Salt and water distributions in the plant root zone under deficit irrigation


KAMAN H., Özbek O.

JOURNAL OF FOOD AGRICULTURE & ENVIRONMENT, vol.10, no.3-4, pp.496-500, 2012 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 10 Issue: 3-4
  • Publication Date: 2012
  • Journal Name: JOURNAL OF FOOD AGRICULTURE & ENVIRONMENT
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.496-500
  • Keywords: Partial root drying, soil water content, salinity map, yield, cucumber, USE EFFICIENCY, SOIL-SALINITY, QUALITY
  • Akdeniz University Affiliated: Yes

Abstract

This study evaluated yield, soil water status and likely salt accumulation within the rooting zone of cucumber that was irrigated with deficit irrigation. A drip irrigation method with seven different treatments was used in this research. The treatments included 3 traditional treatments: full irrigation (100% Class-A Pan evaporation) with no deficit (FULL), 75% and 50% deficit irrigations, designated as DEF75 and DEF50, respectively. Both sides of plant rooting zones, along the row of plants, were wetted uniformly under FULL and traditional deficit irrigation methods. Partial root drying (PRD) irrigation technique was used in the remaining four irrigation treatments. Only half side of the rooting zone was irrigated and the other half side was remained as in dry form during irrigation under the PRD practices. We had four such treatments: (1) A-PRD75 and (2) A-PRD50 where 75% and 50% deficit irrigation, respectively, were applied and the wetted halves of the rooting zone were alternately changed in successive irrigations. (3) FPR75 and (4) F-PRD50 where 75% and 50% deficit irrigation, respectively, were applied but the wetted halves of the rooting zone remained fixed throughout the season. Following the 22(nd) irrigation (122 days after transplanting), a total of 420 gravimetric soil samples in 3 replicates were collected from the plant rooting zones for determining of soil water content. Similar numbers of soil samples were collected at harvest in order to describe soil salinity. The data were, then, used to create maps of soil water content and salinity distribution within the plant rooting zones. As we expected, the treatments FULL and DEF75 had the highest soil water content among the all tested irrigation treatments. Soil water content was proportionally less under the PRD treatments and followed the ranking A-PRD75>A-PRD50>F-PRD75>F-PRD50. The highest salt accumulation was at about 30 cm in soil depth. The salinity maps revealed that the salinity was highest in the areas with the highest dense of roots with the stated exception; the dry side of the rooting zone under the treatment F-PRD50 had the highest salinity but with lowest root density. Cucumber yield was decreased by increasing amount of water level. As a result, levels of deficit irrigation regime and application type have an important effect on cucumber yield.