Nitrogen loss by leaching is considered a major problem, particularly under higher N requirement. Consequently, a study was conducted to determine the effect of decreasing rates of inorganic nitrogen and irrigation scheduling on distribution of both chemically available soil nitrogen and soil moisture content as well as grains yield of corn. To test this assumption, corn (Zea mays, variety single hybrid 10) was selected and four nitrogen treatments were applied at EL-Khatatba area, El-Monofia, Egypt: (a) Control, 100 kg N/ fed as (NH4 NO3, 33% N), (b) 80 kg N/fed + compost, (c) 70 kg N/fed + compost and (d) 60 kg N/fed + compost. The compost added to the soil at the rate of 2 %. As well as three drip irrigation scheduling were applied with fixed total applied water amounts: (1) daily irrigation, (2) three days intervals (every second day) and (3) two days intervals (every third days) with 4L/h emitters. Chemically available nitrogen and soil water content in the intervals soil depths (0-30, 30-60 and 60-90 cm) as well as nitrogen content in plants and grains yield were determined. The results indicate that the root zone was contain higher moisture with application of daily and two days intervals irrigation treatments compared to three days intervals. Application of three days intervals increased water content with the increasing soil depth especially with increasing time of experiment. High amounts of nitrogen were existing in the upper layer (0-30 cm) of the soil and it decreased gradually by going deeper to reach (at 60-90 cm). The total cumulative amounts of nitrogen from 0-60-cm depth were sufficient level with different treatments. The available nitrogen was 290, 283, 243 and 202 mg/Kg soil with application of 100 kg N/fed, (80 kg N /fed + compost), (70 kg N/fed +compost) and (60 kg N/fed +compost) at flowering stage, respectively.
* Associate Prof. of Soil, Fac. of Agric., Ain Shams Univ.
** Assistant Prof. of Agric. Eng., Fac. of Agric., Ain Shams Univ
Chemically available N levels in the soil were increasing and moving downward when soil irrigated three times weekly. Application of 80 Kg N /fed combined with compost and two days intervals or daily irrigation increased markedly nitrogen content in –corn plant and grain yield of corn plants compared with other treatments with respect of irrigation scheduling.