Comparison of Physical and Chemical Properties between Soils of Protected and Open Cultivation in Ningxia Province

Based on distribution of greenhouse in irrigation regions of Ningxia,the soil samples of top soil(0-20 cm) were collected by means of random sampling for both the facility cultivation soil and open cultivation soil.Chemical and physical properties were compared between the soils of protected and open cultivation.The results showed that the water stable aggregate in the protected field were significantly increased compare to the open field,but soil capillary porosities and field water capacities and soil water contents were a few increased,however,the soil bulk densities were significantly reduced.For the chemical properties of the soils,the soil organic matter,salt contents,alkali-hydro.N contents and available P and K in protected fields were significantly increased compared with the open fields,but the pH value in the protected cultivation was lower than open cultivation,and that micronutrient contents did not differ much between the pairs except available Fe.However,the soil available Zn,Cu in the protected cultivation were higher compare to background value,and the soil available Zn,Cu are metal elements.So,feeding plants with fertilizer is an important consideration in this case.