Agricultural practices such as seedbed preparation systems and fertilization especially Anhydrous-Ammonia had a great impact on plant and soil microbial community which were sensitive indicators of changes in soil. A field experiment was carried out at the research farm of Rice Mechanization Center (RMC), Meet El-Deyba, Kafr El-Sheikh Governorate, during growing the winter wheat season 2015-2016 to study the interaction effect of anhydrous-ammonia injection and seedbed preparation systems on wheat growth/yield and soil micro-organisms biological activities. Anhydrous-Ammonia was injected in soil with two levels, of 75 Kg N/fed (A.A.1), and 94 Kg N/fed (A.A.2) which represent 100% and 125% of nitrogen recommended dose and granulated urea, (control) 46.5% at three doses according to agronomy recommendations. While, the applied seedbed preparation systems were Heavy system, HS (Moldboard plough one pass followed by Chisel plough twice and laser leveling), Moderate system, MS (Chisel plough one pass followed by Rotary twice and laser leveling) and Conventional system, CS (Chisel plough twice and wooden leveling). However, the used different wheat cultivars were Gemmiza 11and Shandweel. Soil micro-organism biological activity, wheat plant growth activity and wheat yield and its components were measured and determined to realize the objective of this investigation. The Soil micro-organism biological activity and wheat plant growth activity were done at different three times of 4 days, 1 month after Anhydrous-Ammonia injection and after wheat crop harvesting. The obtained results indicated that:
The population and activity of soil micro-organisms increased as the length of time increased compared with applied Urea fertilizer. Approximately, one month after A.A.1 injection, the populations of a bacterial group were increased by an average of 57.8 and 58.6% while, the fungi group was increased by an average of 53.5 and 55.2% compared with 65.1 and 66.0% for actinomycetes group during growing Gemmiza 11 and Shandweel wheat cultivars, respectively.
Using MS seedbed preparation system gave the highest values of the total grain yield of 18.5, 29.6 and 24.1 Ardb/Fed. were obtained for Gemmiza wheat cultivars compared with 17, 24.8 and 20.3 Ardb/Fed. for Shandweel wheat cultivars under applied fertilizer levels of Urea, A.A.1 and A.A.2, respectively.
Finally, from mentioned above and analyses of yield and its components, the authors recommended the wheat farmers in Egypt using MS seedbed preparation system and applied fertilizer level A.A.1 to get high wheat yield and maintain the soil in a good biological state.