Effect of Azotobacter chroococcum and phosphate solubilizing bacteria on wheat growth, productivity and nutrient availability [electronic resource].

Includes references.

Two field experiments were carried out during two winter seasons of 2002/2003 and 200312004 at EI-Nubaria (highly calcareous soil) and EI-Gemmeiza Agricultural Research Station (Nile Delta soil), to evaluate two inocula to be used as biofertilizers. These inocula are made of Azotobacter chroococcum and phosphate¬solubilizing bacteria (PSB). The inocula may be able to solubilize sources of insoluble phosphate and improve the use of nitrogen in wheat fields under different rates of N and P mineral fertilizers. Wheat growth, yield, N, P-uptake and soil N and P available were recorded. Wheat plant growth was promoted by bacteria combined with mineral fertilizers. Wheat dry weight and plant height were significantly increased by the two inocula in both locations. The nitrogen content and uptake were significantly increased in wheat plants inoculated with Azotobacter chroococcum combined with mineral nitrogen fertilizer with respect to the uninoculated plants in both sites. Similar trend was observed for the phosphorus content and uptake in wheat plants inoculated with PSB inoculum. Common treatment without bacterial inoculation gave very low N or P contents and uptake in plants under low level of mineral fertilization treatments. Wheat yield and yield components were also affected significantly by Azotobacter chroococcum and for PSBinoculation combined with mineral fertilization with respect to the uninoculatedplants in both sites. the grain yield of 2432 and.2670 kg, fed.\ recorded with 100 kg N fed:1, were statistically similar to 2379 and 2510 kg fed: obtained from Azotobacter chroococcum treatment combined with 80 kg N fed:1 for EI-Nubaria and EI-Gemmeiza, respectively. The grain yield of 2688 and 2595 kg fed:1 recorded with 30 kg P20S fed:1, were statistically similar to 2678 and 2636 kg fed:1 obtained from PSB treatment combined with 20 kg P20S fed:1 for the two sites, respectively. The same trend was observed for biological and straw yield for both inocula and the two locations. These results suggest that Azotobacter chroococcum and PSB are able to fix and mobilize more Nand P to the plants and improve plant growth.

Summary in Arabic.

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