This study was carried out at Kafr El-Gonena Village, El-Dakhlia Governorate, during 2008 winter season to identify effect of subsoil tillage on potato response to biofertilization application. The experiment was designed statistically as a split split plots with three replications. The main plots involved the subsoil tillage treatment at 0.30, 0.40 and 0.50 m depth, comparing with no-subsoil tillage, the sub plots involved the soil biofertilization treatment using Blue green Algae, comparing with the bereaved of biofertilization and the sub-sub plots included the tuber inoculation treatment using a combination of microorganisms, comparing with the bereaved of inoculation. The results indicated the following:
The subsoil tillage of 0.40 m depth under Blue green Algae application achieved the more desirable soil characteristics of 1.14 g/cm3 bulk density, 6.04 pH, 2.54 dS/m salinity, 14.14 mm/h infiltration rate and 47, 17.90 and 497 ppm available N, P and K concentration, respectively.
The subsoil tillage of 0.40 m depth under Blue green Algae application required the lower applied irrigation water amount of 5240 m3/fed.
The subsoil tillage of 0.40 m depth under Blue green Algae application and tuber inoculation achieved higher potato tuber yield of 18.80 Mg/fed and higher water use efficiency of 3.58 kg/m3.
Generally, it is recommended to apply the subsoil tillage under biofertilization application to achieve higher potato tuber yield.