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Abstract A green house pot experim~nt was conducted to study th~ effect of organic manuring on the activity of different groups of roicroorganisms and the availability of some Dutritione.l elements. Two soil types were used i west Nubaria sandy’soil and El- Al- &min calcareous soil • The axperi=ent comprised two stagesi in the first the pots were cultivated with lupine which was used as green manure. In the second I stage the soil was. manured by either green manure or stable manure/at the r&te of 400g./ 6 Kg. soil, then cultivated with tomato. Soil samples were taken at 15 days intervals for chemical and microbial analyses. J4icropiological determinations comprise the counts of total bacteria, actinomycetes, fungi, aerobic nitrogen fixers, Cl~~asteurianun and aerobic cellulose decomposers. Soil samples were analyseu for &Tailable phosphorue .and DPrJ.- extractable copper, zinc, iron and manganese. The results obtained were as fellows: 1- Both of the soil samples under experialentation are sandy textured, ; non saline, mildly alkali, of low CEO Yalues and contain Yery low percentage of organic matter, but El-Nubari& soil •••p1e is slightly calcareous while El-Alamin saaple is highly calcareous. s’” - 2 _ The culti vf..tion of both aoi.Ls with lupine enhanced the baetc-riel counts. The application of both green and stable manur-ec increased the density of bacteriaj but the increase was more pronounced i::, the case of stable canurE: than green manure and in the case of sandytban calcareous soil. 3 _ The actinomycetes colonies appearing on the plate COuntB sho~ed lower numbers in manured soils ttan control. This was attributec to more germination of conidia to cyccllial stage in treated samples which resulted in-low colonies numbers than control. 4 _ The fungal population seemed not to be markedly affected by the &ddition of organic matter in both soils. 5 _ The cultivation of sandy soil with lupine increased the counts of aerobic nitrogen fixers represented by azotobacter aore than calcareous soil. Also, organic manuring affected azotobacter count in sandy than c&lcareous soilistable Ilanure was mo,.. effectiTe than 6 _ Clostridium pasteurianum counts were higher in all treatments of . green manure. ------~;...; ------ calcareous soil relatiTe to sandy soil, and stable manure •• latiTe to green manure • 7 _ Aerobic eellulose decomposers showed the same results abtained for Clostridiun Pasteurianua. I . 8 _ ATailable phosphorus showed remarkable increase in stable manure treatment than organic manure and in calcareous soil than sandy soil. ~ - £n op~vslte t.end had been obserTed before aanurlng when sandy Boll showed gradual increase while calcareous soil showed gradual decrease of aTailable phosphorus in both control and lupine-eUltiTated samples, 9- Green and stable manuring increased the amount of extracted eu due to the excretion of organic and inorganic acids during the .icrobiologic~ actiTlty in decomposing the added .anures. . lO-.lthough DTP~-extractable Zn in sandy 80il was little lower than calcareous solI before manuring , the addition of organic manures resulted in higher content of Zn in sandy than~alcareous soil • Howeyer, green .anure was aore effectiTe than stable .anure. II-Stable aanure increased tbe a.ailable Fe content than green manure in both sandy and calcareous soi~ The obserYed increase in DTP~- extractable Fe in aanured treat.ents is due to the release of Fe ions as ~ result of microbiological deco.position of organic matter. |