 plant samples were collected an‎d analyzed for their physical, chemical, an‎d nutritional characteristics. To determine the initial soil hydraulic properties, soil water retention curves were fitted using the van Genuchten model. The coefficients of determination (R² = 0.977–0.992) indicated an excellent fit of the model to the measured data. The results showed that increasing soil compaction an‎d deficit irrigation significantly reduced hydraulic conductivity, aggregate stability, soil moisture content, plant biomass, an‎d the availability of micronutrients. Under severe stress conditions (20% compaction combined with deficit irrigation), available soil iron in sole barley cultivation decreased by approximately 17%. Deficit irrigation also reduced plant zinc concentration from approximately 28 to less than 26 mg kg⁻¹ an‎d decreased biomass production by nearly 30%. In contrast, barley–pea intercropping improved nutrient availability under stress conditions. Available soil iron increased from 17.8 to 20.8 mg kg⁻¹, while available soil copper increased from 1.43 to 1.75 mg kg⁻¹. Biomass production was also approximately 15% greater than that of sole barley. Mycorrhizal inoculation in barley cultivation increased available soil iron by 48%, enhanced plant copper concentration by 74%, an‎d significantly improved soil organic matter an‎d aggregate stability. Similarly, Rhizobium inoculation in pea cultivation increased copper uptake by 75% an‎d significantly enhanced iron an‎d zinc concentrations in plant tissues. The highest performance was observed in the barley–pea intercropping system combined with microbial inoculation (PBR), which under severe stress conditions increased aggregate stability, soil organic matter, soil moisture content, plant biomass, an‎d zinc concentration by 17%, 40%, 24%, 28%, an‎d 39%, respectively, compared with uninoculated intercropping. Overall, the findings demonstrated that integrated cropping systems combined with beneficial microorganisms can effectively mitigate the adverse effects of soil compaction an‎d deficit irrigation. By improving soil physical an‎d hydraulic properties an‎d enhancing micronutrient uptake, these management practices can contribute to sustainable crop production in arid an‎d semi-arid regions.

محمدعلي حاج عباسي جورتاني

مهران شيرواني جوزداني , حميدرضا عشقي زاده

محمدرضا مصدقي , قدرت اله سعيدي