Comparison of soil biological properties and carbon storage of Prosopis cineraria and Prosopis juliflora (Case study: Assaluyeh)

In arid and semi-arid ecosystems, the relationship between tree species and habitat is fragile due to environmental stresses. Native species of Prosopis cineraria and non-native Prosopis juliflora are among the species that in addition to water-soil-plant relationships, affect the life of other animal and plant species in these areas. In these areas, the role of native trees in carbon storage and change in soil properties is important. Soil plays an important role in the carbon cycle and is an important source of carbon storage and tree species can make changes in soil properties and organic carbon storage due to tolerating hard environmental conditions such as high temperatures and radiation. Soil biological properties are a good indicator for measuring soil quality and by examining them, appropriate information about respiration, nutrient cycle, microbial biomass and mineral nitrogen mineralization capacity is obtained. (Prosopis cineraria (L.) Druce) is one of the most important native species in the Sahara-Sindhi area, which has a good ability to establishment and adapt and improves soil properties. The non-native species of (Prosopis juliflora (SW) DC) is widely planted with fast growth and prevention of fine dust as a fodder tree. Trees in these areas can have a range of different effects on the soil under their canopy in various ways and have a vital effect on the richness of soil microorganisms. Due to the importance of both species in this habitat, a comparison of changes in soil biological properties and organic carbon storage under and outside the canopy of Prosopis cineraria and Prosopis juliflora bases was performed in Assaluyeh in Bushehr province.

To measure basic and induce respiration, microbial biomass carbon and nitrification potential, 24 soil samples were collected from 0-30 cm depth randomly from under and outside the canopy of both species. To calculate organic carbon storage of soil with the cylinder in a 1×1 m2 plot, sampling was done from a depth of 0-10 cm of soil to obtain the bulk density and organic carbon. Also for measuring organic carbon storage in litter and grass cover in the same sample plot, litter and grass cover were collected and their weight was recorded. Finally, 120 samples were taken in two location under and outside the canopy of both species.

The results of analysis of fragmented plots showed that the effect of species as the main factor on basic (p<0.05) and induce (p<0.01) respiration was significant and it was in Prosopis cineraria 2.73 and 22.47 mg Co2 in day and hour and in Prosopis juliflora 0.9 and 15.57 mg Co2 in day and hour, respectively was higher in Prosopis cineraria than Prosopis juliflora and had no significant effect on microbial biomass carbon and nitrification potential. The effect of sampling location was significant for all variables studied and under the canopy was greater than outside the canopy.

Due to the positive effect of Prosopis cineraria species on basic and induce soil respiration, preservation and revitalization of this valuable native species is very vital and negative effect of non-native species of Prosopis juliflora on basic and induce soil respiration can reduce microbial activity and upset the balance of the nutrient cycle, especially carbon. Therefore, it is recommended to use native species for improvement and quality of soil in natural forests, afforestation and restoration of ecosystems and the entry of non-native species avoid into the natural forest. Also Prosopis juliflora species is better to be cultivated because high resistance in de- desertification areas and for quicksand stabilization.