Hydro-Physical Behavior of Gypseous Soils Under Different Soil Management in a Semiarid Region of NE Spain.

The hydro-physical properties of gypseous soils, which are commonly associated with dry climates, determine the productivity of rangelands and croplands. The objective of this paper is to study, in the semiarid central Ebro Basin, NE Spain, some hydro-physical properties of gypseous soils under five different contrasted soil managements: soils of ungrazed (N) and grazed (GR) uncultivated lands, and freshly moldboard tilled (MB), cropped (C), and fallowed (F) agricultural soils. The gypsum content of the studied soils, with concentrations that are natural, ranged from 50 to 92%. The soil bulk density (ρb), saturated sorptivity (S10), hydraulic conductivity (K10), and the water retention curve (WRC) of undisturbed soil samples from the 0–10 cm deep soil layer after removing the soil surface crust were calculated. Soil penetration resistance (SPR) for the upper 10 cm soil layer was also measured. Additional measurements of soil surface crust sorptivity (Scrust) and hydraulic conductivity (Kcrust) were conducted. Livestock trampling in GR promoted the highest ρband SPR values. The lack of soil disturbance in N caused that this treatment showed the lowest values ofScrustandKcrust, but the highestS10andK10. The specific behavior of gypseous soils, whose loose aggregates easily collapse during the soil wetting process, showed that the MB freshly tilled soil produced the lowest values ofS10andK10. A typical bimodal function of the WRC was found. Pore size distribution was affected by the soil treatment, with the highest and lowest values under MB and GR treatments, respectively. [ABSTRACT FROM PUBLISHER]