Effect of different rates of nitrogen and irrigation on dry matter and nitrogen content of corn at different growth stages during two sowing dates

الملخص EN

-One field experiment was conducted at Hada Al-Sham Experimental Station, King Abdulaziz University, to study the effect of three different rates of irrigation, based on depletion ratios of 50 %, 25 %, 10 % (IR1, IR2, IR3) and four different rates of nitrogen fertilization (urea), zero, 100, 200, 300 kg / ha (N0, N1, N2, N3) of hybrid corn plant (AGA Seed 215 Cultivar).

Total dry matter accumulation and its parts (leaves, stems, ears, and tassels) as well as the nitrogen content in different plant parts at different growth stages during two successive sowing dates (autumn 1994 and spring 1995) were determined.

The irrigation scheduling processes were designed under constraint of equal total seasonal applied water for different irrigation treatments, which were 90.15 cm/sowing date one (9015 m3/ha/sowing date one) and 82.1 cm/sowing date two (8210 m3/ha/sowing date two) for two sowing dates, respectively.

The first sowing date outcome had a significantly higher leaf area index and dry weight (ear, tassel and total), plant nitrogen percentage (stem, ear and total).

However, the nitrogen percentage of tassel was significantly higher in second sowing date .

All plant variables (dry matters) were higher under the fourth plant stage (maturation) except tassel dry weights.

The nitrogen treatment affected significantly some growth variables, where the N3 treatment gave higher values of dry weight (3202.9 kg/ha for ear, 232.3 kg/ha for tassel and 6438.2 kg/ha for total), and nitrogen percentage (1.98 gm/kg for leaf, and stem), while N2 treatment gave higher values of nitrogen content in plant and its parts, (2.9 gm/kg for total, 2.84 gm/kg for leaf, 1.97 gm / kg for stem, 1.67 gm/kg and 1.56 gm/kg for tassel).

There was no significant effect for the irrigation regimes or interaction treatments (nitrogen treatment and irrigation regimes) on all the studied plant variables.