About Us | Help Videos | Contact Us | Subscriptions

Members of ASA, CSSA, and SSSA: Due to system upgrades, your subscriptions in the digital library will be unavailable from May 15th to May 22nd. We apologize for any inconvenience this may cause, and thank you for your patience. If you have any questions, please call our membership department at 608-273-8080.


Institutional Subscribers: Institutional subscription access will not be interrupted for existing subscribers who have access via IP authentication, though new subscriptions or changes will not be available during the upgrade period. For questions, please email us at: queries@dl.sciencesocieties.org or call Danielle Lynch: 608-268-4976.



This article in SSSAJ

  1. Vol. 50 No. 5, p. 1314-1318
    Received: Nov 4, 1985

Request Permissions


Effect of Sodium Polymetaphosphate on Soil Crust Formation and Runoff/Rain Relations1

  1. M. Ben-Hur,
  2. I. Shainberg and
  3. R. Keren2



The effect of sodium polymetaphosphate (NaPMP) on crust formation and on the amount of runoff was studied with two soils, Typic Rhodoxeralfs (sandy loam) and Xeric Torripsamments (loamy sand), using a rainfall simulator. Increasing the rate of NaPMP application in the range ≤ 100 kg ha−1, increased the rate of crust formation and decreased the final infiltration rate (IR). The increased rate of crust formation increased the fraction of runoff of the total rainfall and decreased the threshold rain needed to form runoff. The dispersant, NaPMP, weakened the stability of the aggregates and increased the amount of clay that migrated with the infiltrating water and accumulated in the “washed in” layer. Hence, the effect of NaPMP was more pronounced in a loamy sand, where the low amount of clay limits the formation of a crust, compared with the sandy loam, which contains enough clay to form a crust. In consecutive short storms of 18 mm each with complete drying between storms, the rate of crust formation was slow and the amount of runoff was low in the control treatment, compared with the high efficiency of NaPMP for increasing runoff. The low amounts of NaPMP required to significantly increase runoff gives the potential for commercial use in runoff farming.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © . Soil Science Society of America