تأثير التناوب بالري السيـحي والتنقيط وملوحة ماء الري على خصائص التربة ونمو النبات في تربة طينية

ABSTRACT

The study has been conducted in the field of Agricultural college university of  Basrah,in Karmat- Ali  during the  spring season 2007  on clay texture  soil in order  to investigate  the effect of  alteration between drip and surface  irrigation  systems, Using saline water 7.0 – 8.5 dSm-1 and low saline water 2.5 – 3.0 dSm-1, under  irrigation level of  100% EP and  Leaching requirement of  20% , on soil properties and sorghum crop growth Parameter . The movement of advance and recession of water throes the  Horizontal  wetting front in furrows have been studded . The experiment was designed by Randomized Complete block design (R.C.B.D) with three replication.The results of this study may summarized as follows: 

1. Using saline  water by alternation of drip and surface irrigation system in trio  cycles starting by drip irrigation and ending by surface irrigation,use low saline water, (Ds.Ds.Sf , Ds.Df.Sf , Df.Ds.Sf) gave high efficiency in preventing  salinity and deterioration of the soil physical properties ,as well as, crop growth from using  single  method (Df ,Sf) .

2. Prevalent of drip irrigation in one cycles leded to reserve of the  soil properties from the effect of  water irrigation, which cause to increase soil water  infiltration  and  storage of water in root zone .

3. Increasing of soil bulk density and reduction  in soil mean weight diameter and water  infiltration  in soil by using surface irrigation low saline water (Sf) .By using the  same irrigation system with saline water (Ss),resulted in more soil deterioration.

4. The treatment of drip irrigation  reduced  the vertical & horizontal distribution of water in soil  as compared  with the surface irrigation ,as well as, soil moisture increased with all treatment with depth by using saline water and decreased horizontal away from the furrows  except ( Df ,Ds) treatment.

5. Significantly increasing in plant lengths  and  dry weights were shown under the drip irrigation treatment ,particularly ,in trio  cycle as compared with surface irrigation treatment at various saline water.

6. Mainly the results indicated that 73% of root system were distributed  within the depth 0-15 cm and the highest roots density were  found under Df  treatment in the same depth. The results showed that 91% of the root system were distributed  around   central distance of  furrow center  0 ± 15 cm, where, the highest roots number were found in trio cycle treatments.

7. Irrigation efficiency was increased under drip irrigation  and  trio cycles treatments with different saline irrigation water as compared with di- cycles treatments (Df.Sf و Ds.Sf( .

8. Prevalent of drip irrigation in one- cycles treatment decreased the frontal water movement of horizontal wetting advance in the furrows and reduction in the ression of water from the soil surface ,whereas,  using saline water treatments gave negative  results  .

9. Decreasing the quantity of  low saline water by two irrigation round substituting by saline water in tri-treatments were not significantly  effect on soil properties and plant growth and  gave almost gave the  same  results  of  using  low saline water during the growing season.