Influence of irrigation water regimes and patterns of nitrogen placement combined with soil compaction on wheat (Triticum aestivum L. )‎ growth

الملخص EN

Irrigation management and pattern of nitrogen application associated with soil compaction are critical factors in wheat growth.

This study aimed to evaluate the effect of irrigation regimes and patterns of nitrogen fertilizer placement in presence of soil compacted layer on some wheat growth parameters.

Germination percentage, plant height, pike length, 10-spike weight, total yield and grain yield were measured.

Sandy loam lysimeter (0.60 x 1.0 and 0.55 m deep) experiments were conducted in a split-plot design with three replications in the experimental agricultural station of Assiut University, for two seasons 2016/2017 and 2017/2018.

The upper layer (0.15 m) in some lysimeters was compacted moderately with a bulk density of 1580 kg/m 3 and used for nitrogen placement, while the other soil lysimeter possessed a bulk density of 1420 kg/m 3 .

The experiment was consisted of two irrigation regimes viz, field capacity (F.C.) and saturation capacity (S.C.) as main plots and five patterns of nitrogen placement and soil compaction: mixed fertilizer in un-compacted surface layer (F.

IN UN-C.S.L.), placed fertilizer above compacted surface layer (F.

ABOVE C.S.L.), placed fertilizer beneath compacted surface layer (F.

BENEATH C.S.L.), mixed fertilizer in compacted surface layer (F.

IN C.S.L.), and placed fertilizer above uncompacted surface layer (F.

ABOVE UN-C.S.L.) as sub plots.

The results indicated that irrigation at F.C.

improved some of wheat growth parameters such as germination percentage, 10-spike weight, total yield and grain yield compared with irrigation at the S.C.

The differences in the values these growth parameters were significant to high significant under the patterns of nitrogen placement and compactions.

Also, it was obvious that moderate compaction, i.e.

bulk density of 1580 kg/m3 , enhanced the studied growth parameters except spike length and grain yield in comparison to non-compacted condition.

Generally, some growth parameters of wheat were affected positively under compacted soil layer under F.C.

Accordingly, the results recommend that for improvement wheat growth grown on sandy loam soil it is preferable to use irrigation at filed capacity with mixing of nitrogen on the compacted surface soil layer.