Field experiments were conducted for two seasons in the clay soil located at South of Sahl El-Hossiniya Research Station, Port-Said Governorate, Egypt. Maize (Zea mays) was used as experimental plant. The current work aims to asses effect of compost application as organic amendment at rates of zero (C0), 5.5(C1), 11.0(C2), and 16.5(C3) Mg f-1 (Mg ”megagram=106 g i.e. metric ton) on yield of maize and some soil physical properties; under irrigation using two water levels of full irrigation (I1) of 3300 m3 f-1 , and deficit irrigation (I2) of 2640 m3 f-1 (80% of full irrigation). Grain yield in non-amended treatments was 1.788 to 2.482 Mg f-1 while it was 2.757 to 6.316 Mg f-1 in compost-amended treatments. Water-use efficiency (in kg grains m-3 water) was 0.542 to 0.940 for no-amended treatments and 0.835 to 2.392 for those compost-amended treatments causing average increase of 34.1, 161.0 and 92.9% for the C1, C2 and C3, respectively. The deficit irrigation I2 surpassed the full one I1 by 58.3%. Soil moisture curves at tensions of 0.01 up to 15.00 atm and available water(AW) increased due to compost. Compost had slight effect on total porosity, but affected the distribution of pore size fractions creating more water-useful pores(i.e. the quickly drainable-, slowly-, drainable-, and water-holding-pores) and decreasing the less-water-useful ones(i.e. the fine capillary pores). Aggregation and aggregate stability increased by compost; the high rate gave 6.8 =% large aggregates while the no compost gave 4.3% only. |
