Potency of Certain Cyanobacterial Strains on Wheat Grown in Sandy and Alluvial Soils

抄録

Recently, a great attention is paid for establishing concept of the associations between wheat plants and a variety of N2-fixing microorganisms. This phenomenon has entered the scientific scene arising from the prospects and the possibilities of their potential application. In this work, cyanobacteria inoculation (Cyano) was applied to wheat cultivated in either clay (alluvial) or sandy soil in a greenhouse experiment under different nitrogen rates to explore their influence after 30 and 65 days from sowing on wheat plant growth, NPK uptake and nitrogen use efficiency. Also, their effect on nitrogen fixing capacity (nitrogenase activity of wheat rhizosphere soil), rhizosphere soil biological activity in terms of dehydrogenase activity (DHA) and CO2 evolution and some soil chemical properties for both clay and sandy soils. Results revealed that the dry weight of wheat plants attained due to the treatment of 75 % N + Cyano was not significantly different from those recorded by the treatment of 100 % N. In both clay and sandy soils, the treatments inoculated with cyanobacteria combined with reduced nitrogen amount (50 and 75 % N) gave higher nitrogen use efficiency by wheat plants percentages compared to those given by the recommended nitrogen rate (100% N). The treatment of 75% N + Cyano gave the highest values of N, P & K wheat plants uptake compared to other tested treatments. The highest nitrogenase activity values could be attributed to the treatment of 75 % N + Cyano in both tested soils compared to those recorded by any of 100 % N for 50 % N + Cyano treatments. The highest values of the soil available N, P & K were due to the treatment of 75 % N + Cyano in both sandy and clay soils at 30 and 65 days. In both tested soils, the treatment of 75 % N + Cyano achieved the highest values of DHA and CO₂ evolution at 30 and 65 days. Generally, it is concluded that cyanobacteria can support wheat growth and enhance the soil fertility; reduce the amount of the mineral nitrogen required for wheat cultivation by 25 %, thus the technology of cyanobacteria inoculation can be considered as eco-friendly process.